Evaluation and development of improved braking model for a motor-assisted vehicle using MATLAB/simulink

Abstract

In recent years, R&D trends in the automobile industry have involved developing vehicles that are eco-friendly and have good fuel economy in order to meet increasingly stringent vehicle emission and fuel economy regulations. Among various environmentallyfriendly vehicles, recently-developed hybrid electric vehicles have been considered a successful technology. To improve the hybrid electric vehicle's efficiency, a regenerative braking system is applied that can save waste braking energy and fuel consumption. To date, much research has been conducted that is related to regenerative brake systems for motor-assisted vehicles. In this study, a vehicle brake model and DC motor model have been developed to predict the braking and electric characteristics of vehicle and motor by using MATLAB/Simulink code and compared with brake performance reference data. Since generating current is a key factor for regenerative braking in a hybrid electric vehicle (HEV) system, electric characteristics are the focus of this study. Therefore, in order to investigate the electric characteristics, analysis is also performed using the DC motor model. The main results obtained by this study are that the vehicle braking dynamics calculated by MATLAB/Simulink simulation were in reasonable agreement with reference values. Using the vehicle brake model, analysis is carried out for investigating the numerical model's characteristics and performances at initial velocity, slip ratio and road conditions. Additionally, experimentation is carried out using a chassis dynamometer and a hybrid electric vehicle, and the data are analyzed.