A Hooke Joint Mounting Vector Optimization Algorithm for Structure Design of a Parallel Robot

The workspace of parallel robots is often limited by structural interference, and Hooke joints are important sources of such interference. To solve the problem of structural interference of Hooke joints in certain postures of parallel robots, a Hooke joint mounting vector optimization algorithm is proposed, which can be used to calculate the best mounting direction according to the tilt range of the Hooke joints. Based on the inverse kinematics of the parallel robot, the tilt range of the driven motor axis fixed on the Hooke joint is analyzed. The minimum envelope circular cone of driven axis vectors is calculated by the optimization algorithm and the cone axis is chosen as the Hooke joint mounting vector. Using this method, the maximum tilt angle of the parallel robot's Hooke joint with respect to the mounting vector is decreased from 42.9° to 28.1°. The algorithm reduces the possibility of structural interference without changing the dimensional parameters of the robot and can be used to guide structural design of other parallel robots with Hooke joints.