DISCRETE-TIME MODEL-REFERENCE ADAPTIVE CONTROLLER DESIGNS FOR ROBOTICMANIPULATORS

On-line computer control with high speed and accuracy is needed in ind ustrial robotics. Thus, discrete-time controller design for robotic ma nipulators is necessary. In this article, the two continuous-time mode l reference adaptive control schemes presented in Yang and Woo (1992) are put forth in discrete forms.The stability analysis stems from Lyap unov's Direct Method (Slotine and Li 1991), which guarantees the asymp totic stability of a system. Like any discrete-time control system, th e time required for the computer to perform the necessary computation may result in extended sampling time, which could degrade the stabilit y of the system. III this article, we obtain the sufficient condition of stability for the designed discrete-time controllers. A set of righ t sampling time and weighting factors are chosen to show the highly ac curate tracking. Through the MATLAB software (PC MATLAB MANUAL 1992) s imulation, we can see that the manipulator does follow the desired tra jectory with high accuracy, even when the payload is changing. It prov es the effectiveness of the designed controllers.