Non-iterative identification and model following control of Hammerstein systems with asymmetric dead-zone non-linearities

A novel non-iterative identification algorithm based on the parameterisation of unknown dead-zone non-linearity is proposed for control of Hammerstein systems in presence of asymmetric dead-zone input. A canonical representation for piecewise linear functions is employed to describe the dead-zone function such that a universal-type parametric model can be established to approximate the entire system. Both the dead-zone parameters (thresholds and slopes) and the coefficients in linear transfer function can be estimated simultaneously using the designed persistent exciting input. A modified model following control scheme is then designed in such a way that the plant output tracks the desired output with satisfactory performance. This method can be applied without a priori knowledge of the dead-zone non-linearity. Numerical simulations are presented to illustrate the effectiveness of the proposed scheme.