基于Smith的非最小相位对象PID控制器设计

针对具有非最小相位时滞的过程,基于Smith预估控制思想,提出一种改进控制方案,对右半平面零点和纯滞后同时进行补偿,使闭环特征方程中不含右半平面零点,从而简化控制器设计。根据期望闭环传函,解析得出PID控制器形式,综合负调、响应时间、ISE以及鲁棒性要求整定控制器参数,针对Smith控制抗扰性较差提出了抗扰性设计。仿真结果表明,该方案对于具有非最小相位时滞的对象有较好的控制效果,并且在模型失配和有干扰输入的情况下,有较好的鲁棒性和抗扰性。

Design of PID Controller for Non-minimum Phase Plants Based on Smith Predictor

A design scheme of PID controller for non-minimum phase plants plus dead time based on Smith predictor is proposed.Both right-half-plane and dead time can be compensated.The RHP and dead time are removed from the characteristic equation so that the control design is greatly simplified.By proposing the desired closed-loop transfer function,the PID controller form is analytically derived.Controller parameter is turned by analyzing the time domain specifications and robust stability.According to the worse interference rejection of Smith control,the interference rejection design is proposed.Simulation results show that the proposed control method can improve the control performance of non-minimum phase plus dead time system,and have better robustness and interferce rejection.