On the Stability of Nonlinear Wheel-Slip Zero Dynamics in Traction Control Systems

The development of modern engines with increasing power, fast dynamics, and responsiveness, as well as changes in system architecture, set new requirements on traction control system design for vehicles. We propose a robust nonlinear control design based on input-output linearization to solve the traction control problem. The oscillatory behavior of the powertrain is taken into account explicitly during the controller design phase. Previous work has not addressed this case and no results on stability are available so far. We proove global asymptotic stability of the nonlinear zero dynamics analytically using a parametric Lyapunov function. The traction controller is implemented on different test vehicles and validated for different driving maneuvers and road conditions. Experimental results obtained with test vehicles and by simulation demonstrate stability, high performance, and robustness of the proposed approach.