Pulse Width Modulation Control of Robots With Structural Flexibility Available to Purchase

The accuracy to which the end effector of a robotic manipulator can be positioned is often limited by structural flexibilities and nonlinear friction. This paper develops a control design methodology for such systems based on pulse width modulation. This methodology achieves comparatively very accurate point-to-point position control and does not require a high fidelity model of either the robot dynamics or the friction behavior. Conditions under which the controller must directly treat plant structural flexibility are presented. Conditions on parameters of the closed loop system that guarantee stability and a well defined level of performance are given. The methodology is demonstrated by application to a six axis industrial robot.