Journal of Control Science and Engineering http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Iterative Learning Control with Forgetting Factor for Linear Distributed Parameter Systems with Uncertainty Thu, 18 Dec 2014 07:06:53 +0000 http://www.hindawi.com/journals/jcse/2014/508573/ Iterative learning control is an intelligent control algorithm which imitates human learning process. Based on this concept, this paper discussed iterative learning control problem for a class parabolic linear distributed parameter systems with uncertainty coefficients. Iterative learning control algorithm with forgetting factor is proposed and the conditions for convergence of algorithm are established. Combining the matrix theory with the basic theory of distributed parameter systems gives rigorous convergence proof of the algorithm. Finally, by using the forward difference scheme of partial differential equation to solve the problems, the simulation results are presented to illustrate the feasibility of the algorithm. Xisheng Dai, Senping Tian, Wenguang Luo, and Yajun Guo Copyright © 2014 Xisheng Dai et al. All rights reserved. Force/Position Hybrid Control of 6PUS-UPU Redundant Driven Parallel Manipulator Based on 2-DOF Internal Model Control Mon, 08 Dec 2014 09:59:44 +0000 http://www.hindawi.com/journals/jcse/2014/857947/ To improve control performance of parallel manipulator, servo control is optimized according to 2-DOF control with Internal Model Control. Position loop of the controller is redesigned based on the original current loop and speed loop. The hybrid force/position control strategy on the basis of cross-coupling is proposed. With mechatronic cosimulation system, it is proved that the force/position hybrid control on the basis of 2-DOF Internal Model Control has better stability and position precision compared with the traditional PID control. The control precision and stability of the parallel manipulator are improved effectively in actual experiment. Two types of compliance operation including peg in hole and surface tracking are realized in 6PUS-UPU parallel manipulator and both have good applicable effect. Kuijing Zheng and Chao Wang Copyright © 2014 Kuijing Zheng and Chao Wang. All rights reserved. Decreasing the Value of Specified Cost Function by Adaptive Controller Based on Modified ACLF for a Class of Nonlinear Systems Mon, 24 Nov 2014 10:14:17 +0000 http://www.hindawi.com/journals/jcse/2014/280951/ A new nonlinear adaptive control law for a class of uncertain nonlinear systems is proposed. The proposed control law is designed by a modified adaptive control Lyapunov function (ACLF) which satisfies a Hamilton-Jacobi-Bellman (HJB) equation. The modified ACLF is derived from transformation of an ACLF. The proposed control law is different from the inverse optimal one in decreasing the value of a cost function specified by a designer. In this paper, we show a transformation coefficient for an ACLF and a design method of a nonlinear adaptive controller. Finally, it is shown by a numerical simulation that the proposed control law decreases the value of a given cost function and achieves the desirable trajectory. Keizo Okano, Kojiro Hagino, and Hidetoshi Oya Copyright © 2014 Keizo Okano et al. All rights reserved. Controllability of Singular Linear Systems by Legendre Wavelets Thu, 20 Nov 2014 06:01:07 +0000 http://www.hindawi.com/journals/jcse/2014/573959/ We propose a new method to design an observer and control the linear singular systems described by Legendre wavelets. The idea of the proposed approach is based on solving the generalized Sylvester equations. An example is also given to illustrate the procedure. Wenxin Yu, Yigang He, Xianming Wu, and Kun Gao Copyright © 2014 Wenxin Yu et al. All rights reserved. A Novel Compound Control Method for Hydraulically Driven Shearer Drum Lifting Thu, 20 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/jcse/2014/691787/ In order to adjust shearer drum swiftly and precisely to adapt to the changes of coal seam, a compound control approach based on cerebellar model articulation control and fractional order PID controller was proposed. As the movement precision and response speed of hydraulic system were determined mainly by the control precision of valve-controlled asymmetrical hydraulic cylinder, its working principle and characteristics were analyzed in this paper, with particular focusing on the asymmetry problem. Furthermore, RBF neural