A General Kinematics Model for Trajectory Planning of Upper Limb Exoskeleton Robots

Abstract

Trajectory planning is a paramount requirement for upper limb rehabilitation robots because that can help stroke patients to receive rehabilitation training, especially in the implementation of activities of daily life. The patient-customized trajectory planning of the robot system is much more fit with human movement. This paper proposes an equivalent kinematics model of the upper limb, which covers all degrees of freedom of the upper limb. The trajectory planning based on this kinematics model is appropriate for upper limb exoskeleton rehabilitation or assistive robots. In addition, the proposed model has been experimentally validated on the prototype of an upper limb exoskeleton robot. The model of the exoskeleton is obtained by simplifying extra degrees of freedom of the kinematics model. And taking movement trajectory of the exoskeleton by cubic polynomial coincides with that by quintic polynomials, which proves that the approach can optimize the approach of trajectory planning. Furthermore, a significant reduction of trajectory generated operation can be achieved, with a consequent remarkable computational time-saving. Finally, results from taking things experiments with the exoskeleton are presented, which verify the usability of trajectory planning.