| When a control system is implemented in a distributed fashion, with multiple processors communicating over a network, both the communication delays associated with the network and the computation delays associated with the processing time can degrade the system's performance. In this case, the performance of the system may depend not only on the performance of the individual components but also on their interaction and cooperation. Most of the existing works that improve the performance of distributed control systems are limited to software and hardware specific applications and/or are attempted largely by simulation or experimentation. This dissertation investigates systematic and analytic methodologies to model, analyze, and design DCS for improved performance.; To examine the effect of time delays on mechanical performance of distributed control systems, a performance degradation framework is proposed. This framework can be used to optimize the system architecture and to give the system designer a guideline to select hardware and software for the system. Furthermore, this framework allows redesigned systems to be easily verified with regard to their timing and performance, and to be incorporated with existing works to further improve their performance.; In many cases, communication limitations are a major obstacle when implementing MIMO systems in a distributed fashion. The state estimator methodology described in this dissertation increases the feasibility of distributed control systems by decreasing the communication requirements. In addition, the framework decreases both the network induced delays and the scheduling requirements. In this methodology, inaccuracies of communicated data are treated as control parameters instead of as software problems. Therefore, this framework enables others to integrate MIMO control algorithms to further improve communication or controller design.; Finally, modular control design issues are explored in the context of a non-orthogonal Reconfigurable Machine Tool, which is a part of realizing the reconfigurable manufacturing systems. A new type of modular cross-coupled controller is developed, which uses a non-symmetric feed-forward cross-coupled controller, to decrease both the conventional contour error and the “In depth” error effectively. |
