Synchronization Control in the Cable Space for Cable-Driven Parallel Robots

Cable-driven parallel robots (CDPRs) have low moving inertia and provide high-speed motion over a large workspace. The main challenges of CDPRs stem from the fact that cables should be in tension during motion control. Cable tension is closely related to the synchronization motion relation between cables which is often omitted in the existing controllers for CDPRs. To solve it, this paper proposes two synchronization controllers in the cable space to realize the synchronization motion between cables, and finally increase the tracking accuracy of the moving platform. The two synchronization controllers are proven to guarantee asymptotic convergence to zero of both tracking error and synchronization error. The trajectory tracking experiments are implemented on a self-built three-DOF CDPR, and the experiments are compared with the traditional augmented proportional-derivative controllers neglecting synchronization. The experimental results indicate that the tracking error and the synchronization error of the moving platform decrease greatly by using the synchronization controllers.