Design and Kinematics Analysis of 3-URS Ankle Rehabilitation Parallel Robot

The ankle rehabilitation robot is essential equipment for patients with clubfoot and talipes valgus to make up for deficiencies of the manual rehabilitation training and reduce the workload of rehabilitation physicians. Based on the physiological model of the ankle joint and the requirement of rehabilitation in physical therapy, an ankle rehabilitation parallel mechanism has three limbs with a universal joint, rotation joint, and spherical joint configures (3-URS ARPM), which had 6-DOF was analyzed and developed. The inverse kinematics problem of 3-URS ARPM was then solved using GRG optimization methods combined with the Banana objective function. As a result, six control solutions of the inverse kinematics of 3-URS ARPM are obtained. Furthermore, the forward kinematics problem is also analyzed through optimization approaches suitable for motor position control. Finally, the kinematic control characteristic of joints variable for 3-URS ARPM is presented in detail, comparing its motion range to the ADAMS software. The numerical simulation results showed an excellent smooth trajectory tracking in real-time control, indicating that this mechanism for ankle rehabilitation with a simple structure has precise control characteristics with the accuracy achieved is . Hence, the developed 3-URS ARPM can be applied to ankle rehabilitation widely.