A Model Free Synchronization Approach to Controls of Parallel Manipulators

A simple synchronized approach to controls of parallel manipulators is proposed, by incorporating a cross-coupling saturated nonlinear proportional-integral (PI) control into a common joint-space linear proportional-derivative (PD) control architecture, where the system stability can be guaranteed. The proposed control strategy does not require any model parameters and is able to stabilize motion of each actuator while synchronizing all actuators' motions, so that differential position errors amongst actuators converge to zero. Experiments conducted on a three-DOF spatial parallel manipulator system demonstrate the effectiveness of the developed approach