Adaptive variable structure position control of servo systems with system uncertainty

This paper deals with adaptive sliding mode control of servo systems with system uncertainty such as nonlinear friction. In the case of servo systems, friction phenomenon causes the reduction of tracking performance because friction is directly related with various internal and external environment conditions such as the level of lubricant, contamination, and temperature. Therefore, to overcome the problems with friction in servo systems, robust control scheme is required. In addition, to actively compensate system uncertainties, adaptive control scheme can be required. This paper proposes adaptive sliding mode control scheme integrating sliding mode control scheme with robustness property and adaptive control scheme with compensating system uncertainty by on-line estimating unknown parameters. The proposed control scheme is verified through computer simulation.