Cartesian control of redundant flexible-joint manipulators

In this paper, the issue of redundant flexible-joint manipulator control is addressed. A new control strategy called hybrid Cartesian-joint control is introduced which consists of a Cartesian tracking controller, a link tracking controller, and a motor tracking controller. The construction of the proposed control scheme is based on the analysis of a flexible-joint non-redundant joint-space scheme, as well as Cartesian-space scheme. Important issues such as the effect of disturbances caused by joint flexibility, control of the manipulator´s self-motion, and the relationship between the disturbances and self-motion are also addressed. A stability analysis for the proposed controller is given, and computer simulations to verify the performance of the proposed control strategy are presented