| The automobile brake performance is one of major performances of automobile. It has an effect on automobile speed performance and road traffic safety. So the automobile brake performance is one of the most important factors in vehicle safety performances. It is also a key indicator and a required inspection item of vehicle safety performance test. On the basis of existing researches about automobile brake performance test methods, each method is discussed to accurately evaluate automobile brake performance, through combining results of model's calculation with tester's.Firstly, tester methods and road methods of automobile brake performance are introduced. As to test equipment of these methods, their basic structure, test parameters, test principle and so on are analyzed. Being based on comparison of tester methods and road methods, major differences between both of them are analyzed.Secondly, the test on the roller opposite force type brake tester is divided into three cases , and corresponding mechanical models are built. Through automobile brake performance test on tester, the models are analyzed and verified. Using mechanical models, influence factors of the testing brake force are analyzed in detail.Then, the mechanical model of the flat type brake tester is generated. Theoretically, the maximum brake force by means of test can be got. Combined with real automobile brake performance test on tester, comparison and analysis between theoretical calculation results and the test results are developed, and influence factors of the testing brake force on the flat type brake tester are discussed and analyzed.At last, by means of the relationship between braking force and braking distance, the relevance between brake performance test on tester and test on road is built. According to the mechanical models of the roller tester and the flat tester, the relationship about the test results on the two testers is built. And by using the real automobile test and example calculation, the accuracy of relevancies is verified.After analysis and research, the conclusions are shown as below. The brake performance test on the roller opposite force type brake tester are affected by the adhesion coefficient between tested wheels and rollers, the adhesion coefficient between non-test wheels and the ground and the structure parameters of the tester. And the two adhesion coefficients are relatively larger impact on test results among the three factors. Then, the influence factors of the test results on the flat type brake tester mainly include the adhesion coefficient between the wheels and the flats and the brake pedal force while testing. And the adhesion coefficient has a larger impact on test results. Finally, the relevancies among the different test methods are established and their accuracy is confirmed. So test results of different test methods are comparable, and the relevancy can provide some theoretical guidance for research on further automobile brake performance evaluation. At the same time, it also provides some helps in actual test woke. |
