Variable parameter robust gradient estimation algorithm with dead zone for the trajectory tracking of the joints of the manipulator

A variable parameter robust gradient estimation algorithm with dead zone is presented in this paper. The concept of the error level is proposed. Selection criteria of the error level are given according to the min-max principle. Good performance of the improved algorithm is verified by the experiments carried out on the robot. With it, a self-tuning PID controller is used for the trajectory tracking of the joints of the manipulator. Good tracking performance shows the effectiveness of the improved robust gradient estimation algorithm.