WSEAS Transactions on Systems and Control

Print ISSN: 1991-8763
E-ISSN: 2224-2856

Volume 9, 2014

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of WSEAS Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

Volume 9, 2014

Title of the Paper: An Existence Result for Non-Convex Optimal Control Problems

Authors: Clara Carlota, Silvia Cha

Abstract: We present new existence results of solutions to autonomous Lagrange optimal control problems, without assuming superlinear growth, nor convexity, on the lagrangian.

Keywords: Optimal control problems, calculus of variations, non-convex integrals

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #71, pp. 687-697

Title of the Paper: Fuel Minimization of a Moving Vehicle in Suburban Traffic

Authors: Thomas Galpin, Yun L. Han, Petros G. Voulgaris

Abstract: In this paper we study how a driver could use traffic light information in order to adapt driving speed profile to save fuel. The mission is given by a final destination to reach (through a set of traffic lights) within a specific deadline and the objective is to minimize the fuel consumption. We assume that the speed between each traffic light is constant and we do not take into account the effects of acceleration and gear shifting. Also, we use an existing model for the fuel consumption which depends quadratically on the speed of the vehicle. For simple cases (one traffic light), we derive analytical results using optimization theory and the Karush-Kuhn-Tucker (KKT) nec- essary conditions for optimality. For more complex and realistic cases, we use Dijkstra’s shortest path algorithm to discretize our decision problem. By “setting nodes” at each distance where there is a traffic light, we can model a realistic situation with an equivalent discrete graph with nonnegative edge costs. Then Dijkstra’s algorithm helps to find the shortest path through this set of nodes. The results indicate that the best strategy is to drive as close to an optimal speed as possible, which is dictated by the vehicle’s characteristics, while avoiding the traffic light blocks. One block look ahead strategies have also shown in simulations to be effective in particular realistic scenarios. It is also shown that, depending on the speed limit, minimal fuel and minimal time strategies may be quite similar.

Keywords: Fuel minimization, Traffic light information, Look ahead strategy, KKT, Dijkstra’s algorithm, Optimization

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #70, pp. 672-686

Title of the Paper: Control of High Density Microcantilever Systems

Authors: Berkem Mehmet, Hussam Sehwail, Petros G. Voulgaris

Abstract: In this paper we build on our earlier work on the control of high density, electrostatically actuated, microcantilever arrays and present simple state feedback controllers that can achieve reasonable performance. These controllers are localized, spatially distributed and yield tracking performances comparable to the performance of the distributed H1 controller proposed in our earlier study, for reference frequencies as high as 3000 rad/sec. These simpler structures come with the cost of worse performance at higher frequencies, relatively inferior robustness to phase shifts and a state availability requirement. Therefore, it can be effectively used for relatively lower bandwidth applications where the states are measurable. The above results are further verified by using a multimodal model of the cantilever system.

Keywords: AFM, Multivariable Systems, Distributed Control, Finite Element Method.

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #69, pp. 658-671

Title of the Paper: Modified Design Method of an Optimal Control System for Precision Motor Drive

Authors: Artur Abdullin, Valentin Drozdov, Andrey Plotitsyn

Abstract: The paper presents an improved design method of an optimal control system of a linear object with elastic coupling. The proposed method of the optimal control system design implies the selection of desired stability degree instead of the penalty matrixes selection procedure for the quadratic functional. The main idea of the method is the new state matrix utilization, which has its eigenvalues at the specified distance to the right from the eigenvalues of the original state matrix. Thereupon the closed loop state feedback system matrix eigenvalues can be assigned at that specified distance to the left from imaginary axis of the complex plane, in other words the desired stability degree of the system can be achieved. The proposed method of the control algorithm design is demonstrated on the control system of the electric drive with two-mass mechanism (plant). Discrete optimal control system was synthesized. Plant’s characteristic was evaluated from bode plot obtained during identification experiment. Unavailable or immeasurable plants state was estimated by reduced-order observer.

Keywords: Optimal control system, discrete control system, reduced-order observer, two-mass mechanism, state regulator, modal control, degree of stability

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #68, pp. 652-657

Title of the Paper: Speed Fuzzy Control Applied to Autonomous Electric Vehicles

Authors: Italo A. Souza-De-Assis, Renan Oliveira, Marcelo A. C. Fernandes

Abstract: A cruise control system for autonomous electric vehicles (AEVs) is presented, based on fuzzy logic. The proposed technique uses three fuzzy systems that act in parallel during three kinetic states of the vehicle: acceleration, moving, and braking. Validation of the procedure used longitudinal simulations of a vehicle powered by a permanent magnet direct current motor. The results indicated that the control system performed satisfactorily, and could be used in AEV applications.

Keywords: Fuzzy Logic, Autonomous Electric Vehicle, Cruise Control

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #67, pp. 640-651

Title of the Paper: Software Intensive GNSS-Based Tracking Systems for Improving Law Enforcement

Authors: Jyri Rajamäki

Abstract: Law enforcement agencies (LEA) constantly seek new cross-border processes and technical solutions that would facilitate their combat against international organized crime. This paper studies how new types of satellite-based tracking sensors, mobile monitoring stations and their associated communication channels for LEA can be understood and designed taking into account the chain-of-custody and monitoring-of-legality requirements. The empirical data was collected within four research projects in 2007-2014. The theoretical framework is built on the design theory of software-intensive systems. For improving law enforcement processes, the three main functions (crime investigation, chain-of-custody and monitoring-of-legality) should be considered all at once. Comprising their separate information systems will avoid triplicate workload. It also will enable multiple other benefits, such as transparency of surveillance and giving a new tool for commonly agreeing of the balance between surveillance and privacy.

Keywords: Chain-of-custody requirements, Crime Investigation, Global navigation satellite systems, Law enforcement, Law enforcement authority, Monitoring-of-legality, Software intensive systems, Technical tracking

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #66, pp. 629-639

Title of the Paper: Digital Control System of Precision Electromechanical Scanner with Elasticity

Authors: Valentin Drozdov, Valentin Tomasov, Sergey Tushev

Abstract: The synthesis of controller algorithm for reversible electromechanical scanner of the telescope scanning axis is discussed. Digital control system is built without intermediate stage of synthesis of analog control law. The modified procedure for the synthesis of discrete optimal control law is introduced. Elasticity influence on static and dynamic characteristics of electromechanical scanner of the telescope scanning axis is discussed. It is shown, that the controller algorithm, which provides specified scanner behavior, could be synthesized in spite of elasticity of mechanical part of scanner. The article provides an overview of modern optical position sensors, which are used in precision drive. The results obtained are recommended for use in high-precision electric drives of precision observations complexes. The article may be helpful for developers of precision electric drives of telescopes and electromechanical scanners.

Keywords: Electromechanical scanner, elasticity, discrete control law, precision electric drive

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #65, pp. 623-628

Title of the Paper: Observer Design for Nonlinear Systems with Interval Time-Varying Delay

Authors: Yali Dong, Wanjun Liu, Shikai Zuo

Abstract: This paper investigates the problem of observer design for a class of nonlinear systems with time-delay and uncertain nonlinearity. Firstly, using the Mean-value Theorem and combining constructing the Lyapunov-Krasovskii functional, the convergence conditions of nonlinear observer for a class of nonlinear systems with time-varying delay and uncertain nonlinearity are established in terms of a linear matrix inequality. Then the new sufficient conditions are derived to ensure the convergence of the observer for a class of nonlinear systems with constant time-delay and uncertain nonlinearity. The simulation results are presented to show the effectiveness of the proposed method.

Keywords: Nonlinear systems; Observer; Asymptotic stability; Time-varying delay

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #64, pp. 614-622

Title of the Paper: Guidance and Control Laws for Quadrotor UAV

Authors: Tain-Sou Tsay

Abstract: In this literature, guidance and control laws using a basic control system have been proposed for analyses and designs of a Quadrotor. The basic control system includes: (a)height Control system using velocity stabilizing in the inner loop; (b)roll, pitch and yaw attitude control systems using angular rate stabilizing in inner loops. Base upon the basic control system, the Xb and Yb body axes velocities control laws and locus tracking laws are added. This application is different from conventional velocity, and position control techniques of conventional fix-fin UAV’s. The major merit of the proposed method is the controlled Quadrotor can tracking the target quickly while keep heading almost not be changed. The proposed method is verified by vast digital simulations. They give good performance.

Keywords: Quadrotor, Guidance and Control Laws, Locus Tracking

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #63, pp. 606-613

Title of the Paper: Design and Implementation of Predictive Current Controller for Photovoltaic Grid-Tie Inverter

Authors: Mahmoud Salem, Yousry Atia

Abstract: This paper presents simplified predictive current controller for 3-ph PWM voltage source inverter connected to the utility grid via filter inductance. By controlling inductance voltage drop, the inverter voltage and hence the injected current can be controlled. The proposed predictive control technique operates with constant switching frequency using space-vector modulation (SVM). In each switching period, the proposed control algorithm computes the required inverter average voltage vector in α–β reference frame in order to follow up the reference current at the end of the switching period. The proposed technique has no need for coordinate transformations or PI controllers. The proposed controller is verified by simulation using MATLAB/Simulink, and is experimentally verified using a fixed point microcontroller (Maple microcontroller). Detailed implementation of the proposed hardware is presented. Both simulations and experimental results are presented in the paper.

