Synchronous Tracking Control of Parallel Manipulators Using Cross-coupling Approach

This paper presents a cross-coupled control approach to the tracking control of parallel manipulators in a synchronous manner. Based on the synchronization goal, the position synchronization error is investigated by considering motion synchronization between each actuator joint and its adjacent ones. A decentralized trajectory tracking controller is then developed with feedback of both position and synchronization errors, formed with a combination of feedforward, feedback and a saturation control. It is proven that this tracking controller can asymptotically stabilize both position and synchronization errors of the system. The proposed controller does not require the explicit use of the system dynamic model. Experiments performed on a 3-DOF parallel manipulator demonstrate improved performance with the proposed synchronous control design. KEY WORDS—Cross-coupled control, parallel manipulators, synchronization, trajectory tracking The International Journal of Robotics Research Vol. 25, No. 11, November 2006, pp. 1137-1147 DOI: 10.1177/0278364906072037 ©2006 SAGE Publications