Adaptive control of 6-DOF parallel manipulator

This paper presents an adaptive controller equipped with disturbance rejection capability for a 6 degrees of freedom (6-DOF) parallel manipulator. The control scheme is proposed given that the 6-DOF parallel manipulator system´s parameters are all subject to uncertainties, and only the positions and the velocities of links are measurable. In this paper, the dynamics of the 6-DOF parallel manipulator is denoted in the Lagrange method, and, as well as an appropriate storage function, some important properties of the dynamics are derived to develop an adaptive controller which, by the penalty signal chosen, can drive the motion tracking error to zero asymptotically. Lyapunov theory is used to guarantee the stability of the system. Simulation results show that the 6-DOF adaptive control system has a good tracking performance in both normal and extreme limited working conditions.