Prescribed-Precision Position Tracking for PMSM Servo Systems via Adaptive Event-Triggered Control Under Switching References and Disturbances

Abstract

The prescribed-precision position-tracking problem for permanent magnet synchronous motor servo systems subject to switchable reference signals and unknown disturbances is addressed in this article. A novel prescribed-performance control scheme is proposed to overcome the critical limitations of conventional approaches, which are unable to maintain stability and performance constraints during reference switching. The cornerstone is a transition-compatible prescribed performance function that ensures guaranteed transient and steady-state performance even after switching reference signals. To enhance robustness, a disturbance rejection strategy integrating a nonlinear disturbance estimator with an estimation error compensation mechanism is proposed, requiring no prior knowledge of disturbances. Furthermore, an adaptive dynamic memory-based event-triggered mechanism is designed to dynamically balance control accuracy with communication resource savings. Rigorous stability analysis proves the uniform ultimate boundedness of the closed-loop system. Extensive experimental results demonstrate that the proposed scheme strictly adheres to prescribed performance constraints under reference switching, reduces triggering events by over 50% compared to advanced alternatives, and achieves superior tracking accuracy under both constant and time-varying loads, effectively resolving the tradeoff between control precision and communication efficiency.