Research on Feed-forward Controller for Electronic Throttle Control of GDI Engine Based on Nonlinear Model

The nonlinear Hammerstein model was designed. The model was used to compensate the dynamic behavior of an electronic throttle body at different operating conditions. It consisted of a static nonlinear function and a dynamic linear function. The static nonlinear function was used to representing the coulomb friction and limp-home return springs and the dynamic linear function was used to representing dynamic piecewise-linear characteristic. An observer model, known as kalman was used for the on-line throttle position and angular velocity estimation. The control strategy was designed which combined the feed-forward control based on Hammerstein model and feedback control based on proportional-integral-derivative (MD) controller. The control structure has the quick response characteristic of the feed-forward control and disturb compensation characteristic of the feedback control. The experimental results revealed that the dynamic position control delay less than 100ms, the static position error less than 0.5 degrees and the controller satisfied requirement of GDI for precise in-charge control.