On the Segment Length Ratio of the Walking Leg of a Hydraulically Actuated Hexapod Robot

For a hydraulically actuated hexapod robot, a kinematic model of the walking leg with three segments is established. The trajectory of foot is planned, and the influence of leg length ratio on walking speed, joint angular velocity and acceleration, workspace of foot and body flexibility is analyzed. The indexes are reasonable when coxa proportion is between 0～ 0.1 and thigh proportion is between 0.4～ 0.5. The physical model of leg is established according to the segment length ratio 0.09:0.455:0.455, and the performance testing system of leg is developed. Experimental results show that there is no extreme position of hydraulic cylinder and dead point in the process of joint movement. The maximum speed and the maximum acceleration of joints can satisfy the performance requirements. Repetition deviation of the maximum speed of joints is less than 0.2°/s, and the repetition deviation of the maximum acceleration is less than 0.7°/s². The rationality and feasibility of the analysis results of segment length are verified.