Fractional Order Coulomb Friction Compensation: Convergence Analysis and Experimental Validation on a Fractional Horsepower Dynamometer

A new fractional order adaptive scheme is proposed for the Coulomb friction compensation in a servo control system. This adaptive compensator is designed such that it can estimate the unknown Coulomb friction coefficient; therefore, the zero convergence of the error system will be guaranteed. The design procedure of the proposed control scheme is very simple and its application is easy. Also, the friction in the servo control system is compensated by a good tracking performance. The comparison shows that the fractional order compensator has less tracking error and better response. A fractional horsepower dynamometer was developed as a general purpose hardware-in-the-loop real-time simulation platform to emulate Coulomb friction as a mechanical nonlinearity. The simulation and experimental results demonstrate that the proposed controller has a satisfactory performance and diminishes friction characteristics.Copyright © 2013 by ASME