network was applied to obtaining reasonable tuning parameters and a control algorithm of proposed controller was designed. Finally, laboratory experiments were developed to verify the validity and effectiveness of proposed compound control method. The testing results, compared with those for other controllers, proved that the proposed compound control method can acquire high movement precision and respond speed in the system of hydraulically driven shearer drum lifting with different control conditions. Lei Si, Zhongbin Wang, Xinhua Liu, and Lin Zhang Copyright © 2014 Lei Si et al. All rights reserved. Partial Pole Placement in LMI Region Sun, 16 Nov 2014 09:37:11 +0000 http://www.hindawi.com/journals/jcse/2014/840128/ A new approach for pole placement of single-input system is proposed in this paper. Noncritical closed loop poles can be placed arbitrarily in a specified convex region when dominant poles are fixed in anticipant locations. The convex region is expressed in the form of linear matrix inequality (LMI), with which the partial pole placement problem can be solved via convex optimization tools. The validity and applicability of this approach are illustrated by two examples. Liuli Ou, Shaobo Han, Yongji Wang, Shuai Dong, and Lei Liu Copyright © 2014 Liuli Ou et al. All rights reserved. Research on Application of Regression Least Squares Support Vector Machine on Performance Prediction of Hydraulic Excavator Tue, 11 Nov 2014 11:44:22 +0000 http://www.hindawi.com/journals/jcse/2014/686130/ In order to improve the performance prediction accuracy of hydraulic excavator, the regression least squares support vector machine is applied. First, the mathematical model of the regression least squares support vector machine is studied, and then the algorithm of the regression least squares support vector machine is designed. Finally, the performance prediction simulation of hydraulic excavator based on regression least squares support vector machine is carried out, and simulation results show that this method can predict the performance changing rules of hydraulic excavator correctly. Zhan-bo Chen Copyright © 2014 Zhan-bo Chen. All rights reserved. Transformation of CLF to ISS-CLF for Nonlinear Systems with Disturbance and Construction of Nonlinear Robust Controller with Gain Performance Tue, 04 Nov 2014 06:51:53 +0000 http://www.hindawi.com/journals/jcse/2014/527893/ A new nonlinear control law for a class of nonlinear systems with disturbance is proposed. A control law is designed by transforming control Lyapunov function (CLF) to input-to-state stability control Lyapunov function (ISS-CLF). The transformed CLF satisfies a Hamilton-Jacobi-Isaacs (HJI) equation. The feedback system by the proposed control law has characteristics of gain. Finally, it is shown by a numerical example that the proposed control law makes a controller by feedback linearization robust against disturbance. Keizo Okano, Kojiro Hagino, and Hidetoshi Oya Copyright © 2014 Keizo Okano et al. All rights reserved. Nonlinear Current Control for Reluctance Actuator with Hysteresis Compensation Tue, 21 Oct 2014 11:01:39 +0000 http://www.hindawi.com/journals/jcse/2014/150345/ The next-generation fine stage of the wafer scanner needs a suitable actuator to meet the requirements of high speed, high acceleration, and high precision. The voice coil actuator is no longer the best choice because of its large size and the heat dissipation is difficult to solve. The reluctance actuator can provide a big force based on a unique property of small volume and low current, making it a very suitable candidate. But the strong nonlinearity such as the hysteresis between the current and force limits the reluctance actuator applications in nanometer positioning. This paper proposes a nonlinear current control configuration with hysteresis compensation using the adaptive multilayer neural network. Simulation results show that the hysteresis compensator is effective in overcoming the hysteresis and is promising in precision control applications. Yu-Ping Liu, Kang-Zhi Liu, and Xiaofeng Yang Copyright © 2014 Yu-Ping Liu et al. All rights reserved. Design of Iterative Learning Control Method with Global Convergence Property for Nonlinear Systems Thu, 02 Oct 2014 00:00:00 +0000 http://www.hindawi.com/journals/jcse/2014/351568/ We address an iterative learning control (ILC) method for overcoming initial value problem caused by local convergence methods. Introducing