PID-Type Control of Robot Manipulators by Using Gravity and Inertial Effects Compensation

The paper describes an approach to the robot manipulator control based on a compensation of non-linear gravity terms and inertial terms in the robot motion equations and applying the PD or PID-type control law. While benefits of the compensation of the gravity force effects are well known, the inertial effects compensation, which seems to be more difficult to implement, brings additional enhancement of the control quality. An approximate compensation can be carried out in a relatively simple and efficient way, if the robot dynamics is represented by a mass-point model. The remaining influences can be treated as disturbances. Unlike the inverse dynamics approach, complete and precise mathematical model of the robot is not needed, which is an important advantage, since models of robots containing more than three links are usually very complex and difficult to obtain.