Flexible Cable-Driven Parallel Manipulator Control: Maintaining Positive Cable Tensions

In this brief, a planar cable-driven parallel manipulator is controlled using a strictly positive real compensator, cable pretension is explicitly accounted for, and cable slack is avoided. A strictly positive real controller is implemented using actuator saturation prevention techniques and the solution to a linear programming problem to ensure that the cable tensions remain strictly positive. Pretension torque is directly accounted for when determining the input-output stability of the closed-loop system. Numerical simulations demonstrate that the controller can track high-acceleration trajectories with the same precision as a state-of-the-art controller from the literature, while maintaining positive cable tensions.