Keywords: Predictive Current Control, SVM, Grid-Tie, Distributed Power Generation Systems

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #62, pp. 597-605

Title of the Paper: The Optimal Control Problem with Terminal Condition and Random Intervention Times

Authors: Qiuyuan Wang

Abstract: This paper is devoted to an impulse control problem where the control can only be exerted at the arrival times of the Poisson process N. We generalized control state process and cost function, under some assumptions, we obtained more general results. At the same time, we got the optimal control in special case.

Keywords: Stochastic control, Random intervention times, Value function, Generalized Ito formula

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #61, pp. 590-596

Title of the Paper: Robust Predictive Control Combined with an Adaptive Mechanism for Constrained Uncertain Systems Subject to Disturbances

Authors: Tae-Hyoung Kim

Abstract: This paper proposes a discrete-time adaptive model predictive control (MPC) algorithm for a class of constrained linear time-invariant systems subject to state-dependent disturbances, which updates the estimate of uncertain system parameters on-line and produces the control input ensuring the constraint fulfillment. This method is based on an adaptive mechanism and a robust MPC algorithm using the comparison model which enables to estimate the future prediction error bound. First, the parameter estimation method for MPC based on the moving horizon estimation is introduced. It allows to predict explicitly the worst-case estimation error bound over the prediction horizon. Second, we propose an adaptive-type MPC strategy developed by combining an on-line parameter estimator with a robust MPC method based on the modified comparison model. The MPC controller designed in this way guarantees constraint fulfillment, closed-loop stability and feasibility in the presence of uncertain system parameters and state-dependent disturbances. A numerical example demonstrates the unique features of the proposed approach.

Keywords: Constrained systems, model predictive control, parameter estimation, robust stability

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #60, pp. 574-589

Title of the Paper: Active Roll Control Strategy using Fuzzy Logic Control Active Suspension

Authors: Amrik Singh Phuman Singh, Intan Zaurah Mat Darus

Abstract: An active roll control system using a combination of feedback and feedforward fuzzy logic control active suspension for enhancement of vehicle roll dynamics is presented in this paper. The dynamics model representing the vehicle behavior was first developed and then modeled in the Matlab/SIMULINK environment. The tire model used was developed based on tire test data using loop up table method. The validity of the vehicle model was verified using CarSim software for double lane change maneuver. The inputs to the feedforward fuzzy logic control were the driver steering wheel angle and vehicle longitudinal velocity and the output of the feedforward fuzzy logic control was the counter roll moment. For the feedback fuzzy logic control, the roll angle error and error rate were the inputs whereas the counter roll moment was the output. The effectiveness of the proposed control system was demonstrated for fishhook, step steer, and double lane change maneuvers and this vehicle roll control system has shown its capability in reducing vehicle rollover propensity.

Keywords: Active roll control, Rollover, Fishhook, CarSim, Fuzzy logic control

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #59, pp. 566-573

Title of the Paper: Design and Implementation of an Optimized Sliding Mode Controller and Compared with a Conventional MPPT Controller for a Solar System

Authors: Venkata Ratnam Kolluru, Shiva Shankar Sarode, Rajesh Kumar Patjoshi, Kamalakanta Mahapatra, Bidyadhar Subudhi

Abstract: This article gives a broad idea about Sliding Mode Controller (SMC) implementation to a DC-DC Boost Converter for a Photovoltaic (PV) system to track Maximum Power Point (MPP). SMC implementation meets three conditions like (i) Hitting, (ii) Existence and (iii) Stability. Single exponential PV model is designed for lighting applications, and PV output is connected to a Boost converter to regulate and increase the voltage up to desired level. SMC is implemented in a feedback manner with capacitor voltage and inductor current. The steady state condition occurred at around 0.1sec, and tracking 1.13% extra power at Standard Test Conditions (STC). The results of SMC are compared with Incremental conductance (Inc Cond) Maximum Power Point Tracking (MPPT) controller; the models are simulated in MATLAB/SIMULINK.

Keywords: DC DC Boost Converter, Incremental Conductance Controller, Maximum Power Point, Photovoltaic, SMC, STC

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #58, pp. 558-565

Title of the Paper: Study on Clutch Control Technology and Shift Control Strategy for Automated Mechanical Transmission with Magnetic Powder Clutch

Authors: Xu Shanzhen, Wang Cheng

Abstract: Since there is more space for the shift quality and transmission efficiency of conventional automated mechanical transmission (AMT) to improve, a novel electric AMT with magnetic powder clutch (MAMT) was proposed and studied in this project. The major technological problems of MAMT about control technology for magnetic powder clutch and comprehensive shift rules were studied based on theoretical analysis and simulation research. The fuzzy controller was designed, which realized the intelligent control for the engagement and disengagement of magnetic powder clutch when the vehicle starts and shifts. The comprehensive shift rules were created based on fuzzy reasoning and weight method. The simulation model for the whole vehicle was built and the off-line simulation was carried out. The simulation results obtained by 15-condition method showed that the built simulation model for the whole vehicle was correct. The simulation results of continuous upshift with 80% throttle opening showed that the control model for the magnetic powder clutch was reasonable and the shift quality was improved. The simulation results for fundamental shift rules and comprehensive shift rules with the specific vehicle speed and the throttle opening showed that the comprehensive shift rules created in this paper can reduce the shifting frequency and improved the shifting quality.

Keywords: magnetic powder clutch, AMT, fuzzy control, comprehensive shift rules, simulation

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #57, pp. 547-557

Title of the Paper: Bayesian Decision Analysis for Recurrent Ovarian Cancer

Authors: Chi-Chang Chang, Chih-Jen Tseng, Ting-Huan Chang, Chiu-Hsiang Lee

Abstract: All cancers are usually classified further according to the extent or stage of disease so that therapies may be tailored to the particular disease stage. Moreover, detection of asymptomatic recurrences is associated with prolonged overall survival and survival from the time of initial detection of recurrence. This study applied Bayesian decision theorem to an inferential problem of recurrent ovarian cancer in survival analysis. A formulation is considered where individual was expected to experience repeated events, along with concomitant variables. In addition, the sampling distribution of the observations is modelled through a proportional Nonhomogeneous Poisson process. Finally, this paper develops a systematic way to integrate the expert’s opinions which will furnish clinician with valuable support for quality medical decision making.

Keywords: Bayesian Decision Analysis; Recurrent Ovarian Cancer; Nonhomogeneous Poisson process

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #56, pp. 540-546

Title of the Paper: Refining of Crude and its Corrosion Control using Distributed Control System

Authors: S. Ramraj, C. Anandaraj

Abstract: Distillation separates compounds by the variation in how effortlessly they vaporize. The two main types of standard distillation comprise unremitting distillation and batch distillation. Unremitting distillation, as the name says, unremittingly takes a feed and separates it into two or more products. Batch distillation takes on lot (or batch) at a time of feed and splits it into products by selectively removing the more unstable fractions over time. Other ways to categorize distillation are by the equipment type (trays, packing), process configuration (distillation, absorption, stripping, isotropic, extractive, complex), or process type (refining, petrochemical, compound, gas treating). Many industries use distillation for critical separations in making useful products. These industries include petroleum distillation, beverages, compound processing, petrochemicals, and natural gas processing. The general distillation column element is comprises feed device, Random packing and support grid.

Keywords: DCS, Distillation, Corrosion control, Catalytic cracking Utility boilers, polymerization, Sulfur recovery

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #55, pp. 533-539

Title of the Paper: Multi-Agent System Rendezvous via Refined Social System and Individual Roles

Authors: Yunzhong Song, Wei Zhao

Abstract: In order to explore the rendezvous problems of leader-follower multi-agent system further, three different kinds of strategies, namely the democracy strategy, the autarchy strategy as well as the mixed strategy, which were inspired by the mankind system, were put forward based on the heterogeneous peculiarities of the social status and the individual roles of the swarm of the multi-agent system, whereas the last strategy was composed of the democracy one and the autarchy one. It was assumed that only the leader agents were capable of knowing the details of the global task, which was to search for and come to the same targeted object, for the follower agents, if they were kept connected with the corresponding leader ones, they could also be empowered the privilege of the location of the rendezvous task in indirect ways. It was concluded that among this arena, agents were finally divided into four different categories, that were the agent where it represented the targeted object, the leader agents where they played the leading roles and the common follower agents where they had some connections with the leader ones and the isolated follower agents where they were failed in connection with the leader ones. Results demonstrated that, the democracy strategy could fulfill the rendezvous task in an easiest way in expenses with a long convergent time and the autarchy democracy could come to the targeted object quickly with the cost of the risk of failing in completing the rendezvous task of the isolated follower agents, while the mixed strategy cared about both of the convergent speed and the utmost task, would take autarchy strategy when the connections were available for the follower agents to the leader ones, and the democracy rules had to be used when the connection to the leader agents was not possible. Both the models and the topological structures were provided to elucidate the specifications of the three strategies, and moreover, they were explained even further in a set of case studies with simulation work in the leader-follower multi-agent networks, which consisted of 4 leader agents and 5 follower agents.

