Inverse kinematics and workspace analysis of a bio-inspired flexible parallel robot

This paper presents the inverse kinematics and workspace analysis of a cable-driven flexible parallel robot mimicking pitch and roll movements of human neck. The fixed base and moving platform of the robot are connected by three cables and a compression spring. The spring serves as cervical spine to support and facilitate the motion of moving platform corresponding to human head. The cables serve as the muscles around human neck to drive the robot. Quaternion method is employed to obtain the rotation transformation matrix between the base coordinate frame attached to the fixed base and the moving coordinate frame attached to the moving platform. By combining the equations of force and moment balance together with lateral bending equations of the compression spring, inverse kinematics of the parallel robot is solved. Based on the force and moment balance model, the wrench closure workspace of the robot is analyzed with constrain of positive cable tension. Simulations were performed to demonstrate the correctness and feasibility of the inverse kinematics and workspace analysis of the parallel robot.