Robust discrete nonlinear feedback control for robotic manipulators

Nonlinear feedback control algorithms for manipulators utilize a complete (coupled and nonlinear) dynamic robot model to decouple the robot joints. In the companion article¹ we outlined the practical problems introduced by modeling inaccuracies, unmodeled dynamics and parameter errors. We then introduced the α‐computed‐torque nonlinear feedback control algorithm which is robust in the presence of the aforementioned error sources. In this article, we apply the insight gained from the α‐computed‐torque algorithm to design a robust discrete‐time (accelerometer‐free) computed‐torque robot‐control algorithm founded upon our discrete dynamic robot model.² Numerical experiments with the cylindrical robot confirm both the robust disturbance rejection characteristics and the practical applicability of our discrete‐time computer‐torque control algorithm.