Keywords: Leader-follower multi-agent network; Rendezvous problems; The democracy strategy; The autarchy strategy; The mixed strategy; Refined Social System

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #54, pp. 526-532

Title of the Paper: Low-Speed Sensorless Control of DFIG Generators Drive for Wind Turbines System

Authors: Badre Bossoufi, Hala Alami Aroussi, ElMostafa Ziani, Ahmed Lagrioui, Aziz Derouich

Abstract: In this paper, we present a nonlinear robust control of active and reactive power by the use the PI regulators control (FOC) a Double-Fed Asynchronous Generator (DFIG) system incorporated in a wind-turbine. The power transfer between the stator and the network grid is carried out by acting on the rotor via a bidirectional signal converter. Initially, a control strategy of the MPPT-DFIG is presented. Thereafter, a new control technique for wind systems is presented. This control technique is based on an SVW placement control strategy. The overall stability of the system is shown using SVW block. The performance and robustness are analyzed and compared by simulation based Matlab / Simulink software.

Keywords: DFIG-Generator, Rotor Control, Matlab/Simulink, Wind-Turbine, MPPT Control, SVW

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #53, pp. 514-525

Title of the Paper: Modeling Automotive Palm Oil Biodiesel Engine Using Multi-Objective Optimization Differential Evolution Algorithm

Authors: Robiah Ahmad, Mohd Zakimi Zakaria, Azuwir Mohd Nor, Hishamuddin Jamaluddin

Abstract: Modeling automotive palm oil biodiesel engine using the propose algorithm called multi-objective optimization differential evolution (MOODE) is carried out in this paper. The performance of the system is analyzed to study the dynamic behaviors of using biodiesel in running the engine. An adequate modeling of the system is needed to design an exclusive engine controller. The biodiesel engine is treated as a black box where the acquired input-output data is used in the modeling processes. Two objective functions are considered for optimization; minimizing the number of term of a model structure and minimizing the mean square error between actual and predicted outputs. Nonlinear auto-regressive with exogenous input (NARX) model is used to represent the mathematical model of the investigated system. To obtain an optimal model for representing the dynamic behavior of automotive palm oil biodiesel engine, the model validity tests have been applied. Therefore, MOODE can be applied for other processes to find an optimal model structure as long as those processes have reliable input output data.

Keywords: System identification, multi-objective optimization, differential algorithm, mathematical model, palm oil biodiesel, NARX model

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #52, pp. 500-513

Title of the Paper: Shooting Control Algorithm Based on Emendation of Model Error of Assumed Relative Target Motion

Authors: Heng Liu, Wei Mei, Gan-Lin Shan

Abstract: Model error of assumed relative target motion is the major factor to influence calculation precision of firing data of fire control system for modern antiaircraft artillery, and is most difficult to overcome, so shooting control algorithm featured on Resemble Closed-loop emendation of firing data and Future Airspace Window System (FAWS) is proposed. Taking example for anti-ship missile with lengthways zigzag maneuver, the mathematical model of calculating emendation value of firing data by Resemble Closed-loop method is established, and the validity of adopting FAWS is analyzed. Monte Carlo simulation is completed under different conditions, whose results validate the feasibility of the algorithm, which provides an effective measure to overcome model error of assumed relative target motion.

Keywords: Automatic Control; Antiaircraft Artillery; Fire Control System; Model Error of Assumed Relative Target Motion; Resemble Closed-loop Fire Correction; FAW

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #51, pp. 492-499

Title of the Paper: Controller Design for Temperature Control of Heat Exchanger System: Simulation Studies

Authors: Subhransu Padhee

Abstract: This paper analyzes the performance of different controllers such as feedback, feedback plus feed-forward and internal model controller to regulate the temperature of outlet fluid of a shell and tube heat exchanger to a certain reference value. The transient performance and the error criteria of the controllers are analyzed and the best controller is found out. From the simulation results, it is found out that the internal model control outperforms feedback PID and feedback plus feed-forward controller.

Keywords: Feedback controller, Feedback plus feed-forward controller, internal model controller

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #50, pp. 485-491

Title of the Paper: Condition Diagnosis of Bearing System Using Multiple Classifiers of ANNs and Adaptive Probabilities in Genetic Algorithms

Authors: Lili A. Wulandhari, Antoni Wibowo, Mohammad I. Desa

Abstract: Condition diagnosis in bearing systems needs an effective and precise method to avoid unacceptable consequences from total system failure. Artificial Neural Networks (ANNs) are one of the most popular methods for classification in condition diagnosis of bearing systems. Regarding to ANNs performance, ANNs parameters have important role especially connectivity weights. In several running of learning processes with the same structure of ANNs, we can obtain different accuracy significantly since initial weights are selected randomly. Therefore, finding the best weights in learning process is an important task for obtaining good performance of ANNs. Previous researchers have proposed some methods to get the best weights such as simple average and majority voting. However, these methods have some limitations in providing the best weights especially in condition diagnosis of bearing systems. In this paper, we propose a hybrid technique of multiple classifier-ANNs (mANNs) and adaptive probabilities in genetic algorithms (APGAs) to obtain the best weights of ANNs in order to increase the classification performance of ANNs in condition diagnosis of bearing systems. The mANNs are used to provide several best initial weights which are optimized by APGAs. The set optimized weights from APGAs, afterward, are used as the best weights for condition diagnosis. Our experiment shows mANNs-APGAs give better results than of the simple average and majority voting in condition diagnosis of bearing systems. This experiment also shows the distinction of maximum and minimum accuracy in mANNs-APGAs is lower than the two existing methods.

Keywords: Adaptive Probabilities Genetic Algorithms, Bearing Systems, Condition Diagnosis, Majority Voting, Multiple Artificial Neural Networks, Simple Average

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #49, pp. 473-484

Title of the Paper: Centralized Sliding Mode Control of Power System with UPFC

Authors: Amar Hamache, Hachemi Chekireb

Abstract: In this article is proposed a Centralized Sliding Mode Control (CSMC) applied to a UPFC device for controlling power flow and enhancing power system stability. First, we establish a state-space dynamic model of UPFC based on Kirchhoff’s equations and (d-q) transformation. This model includes the two voltage source inverters and the DC bus voltage link. Furthermore, in order to cancel the effect of uncertainties which can affect this plant, we develop a centralized version of sliding mode control based on this state model. In the case where the proposed control scheme is used, we simulate the operation of UPFC equipping a High Voltage (HV) electrical line interconnecting two stable nodes. The simulation results show that it is possible and achievable to control the power flow with satisfactory performances regardless of the parameter uncertainties affecting the model plant.

Keywords: FACTS, UPFC, Electrical Power System, Real Power, Reactive Power, Sliding Mode Control, Lyapunov Function

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #48, pp. 464-472

Title of the Paper: Research on Price Game Process and Wavelet Chaos Control of Three Oligarchs’ Insurance Market in China

Authors: Wenbo Ren, Junhai Ma

Abstract: Based on the actual data, this paper shows Chinese insurance market monopoly status through the Market Concentration Rate, and established the repeated price game model for three oligarchs with delayed decision according to Bertrand model. Discussed the two main goals of insurance companies faced in the game process: the expansion of profit and market share. Through the application of nonlinear dynamics theory, this paper makes the analysis and dynamic simulation of the game model, studies the existence and stability of equilibrium point of the system, reveals the dynamic evolution process of market under the different price adjustment speed and the different concern degree of profit. Then have numerical simulation to the system, and gives the complex dynamic characteristics, such as Lyapunov exponent, strange attractor, sensitivity to initial value. Due to wavelet function has good time-frequency localization ability; this paper introduces different wavelet functions to have the chaos control to the system, results shows that wavelet function has a good convergence effect to the chaotic state of the system. The research results of this paper have very good guidance on macro adjustment and control of the insurance market.

Keywords: Price game, Three oligarchs, Market share, Delayed decision, Chaos control

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #47, pp. 454-463

Title of the Paper: Neural Network Modeling and Identification of Naturally Ventilated Tropical Greenhouse Climates

Authors: Robiah Ahmad, Md.Norazlan Md.Lazin, Saiful Farhan Mohd Samsuri

Abstract: Naturally ventilated tropical greenhouse is classified as a complex system because it involves with nonlinear process and multivariable system. The purpose of this study is to determine the mathematical model of NVTG climates to in order to describe and predict the dynamic behavior of temperature and humidity inside NVTG for development of its control system. The modeling of the system is divided into two parts namely parametric and nonparametric modeling. The auto regressive with exogenous input, ARX and nonlinear auto regressive with exogenous input, NARX model were used for the parametric models while neural network auto regressive with exogenous input, NNARX model was used for the nonparametric model. The recursive least square estimation, RLSE, was used for the parameter estimation of the parametric model while the artificial neural network, ANN used the Levenberg-Marquardt method for predicting the performance parameter of NVTG system for the nonparametric model. All the models established were validated using statistical validation method such as mean square error (MSE), root mean square error (RMSE), error index (EI) and for the nonparametric model it added with the correlation coefficient, (R). From the result, the best model for parametric model is identified with the error index of 0.0573 for temperature and 0.0362 for humidity. The best non-parametric model gives error indexes of 0.0025 for temperature and 0.0024 for humidity.

Keywords: Parametric, Non-parametric, Identification, Neural Network, Naturally Ventilated Tropical Greenhouse

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #46, pp. 445-453

Title of the Paper: Stability and Performance Analysis of Fractional Order Control Systems

Authors: Santosh Kr. Choudhary

Abstract: Fractional order system model represents the plant more adequately than integer order model. Fractional order controller is naturally the suitable choice for these fractional order models as well as it is widely used for integer order model also.The significance of fractional order control is that it is a generalization of classical control theory. Most of the works in fractional order control systems are in theoretical nature and controller design and implementation in practice is very small. In this paper, stability and performance analysis of fractional order control systems are briefly explained. To show the effectiveness of article, paper demonstrates illustrative design examples. The major purpose of this paper is to draw attention to the non-conventional way of system analysis and its control.

