Applied simulation to evaluate the quality of control of networked control systems

摘要

A current tendency in the research of fieldbus based control systems such as CAN (Controller Network Area) is the use of networked control systems (NCS). This new approach differs from the traditional fieldbus systems in that the controller and the plant are physically separated and connected through an industrial network. The main challenges related to the development of NCS are the degenerative effects caused by the inclusion of the communication network in the closed loop control system. In order to minimize these effects, simulation tools for NCS have been developed to assist the designer in the study of the network influence in the NCS quality of control. This paper presents the application of two simulation tools in evaluating the quality of control of the NCS that compose a CAN-based research platform. The tools are used to evaluate the main configuration parameter that affects the performance of the NCS platform and to verify how sensitive the control loops are under various timing conditions including different messages sampling times and network delays. Therefore, the results of the simulations lead to the conclusion that despite the messages sampling time is the most significant factor in the design of NCS, its influence was related to the kind of system with bigger effects in NCS with fast dynamics.