Research on Precision Speed Control of TWUSM Using Discrete-Contact-Model-Based MIW-NMPC

Aiming at the problems of low control efficiency and great regulation difficulty of traveling wave ultrasonic motors (TWUSMs) caused by nonlinearity, strong coupling characteristics, and parameter uncertainty, this paper proposes a speed regulation scheme based on discrete contact modeling and monotonically increasing weighted nonlinear model predictive control (MIW-NMPC). On the basis of analyzing the existing TWUSM models, a discrete contact model of the motor is constructed, which reduces the modeling complexity while completely retaining the core dynamic characteristics of the motor's operating mechanism. Based on this model, the MIW-NMPC algorithm for the precision speed control of TWUSM is designed, and its feasibility and stability are deduced and verified. Comparative simulations and experimental results demonstrate that the proposed discrete-model-based MIW-NMPC scheme can effectively enhance the precision and dynamic response of TWUSM speed control, offering a novel technical approach for its high-precision speed regulation applications.