H-infinity vehicle control using nondimensional perturbation measures

Robust controller design techniques have been applied to the field of vehicle control to achieve many different performance measures: robust yaw rate control [1], robust lateral positioning using one [2, 3] or more [4-6] driver inputs, robust observer design, and so on. A difficulty with many published approaches is to obtain an adequate description of the model uncertainty. Most bounds on plant frequency responses or parameter perturbations are based on ad-hoc limits that rely primarily on the designer's personal choice. The resulting controller design is therefore often vehicle specific, and is suitable only for application to a single design vehicle. This work shows that (a) the description of model uncertainty is not a design variable, (b) meaningful bounds on model uncertainty can be obtained from data and should be sought, and (c) these bounds can be used to generate a single controller suitable for any vehicle.