Adaptive Pulse Amplitude Pulse Width Control of Systems subject to Coulomb and Viscous Friction

The focus of this paper is on adaptive control of maneuvering rigid bodies in the presence of friction. The paper describes a simple technique which include Pulse Amplitude and Pulse Width modulation to progressively move the system to the desired final position. To account for uncertainty in estimated friction coefficients and approximated system model, an adaptation algorithm is necessary to accurately track the desired position. The proposed technique is suited for discrete time implementation and is illustrated on a rest-to-rest maneuver. The proposed technique is shown to considerably reduce the steady state error which exists in previously proposed Pulse Width controllers.