1993 Volume 5 Issue 6 Pages 1424-1438
In this paper, we propose a practical complete decentralized control scheme that does not exchange information among its subsystems, using a hybrid controller which is composed of a feedback controller and a fuzzy controller for a interconnected system in which there are uncertainties caused by interactions among the subsystems. A feedback controller, which is based on conventional control theory, is designed to feedback the state of the subsytem using the mathmatical model applied for the local subsystem. On the other hand, the fuzzy controller, which is activated by a control error caused by uncertainties, generates the auxilary control input as its output to compensate the control error using fuzzy inference and the linguistic contol rule which is based on human control behavior. The fuzzy controller, which is proposed in this paper, determines its own control input which is cooperating with the feedback controller by including the output of the feedback controller as its fuzzy input variables. The linguistic control rules designed in this paper are very similar to human reasoning and thinking, therefore, it is easy to understand the application of these rules. And it makes possible to share a common rule set to execute inference in every subsystem because of its generality, and every subsystem only needs a small memory load. Furthermore, by using meta-rules as well as general rules, each subsystem has adaptability for input information and can determine the output adequately to match the changing situation. The hybrid controller proposed in this papar has been designed to support experimental trials to link the conventional control theory with the fuzzy control. And, this decentralized control scheme doesn't need any information to be exchanged, nor doesn't require redesign or adjustment when the new subsytems are joined. It is shown that the proposed hybrid controller gives a desirable control performance by the numerical simulations provided.
