Fast-motion trajectory generation for a new direct-drive planar parallel manipulator

A new direct-drive planar parallel robotic manipulator is presented for fast-motion positioning in this paper. Because of the nonlinearity of kinematics and dynamics of the robotic manipulator, the achievable maximum velocity and maximum acceleration vary at different points and directions in the whole workspace. In order to make the manipulator move with fully high velocity and high acceleration along the specified trajectory in the workspace, a fast-motion trajectory generation technique is introduced in details. Given the limitations on speed and torque of the actuators, the available values of maximum velocity and maximum acceleration along the specified trajectory are firstly derived. Then, based on these values, several motion profiles are generated with different acceleration and deceleration characteristics. Finally, the experiments of trajectory generation are conducted on the new robotic manipulator, which moves along the trajectories with the unsymmetrical velocity profiles, and the results validate the proposed technique.