An Efficient Identification Method for Friction in Single-DOF Motion Control Systems

This brief describes a new identification method for friction in single-degree-of-freedom (DOF) motion control systems, in which the friction model is not necessarily linear in parameters. The proposed method works well with any measurement data of velocity and input control force, as long as the initial and final velocities are identical. Most importantly, the proposed method requires neither the information of acceleration nor the accurate information of mass for its implementation, in contrast with the previously known offline identification methods. This feature is due to the orthogonality property between acceleration and any function of velocity, which is a unique property of single-DOF motion control systems. The performance of the proposed method is demonstrated through some simulation and experimental results.