On the optimal design of an automotive lateral controller

An optimization approach is used to design a velocity-adaptive, lateral controller to meet requirements pertaining to lateral-position, tracking accuracy, robustness, and ride comfort. The resulting controller, which is nonlinear with velocity, requires full-state feedback and thus an observer is included. The observer/controller compensator was implemented using a 16-bit microcomputer and evaluated in a laboratory study wherein vehicle lateral dynamics were simulated on an analog computer. Excellent lateral control, i.e. close tracking (with absolute value of lateral-position error below 0.024 m in curve tracking), good sensitivity to disturbance forces, and probable ride comfort resulted. The selected control algorithm was realized using some 5% of the available computation time, thus allowing the microcomputer to be used for other control functions and vital-function monitoring