Trajectory planning of lower limb rehabilitation action for cable-driven rehabilitation robots

In view of the problem that the current research rarely pays attention to the planning of actual rehabilitation actions, a trajectory planning strategy of the lower limb rehabilitation actions for cable-driven rehabilitation robots (CDRRs) is presented in this paper. First, the inverse kinematics model and forward kinematics model of the patient’s lower limb meeting the needs of rehabilitation training were established. Then, a direct solution method based on space geometry was proposed according to the state and constraints of the patient. The mapping from the patient’s lower limb end point trajectory to the patient’s lower leg trajectory was realized by the above two ways. Finally, considering of the movement of the winders, the inverse kinematics model of the reconfigurable CDRR was derived. Through a reasonable cable distribution, patient’s lower leg was regarded as the mobile platform of the CDRR, and the mapping between the ankle joint trajectory of the patient’s lower limb and the cable length change of the CDRR was finally realized. Taking flexion knee joint rehabilitation action as an example, it is shown that this trajectory planning strategy can plan the trajectory of the required rehabilitation action in a three-dimensional space in the simulation and experimental results.