Automotive drive by wire controller design by multi-objective techniques

The presence of flexibility in automotive drivelines, coupled with nonlinear elements such as gear lash leads to the presence of an undesirable oscillatory acceleration response to step changes in throttle input. This oscillation is generally low frequency (approximately 2-5kHz) and can be of sufficient amplitude to cause driver discomfort and subjective disappointment with the driveability of the vehicle. A pole placement controller is developed for a “drive-by-wire” (electronically operated throttle) system, with the objective of reducing or eliminating the oscillatory response. The results of an existing factorial study are used to calculate the required number of poles. Due to the inherent nonlinearities present in the system and the various constraints which must be applied to the controller design, the polynomial values for the pole placement controller are selected by the application of multi-objective optimisation. The controller is shown to achieve excellent performance and robustness to parameter variations and operating conditions.