Linear parameter-varying control of hysteresis for active microgravity isolation

This work considers the use of linear parameter-varying methods to control a vibration isolation system with stiffness hysteresis. From a linear parameter-varying design perspective hysteresis is modeled as a stiffness parameter that takes values in a compact convex set with vertices determined from displacement constraints that exist in the system. The resulting controller consists of two vertex controllers along with interpolation based on the current measured stiffness. The proposed method is demonstrated on a simplified model of the active rack isolation system (ARIS), which is the primary vibration suppression system for providing a microgravity environment aboard the International Space Station (ISS). Simulations show that the parameter-varying design is stable and that robust isolation performance is achieved over the range of displacements considered.