An alternative approach to automotive ESC based on measured wheel forces

Abstract

Traditional electronic stability control (ESC) systems act on one or more wheels on the basis of a logic aiming at the control of variables that cannot be directly measured (vehicle sideslip angle and the tyre slip). Hence, a vehicle state estimator capable of evaluating the needed variables from the data of the input sensors is necessary. In the present paper, the authors discuss a different approach to the estimation problem, assuming that the forces acting on the wheels can be directly measured. The ESC feed-forward control logic is designed through a vehicle frequency response analysis in order to obtain a faster active system activation. The variable controlled by the logic is the tyre longitudinal force. Experimental results obtained on an ESC hardware-in-the-loop test bench prove the validity of the approach, showing enhanced dynamic performances, together with the limits due to the delays in the actuation of the ESC motor pump, which needs some time to build the pressure requested for the intervention on the selected callipers. Finally, the tests demonstrate the opportunity of closing the control loop on a variable (i.e. the force) that can be directly measured.

Keywords:

• electronic stability control
• load sensing bearings
• hardware-in-the-loop