Keywords: Fractional order systems, fractional order PI D controller, PID Controller, stability, performance, modelling & simulation

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #45, pp. 438-444

Title of the Paper: Adaptive Regenerative Braking for Electric Vehicles with an Electric Motor at the Front Axle using the State Dependent Riccati Equation Control Technique

Authors: Sven Jansen, Mohsen Alirezaei, Stratis Kanarachos

Abstract: In this paper a novel adaptive regenerative braking control concept for electric vehicles with an electric motor at the front axle is presented. It is well known that the “phased” type regenerative braking systems of category B maximize the amount of regenerative energy during braking. However, there is an increased risk of maneuvering capability loss especially during cornering. An integrated braking controller which determines - in a single step - the desired yaw moment and allocates the braking demand between hydraulic brakes and electric motor during cornering is designed using the State Dependent Riccati Equation (SDRE) method. A unique method for deriving the State Dependent Coefficient (SDC) formulation of the system dynamics is proposed. Soft constraints are included in the state dynamics while an augmented penalty approach is followed to handle hard constraints. The performance of the controller has been evaluated for different combined cornering-braking scenarios using simulations in a Matlab/Simulink environment. For this an eight degrees of freedom (DOF) nonlinear vehicle model has been utilized. The numerical results show that the controller is able to optimize (locally) the amount of regenerative braking energy while respecting system’s constraints such as tire force saturation, vehicle yaw rate and slip angle errors.

Keywords: Regenerative braking and cornering, stability, State Dependent Riccati Equation controller, optimization, state estimation

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #44, pp. 424-437

Title of the Paper: Missile Gimbaled Seeker Tracking Using Finite-Horizon State Dependent Riccati Equation

Authors: Ahmed Khamis, Ahmed M. Kamel, D. Subbaram Naidu

Abstract: The majority of homing guided missiles use gimbaled seekers. The equations describing seeker gimbal system are highly nonlinear. Accurate nonlinear control of the motion of the gimbaled seeker through the attached DC motors is required. In this paper, an online technique for finite-horizon nonlinear tracking problems is presented. The idea of the proposed technique is the change of variables that converts the nonlinear differential Riccati equation to a linear Lyapunov differential equation. The proposed technique is effective for wide range of operating points. Simulation results for a realistic gimbaled system with different engagement scenarios are given to illustrate the effectiveness of the proposed technique.

Keywords: Finite-Horizon state dependent Riccati equation, nonlinear tracking, gimbaled missile seeker

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #43, pp. 415-423

Title of the Paper: Spectral Approach to H∞-Optimal SISO Synthesis Problem

Authors: Evgeny Veremey, Margarita Sotnikova

Abstract: This paper is devoted to a particular case of H∞-optimization problem for LTI systems with scalar control, external disturbance and measurement noise. This problem can be numerically solved with the help of the well-known universal approaches based on Riccati equations, LMI or maximum entropy technique. Nevertheless, in our opinion there exists a possibility to implement a special form of spectral approach, using polynomial factorization for the mentioned particular situation. The correspondent technique is proposed with the aim to increase a computational efficiency of the synthesis and to present an optimal solution in a specific form, which is convenient for investigation. Some theoretical details are discussed and numerical algorithms are developed for practical implementation. Theirs applicability and effectiveness are illustrated by the examples of H∞-optimal synthesis.

Keywords: Control system, control law, synthesis, stability, optimization, H infinity control

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #42, pp. 405-414

Title of the Paper: Optimal Control of Mobile Robot’s Trajectory Movement

Authors: Aleksey A. Kabanov

Abstract: This paper is devoted to the development of an optimal control system of trajectory movement of a mobile robot. Synthesis of the trajectory control law is based on the methods of optimal control and asymptotical methods of singular perturbation theory. Singular perturbation theory’s methods are used for reducing the order of the solving problem and it helps to simplify the realization of the control law. Proposed system has two control loops: position control loop and velocity control loop. Based on this, the structure of the control system is represented by two modules: the reference and the executive. In this work the results of experimental verification of the trajectory control system at the mobile robot Rover5 with the tank-type chassis are presented.

Keywords: Trajectory control, quadratic performance index, optimal control, mobile robot, tracked chassis

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #41, pp. 398-404

Title of the Paper: Asymptotic Stability Conditions for Certain Classes of Mechanical Systems with Time Delay

Authors: Alexander Aleksandrov, Elena Aleksandrova, Alexey Zhabko

Abstract: The stability of the trivial equilibrium position of certain classes of mechanical systems with time-varying delay is studied. The considered systems are described by the second order differential equations in the Lagrange form. It is assumed that velocity forces are linear, whereas for positional forces both linear case and essentially nonlinear one are investigated. On the basis of the decomposition method, sufficient conditions of the asymptotic stability of the equilibrium position are found. It is shown that the proposed approach can be used for the stability analysis of hybrid mechanical systems with switched positional forces. Three examples are presented to demonstrate the effectiveness of the obtained results.

Keywords: Mechanical systems, asymptotic stability, Lyapunov function, delay, hybrid system

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #40, pp. 388-397

Title of the Paper: An Online Adaptive PSS based on RBF Neural Network Identifier

Authors: Kai Xu, Shanchao Liu

Abstract: The design of a conventional power system stabilizer (PSS) based on linearized model cannot guarantee its performance in practical operating, so some intelligent techniques have been used. However, the parameters cannot update online in most of these mehods, thus the performance cannot be further improved. This paper adopts the design method of adaptive neural-fuzzy based power system stabilizer (ANFPSS). It consists of two separate neural networks, namely radial basis function neural network (RBFNN) identifier and adaptive neuro-fuzzy controller (ANFC). Meanwhile, particle swarm optimization (PSO) algorithm is used to obtain appropriate initial parameters of the RBFNN identifier. Based on the optimized initial parameters, the RBFNN online identifier provides a dynamic model of controlled plant and updates the adaptive link weights of the ANFC. Simulation results on a single machine infinite bus power system demonstrate that the proposed stabilizer is effective in damping low-frequency oscillations as well as improving system dynamic stability. In addition, the proposed approach provides superior performance when compared to IEEE PSS2B.

Keywords: Power system stabilizers, particle swarm optimization, neural network identifier, neuro-fuzzy controller

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #39, pp. 379-387

Title of the Paper: On the Fuzzy Control of Nonlinear Discrete Systems Affine in the Control

Authors: Ikbel Ben Cheikh Ahmed, Dhaou Soudani, Mohamed Benrejeb

Abstract: In this paper, we focus on modeling and control of discrete nonlinear systems affine in control. A comparative study, in a discrete time, between two control strategies is developed to learn the input properties of fuzzy systems of Takagi-Sugeno constant to conclusions.

Keywords: Nonlinear system affine in the control system of Takagi-Sugeno, input-output representation, inversion, linearization input-output fuzzy optimization H-infinity stability, fuzzy controller, the control signal, internal model, discrete system

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #38, pp. 367-378

Title of the Paper: Risk and Hazard Control Hosted on Cloud

Authors: Gheorghe Florea, Radu Dobrescu

Abstract: We live in a modern industry based society where automation undoubtedly is the key for success. The technology has been changing over the last decades towards full control systems and the requirement specifications for Safety Instrumented Systems (SIS) forms the central network for the process risk and hazard assessment to be carried out. Process Control has evolved very much in the last years. Plants become more complex, they require more efficiency and reduced costs while maintaining the product quality. Advanced process control appeared to be the most effective technology to realize these objectives, but it is not enough anymore. Process control and optimization represent the current base for safer and more efficient industrial plants, while risk management represents the base for new control algorithms and strategies. There is a stringent need for the enhancement of process operations at plant production management level, because plants should often operate near criticality, meaning in conditions far from ideal ones from the point of view of control and stability. Risk and hazard control is for sure one modern approach to keep plant running even under big perturbations or uncertainty. Emerging technologies used for design and implementation; modeling, simulation, concurrent engineering, on line diagnosis, merger techniques needs big computational capabilities that Cloud can offer.

