Maintaining positive cable tensions during operation of a single degree of freedom flexible cable-driven parallel manipulator

This paper investigates the control of a single degree of freedom flexible cable-driven parallel manipulator (CDPM) with a focus on maintaining positive cable tensions. A control architecture that uses a particular saturation prevention function is used to force the control torques to remain within limits that maintain positive cable tensions. The maximum and minimum allowable control torque limits are calculated by solving a linear programming problem on an element-wise inequality involving the equations of motion of the system. It is shown that the controller is input strictly passive and the closed-loop system is input-output stable. Numerical simulation results compare the performance of the proposed controller to that of an existing controller from the literature.