Testing, Computer Simulation and Analysis of Vehicle Dynamic Performance During Braking of a Small Car with ABS

Road safety is becoming a strategic issue for sustainable development of India. Increasing vehicle population and low road density (India has 2.56 km road/thousand population and 768 km road/thousand km² of total land.) are aggravating the problem. Introduction of modern safety features in small cars are inevitable to improve the safety scenario. Recently Anti-lock Braking System (ABS) has been started to be introduced in low segment family cars. But still the effect of ABS, fitted on these cars, in reducing the road accident are debatable and in-depth studies are required in this field. A thorough investigation of usefulness of ABS on Indian road condition took place in this paper.

An instrumented vehicle has been used to study the braking performance of a small family vehicle with ABS ON and OFF condition on two different types of road surfaces, namely dry and wet. In addition to the vehicle performance the focus has been given to the vehicle stability criteria. A computer model, developed using the commercial multi-body dynamic system simulation software, has been used for simulation study. Braking performance in wet road condition was distinctively poor than dry road condition and the average deceleration for wet road condition was less (average 19.7%) than dry road condition. ABS-ON condition produced overall 11.2% more ‘average deceleration’ than ABS-OFF condition, hence expected to improve braking performance. Effect of ABS-ON was more prominent to improve braking performance in terms of better average deceleration on higher speed (here 60 km/h and 80 km/h) than low speed (here 40 km/h) for both dry and wet roads. On higher speed ABS-ON condition showed 6.5% overall better average deceleration for wet road condition. Average and peak values of pitch angle during braking for all conditions were found to be quite satisfactory. It is expected that the results of this study will be helpful to improve the road safety.