Towards Oscillation Suppression of a Manipulator with Physical Constraints: a Trajectory Planning Approach

Oscillation problem is one of the most critical factors that intensify the mechanical wear and reduce the accuracy of a manipulator significantly. Oscillation suppression of a manipulator and achieving the high accuracy and high productivity simultaneously in path tracking is a challenging issue due to the existence of physical constraints. In view of this, a trajectory planning based modular framework, which generates an optimized trajectory for a manipulator, is developed to reduce the oscillation of a manipulator on the occasion of fast position control. The original joint space waypoints obtained via inverse kinematics are first interpolated to obtain a path-velocity decomposition form expression. Subsequently, the assigned joint physical constraints are converted to the corresponding bounds in the parametric space via a bounds estimator in real time. Then a nonlinear filter is adopted to optimize the parameter trajectory. Finally, the planned parameter trajectory is substituted into the geometric path function to obtain the planned trajectory for each joint. Practical experimental results are provided to validate the superior motion tracking performance of the proposed approach.