a feedback recursive form of tracking errors into iterative learning law, this algorithm can avoid a crude linear approximation to nonlinear plants to reach global convergence property. The algorithm’s structure is entirely illustrated. Under assumptions, it is guaranteed that tracking errors of the closed-loop system converge to zero. Besides, we discuss the roles of parameters in iterative learning law for algorithm realization, and a nonlinear case study is presented to demonstrate the effectiveness and tracking performance of the proposed algorithm. Guang-Wei Xu, Cheng Shao, and Yu Han Copyright © 2014 Guang-Wei Xu et al. All rights reserved. Sliding Mode Control for Electrohydrostatic Actuator Sun, 28 Sep 2014 11:16:32 +0000 http://www.hindawi.com/journals/jcse/2014/481970/ Electrohydrostatic actuator (EHA) is a new actuator for next generation aircraft actuation system. This actuator is essentially a nonlinear system; response speed and accuracy are the main consideration. We use sliding mode control for this nonlinear system in this paper. The variable structure filter (VSF) is introduced to obtain the unmeasured states. Derivation of the VSF gain based on the reaching law is presented in this paper. To improve the response speed and accuracy, a nonlinear function is introduced to construct the nonlinear sliding surface using the estimated states generated by VSF. Simulation results show that low settling time and quick response are obtained by using the nonlinear sliding surface. Shi Zhengqiang, Tang Zhiyong, and Pei Zhongcai Copyright © 2014 Shi Zhengqiang et al. All rights reserved. Research on Visual Servo Grasping of Household Objects for Nonholonomic Mobile Manipulator Wed, 24 Sep 2014 00:00:00 +0000 http://www.hindawi.com/journals/jcse/2014/315396/ This paper focuses on the problem of visual servo grasping of household objects for nonholonomic mobile manipulator. Firstly, a new kind of artificial object mark based on QR (Quick Response) Code is designed, which can be affixed to the surface of household objects. Secondly, after summarizing the vision-based autonomous mobile manipulation system as a generalized manipulator, the generalized manipulator’s kinematic model is established, the analytical inverse kinematic solutions of the generalized manipulator are acquired, and a novel active vision based camera calibration method is proposed to determine the hand-eye relationship. Finally, a visual servo switching control law is designed to control the service robot to finish object grasping operation. Experimental results show that QR Code-based artificial object mark can overcome the difficulties brought by household objects’ variety and operation complexity, and the proposed visual servo scheme makes it possible for service robot to grasp and deliver objects efficiently. Huangsheng Xie, Guodong Li, Yuexin Wang, Zhihe Fu, and Fengyu Zhou Copyright © 2014 Huangsheng Xie et al. All rights reserved. A Parametric Learning and Identification Based Robust Iterative Learning Control for Time Varying Delay Systems Tue, 23 Sep 2014 09:06:56 +0000 http://www.hindawi.com/journals/jcse/2014/471921/ A parametric learning based robust iterative learning control (ILC) scheme is applied to the time varying delay multiple-input and multiple-output (MIMO) linear systems. The convergence conditions are derived by using the and linear matrix inequality (LMI) approaches, and the convergence speed is analyzed as well. A practical identification strategy is applied to optimize the learning laws and to improve the robustness and performance of the control system. Numerical simulations are illustrated to validate the above concepts. Lun Zhai, Guohui Tian, and Yan Li Copyright © 2014 Lun Zhai et al. All rights reserved. Design of Second-Order Sliding Mode Guidance Law Based on the Nonhomogeneous Disturbance Observer Mon, 22 Sep 2014 09:24:48 +0000 http://www.hindawi.com/journals/jcse/2014/890824/ Considering the guidance problem of relative motion of missile target without the dynamic characteristics of missile autopilot in the interception planar, non-homogeneous disturbance observer is applied for finite-time estimation with respect to the target maneuvering affecting the guidance performance. Two guidance laws with finite-time convergence are designed by using a fast power rate reaching law and the prescribed sliding variable dynamics. The nonsingular terminal sliding mode surface is selected to improve