DISCRETE-TIME LEARNING CONTROL FOR ROBOTIC MANIPULATORS

A discrete-time learning control for robotic manipulators is studied u sing its pulse transfer function. Firstly, the discrete-time learning stability condition which is applicable to single-input two-outputs sy stems is derived. Secondly, the stability of the learning algorithm wi th a position signal is studied. In this case, when the sampling perio d is small, the algorithm is not stable because of an unstable zero of the system. Thirdly, the stability of the algorithm with position and velocity signals is studied. In this case, we can stabilize the learn ing control system which is unstable in the case of learning with only the position signal. Finally, simulation results on the trajectory co ntrol of robotic manipulators using the discrete-time learning control are shown. The simulation results agree well with the analytical resu lts.