Friction compensation in a pneumatic actuator using recursive least square algorithm

For many years pneumatic actuators have had a significant role as a technology in many applications. But nonlinearities such as air compressibility and friction make pneumatic systems difficult to apply in accurate control strategies. In this paper, pneumatic cylinder actuator system has been modeled considering a nonlinear friction characteristic. Since the unknown friction parameters cannot be directly measured, an indirect method is utilized, in this paper, for estimating them. Parameter estimation is performed by using the appropriate algorithm beside the real data acquired from experimental setup. The result reveals very good convergence. The developed model is then used for simulation studies, and comparison of the experiment and simulation results exhibit very good agreement between them.