Analysis and experimental evaluation of a robust saturated PI velocity controller for robot manipulators

It is well-know that many industrial manipulators use an embedded linear PI joint velocity controller to guarantee motion control through proper velocity commands. However, although this control scheme has been very successful in practice, no much attention has been paid to design new PI control structures. The problem of analyzing a saturated PI velocity joint velocity controller is addressed in this paper. By using the theory of singularly perturbed systems, the closed-loop system is studied. An experimental study in a planar two degrees-of-freedom direct-drive robot is also presented, confirming the advantage of the new saturated PI joint velocity controller.