Mechanism Design And Simulation Of Under-actuated Quadruped Robot

For the research of quadruped robot under-actuated characteristic, It can complete more complex movements of quadruped robot using its own structural features in the case of less drive. This paper has carried on the under-actuated quadruped robot mechanism design and simulation.According to the mammals "dog legs" structure, the design requirements of quadruped robot has been put forward, the joint drive way and the drive scheme is determined. Kinematics modeling and one leg D-H coordinate of the quadruped robot were built based on D-H rule. The leg mechanism relative to the body coordinate system at the end of the attitude matrix and position coordinates were deduced by the bar quadruped robot based on geometric parameters and joint variables. Inverse kinematics modeling of under-actuated quadruped robot was built to get the relative to the body coordinate system at the end of the leg mechanism position and each joint variable expression. Its Jacobian matrix is deduced by each joint angular velocity and angular acceleration of the leg mechanism. The foot end quadruped robot workspace cloud by using the Monte Carlo method to verify the quadruped robot without interference phenomenon between the legs.A simplified model of the under-actuated quadruped robot mechanism was established. The method of dynamic analysis was discussed. The Lagrange equation and the dynamic equation and matrix of each joint torque were derived by the dynamics analysis of the under-actuated quadruped robot model.3D modeling of under-actuated quadruped robot was built using Pro/E software f and it was imported into ADAMS environment to establish the virtual prototype model. To get one leg quadruped robot in motion of hip and knee motion law, one leg of quadruped robot simulation was conducted. Referring to the diagonal gait of quadruped robot movement characteristic, the under-actuated quadruped robot joint control law was verified. Through kinematics and dynamics simulation of under-actuated quadruped robot in flat road surface and uneven pavement, the kinematics simulation results indicate that movement of quadruped robot was in accordance with a predetermined path and it could run smoothly. The movement of under-actuated of quadruped robot indicated it has the superiority on the uneven road surface.The planar model of under-actuated quadruped robot running gait was presented through bionics research of the four-legged mammal, and has carried on the flat ground to run to the gait and the comparison of uneven ground simulation. Results show that the under-actuated quadruped robot can adjust its structure to adapt to the change of external environment in the absence of any feedback control and can realize running gait stable.