Keywords: Risk and hazard control, levels of protection, concurrent engineering, algorithms for hazard and risk management, generic algorithm representation

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #37, pp. 356-366

Title of the Paper: Intelligent Hybrid Controller for Identification and Control of Micro Permanent-Magnet Synchronous Motor Servo Drive System Using Petri Recurrent-Fuzzy-Neural-Network

Authors: Fayez F. M. El-Sousy

Abstract: This paper proposes an intelligent hybrid control system (IHCS) for identification and control of micro-permanent-magnet synchronous motor (micro-PMSM) servo drive to achieve high precision tracking performance. The proposed control scheme incorporates a computed torque controller (CTC) based on the sliding-mode technique, a Petri recurrent-fuzzy-neural-network (PRFNN) controller (PRFNNC) and a PRFNN identifier (PRFNNI). First, a CTC is designed to stabilize the micro-PMSM servo drive system. However, particular information about the uncertainties of the micro-PMSM servo drive is required in the CTC law so that the corresponding control performance can not influenced seriously. Then, to improve the robustness of the servo drive system an IHCS is proposed. In the IHCS, the PRFNNC is used as the main tracking controller to mimic the CTC law and to preserve favorable model-following characteristics while the PRFNNI is utilized to identify the sensitivity information of the micro-PMSM servo drive system required for the PRFNNC. The online adaptive control laws are derived based on the Lyapunov stability theorem, the Taylor linearization technique and the back propagation method so that the stability of the micro-PMSM servo drive system can be guaranteed under occurrence of servo drive uncertainties. A computer simulation is developed to demonstrate the effectiveness of the proposed IHCS. The dynamic performance of the servo drive has been studied under load changes and parameters uncertainties. Accurate tracking response can be obtained due to the powerful online learning capability of PRFNN. In addition, the position tracking performance is significantly improved using the proposed IHCS and robustness to external disturbances can be obtained as well. Finally, the simulation results confirm that the IHCS grants robust performance and precise response regardless of load disturbances and micro-PMSM servo drive system parameter uncertainties.

Keywords: Computed torque control, intelligent control, Lyapunov stability theorem, micro-permanentmagnet synchronous motor, Petri net (PN), recurrent-fuzzy-neural-network, sliding-mode control

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #36, pp. 336-355

Title of the Paper: Continuous-Time and Discrete Multivariable Decoupling Controllers

Authors: Marek KubalĨík, Vladimír Bobál

Abstract: The paper is focused on a design and implementation of a decoupling multivariable controller. The controller was designed in both discrete and continuous-time versions. The control algorithm is based on polynomial theory and pole – placement. A decoupling compensator is used to suppress interactions between control loops. The controller integrates an on – line identification of an ARX model of a controlled system and a control synthesis on the basis of the identified parameters. The model parameters are recursively estimated using the recursive least squares method.

Keywords: Multivariable control, control algorithms, adaptive control, polynomial methods, pole assignment, recursive identification

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #35, pp. 327-335

Title of the Paper: An Improved Proportional Quasi-Resonant Control of Wind Power GCI under Unbalanced Grid Conditions

Authors: Xu Deqiang, Jin Zhijian

Abstract: With conventional control strategy under unbalanced grid conditions, power fluctuations will be gener-ated in the input active power and reactive power of the wind power Grid Connected Inverter (GCI). In this paper, a novel sequence extraction method is proposed in the voltage components decomposition. Based on second order generalized integrator (SOGI) with PLL, a decomposition module with an ability of frequency adaptation is built up, called FA-SOGI. To avoid the sequence extraction of grid current, a novel proportional quasi-resonant con-troller implemented also by FA-SOGI within αβ stationary coordinate system is introduced to improve inner-loop current control performance. With two objectives of active power fluctuation suppression and reactive power fluctuation suppression, the proposed strategy is verified by simulation and experiment. The results show that the sequence decomposition module is correct and the power fluctuations can be obviously suppressed and DC-bus voltage can be steady.

Keywords: Proportional quasi-resonant (PQR), power fluctuations, unbalanced grid, grid connected inverter (GCI), second order generalized integrator with frequency adaptation (FA-SOGI)

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #34, pp. 318-326

Title of the Paper: Improvement of Conventional Traffic Signaling Device - Self Routing Traffic Light System

Authors: S. T. Tan, N. H. Noraini, K. L. Tan

Abstract: Traffic congestion becomes a serious issue nowadays especially at urban cities area. When road users come at the intersection point, there is always a conflict “who can go first” on their mind. Due to the high volume of vehicles on the road, intersection points need a traffic signaling device to control the traffic flow. That is the reason traffic signalling device is installed at most of the intersection point especially in urban cities. Traffic signaling device is used to ensure the smoothness of traffic flow and provide time system and direction to road users. Therefore, road users are clear to cross over the intersection point. However, road users still need to spend a lot of time for waiting their turn at the intersection point. This is because the conventional traffic signaling device not intelligent enough to control a high volume of vehicles. The objective of this paper is to propose a new programming method for traffic signaling device which is called “Self Routing Traffic Light” as it is to reduce road user’s waiting time at the intersection point. One of the simulations called “Simulation of Urban Mobility (SUMO)” is used to create simulation and collecting data. According to the simulation, several methods is used to control the traffic signaling device such as sequencing method and sensor demand method for conventional traffic light system and proposed method. From the data analysis, the waiting time and travel time of road users spent at the intersection point between conventional methods and proposed method is decreased. As a conclusion, the proposed method will be a practical solution for those traffic signaling device which will be installed at intersection point to ensure the efficiency of traffic flow.

Keywords: Traffic Signaling Device; Simulation; Vehicles; Traffic Flow; Intersection Point; Traffic Congestion

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #33, pp. 309-317

Title of the Paper: Finite Frequency H- /H∞ Stability of Singularly Perturbed Systems

Authors: A. Zouhri, M. Ben Yakhlef, I. Boumhidi

Abstract: In this paper, the problem of finite frequency H- /H∞ control for singularly perturbed systems based on GKYP lemma is studied. The objective of the H- /H∞ control problem is to design a controller such that the resulting closed-loop system is stable, and the transfer function is bounded real for singularly perturbed systems at low and high frequencies. By employing GKYP lemma, respectively, on the slow and fast subsystem, the problems of the reduced order subsystems are solved in terms of linear matrix inequalities (LMIs). The two frequency- scale solution for the full-order SPS constructed in this paper uses the solutions of two well-defined lower-order problems, and therefore it is numerically better conditioned. An iterative algorithm for the computation of the BMIs is presented. The effectiveness of the proposed method is demonstrated through comparing with positive real control design method.

Keywords: Singularly Perturbed Systems (SPS); H- /H∞ control; finite frequency; Kalman-Yakubovich-Popov (KYP) lemma; linear matrix inequalities (LMI)

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #32, pp. 302-308

Title of the Paper: Dynamic Behaviors of N-Species Cooperation System with Distributed Delays and Feedback Controls on Time Scales

Authors: Meng Hu, Lili Wang

Abstract: This paper is concerned with a n-species cooperation system with distributed delays and feedback con- trols on time scales. For general nonautonomous case, by using differential inequality theory and constructing a suitable Lyapunov functional, sufficient conditions which guarantee the permanence and the global attractivity of the system are obtained. For the almost periodic case, by using the Razumikhin type theorem, sufficient conditions which guarantee the existence of a positive almost periodic solution of the system are obtained. Finally, an example and numerical simulations are presented to illustrate the feasibility and effectiveness of the results.

Keywords: Cooperation system; Permanence; Global attractivity; Almost periodic solution; Time scale.

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #31, pp. 291-301

Title of the Paper: Parallel OBF-Wavelet Network Model for Nonlinear Systems Identification

Authors: H. Zabiri, M. S. Fadzil, Y. C. Bong, L. D. Tufa, M. Ramasamy

Abstract: In the present work, a linear Orthonormal Basis Filters (OBF) model is integrated with nonlinear Wavelet Network (WN) model in parallel structure for nonlinear systems identification. The overall nonlinear model is taken as the sum of these two models and analyzed using two case studies. The effectiveness and the model performance within the model development region as well as under extrapolating conditions are studied. The results showed that the proposed parallel OBF-WN performed better than other conventional models in both regions of operations.

Keywords: Modeling Nonlinear systems, OBF, Wavelet networks

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #30, pp. 285-290

Title of the Paper: Precise Control of the Piston Position and the Pressure of Cylinder Chambers for the Pneumatically Actuated Leg

Authors: Zhe Li, Hongwei Yan, Xingwang Su

Abstract: In the pneumatically actuated leg control system, precise control of the piston position and the pressure of cylinder chambers is a tricky problem. In this paper, a new control scheme is introduced, in which the gas internal energy of the cylinder’s two chambers is used as the set point for PD controller. The proposed control scheme is essential to control the piston position and the chamber pressure simultaneously. A pneumatic position servo model is developed by Simulink tools in the form of an S-function. The maximum steady-state error of 0.19 mm for the piston position and 0.001 MPa for the chamber pressure have been verified in simulations. The test rig of the vertical hopping is constructed, and the experimental results of the pneumatic position servo control on the pneumatically actuated leg show that the chamber pressure error is less than 0.002 MPa, the piston positioning error is less than 0.31 mm and there is no overshooting. The experimental results also show that the established mathematical model and the simulation results are correct. Consequently, the practical experiments of vertical hopping are successful, which validates the proposed method further.

Keywords: Piston position, the chamber pressure, the gas internal energy, the pneumatically actuated leg, vertical hopping

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #29, pp. 277-284

Title of the Paper: Fault Detection and Isolation of Fuzzy System with Uncertain Parameters using the Bounded Approach

Authors: Hassene Bedoui, Atef Khedher, Kamel Ben Othman

Abstract: This paper deals with the problem of state estimation and fault detection and localization of nonlinear systems with uncertain parameters. The multiple model approach is used to model the nonlinear system. This approach is based on the use of fuzzy systems principle. Uncertain parameters are modeled using the bounded approach. The technique proposed in this work is used for linear case but never in the case of nonlinear systems, which presents the main contribution in this paper. The principle of the proposed method is to consider that the system parameters are uncertain and the distribution value is unknown at the time of the court. Only the extreme bounds are known in advance. Using this method it is possible to generate fault indicators (named also residuals). These residuals are not sensitive to the parameter uncertainties and allow detecting and locating the faults affecting the system. A numerical example is showing the effectiveness of the presented method.

