Trajectory planning of upper limb exoskeleton rehabilitation Robot based on polynomial interpolation

Abstract

This paper proposed a new 6-DOF upper limb exoskeleton rehabilitation robot(ULERR). Based on the designed upper limb exoskeleton robot, its kinematics is solved. A multi-valued difference function is proposed to realize the smooth and continuous motion trajectory of the upper limb exoskeleton robot during the rehabilitation training process, and the velocity and acceleration changes in the joint motion trajectory are smooth and continuous, and there is no sudden change in the change process. In the point-to-point (PTP) motion of passing path points, the “4-3-4” polynomial interpolation algorithm combined with quartic and cubic polynomials is adopted. According to experiments, it proved that the “4-3-4” polynomial interpolation can make the speed change of each joint smooth and continuous and obtain a stable trajectory, it also reduces the maximum acceleration of the joint after cubic polynomial interpolation, makes the acceleration change more stable and reduces the impact of the mechanism. The experiments proved the feasibility and stability of this method.