Synchronization control for a crustal movement simulation system based on a fuzzy logic strategy

Crustal movement is a key factor affecting water cycle and related land surface processes. In this paper, the principle of a class of crustal movement simulation system (CMSS) is introduced. The CMSS proposed in this study is composed of twelve sets of four-legged parallel manipulator with three degrees of freedom. The structure of the parallel manipulator with actuation redundancy is analyzed. In the conventional controller design for parallel manipulator, the controller for each kinematic chain usually works independently without considering motion states of other kinematic chains. Therefore, the platform performance is easily deteriorated duo to the lack of coordination between these kinematic chains. In this paper, a synchronization error is developed based on the mechanism characteristic of multiple kinematic chains. Then, a synchronization controller is designed using the proposed synchronization error and fuzzy logic strategy. In our design, each kinematic chain not only tracks its own desired trajectory, but also cooperates with other kinematic chains. Therefore, according to synchronization error, the synchronization controller will determine that which chain should be speeded up or slowed down. Experimental results demonstrate the performance of the proposed control scheme in terms of tracking accuracy and robustness to interferences.