Adaptive controller-observer design for 6-DOF parallel manipulators

In this paper, a design scheme of an adaptive controller-observer is proposed for trajectory tracking control of robot manipulators with parameter uncertainties and with position measurements only. The controller and observer are designed in an integrated framework. A new observer and parameter adaptation law are applied to guarantee the tracking errors and observer errors converge simultaneously. In this scheme, the estimated inertia matrix is not necessarily assumed to be invertible and no velocity approximation is used, so the sampling period is not strictly restricted and the controller output signal is smooth. The locally asymptotic stability of the closed-loop system is proven based on Lyapunov approaches. Simulation results with a 6-DOF parallel manipulator demonstrate that although the system parameters are unknown, the proposed adaptive controller-observer can also achieve high performance without direct measurement of velocities.