Stabilization of Cable Driven Robots Using Interconnection Matrix: Ensuring Positive Tension

Cable driven parallel robots are closed-loop kinematic chains, where the end-effector is attached to the base by a number of cables. Because of the nature of cables, a major issue in control of these robots is ensuring positive tensions. When the robot is not redundant, this issue is of utmost importance for the controller synthesis. In the case of point to point motion control, the trajectory is not specified beforehand, thus negative tension may occur. In order to resolve this issue, interconnection and damping assignment passivity based control (IDA - PBC) is employed. IDA-PBC is a well-known method for control of underactuated systems where desired damping and interconnection between subsystems are imposed. Interconnection matrix is a skew-symmetric matrix which doesn't have an effect on stability, but it greatly influences the transient response of the system. In this paper, the interconnection matrix is exploited to ensure positive tension in fully actuated cable driven robots. The results are verified through simulation on a 3-DOF suspended cable driven robot.