Application of a Modified PSO Algorithm to Self-Tuning PID Controller for Ultrasonic Motor

Abstract

The ultrasonic motor (USM) has a heavy nonlinearity and time-varying characteristics which vary with driving conditions.Because of no-exact mathematical model of USM, it is difficult to control USM. PID controller can be designed without using the expression model of plant, but it is hard to compensate the nonlinearity and characteristic changes of USM. This paper presents a self-tuning scheme using a modified particle swarm optimization (MPSO) for PID controller to overcome the dynamic characteristics of USM. A modified PSO employs the strategy that nonlinearity decreases the value of inertia weight from a large value to a small value. This strategy is to improve the performance of the standard PSO in global search and fine-tuning of the solution. The effectiveness of the proposed method is verified by numerical simulation and experimental investigation.The results demonstrate that the proposed method can improve the accuracy of USM.