Vehicle Stability Test And Analysis Under Abnormal Conditions

With the tremendous progress in automotive technology, the mighty increase in the number of cars, the improvement of the car speed, traffic has become a serious global problem. In order to reduce traffic accidents and losses caused by traffic accidents, as far as possible to avoid casualties, a study of traffic accidents has been paid more attention. At present, research on traffic accidents are no longer limited to passive safety and active safety. Researchers begin to pay more efforts on the causes of accidents, as well as the movement of vehicles in events a few seconds before accidents happened. The research result can give more correct method of operation to the driver, as much as possible to avoid or reduce losses caused by traffic accidents. In order to investigate the car in the movement of abnormal conditions, this paper conducted a study of vehicle road test system based on GPS and gyroscopes, and automobile brake testing and analysis in different road adhesion coefficient.By analyzing the principle of GPS position and the characteristics of gyroscopes, this paper using GPS sub-system and gyroscope, established vehicle road test system, using MATLAB platform developed data processing software.Based on the combination of differential GPS subsystem and gyroscopes of the road test systems, we conduct a vehicle road test, using the methods of mathematical statistics carried out error analysis, verify the differential GPS positioning system with high precision, carry out a comparative analysis of the trajectories of vehicles, speed, heading angle and it shows that the system meets the accuracy requirements of car road tests.When the car on different road adhesion coefficient brakes, the braking force in the two sides is not equal, then the car will have a turn under the rotary torque. In this paper, using the road test system, braking test is mainly conducted when both sides of the wheel are in different road adhesion coefficient, abnormal working conditions are set that:(1) braking test on separateμroad with normal pressure;(2) braking test on separateμroad with 0.1MPa pressure of right front wheel;(3) braking test on separateμroad with 0.1MPa pressure of right rear wheel. Finally, contrast braking test was carried out when the right front wheel is at pressure 0.2MPa and 0.1MPa as well as docking experiment at normal pressure.Tests showed that use of the road test systems, data process quickly with high precision.Through experimental analysis, braking on the different adhesion coefficient road, the car turns to the side of a high adhesion coefficient. while the right front wheel is on the low adhesion coefficient road with 0.1MPa pressure, braking will make the car rollover when it passes towards high adhesion coefficient road from low adhesion coefficient road; when right rear wheel is at 0.1MPa pressure and right side wheel is at high adhesion coefficient road, braking makes the car flick with large lateral displacement, the car turns left when the right rear wheel at low adhesion coefficient road with little lateral displacement.