A Hybrid sliding mode control and bounded variable least squares framework for an eight-cable-driven parallel robot

Abstract

Cable-driven parallel robots (CDPRs) have attracted considerable attention due to their advantages in large workspace, lightweight structure, and high dynamic performance. However, the control of eight-cable-driven parallel robot systems remains challenging because of their nonlinear and strongly coupled dynamics, as well as the requirement that cable tensions must remain within feasible bounds during operation. This paper proposes a hybrid control framework combining Sliding Mode Control (SMC) and Bounded Variable Least Squares (BVLS) for trajectory tracking and cable tension distribution of an eight-cable-driven parallel robot, where the SMC strategy is employed to achieve robust tracking performance under nonlinear and uncertain operating conditions. The desired control wrench generated by the SMC is subsequently allocated into feasible cable tensions through the BVLS algorithm, which determines an optimal least-squares tension solution subject to bounded cable tension constraints. Simulation results demonstrate that the proposed control framework achieves fast transient response and high tracking accuracy for both translational and rotational motions, while all cable tensions remain within the prescribed feasible bounds.