Development of a general friction identification framework for industrial manipulators

The paper proposes a general friction identification framework for industrial manipulators, including the automatic handling of all the required phases, from data acquisition and processing up to parameters identification. A complete static friction model is used, with the insertion of a rough approximation of the hysteretic behavior of friction; switching to a possible simpler model is also automatically executed when possible. The proposed solution has been implemented in a software module, which has been integrated into the control architecture of an industrial robot, and experimentally tested. The results have shown that a very accurate reconstruction of the actual motor currents is provided, when the friction estimated using the proposed framework is inserted in the robot dynamic model.