dynamic characteristics of missile autopilot. Furthermore, the finite-time guidance law with dynamic delay characteristics is designed for the target maneuvering through adopting variable structure dynamic compensation. The simulation results demonstrate that, for different target maneuvering, the proposed guidance laws can restrain the sliding mode chattering problem effectively and make the missile hit the maneuvering target quickly and accurately with condition of corresponding assumptions. Huibo Zhou, Shenmin Song, Junhong Song, and Jing Niu Copyright © 2014 Huibo Zhou et al. All rights reserved. Boundary Control for a Kind of Coupled PDE-ODE System Sun, 14 Sep 2014 00:00:00 +0000 http://www.hindawi.com/journals/jcse/2014/946736/ A coupled system of an ordinary differential equation (ODE) and a heat partial differential equation (PDE) with spatially varying coefficients is discussed. By using the PDE backstepping method, the state-feedback stabilizing controller is explicitly constructed with the assumptions and , respectively. The closed-loop system is proved to be exponentially stable by this controller. A simulation example is presented to illustrate the effectiveness of the proposed method. Yuanting Wang, Fucheng Liao, Yonglong Liao, and Zhengwei Shen Copyright © 2014 Yuanting Wang et al. All rights reserved. Multiobjective Optimization of PID Controller of PMSM Sun, 31 Aug 2014 06:22:56 +0000 http://www.hindawi.com/journals/jcse/2014/471609/ PID controller is used in most of the current-speed closed-loop control of permanent magnet synchronous motors (PMSM) servo system. However, , , and of PID are difficult to tune due to the multiple objectives. In order to obtain the optimal PID parameters, we adopt a NSGA-II to optimize the PID parameters in this paper. According to the practical requirement, several objective functions are defined. NSGA-II can search the optimal parameters according to the objective functions with better robustness. This approach provides a more theoretical basis for the optimization of PID parameters than the aggregation function method. The simulation results indicate that the system is valid, and the NSGA-II can obtain the Pareto front of PID parameters. Qingyang Xu, Chengjin Zhang, Li Zhang, and Chaoyang Wang Copyright © 2014 Qingyang Xu et al. All rights reserved. ESO-Based Fuzzy Sliding-Mode Control for a 3-DOF Serial-Parallel Hybrid Humanoid Arm Sun, 03 Aug 2014 12:48:09 +0000 http://www.hindawi.com/journals/jcse/2014/304590/ This paper presents a unique ESO-based fuzzy sliding-mode controller (FSMC-ESO) for a 3-DOF serial-parallel hybrid humanoid arm (HHA) for the trajectory tracking control problem. The dynamic model of the HHA is obtained by Lagrange method and is nonlinear in dynamics with inertia uncertainty and external disturbance. The FSMC-ESO is based on the combination of the sliding-mode control (SMC), extended state observer (ESO) theory, and fuzzy control (FC). The SMC is insensitive to both internal parameter uncertainties and external disturbances. The motivation for using ESO is to estimate the disturbance in real-time. The fuzzy parameter self-tuning strategy is proposed to adjust the switching gain on line according to the running state of the system. The stability of the system is guaranteed in the sense of the Lyapunov stability theorem. The effectiveness and robustness of the designed FSMC-ESO are illustrated by simulations. Yueling Wang, Runjie Shi, and Hongbin Wang Copyright © 2014 Yueling Wang et al. All rights reserved. An Approach to Evaluating Computer Network Security with Intuitionistic Trapezoidal Fuzzy Information Thu, 17 Jul 2014 12:15:30 +0000 http://www.hindawi.com/journals/jcse/2014/604920/ We investigate the multiple attribute decision-making problems for evaluating the computer network security with intuitionistic trapezoidal fuzzy information. We utilize the intuitionistic trapezoidal fuzzy weighted average (ITFWA) operator to aggregate the intuitionistic trapezoidal fuzzy information corresponding to each alternative and get the overall value of the alternatives and then rank the alternatives and select the most desirable one(s) according to the distance between the overall value of the alternatives and ideal solution. Finally, an illustrative example for evaluating the computer network security is given. Ming Xue Copyright © 2014 Ming Xue. All rights reserved. Cost Control Method and Software in Bidding Process Based on