Application of orientation interpolation of robot using unit quaternion

Abstract

Orientation interpolation has a great effect on the performance of industrial robot. Considering the singularity and unnatural rotation which are drawbacks of Euler angles in orientation interpolation of industrial robot, a novel interpolation method which is based on unit quaternion was presented. To achieve high order smoothness of orientation movement, sine-jerk trajectory planning combined with unit quaternion was developed for the orientation interpolation, which could guarantee C3 continuity of the orientation trajectory and has the potentials to control velocity and acceleration of robot, while traditional Spherical Linear Interpolation (SLERP) with unit quaternion can only generates C1 continuous trajectory. To test the validity of the orientation algorithms, a simulation platform based on a 6-DOF (degree of freedom) arc welding industrial robot including inverse kinematic and inverse dynamic of robot was built up. The simulation results indicated that the proposed approach is effective in the application of orientation interpolation of industrial robot.