In this paper, we propose a PID control design method for decentralized control systems from the inverse linear quadratic problem viewpoint by using the structure of controllers obtained by the ILQ(Inverse Linear Quadratic) design method. First, we show an optimal decentralized PID design method for systems with relative degree no more than 2 and block diagonal decoupling matrix. Then, we derive a necessary and sufficient condition for the stability of the closed loop system using our proposed design method of decentralized PID control in the case where the decoupling matrix is not block diagonal. Moreover, we show that a desired transient response with decoupled input/output characteristics can be achieved by our decentralized PID controller. Finally, we illustrate the effectiveness of our proposed method by simulation.Key Words: decentralized control, PID control, optimal control, decoupling control 1.
When a continuous-time system with relative degree greater than or equal to three is discretized using a zero-order hold, at least one of the zeros of the resulting sampled-data model is unstable for small sampling periods. Thus, attention is here focused on continuous-time systems with relative degree less than or equal to two. This paper analyzes the zeros of the sampled-data models corresponding to the continuous-time systems mentioned above and gives approximate expressions of the zeros as power series expansions with respect to a sampling period. Further, the stability of the zeros is discussed for small sampling periods and a new stability condition is derived.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.