Gray System Forecast Thu, 17 Jul 2014 10:49:28 +0000 http://www.hindawi.com/journals/jcse/2014/296241/ With the fast development of social economy, the competition between enterprises in construction projects becomes more and more serious. The cost control method is proposed to the bidding process of enterprises based on the gray system forecast. At the same time, the cost control software is also constructed to the bidding process of enterprises. Experimental results suggest that the proposed approach is feasible and correct. Xi-Liu Zhou Copyright © 2014 Xi-Liu Zhou. All rights reserved. Research on the Evaluation Model of Urban Tourism Management Efficiency with Uncertain Linguistic Information Thu, 17 Jul 2014 08:09:19 +0000 http://www.hindawi.com/journals/jcse/2014/582454/ We investigate the multiple attribute decision making problems for evaluating the urban tourism management efficiency with uncertain linguistic information. We utilize the uncertain linguistic weighted averaging (ULWA) operator to aggregate the uncertain linguistic information corresponding to each alternative and get the overall value of the alternatives and, then rank the alternatives and select the most desirable one(s). Finally, a numerical example for evaluating the urban tourism management efficiency with uncertain linguistic information is used to illustrate the proposed model. Song-Mao Wang, Liang-Yan Fang, and Feng Deng Copyright © 2014 Song-Mao Wang et al. All rights reserved. An Approach to Evaluating Enterprise Financial Performance Based on the Control Inheritance of Family Businesses with Intuitionistic Fuzzy Information Thu, 17 Jul 2014 08:04:19 +0000 http://www.hindawi.com/journals/jcse/2014/704687/ We investigate the multiple attribute decision making problems for evaluating the enterprise financial performance based on the control inheritance of family businesses with intuitionistic fuzzy information. We utilize the intuitionistic fuzzy Bonferroni mean (IFBM) operator to aggregate the intuitionistic fuzzy information corresponding to each alternative and get the overall value of enterprise financial performance and then rank the enterprises and select the most desirable one(s) by using the overall value of enterprise financial performance. Finally, an illustrative example for evaluating the enterprise financial performance based on the control inheritance of family businesses is given to verify the developed approach and to demonstrate its practicality and effectiveness. Hui Liu Copyright © 2014 Hui Liu. All rights reserved. An Approach to Evaluate the Clothing Creative Design with Dual Hesitant Fuzzy Information Sun, 13 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/jcse/2014/352619/ The problem of evaluating the clothing creative design with dual hesitant fuzzy information is the multiple attribute decision making problem. In this paper, we have utilized dual hesitant fuzzy hybrid average (DHFHA) operator to develop the model to solve the multiple attribute decision making problems for evaluating the clothing creative design. Finally, a practical example for evaluating the clothing creative design is given to verify the developed approach. Ya-Mei Li Copyright © 2014 Ya-Mei Li. All rights reserved. Inflight Parameter Identification and Icing Location Detection of the Aircraft: The Time-Varying Case Thu, 10 Jul 2014 07:02:42 +0000 http://www.hindawi.com/journals/jcse/2014/396532/ This paper considers inflight parameter identification and icing location detection of the aircraft in a more common time-varying nature. In particular, ice accumulation is modeled as a continuous process, and the effect of the ice upon aircraft dynamics is to be accreted with time. Time-varying case of the Hinf algorithm is implemented to provide inflight estimate of aircraft dynamic parameters, and the estimated results are delivered to a probabilistic neural network to decide icing location of the aircraft; an excitation measure of the aircraft is also adopted in the network input layer. A database corresponding to different icing cases and severities was generated for the training and test of the detection network. Based on the test results, the icing detection framework presented in this paper is believed to be with promising applicableness for our further studies. Yiqun Dong and Jianliang Ai Copyright © 2014 Yiqun Dong and Jianliang Ai. All rights reserved. Synthesis of Decentralized Variable Gain Robust Controllers