Keywords: Interval analysis, state estimation, fault detection, bounded approach, uncertain system

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #28, pp. 269-276

Title of the Paper: Utility Portfolio Optimization with Liability and Multiple Risky Assets under the Extended CIR Model

Authors: Hao Chang, Ji-Mei Lu

Abstract: This paper studies an asset and liability management problem with extended Cox-Ingersoll-Ross (CIR) interest rate, where the financial market is composed of one risk-free asset and multiple risky assets and one zero-coupon bond. We assume that risk-free interest rate is driven by extended CIR interest rate model, while liability is modeled by Brownian motion with drift and is generally correlated with stock price. Firstly, we use stochastic optimal control theory to obtain Hamilton-Jacobi-Bellman (HJB) equation for the value function and choose power utility and exponential utility for our analysis. Secondly, we obtain the closed-form solutions to the optimal investment strategies by applying variable change technique. Finally, a numerical example is presented to analyze the dynamic behavior of the optimal investment strategy and provide some economic implications for our results.

Keywords: CIR interest rate model; liability process; dynamic portfolio selection; stochastic optimal control; optimal investment strategy

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #27, pp. 255-268

Title of the Paper: Solid Oxide Fuel Cell with DC-DC Converter System: Control and Grid Interfacing

Authors: Kanhu Charan Bhuyan, Rajesh Kumar Patjoshi, Subhransu Padhee, Kamalakanta Mahapatra

Abstract: Fuel cell unit generally has low voltage DC as output. To increase the output voltage, fuel cell stack is used where number of single unit fuel cell are connected in series or parallel. To step-up or step-down the output voltage of solid oxide fuel cell (SOFC), DC-DC converter is used. The DC output voltage of the converter is converted to AC with the help of DC-AC inverter. This paper develops MATLAB/Simulink model of fuel cell based power system (FCPS) comprising of fuel cell stack, DC-DC converter and DC-AC inverter. Sliding mode control (SMC) scheme is implemented in DC-DC buck converter, which guarantees stable output voltage despite transient variations in output voltage of fuel cell. Hysteresis current controller (HCC) scheme is implemented in DC-AC inverter which enables the fuel cell stack to supply utility AC voltage to grid and other power applications.

Keywords: Fuel Cell Stack, Fuel Cell Power System, Sliding Mode Controller, Hysteresis Current Controller

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #26, pp. 247-254

Title of the Paper: A Preventive Control Model for Static Voltage Stability Considering the Active Power Transfer Capabilities of Weak Branches

Authors: Xiuqiong Hu, Zhouyang Ren, Yiming Li

Abstract: The voltage instability of power system often occurs when the active power on one or more weak branches exceeds its transfer capability. This paper presents a preventive control model for voltage stability using the active power transfer capabilities of weak branches as static voltage stability margin constraints. A local line-based voltage stability index is used to determine the critical contingencies, weak branches and transfer capability of each weak branch. A static security analysis method, which is based on DC power flow equations, is used to establish the non-linear active power flow expressions on weak branches following each critical contingency. The static voltage stability margin constraints can be obtained from the active power flow expressions and transfer capabilities of weak branches. A quadratic optimal model for preventive control including the proposed static voltage stability margin constraints is presented. The simulation results for the IEEEE14-bus system and IEEE118-bus system demonstrate the correctness and effectiveness of the proposed preventive control model for static voltage stability.

Keywords: Electric power system; Voltage control; Preventive control; Static voltage stability; Weak branches; Quadratic optimal model

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #25, pp. 238-246

Title of the Paper: Monitoring and Detecting Health of a Single Phase Induction Motor Using Data Acquisition Interface (DAI) module with Artificial Neural Network

Authors: Ainul Anam Shahjamal Khan, Adittya Ranjan Chowdhury, Md. Shahriar Haque

Abstract: This paper deals with the problem of detection of induction motor incipient faults and usefulness of Artificial Neural Network (ANN) in this respect. The research work diagnoses the three major faults such as stator inter-turn faults, bearing faults and misalignment faults using some measurable parameters (motor intake current, speed and body temperature). The experimental data for three measurable parameters were generated in the laboratory on specially connected single phase induction motor. The measurable parameters were obtained by a Data Acquisition Interface (DAI) module and neural network algorithm was achieved by using MATLAB programming language. Experimental results show that it is a very good choice to detect incipient faults in single phase induction motor using an ANN algorithm.

Keywords: Monitoring, Detecting, Single phase induction motor, Data Acquisition Interface (DAI) module, Artificial Neural Network

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #24, pp. 229-237

Title of the Paper: Improved Performance of the Positive Output Elementary Split Inductor-Type Boost Converter using Sliding Mode Controller plus Fuzzy Logic Controller

Authors: K. Ramash Kumar, S. Jeevananthan, S. Ramamurthy

Abstract: This article presents a design of variable frequency based reduced-order sliding mode controller (ROSMC) plus fuzzy logic controller (FLC) for positive output elementary split inductor-type boost converter (POESITBC). Because of the time varying switched mode of operation, the dynamic characteristics of POELSITBC is non-linear in nature. The conventional controllers are not able to improve the dynamic performance under the line and load variations. In order to enhance the dynamic characteristics together with the inductor current and output voltage regulation of the POTSITBC, a ROSMC plus FLC is developed. The designed ROSMC is fit to the naturally variable-structured POESITBC when expressed in the reduced order state-space average based model. The ROSMC is act as an inner current loop control for POESITBC and the FLC is act as an outer loop for the same converter, which are used to regulate the inductor current, regulate output voltage and reduce the steady state error as well as the outstanding initial start-up response of the converter in spite of line and load changes. The performance of the developed controller is validated at different working regions through the MATLAB/Simulink model over a ROSMC plus proportional-double integralcontroller (PDIC). Simulated results are indicated that designed controller can acquire the superior output voltage and inductor current regulations at different stages.

Keywords: DC-DC power conversion, positive output elementary split inductor-type boost converter, sliding mode controller, proportional double integral controller, state-space average method

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #23, pp. 215-228

Title of the Paper: A New Velocity Estimator for Motion Control Systems

Authors: Jian Mao, Huawen Zheng, Yuanxin Luo

Abstract: In motion control systems, differentiated position signal is commonly used to estimate velocity, and used for speed feedback control. Position quantization error can result in the amount of noise jamming, which affects system control precision and stability. In this paper, a reliable velocity estimator is proposed to estimate velocity from the measured position. This estimator consists of two parts: a traditional moving-average filter for data smoothing process, and a closed-loop PID controller to compensate the phase lag caused by smoothing process. Simulation and experimental results demonstrate that the quantization error in the velocity feedback signal can be reduced dramatically when the proposed estimator is used for velocity estimation, the estimated signal has fewer phase lag than the traditional velocity estimation method, and the current noise of motor is reduced as well.

Keywords: Velocity Estimator, Motion Control, PID

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #22, pp. 209-214

Title of the Paper: Electromagnetic Rotary Tables for Mill and Drill Machining

Authors: Mario Stamann, Thomas Schallschmidt, Roberto Leidhold

Abstract: The following paper shows the control and the practical use of magnetic bearings as rotary tables for mill and drill machining of heavy workpieces. In contrast to conventional rotary tables, magnetic bearings have certain advantages, which can only be used, if a stable and exact position control in five degrees of freedom is implemented. The main focus of this paper is on the cascade control with optimal disturbance rejection, sliding mode control and the decoupling of degrees of freedom.

Keywords: Magnetic bearing, rotary table, degree of freedom, disturbance rejection, cascade control, sliding mode control, decoupling control, multivariable control

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #21, pp.199-208

Title of the Paper: Time Scale Analysis and Synthesis of Deterministic and Stochastic Wind Energy Conversion Systems

Authors: Shaleena Jaison, D. Subbaram Naidu, Dawid Zydek

Abstract: The threat of climate change and diminishing fossil fuels demands nothing short of an energy revolution, a transformation which is already underway as renewable energy markets exhibit enormous and steady growth. This paper presents design of optimal control schemes for Wind Energy Conversion Systems (WECS) based on a time scale technique. The dynamics governing the mechanical components of a variable speed wind turbine are decoupled to bring about model order reduction, facilitating computationally efficient control schemes. Linear Quadratic Regulators (LQR) and Linear Quadratic Gaussian (LQG) controllers for deterministic and stochastic WECS models are discussed at length. Comparisons were made between controllers for the reduced order and full order systems. The results manifest the effectiveness of the proposed method, which provides comparable control while reducing model order and increasing computational efficiency.

Keywords: Linear Quadratic Gaussian Control, Linear Quadratic Regulator, Time Scales, Wind Energy Conversion Systems

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #20, pp.189-198

Title of the Paper: Passive Attitude Control for Spacecraft

Authors: Lina Wang, Zhi Li

Abstract: The stability of spacecraft attitude is studied with considering sinusoidal disturbance. A passive attitude controller without angular velocity measurement for spacecraft described by quaternion is designed. The passive controller has no information related to system parameters. So it has robustness to model error and uncertainty of model parameters. The stability of spacecraft attitude control with considering external sinusoidal disturbance can be proved by applying Lyapunov approach and LaSalle Invariance Principle. Simulation results demonstrate the effectiveness of the designed attitude controller.

