Design, Simulation and Kinematic Validation of a Hip Prosthetic Mechanism with a Multimotor Function

We previously developed a powered hip prosthetic mechanism with kinematic functions of hip flexion–extension and abduction–adduction, and its theoretical and simulation-based kinematics were verified. Because internal–external hip rotation has a positive effect on the movements of human lower limbs according to medical research, we developed a novel hip prosthetic mechanism based on a previous hip prosthesis that possesses motion characteristics similar to those of a human bionic hip, and the motion characteristics of multiple Degrees-of-Freedom (DoFs) were analyzed after kinematic modeling. Then, a walking model of the human‒machine model was established, and the walking stability of an amputee, which reflects the rehabilitation effect, was explored while the hip prosthetic mechanism considered the internal–external rotation of the hip. Finally, a prototype and its verification platform were built, and kinematic validation of the hip prosthetic mechanism was carried out. The results showed that the designed Parallel Mechanism (PM) possesses human-like motion characteristics similar to those of a human bionic hip and can be used as a hip prosthesis. Moreover, the existing motion characteristic of internal–external hip rotation can enhance the walking stability of an amputee via this hip prosthetic mechanism.