Robust Constant-Amplitude Input Shapers with Selectable Duration

摘要

Vibration is a problem for many mechanical systems. Although there are many sources of vibration, simply moving a flexible system will generally cause it to vibrate. One technique for limiting undesired motion-induced vibration is input shaping. This paper investigates the input-shaper design for slewing spacecraft flexible appendages actuated by stepper motors or other constant-amplitude actuators. The primary challenge encountered in designing input shapers for stepper motors is the inherent discretization in both command amplitude and time. Also, spacecraft often have the additional requirement of maintaining a desired pointing angle. This paper describes an input-shaping technique compatible with stepper motors that has robustness to the modeling error in the vibration frequency of the appendages. The effectiveness of the approach is evaluated using a dynamic model of a spacecraft with a flexible appendage using proportional-derivative attitude control.