负压伺服控制系统的自调整模糊PID控制

Self-tuning fuzzy-PID controller design for vacuum servo control system

针对负压伺服控制系统随压力工作点变化的强非线性和低工作压力时的非对称性,设计了自调整模糊PID控制器.该控制器由PID类型模糊控制器(FPIDC)和模糊自调整机构复合构成,自调整机构以压力工作点和FPIDC的前级输出值为参变量,实现了FPIDC输出比例因子的在线自适应调整.实验研究表明:该控制器对压力工作点变化适应性较好,且在工作压力较低时保持良好的动态性能,解决了常规PID控制器难以适应不同压力工作点以及由低压时充气、抽气非对称性引起的动态跟踪性能较差的问题,实现了负压伺服控制系统的高精度和快速响应.

The performance of vacuum servo control system is highly nonlinear with the change of working point, and when the working point is approaching the low pressure, the system has bad dy- namic response due to its asymmetry. To enhance the performance of the system, a self-tuning fuzzy- PID （proportion integration differentiation） controller was designed. The controller was made up of a FPIDC （PID type fuzzy controller） and a fuzzy gain tuning mechanism, by which on-line SF （scaling factor） adjusting of the FPIDC was implemented. The pressure working point and the output of FPIDC related to the system features were chosen as the input parameters of the fuzzy gain tuning mechanism. Experiments results show that the proposed scheme has a remarkable improvement in adapting to the change of the working point and achieves better dynamic performance. It was solved that conventional PID controller canrt adjust to the change of the working point and stable perform- ance on different working points was ensured. The influence of asymmetry was also eliminated owing to the tuning on line of the controller, and high accuracy and fast response was reached.