Cable suspended robots: Control approaches and applications

Cable-suspended robots are structurally similar to parallel actuated robots but with the fundamental difference that cables can only pull the end-effector but not push it. For cable driven systems, the positivity of inputs presents a big challenge for the control system design. If cables becomes slack, the intended control inputs can not be delivered to the end-effector through the cables. Not only will this degrade the performance of the system but may also destabilize it.; This thesis presents methods for control of cable suspended robots that keep the cables in tension. The approaches presented in this thesis can be broadly classified as those that (i) properly choose the reference commands, (ii) choose the control inputs that respect the input constraints while ensuring asymptotic stability of the closed-loop system. Within these frameworks, a null space control approach and Control Lyapnov Function (CLF) approach are also investigated for cable suspended robots. Additionally, several applications of cabe robots are presented. The effectiveness of the proposed methods are verified by computer simulations and experiments with planar and spatial cable robots.