| Summary: | 碩士 === 國立臺北科技大學 === 自動化科技研究所 === 93 === High nonlinearity and time variation are very common in hydraulic servo systems. The system parameters are varying from time to time and due to different operation conditions. Demands for wide range of operation conditions, such as different positioning range, make a linearization model, linearized around a single operation point, inaccurate to describe the system dynamic behavior. Therefore, a traditional PID controller, which used to work well in a linear system, will not be able to work satisfactorily for the highly nonlinear system with time varying system parameters. In order to counter the problem, we proposed a nonlinear controller of an architecture of fuzzy PID, to dynamically tune the PID gains so that an optimal performance outcome can be obtained. In the past, there are plenty of advanced control strategies have been proposed in literatures to solve the hydraulic servo system, such as fuzzy controller, self-tuning adaptive controller, self-tuning PID controller and robust controller etc. However, most of them were using the PC-based framework. At the time being, PLC is the most popular controller used for manufacturing machines. In this paper, a framework of using PLC as the controller unit, combining the fuzzy PID control strategy, will provide a very high potential solution in practice for the industry of hydraulic servo system applications. This technology will also help domestic companies to build up their own core technology in servo control aspects.
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