Keywords: Spacecraft attitude, Passive control, Quaternion, Sinusoidal disturbance

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #19, pp.183-188

Title of the Paper: Design of Fractional Order PID Controller for DC Motor Using Evolutionary Optimization Techniques

Authors: Ashu Ahuja, Sanjeev Kumar Aggarwal

Abstract: In this paper, a comparison of various Evolutionary Optimization (EO) techniques has been performed for controller tuning (PID and FOPID) for DC motor speed control applications. Three techniques have been considered, which are: genetic algorithm (GA), particle swarm optimization (PSO), and differential evolution (DE). A fixed structure PID and FOPID controller has been considered. Usually in literature, comparison has been carried out based on time domain performance indices; whereas, in this work, mixed sensitivity H∞ method is considered as the fitness function for the comparison of various EO techniques in order to assess the robustness of the designed system. It has been shown that GA optimized FOPID controller has better robustness with respect to model uncertainties.

Keywords: Controllers, differential evolution, DC motor, genetic algorithm, mixed sensitivity function, particle swarm optimization

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #18, pp.171-182

Title of the Paper: Sampled-DataModels for Nonlinear Systems via the Taylor-Lie Series and Multirate Input

Authors: Cheng Zeng, Shan Liang

Abstract: It is well-known that the existence of unstable zero dynamics is recognized as a major barrier in many control problems. This paper investigates an approximate sampled-data model for nonlinear systems by the use of multirate input and hold such as a generalized sample hold function (GSHF), and further analyzes the sampling zero dynamics of the sampled-data model to show a condition which assures the stability of the sampling zero dynamics of the model. The results presented here show how sampling zero dynamics of the obtained model can be arbitrarily placed. In a word, the stability of the sampling zero dynamics is definitely improved compared with a zero-order hold (ZOH) or a fractional-order hold (FROH).

Keywords: Nonlinear systems, Sampled-data models, Zero dynamics, Generalized sample hold function

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #17, pp.160-170

Title of the Paper: Double Closed-Loop Control Scheme of Yaw Rate for Active Front Steering System

Authors: Jianwei Wei, Wanzhong Zhao, Weiyan Shang

Abstract: Steering system is an important man-machine interface, for which transmits driver's lateral control intention to the vehicle. In order to improve the vehicle lateral stability, a double closed-loop control scheme of yaw rate for active front steering system was proposed in this paper. To investigate the control effects of the double closed-loop control scheme of yaw rate, a two degree-of-freedom (2DOF) vehicle model and brushless dc motor (BLDCM) model were built, as well as numerical simulations and virtual tests based on CarSim software were conducted at different limiting conditions. Results indicate that response delay of vehicle driving on the road with low adhesion coefficient could be reduced with the help of the proposed yaw rate control scheme, as well as effects of unexpected yaw disturbance on response characteristics of vehicle could be weakened effectively.

Keywords: Vehicle, active front steering, yaw rate control, brushless dc motor (BLDCM), double closedloop control, CarSim

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #16, pp.150-159

Title of the Paper: Geometric Structures Using Model Predictive Control for an Electromagnetic Actuator

Authors: Paolo Mercorelli

Abstract: Control of permanent magnetic actuators is not an easy task because of the presence of the nonlinear quadratic terms of the currents. In order to achieve a suitable controlled dynamics canceling the effect of the nonlinearity, a new control strategy has been conceived. The proposed strategy combines the geometric eigenvector concept through a pre-compensation action and a Model Predictive Control (MPC) strategy. The pre-compensation action is conceived through an input partition matrix based on the eigenvector concept. It is known that each eigenvector represents an invariant subspace for the system and this property is useful to realize a very simple control technique which is able to speed up the controlled dynamics without incurring oscillations. This technique can be applied to a large variety of actuators. Simulation results are reported to validate the proposed strategy.

Keywords: Geometric control, Linear control, Model predictive control

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #15, pp.140-149

Title of the Paper: Time Scale Analysis and Synthesis for Model Predictive Control

Authors: Yan Zhang, Hoa Nguyen, D. Subbaram Naidu, Yun Zou, Chenxiao Cai

Abstract: This paper presents time scale analysis and synthesis (control)methodology forModel Predictive Control (MPC). In thismethod, a higher-order plant with a two-time (slow and fast) scale character is analyzed (decoupled) into low-order slow and fast subsystems and sub-augmented systems. Then slow and fast subcontrollers based on MPC method are synthesized (designed) separately and a composite MPC is obtained. The methodology is illustrated for a high-order Wind Energy Conversion Systems (WECS) with Permanent Magnet Synchronous Generators (PMSG). The results show that the performance of the system with composite MPC is very close to that of the MPC of the original high-order system showing the superiority of the proposed method in terms of separation of dynamics, simplicity in designing model predictive controllers and reduced computational effort.

Keywords: Singular perturbations, wind energy conversion systems, time scales, model predictive control, order reduction

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #14, pp.130-139

Title of the Paper: Active Suspension System for Passenger Vehicle using Active Force Control with Iterative Learning Algorithm

Authors: Rosmazi Rosli, Musa Mailah, Gigih Priyandoko

Abstract: The paper describes the practical implementation of a new hybrid control method to a vehicle suspension system using Active Force Control (AFC) with Iterative Learning (IL) and proportional-integral-derivative (PID) control strategy. The overall control system essentially comprises three feedback control loops to cater for a number of specific tasks; the innermost loop for the force tracking of the pneumatic actuator using a PI controller, the intermediate loops implementing AFC with IL algorithm strategy for the compensation of the disturbances, and the outermost loop using a PID controller for the computation of the desired force. A number of experiments were carried out on a physical quarter car test rig with hardware-in-the-loop simulation (HILS) feature that fully incorporates the theoretical elements. The performance of the proposed control method was evaluated and benchmarked to examine the effectiveness of the system in suppressing the vibration effect. It was found that the experimental results demonstrate the superiority of the active suspension system with AFCIL scheme compared to the PID and passive counterparts. The vertical body acceleration and displacements are clearly reduced, thereby implying that the ride comfort aspect of the system is improved via the proposed control scheme.

Keywords: Active Suspension, Active Force Control, Iterative Learning Algorithm, Ride Comfort, Hardware-in-the-loop Simulation

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #13, pp.120-129

Title of the Paper: A Novel SVPWM Modulation Algorithm of Voltage Source Rectifier with Minimized Switching Losses

Authors: Yang Xi-Jun, Ma Hong-Xing, Li Hua-Wu, Cao Zhong-Sheng, Yang Xing-Hua

Abstract: Since PWM voltage source rectifier (VSR) can not only provide high-quality DC voltage but also realize four-quadrant operation, it is widely used in many applications. In order to improve the overall efficiency of rectifier, it is required to reduce its switching count and switching loss. Given that the switching loss of rectifier is closely related with its modulation algorithms, the existing modulation algorithms should be optimized. At first, what presented in the paper is the theoretical derivation of the multi-solution principle of VSR, as well as the theoretical analysis of the essential relationship between SPWM and SVPWM. Then the minimized switching loss SPWM and SVPWM modulation algorithms injecting zero-sequence component into the objective function of rectifier are presented, and a power loss formula of power device is also provided. The rectifier with minimized switching loss SPWM and SVPWM modulation algorithms is simulated by means of MATLAB/SIMULINK. Then the experimental platform of VSR with minimized switching loss PWM modulation algorithm is realized based on DSP F28335, which has verified the above theoretical analysis and simulation results. The results show that the overall efficiency of the rectifier with minimized switching loss PWM modulation algorithm increases about 2~3% compared to traditional SPWM and SVPWM modulation algorithms.

Keywords: Voltage source rectifier; Multi-solution; Objective function; Zero-sequence component; Minimized switching loss PWM

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #12, pp.108-119

Title of the Paper: Performance Comparison between Sliding Mode Control and Active Force Control for A Nonlinear Anti-Lock Brake System

Authors: Mohammed Hussin Al-Mola, Musa Mailah, Pakharuddin Mohd Samin, Abdul Halim Muhaimin, Mohd Yunus Abdullah

Abstract: The Anti-lock braking system (ABS) is the most common safety system in the vehicles, which works to increase the generating braking force between the tire and the road surface in way to keep the stability in vehicles during braking. The high nonlinearity due to the interaction between the tire and road, the uncertainties in vehicle dynamics always exist and using the standard PID controller will not be accurate enough to the extent required to deal with the uncertainties. Two robust control techniques, the sliding mode control (SMC) and an intelligent active force control (AFC) that both of them deal with the dynamic systems to provide durability and quell the unrest that may found in the system. In this paper highlights the ability of this proposed technique to improve the dynamic system robustly by combining them with standard PID in one control scheme (PID-AFC) comparing with (PID-SMC). Results showed the robustness of AFC and solo performance to improving the slip track without chattering phenomenon and thus reduce the stopping distance of the vehicle compared to other control schemes.

