Friction Identification and Compensation in Robotic Manipulators

In this paper, friction identification and friction compensation in the joints of a robotic manipulator are studied. The friction force is modeled using a single-state dynamic model that is utilized in the friction compensation algorithm. A new method for identifying the parameters of the aforementioned model in a robotic manipulator is presented. To evaluate the performance of this method, two different manipulators with different friction characteristics are examined. A 2-DOF manipulator that is used for high-speed micrometer precision manipulation and a 4-DOF macromanipulator that is used for long-reach positioning tasks are considered. It is shown that despite the different nature of the two manipulators, the same method can effectively improve the speed, accuracy, and smoothness of the manipulation in both cases.