for Large-Scale Interconnected Systems with Structured Uncertainties Wed, 09 Jul 2014 10:39:52 +0000 http://www.hindawi.com/journals/jcse/2014/848465/ In this paper, we propose a decentralized variable gain robust controller which achieves not only robust stability but also satisfactory transient behavior for a class of uncertain large-scale interconnected systems. For the uncertain large-scale interconnected system, the uncertainties and the interactions satisfy the matching condition. The proposed decentralized robust controller consists of a fixed feedback gain controller and a variable gain one determined by a parameter adjustment law. In this paper, we show that sufficient conditions for the existence of the proposed decentralized variable gain robust controller are given in terms of LMIs. Finally, a simple numerical example is included. Shunya Nagai and Hidetoshi Oya Copyright © 2014 Shunya Nagai and Hidetoshi Oya. All rights reserved. FxLMS Method for Suppressing In-Wheel Switched Reluctance Motor Vertical Force Based on Vehicle Active Suspension System Wed, 04 Jun 2014 12:06:54 +0000 http://www.hindawi.com/journals/jcse/2014/486140/ The vibration of SRM obtains less attention for in-wheel motor applications according to the present research works. In this paper, the vertical component of SRM unbalanced radial force, which is named as SRM vertical force, is taken into account in suspension performance for in-wheel motor driven electric vehicles (IWM-EV). The analysis results suggest that SRM vertical force has a great effect on suspension performance. The direct cause for this phenomenon is that SRM vertical force is directly exerted on the wheel, which will result in great variation in tyre dynamic load and the tyre will easily jump off the ground. Furthermore, the frequency of SRM vertical force is broad which covers the suspension resonance frequencies. So it is easy to arouse suspension resonance and greatly damage suspension performance. Aiming at the new problem, FxLMS (filtered-X least mean square) controller is proposed to improve suspension performance. The FxLMS controller is based on active suspension system which can generate the controllable force to suppress the vibration caused by SRM vertical force. The conclusion shows that it is effective to take advantage of active suspensions to reduce the effect of SRM vertical force on suspension performance. Yan-yang Wang, Yi-nong Li, Wei Sun, Chao Yang, and Guang-hui Xu Copyright © 2014 Yan-yang Wang et al. All rights reserved. Advances in Methods for Networked and Cyber-Physical System Thu, 29 May 2014 08:31:49 +0000 http://www.hindawi.com/journals/jcse/2014/496075/ Jason Gu, Xiaomei Qi, Ying Wang, Fei Liu, and Chengjin Zhang Copyright © 2014 Jason Gu et al. All rights reserved. Distributed Event-Triggered Control of Multiagent Systems with General Linear Dynamics Mon, 26 May 2014 00:00:00 +0000 http://www.hindawi.com/journals/jcse/2014/698546/ This paper discusses the event-triggered consensus problem of multiagent systems. To investigate distributed event-triggering strategies applied to general linear dynamics, we employ a dynamic controller to convert the general linear dynamic to the single-integrator model by a change of variable. The consensus value of these new states is a constant so that the distributed event-triggering scheme is obtained under periodic event detections, in which agents with general linear dynamics require knowledge only of the relative states with their neighbors. Further, an event-triggered observer is proposed to address the case that only relative output information is available. Hence, the consensus of both the state-based and observer-based cases is achieved by the distributed event-triggered dynamic controller. Finally, numerical simulations are provided to demonstrate the effectiveness of theoretical results. Xieyan Zhang and Jing Zhang Copyright © 2014 Xieyan Zhang and Jing Zhang. All rights reserved. JAUS to EtherCAT Bridge: Toward Real-Time and Deterministic Joint Architecture for Unmanned Systems Sun, 27 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/jcse/2014/631487/ The Joint Architecture for Unmanned Systems (JAUS) is a communication standard that allows for interoperability between Unmanned Vehicles (UVs). Current research indicates that JAUS-compliant systems do not meet real-time performance guidelines necessary for internal systems in UVs. However, there is a lack of quantitative