Investigation of Slow-Active Suspension System’s Non-linearity on The Performance of The Anti-lock Brake System

Abstract

This paper presents an advanced integrated controller design for military vehicle slow-active suspension system and anti-lock brake system (ABS) considering the effect of the suspension components non-linearity on the braking dynamics. The presented investigation is applied to a quarter vehicle model using the Magic Formula tire model and the actual characteristics for suspension damper (throttle valve) and spring (gas spring). The suspension controller is designed based on LQR using a linearized vehicle model and the ABS controller is designed based on ON/OF control methodology using tire skid ratio of 15% as a reference value. The mathematical derivations as well as the control techniques are numerically implemented in MATLAB environment. Several simulation results are carried out considering typical performance measures such as stopping time, stopping distance and vehicle body vertical acceleration. The results illustrated that, the integrated controller reduces the stopping distance on different road surfaces and therefore improves the braking performance to avoid or reduce the impact of vehicle accident.