Keywords: Anti Lock Brake System; Active Force Control; Sliding Mode Control; Proportional-Integral-Derivative Controller; Robust control; Wheel Slip

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #11, pp.101-107

Title of the Paper: FPGA-Based Implementation Sliding Mode Control and Nonlinear Adaptive Backstepping Control of a Permanent Magnet Synchronous Machine Drive

Authors: Badre Bossoufi, Mohammed Karim, Ahmed Lagrioui

Abstract: In this paper, the adaptive and non-adaptive nonlinear Backstepping control approach for a permanent magnet synchronous motor drive is discussed and analyzed. We present a Matlab&Simulink simulation and experimental results from a benchmark based on FPGA. The design of a controller for a nonlinear system where the state vector dimension is high, can often be a difficult task, if not impossible. The Backstepping technique provides a systematic method to address this type of problem. It combines the notion of Lyapunov function and a controller procedure recursively. First, the adaptive and no adaptive Backstepping control approach is utilized to obtain the robustness for mismatched parameter uncertainties. The overall stability of the system is shown using Lyapunov technique. The simulation results clearly show that the proposed scheme can track the speed reference. Secondly, some experimental results are demonstrated to validate the proposed controllers. The experimental results carried from a prototyping platform are given to illustrate the efficiency and the benefits of the proposed approach and the various stages of implementation of this structure in FPGA.

Keywords: Not Adaptive Backstepping control; Backstepping Design Technique; FPGAs; Permanent Magnet Synchronous Machine (PMSM); Lyapunov Stability; Robust Adaptive Control; Systems Generator; Reusability

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #10, pp.86-100

Title of the Paper: Development of Fuzzy Logic Controller by Particle Swarm Optimization Algorithm for Semi-Active Suspension System using Magneto-Rheological Damper

Authors: Mat Hussin Ab Talib, Intan Z. Mat Darus

Abstract: The performance of fuzzy logic (FLC) and PID controllers optimized by particle swarm optimization (PSO) for semi-active suspension system using magneto-rheological (MR) damper are investigated. MR damper is an intelligent damper filled with particle magnetic polarizable and suspended into a liquid form. The Bouc-Wen model of MR damper is used to determine the required damping force based on force-displacement and force-velocity characteristics. During this research, the scaling factors of FLC and the gain parameters of PID controller will be optimized using the intelligent PSO technique to achieve the lowest Mean Square Error (MSE) of the system response. The performance of the proposed controllers based on intelligent PSO technique will be compared with the performance of passive suspension system for the body displacement, body acceleration, tire displacement and tire acceleration. Two different disturbances namely bump and hole, and random signals is implemented into the system. The simulation results demonstrates that the PSO tuned FLC exhibits an improvement to the ride comfort and has the smallest MSE as compared to the performance of PSO tuned PID and passive suspension system.

Keywords: Suspension system, semi-active, fuzzy logic controller (FLC), PID controller, particle swarm optimization (PSO)

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #9, pp.77-85

Title of the Paper: On the Control of Micro Ball Grid Array (μBGA) Production Systems

Authors: Ioannis Friganiotis, Panagiotis Spanos

Abstract: In this paper, two novel control implementations for the production of Ball Grid Arrays (BGA) at the micro scale are presented. The first is a linear control algorithm; the second is an adaptive neural network. The linear control algorithm was developed to manage the key control parameters of the system and to reach the desired performance as fast as possible based on measurements of system’s output. The neural network uses an adaptive control architecture for controlling the performance of the system. This architecture dynamically assigns weights to output variables, in current point time as well as in previous points in time, and uses them as control inputs to improve both production performance and stability. Brief theoretical background, experimental validation and a comparison of the two algorithms in terms of performance and stability are provided.

Keywords: Control software, μBGA, linear control algorithm, neural network, adaptive control architecture

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #8, pp.67-76

Title of the Paper: Self-Tuning Active Vibration Controller using Particle Swarm Optimization for Flexible Manipulator System

Authors: Hanim Mohd Yatim, Intan Z. Mat Darus

Abstract: This paper presents the development of an optimal self-tuning PID controller for vibration suppression of flexible manipulator structures using particle swarm optimization (PSO). A simulation environment characterizing the dynamic behavior of the flexible manipulator system was first developed using finite difference (FD) approach to acquire the input-output data of the system. The global search technique of PSO is used to estimate the model transfer function through parametric identification in comparison to the conventional recursive least square (RLS) method. Next, the control structure comprises conventional PID controller and an intelligent PID incorporated PSO controller for position and vibration control respectively acted on flexible manipulator model system. Behavior of system response including hub angle and end-point displacement are recorded and assessed. The validation of the algorithm is presented in time and frequency domains. It was demonstrated that proposed controller is effective to move the flexible link to the desired position with suppression of vibration at end-point of a flexible manipulator structure.

Keywords: Active vibration control; single-link flexible manipulator; particle swarm optimization, PID controller

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #7, pp.55-66

Title of the Paper: Global Exponential Stability of FCNNs with Distributed Delays

Authors: Qianhong Zhang, Jingzhong Liu

Abstract: This paper is concerned with fuzzy cellular neural networks with distributed delays. Sufficient condi- tions on the existence, uniqueness and global exponential stability of equilibrium point are established by using the Homeomorphism theory and applying elementary inequality 2ab ≤ a2 + b2. Moreover an example is given to illustrate results obtained.

Keywords: Fuzzy cellular neural networks, Global exponential stability, Homeomorphism theory, Lyapunov functional, Distributed delays

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #6, pp.47-54

Title of the Paper: Higher Order Sliding Mode Control: A Control Lyapunov Function Based Approach

Authors: Shyam Kamal, B. Bandyopadhyay

Abstract: The paper presents a new method for higher order sliding mode control using control Lyapunov function for chain of integrator system with nonlinear uncertainties. The stability proof of the suggested scheme is analyzed in terms of two Lyapunov functions using appropriate switching function. Using these Lyapunov functions and switching scheme it is proved that, output and its higher order derivatives converge to origin in finite time. Simulation results illustrate the efficacy of the method.

" Higher order sliding mode control, Control Lyapunov function, Finite time stability

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #5, pp.38-46"

Title of the Paper: A Design on New Error Compensator for Fractional PI Controller and Its Application

Authors: Mazidah Tajjudin, Ramli Adnan

Abstract: Fractional-order controller was proven to perform better than the integer-order controller. However, the absence of a pole at origin in the approximated transfer function produced marginal error in fractional-order control system. This study demonstrated the design of an error compensator that comprises of a very small zero and a pole at origin to produce a zero steady-state error for the closed-loop system. Some modification on the error compensator was suggested for different order fractional integrator that can improve the overall phase margin. The proposed method can eliminate the steady-state error and additionally improved the percentage overshoot of the closed-loop response. The study was validated on steam temperature control of a steam distillation process that exhibits an s-shape step response. Hence, the PI controller was tuned using the Ziegler-Nichols rules and applied for both integer and fractional PI. Significant improvement of the fractional PI and the enhancement of the proposed error compensator was discussed evidently through simulation and supported by experimental applications.

Keywords: Fractional-order control; Fractional PI; Oustaloup’s Recursive Approximation; Ziegler-Nichols tuning; steam temperature control; hydro-steam distillation

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #4, pp.28-37

Title of the Paper: Computer Based Control with Real-Time Capabilities

Authors: Michal Blaho, Samuel Bielko, Ludovít Farkas, Peter Fodrek

Abstract: Control systems in many fields require perfect time accuracy and reliability. That is why guaranteed real-time behavior is needed. It is evident by the growing trend of the use of fieldbuses in building of Networked Control Systems. The software layer has a very significant influence on the system performance and requires thorough examination before the utilisation of a specific real-time system. The goal of this paper is to present and examine run-time environments that support real-time capabilities. We compare the performance of RTAI and Java Real-Time System in controlling of a sample plant with quick response and present our previously developed real control systems that are based on the use of RTAI that runs the real-time layer of the control system and Java that is responsible for the user interaction.

Keywords: Real-time control, RTAI, Java Real-Time System, RC-RC filter, Networked Control Systems, Fieldbus

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #3, pp.16-27"

Title of the Paper: MRAC Based PI Controller for Speed Control of D.C. Motor Using Lab View

Authors: Sumit Kumar Sar, Lillie Dewan

Abstract: When the parameter of any systems changes with respect to time then the constant gain PI controller action is not effective. In case of MRAC based design the adjustable PI gain parameters corresponding to changes in plant will be determined by referring to reference model specifying the property of desired control system. This paper presents the method to design MRAC based PI controllerfor speed control of D.C. motor using Lab VIEW software tool.

Keywords: MRAC, Adaptive Control, LabVIEW, DC Motor

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #2, pp.10-15

Title of the Paper: New Methodology for Chattering Suppression of Sliding Mode Control for Three-phase Induction Motor Drives

Authors: Marizan Sulaiman, Fizatul Aini Patakor, Zulkifilie Ibrahim

Abstract: Chattering is undesirable phenomenon when dealing with sliding mode control. This paper proposed a new method for addressing chattering with a simple and easy implementation in Digital Signal Processor (DSP). This is realized by replacing the discontinuous function in conventional sliding mode control with statedependent auto-tuning of boundary layer in fast sigmoid function and state-dependent switching gain, for threephase induction motor speed control. This method allows chattering reduction in control input, while keeping the robustness characteristics of sliding mode control. The performance of the proposed control is verified in emulation induction motor drives using Digital Signal Processor TMS320F2812 board, with different speed command and load disturbances.

Keywords: Sliding mode control, chattering, induction motor, digital signal processor

WSEAS Transactions on Systems and Control, ISSN / E-ISSN: 1991-8763 / 2224-2856, Volume 9, 2014, Art. #1, pp.1-9

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