A new control design methodology for robotic manipulators with flexible joints

In this paper, we present a simple controller structure for robotic manipulators which contain flexible joints of arbitrary compliance between the actuating motors and the robot links. The proposed controller structure results in a singularly perturbed system whose boundary layer system is linear, time-invariant and exponentially stable. With the proposed structure, most of the control design effort is based on the reduced order model associated with the singularly perturbed system. This reduced order model has the structure of a rigid robot; hence there are many available design methods for the major portion of the control design. We impose no restrictions on the stiffness of the joints; hence robots with very flexible joints can be successfully treated, Numerical simulation results for a single link manipulator are included.