Research on a modified smith control based on fuzzy algorithm

For the first-order integral process with large time delay, by introducing an inertial term which is regarded as a low-pass filter in system´s main feedback loop, a modified smith predictor (MSP) was presented. Further, the MSP controller and fuzzy PID controller are combined to make an intelligent control system to deal with systems with uncertainty and long time delay. By turning the PID parameters and smith predictor´s filter time constant online, the intelligent system has advantages of strong disturbance rejection capability, high steady precision and low dependence on the controlled plant´s precise mathematical model compared with conventional smith predictor and fuzzy PID controller, simulation results demonstrate the effectiveness of the proposed method.