Cartesian Controller´s Evaluation in Joint Space

This paper addresses the problem of position control for robot manipulators. A new family of controllers for robot manipulators on Cartesian coordinates with gravity compensation is presented. The simple PD-type Cartesian controller can be found among this family of controllers. The main contribution of this paper is to prove that the closed-loop system composed by full nonlinear robot dynamics and the new family is asymptotically stable in local sense in agreement with Lyapunov´s direct method and La Salle´s invariance principle. To illustrate the performance of new controllers family, time-real experimental results on a two degrees of freedom direct-drive arm are also presented