Diagonal trot gait planning and simulation analysis of closed chain quadruped robot

WANG Yong-ming, MA Teng-fei, WEI Qiang

（School of Mechanical Engineering, Anhui University of Technology, Ma'anshan 243032, China）

Abstract: Aiming at the instability problem of fast walking of closed chain quadruped robot, the dynamic stability of the robot under the diagonal trot gait was discussed by using the zero moment point theory, and the expression of the tilting angle was derived when the robot lost stability around the supporting diagonal. Taking the duty ratio β=0.5, the timing sequence of the swing leg of the quadruped robot under the diagonal trot gait was analyzed. By using ADAMS simulation software, the virtual prototype model of closed chain quadruped robot was established. Based on the diagonal trot gait, the driving functions of the main and secondary closed chain cranks of walking legs were planned and the relevant simulation parameters were set. Then the motion simulation experiment of the robot was carried out, and the displacement curves and velocity curves of the center of mass and foot end of the robot were obtained. The results indicate that the moving speed of the closed chain quadruped robot is about 0.85 m/s, and the fluctuation degree is about 3.6 mm. Under the diagonal trot gait,the quadruped robot can achieve stable walking movement at medium speed. The step length of the foot trajectory under the diagonal trot gait is about 350 mm and the step height is about 80 mm, which basically meets the step requirements.

Key words: closed chain quadruped robot; diagonal trot gait; tilting angle; gait planning; simulation analysis