One end of the torsion bar is connected with the frame, and the other end is connected with the wheel by a swing arm. When the wheel meets the ground obstacle and jumps up, the wheel will drive the swing arm to rotate a certain angle around the axis of the torsion bar, causing torsion deformation (elastic deformation) . At the same time, the elastic deformation energy stored by the torsion bar will be released when the wheel breaks away from the obstacles, making the force transmission mechanism and the wheel return to position quickly.