Variable structure observer design for flexible joint manipulators

Abstract

Structural flexibility adversely affects the dynamic and even static performance of controllers designed for rigid robots. We present a variable structure observer that requires only measurement of link positions to estimate the full state of a flexible joint manipulator. We propose a methodology to design the observer by solving simultaneously a Lyapunov equation and a matching condition. Limitations of the observer are outlined and simulation results demonstrate the robustness of the observer.