Optimization and Control of a Planar Three Degrees of Freedom Manipulator with Cable Actuation

The paper analyzes a planar three degrees of freedom manipulator with cable actuation. Such a system can be understood as a special type of hybrid parallel kinematic mechanism composed of the rigid serial chain and the additional auxiliary cable system. The advantage of the auxiliary cable mechanism is the ability to reconfigure the whole system. The fulfillment of sufficient prestressing is the constraint of the optimization process. Computed Torque Control with a cable force distribution algorithm is implemented. The control algorithm performance is examined on different trajectories, including non-smooth motion requests, and its robustness is tested by randomly generated errors of the model parameters in regulators. The results demonstrate that the optimized structure is capable of controlling the manipulator motion and keeping the cable prestressing within the given limits.