data illustrating the performance shortcomings of JAUS or clear explanations on what causes these performance issues or comparisons with existing internal communication systems. In this research, we first develop a basic C++ implementation of JAUS and evaluate its performance with quantitative data and compare the results with published performance data of Controller Area Network (CAN) to determine the feasibility of the JAUS standard. Our results indicate that the main reason of JAUS’s poor performance lies in the latency inherent in the hierarchical structure of JAUS and the overhead of User Datagram Protocol (UDP) messages, which has been used with JAUS and is slower than the high-speed CAN. Additionally, UDP has no scheduling mechanism, which makes it virtually impossible to guarantee messages meeting their deadlines. Considering the slow and nondeterministic JAUS communication from subsystems to components, which is JAUS Level 3 compliance, we then propose a solution by bringing Ethernet for Control Automation Technology (EtherCAT) to add speed, deterministic feature, and security. The JAUS-EtherCAT mapping, which we called a JEBridge, is implemented into nodes and components. Both quantitative and qualitative results are provided to show that JEBridge and JAUS Level 3 compliance can bring not only interoperability but also reasonable performance to UVs. Jie Sheng, Sam Chung, Leo Hansel, Don McLane, Joel Morrah, Seung-Ho Baeg, and Sangdeok Park Copyright © 2014 Jie Sheng et al. All rights reserved. State Estimation and Model-Based Control of a Pilot Anaerobic Digestion Reactor Tue, 22 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/jcse/2014/572621/ A state estimator and various model-based control systems have been designed for a real anaerobic digestion (AD) pilot reactor fed with dairy manure. The model used is a modified Hill model which is a relatively simple dynamical AD process model. The state estimator is an Unscented Kalman Filter (UKF) which uses only methane gas flow measurement to update its states. The model and the state estimates are used in different control systems. One of the control systems aims at controlling the methane gas flow to a setpoint. Simulations indicate that the setpoint tracking performance of a predictive control system is considerably better comparing with PI control, while disturbance compensation is not much better. Consequently, assuming the setpoint is constant, the PI controller competes well with the predictive controller. A successful application of predictive control of the real reactor is presented. Also, three different control systems aiming at retaining the reactor at an operating point where the volatile fatty acids (VFA) concentration has a maximum, safe value are designed. A simulation study indicates that the best control solution among the three alternatives is PI control based on feedback from estimated VFA. Finn Haugen, Rune Bakke, and Bernt Lie Copyright © 2014 Finn Haugen et al. All rights reserved. Application of Combinatorial Interaction Design for DC Servomotor PID Controller Tuning Wed, 16 Apr 2014 08:59:20 +0000 http://www.hindawi.com/journals/jcse/2014/576868/ Combinatorial optimization has been used in different research areas. It has been employed successfully in software testing fields to construct minimum set of combinations (i.e., in terms of size) which in turn represents the minimum number of test cases. It was also found to be a successful approach that can be applied to solve other similar problems in different fields of research. In line with this approach, this paper presents a new application of the combinational optimization in the design of PID controller for DC servomotor. The design of PID controller involves the determination of three parameters. To find optimal initial PID parameters, different tuning methods have been proposed and designed in the literature. The combinatorial design is concerned with the arrangement of finite set of elements into combinatorial set that satisfies some given constraints. Consequently, the proposed method takes the interaction of the input parameters as a constraint for constructing this combinatorial set. The generated sets are then used in the proposed tuning method. The method proved its effectiveness within a set of experiments in a simulated environment. Mouayad A. Sahib, Bestoun S. Ahmed, and Moayad Y. Potrus Copyright © 2014 Mouayad A. Sahib et al. All rights reserved.