Robust Nonlinear Proportional-Integral Control for Active Braking Control Systems

In road vehicles, wheel locking can be avoided by means of electronic anti-lock braking systems (ABS). The main challenge in designing closed-loop braking controllers is the need to cope with unknown road conditions and consistent variations in the vertical load exerted on the tires during braking. In this work a nonlinear output feedback proportional integral control law for active braking control systems is proposed, which does not require any knowledge either of the current road condition or of the instantaneous value of the vertical load. This control law guarantees bounded control action and can cope also with input constraints. The design is performed via Lyapunov-based methods and its effectiveness is assessed via simulations