Nonlinear brake control of a Formula 1 racing car and the small step to nonlinear vehicle dynamic control

Brake system dynamics are governed by highly nonlinear effects when required to propagate high hydraulic pressure within a short amount of time to the brake calipers. Due to substantially more demanding conditions and requirements in a Formula 1 car’s brake system do not only these effects have a bigger impact, but make it also more difficult to robustly control the brake caliper pressure when brake-by-wire is adopted. The control system presented in this paper originates from Alfa Romeo Sauber F1 Team’s desire (today Alfa Romeo Racing) for an alternative algorithm with enhanced robustness and similar performance when compared to the existing proportional- integral based one. To this purpose, an innovative nonlinear controller based on back-stepping methods and adapted robust control has been developed. Its ability to cope for model uncertainties and unknown disturbances, while guaranteeing stability over the full nonlinear operational range and asymptotic error convergence, are the focus of this work alongside the illustration of the controller’s working principles and the small step to reach nonlinear vehicle dynamic control.