Modeling and control of rocking in cable-riding systems

Cable-riding suspended systems are commonplace, with applications ranging from ski lifts to tramways to material movers in mining operations. Another, more recent application is the robotic inspection of cables using robots that ride along the cables which they are inspecting. The Expliner robot is one such device. It inspects live, high-voltage power lines while moving along them. For all of these cable-suspended systems, rocking oscillation can reduce safety and efficiency of operation. This paper presents a model to identify the key dynamic factors of this rocking motion. Then, input shaping is used to limit rocking from both motion along the cable and controlled center-of-mass shifts.