Kinematics and multi-body dynamics of a bio-inspired quadruped robot with nine linked closed chain legs

This paper deals with the procedure of the analyzing the nine linked closed chain leg mechanism. Each leg is provided with two degrees of freedom, one at the crank of mechanism at the hip joint and other by the adjustable lower link length mechanism. Satisfying the constraints imposed on the robot velocity, ground height of the body, leg stroke length, body dimensions; the support polygon is built and path of foot of the leg in swing phase is obtained. Based on the path followed by the robot, inverse kinematics of each leg is carried from which the angular velocity of the crank and the linear velocity of the leg extension are obtained with respect to time. This inverse kinematics data is further fed to the dynamic simulator to obtain the torque required at the crank, force required for lower link extension and forces exerted on each joint. The dynamic results obtained are used for the finite element analysis (FEA) of the robot components.