Friction in Servo Machines: Analysis and Control Methods

Analysis tools and compensation methods for the automatic control of systems with friction are surveyed. The literature reviewed is principally that of the controls and mechanics communities, and the perspective taken is that of the controls engineer. Over 180 papers are cited. The analysis tools discussed are describing functions, algebraic analysis, phase plane analysis and simulation. All major compensation techniques are described including both those which employ friction models (fixed and adaptive feedforward compensation) and those which do not (stiff PD, integral, dither, impulsive and dual mode control). A summary of current engineering practice in industry is reported and a paradigm for future research is proposed.