Optimal RRT* Planning and Synchronous Control of Cable-Driven Parallel Robots

Cable-driven parallel robots (CDPRs) can provide high speed and heavy payload over large workspace by using multiple flexible cables. The main challenge of CDPRs stems from the motion control in which cables should avoid interferences and coordinate each other during the whole workspace. To solve it, a comprehensive motion control scheme including the optimal path planning and the synchronization control is proposed. Based on the improved Rapidly-exploring Random Tree (RRT*) algorithm, the path generation process with a novel cost function is presented to ensure the optimal path and the obstacle avoidance. Moreover, the Potential Field Guided (PFG) method is designed to further improve the efficiency of the planning algorithm. In order to validate that the moving platform can track the feasible path well, a synchronization controller is developed on the basis of the dynamic model. The simulations and experiments are implemented on a self-built 4-3 (4 cables with 3 DOF) CDPR. The results indicate that the proposed planning algorithm has much better efficiency than the RRT* algorithm, and the synchronization controller can get high tracking accuracy.