Wheel slip control of road vehicles via Switched Second Order Sliding Modes.

Longitudinal wheel slip control is a crucial problem in automotive systems, as it it is the basis for traction, braking and stability control. As slip dynamics are critically dependent on the vehicle speed, it is interesting to devise an adaptation of the controller parameters with respect to this variable. Specifically, slip dynamics get faster and thus more difficult to govern for the rider as speed decreases: hence, at low speed one would willingly lose tracking performance in exchange for increased safety. To achieve this, we propose a novel Switched Second Order Sliding Mode (S-SOSM) control strategy, which allows to enhance the closed-loop performance and to tune them to the current working condition. Specifically, the S-SOSM control problem is formulated and discussed, and its validity assessed on a specific instance of the wheel slip control problem, that is the traction control of two-wheeled vehicles.