State and output feedback control in model-based networked control systems (original) (raw)
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The International Conference on Information Networking 2013 (ICOIN), 2013
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Observer-based output tracking control for a class of linear networked control systems
Proceedings of the 2011 American Control Conference, 2011
This paper is concerned with the problem of model reference tracking control for a class of linear networked control systems (NCSs) in which a controlled plant is connected to an observer-based controller via a communication network. In the presence of network-induced delays and packet dropouts in the sensor-to-controller and controller-to-actuator connections, the inputs of the plant and the controller are updated in an asynchronous way. In this case, the resulting NCS is equivalent to a linear system with two interval time-varying delays. A sufficient stability condition that ensures the NCS with an H ∞ tracking performance is derived by using a Lyapunov-Krasovskii functional approach. Due to the asynchronous input errors, a separation principle cannot be used to design the observer-based controller. A novel design algorithm of tracking control is presented by using the stability condition and a particle swarm optimization (PSO) technique. The effectiveness of the algorithm is illustrated by a numerical example.
Design of Networked Control Systems With Explicit Compensation for Time-Delay Variations
IEEE Transactions on Systems, Man, and Cybernetics, Part C (Applications and Reviews), 2010
In this paper, the effects of network delay among interconnecting elements of a distributed computer network control system are analyzed. Experimental tests have been accomplished to show the influence of the combined effects of the network delay (between sensor/controller and controller/actuator) on the overall performance of a feedback control system. For this purpose, a proportional-plus-integral (PI) controller has been used. This controller has been designed, using the well-known direct synthesis method and implemented in a didactic networked control system platform. Corresponding (z-transform) difference equations have been used, assuming time-triggered (regular) samplings. The augmented PI controller (with compensation of the control signal and estimation of missing measurements) is developed. Stability analysis is performed to verify the validity of this scheme. The results presented in the paper show that the dynamic behavior of the closed-loop system can be improved using the proposed technique. Index Terms-Digital controllers, effects of time delay, networked control systems (NCSs), time-delay compensation. I. INTRODUCTION W HILE conventional control systems make use of analog or digital technology to send control signals over the loop, in modern computer control systems, the control loop is almost entirely closed over a communication network. In this networked system, the sensor, the actuator, and the controller are elements that share information by exchanging messages over the network. The great availability and ever-decreasing costs of the networked digital technology have been responsible for the replacement of the traditional point-to-point link for broadcast transmission. This change represents an important breakthrough toward effective control decentralization, resulting in significant cost reduction with wiring and maintenance [1], [2]. Such a control architecture is now been denominated networked control systems (NCSs) [3], [4]. NCSs present better characteristics in terms of modularity and scalability, offering more design options. Nevertheless, the presence of a network in the control loop has the drawback of introducing time delays in the communications among field