Résumé
This paper deals with closed-shape geometric reference trajectories generation and dynamic control of redundantly actuated parallel kinematic manipulators. Geometric trajectories if generated by means of trigonometric functions may show inherent discontinuities regarding velocities and/or accelerations which may cause problems for the drives. In order to overcome this issue and to generate C 2 continuous refernce trajectories, we propose a novel technique consisting of modifying the motion profile while preserving the overall geometric shape of the trajectory in the operational space. Regarding the control strategy and to deal with the actuation redundancy, an extended version of the PD controller with computed feedforward is proposed. The computed control inputs, before being applied to the actuators, are first projected using a regularization matrix based on the manipulator's kinematics in order to remove the antagonistic internal forces. The overall proposed strategy including the trajectory generator as well as the controller are experimentally validated on the Dual-V robot, a three-degree-of-freedom redundantly actuated parallel kinematic manipulator developed in our laboratory.