IMPROVED DIRECTIONAL STABILITY IN TRACTION CONTROL SYSTEM

Abstract

The traction control system (TCS) comprises a slip control subsystem and a directional stability subsystem. The slip controller can enhance the traction performance by maintaining the slip ratio within an appropriate range. Additional information about the lateral behaviour of the vehicle is necessary to enhance the directional stability during cornering or lane change on slippery roads. With an assumption of slowly varying steering input, a new method to measure the mixture of yaw rate and lateral acceleration, using the speed difference of non-driven wheels, is proposed. Using this measurement, the controller imposes independent pressure to each driven wheel and improves the stability during cornering on slippery roads or acceleration on split-μ roads without additional sensors such as yaw rate and lateral acceleration sensors. The proposed method is verified through simulation based on a 15-degrees-of-freedom (15 DOF) passenger car model.