Kinematics, Dynamics and Simulation of a Novel Schönflies-Motion Parallel Mechanism

To meet the requirement of automatic pickup for high-speed parallel mechanisms, a new type of high-speed parallel mechanism which can realize Schönflies motion is presented. Each branch chain in this parallel mechanism contains two parallelograms, which can increase the stiffness of the branch chain. The overall degree of freedom (DOF) of the parallel mechanism are analyzed based on the screw theory, and the kinematic characteristics of mechanism are determined as three translational and one rotational (3T1R) DOFs. Combining the structure characteristics of the mechanism, the kinematic constraint equations are constructed, thus the kinematic forward/reverse solutions are derived to establish the velocity and acceleration models, followed by the limit coordinate search method to obtain the reachable workspace of the mechanism. Based on the virtual work principle, a rigid body dynamics model of the mechanism is established, and the numerical results are compared with the simulation results of multi-body dynamics software to verify the correctness and validity of the theoretical model.