Robust servo motion control of air motor systems

The major objectives of the paper are to investigate the characteristics of servo-controlled air motor systems and to develop robust control strategies to overcome uncertainties and nonlinearities caused largely by the compressibility of air and in the mechanical configuration and operation of air motors. In this paper, the servo-controlled air motor systems are modelled as a class of cascade connection of two uncertain nonlinear affine systems. Then, Fourier series approximation is adopted to resolve the problem of discontinuity in the system model. Subsequently, based on previous research work by Wang and Goodall (1995), a class of robust feedback control is proposed. It is shown that better profile following can be achieved and the robustness of the controller is guaranteed.