An experimentally corroborated framework for emulating wheel lock in a heavy vehicle brake dynamometer

Abstract

Wheel lock in a vehicle during braking is detrimental to its safety, in addition to causing poor braking performance. Wheel slip regulation algorithms could potentially prevent wheel lock and are hence required to be tested and tuned thoroughly prior to in-vehicle deployment. Generally, software-in-the-loop and hardware-in-the-loop tests are explored before on-road vehicle testing. A brake dynamometer can potentially be utilized for wheel slip regulation testing, and this can be placed in between hardware-in-the-loop tests and on-road vehicle testing. Prior to evaluation of wheel slip regulation on a brake dynamometer, it is imperative to realize a wheel lock scenario. This work proposes a methodical framework for emulating wheel lock in a brake dynamometer. In this study, the dynamic effects during braking, particularly load transfer, wheel slip and tyre–road interactions, are subsumed into a single variable termed ‘equivalent inertia’ to replicate a wheel lock event. The variations of this variable were captured through extensive tests on a hardware-in-the-loop platform that consists of a pneumatic brake setup interfaced with IPG TruckMaker® co-simulated with MATLAB/Simulink®, across varying load, road and braking conditions. Equivalent inertia profiles thus generated were then realized in the brake dynamometer, via mechanical discs and electrical inertia. Angular speed profiles from hardware-in-the-loop and dynamometer tests were compared to corroborate the framework. A close correlation between the profiles, highlighted by the root mean square deviation of the order of 100 rad/s, established the effectiveness of the proposed scheme.