Design and Experimental Study of Parallel Hip Joint

Currently, humanoid robots are widely used in human-machine interaction and service fields. However, most humanoid robots use serial hip joint mechanisms, which face insufficient drive under high loads, leading to interference during movement and unnatural gait. This paper proposes a novel parallel hip joint mechanism. By combining drive units in the sagittal and coronal planes in parallel, higher torque output can be achieved in two degrees of freedom without changing the drive unit model. First, the parallel hip joint structure is designed, kinematics and dynamics models are established, and a simulation model is built for verification. Second, key parameters are optimized using the NSGA-II algorithm, and overall structural design is completed through strength verification. Finally, experimental validation of the proposed parallel hip joint mechanism shows significantly better torque output performance compared to traditional serial hip joints. This parallel hip joint mechanism has broad application prospects in humanoid robots and other service robots.