Robot Joint Trajectory Tracking Control Algorithm with Human-like Smooth Reaching Motion Profile Based on Sole Velocity Feedback

This study proposes a novel model-free robot manipulator joint position and velocity tracking controller with a simple structure for controlling a robotic manipulator with human-like reaching motion according to human movement characteristics. The proposed design guarantees the responses of the tracking error within preset bounds using velocity feedback. A structurally and computationally natural logarithmic controller is designed to achieve joint position and velocity tracking of a desired trajectory of a reaching motion profile with prescribed performance (PP) bounds. Simulations of a three-degree-of-freedom spatial manipulator with the PP controller confirm the conclusions even in case of typical input disturbances. Results show that the PP controller outperforms the traditional position and derivative (PD) trajectory tracking controller without requiring excessive control effort. The proposed controller that uses sole velocity feedback achieves the control objective with bell-shaped joint velocity profiles and joint consistency. Thus, the proposed controller outperforms the traditional PD trajectory tracking controller that uses position and velocity feedback with comparable control effort. The experiment with a KURA robot manipulator demonstrates that the control algorithm of sole velocity feedback can be used to achieve smooth reaching movements within a short travelling time of less than 1 s. The movements are characterised by bell-shaped joint velocity profiles and joint position consistency similar to human movements.