Optimal distribution ofbraking and steering tire forces subject to stabilityconstraints


Department of Mechanical Engineering, Amirkabir University of Technology, 424 Hafez Avenue, Tehran 15914, Iran


This paper presents an integrated vehicle dynamics control which managesto coordinatesteering and braking subsystems using optimal distribution of tire forces (ODF). Specifically,we introduce an ODF scheme which treats thestandard stability conditions of the phase-plane as inequality constraints in the optimization problem. The established scheme works to fulfill the objectives of a higher-level controller as much as possible without violating vehicle dynamics stability conditions. A sliding mode enhanced adaptive high-level control assesses the desired total yaw moment and lateral force for the vehicle control. The proposed controller only requires the online adaptation of control gains without acquiring the knowledge of upper bounds on system uncertainties. An optimization problem incorporating six inequality constraints is solved analytically by Karush-Kuhn-Tucker (KKT) conditions. To coordinate braking and steering subsystems, a phase-plane based adaptation mechanism is suggestedto adjust the weighting coefficients in the considered cost function. The simulation cases show that the vehicle stability can be improved effectively by the suggested scheme