Modeling And Simulating Research On Vehicle Automatic Emergency Braking System

Now the vehicle active safety issue has become a key research area in automotive industry. Automatic emergency brake system is a new kind of active safety system, and also become one of the key research systems in automotive industry. The functions of the system are both:?Forward collision warning. Remind drivers by sound and light alarm when the vehicle in risk of collision. ?Automatic braking When possibility of danger increasing, but the driver did not take any measures to brake, the system brakes automatically to avoid a collision or reduce speed when collision happen to reduce injuries.In this paper, through join-simulation method research the application of the time index of Tb control strategies in AEB system. And conduct some preliminary research about AEB system.Firstly analysis the concept, function, system composition, key problems of the AEB system. Do the overall planning of join-simulation process according to the key problems. Secondly establish the whole vehicle model. Virtual experimental are done to verify the overall model, the results show that the error is within 5%, and response quickly. Thirdly deliberate the control strategy of AEB system, including principle of target detection, target classification, braking strategy. Calculate the time index Tb. Propose a control strategy: when Tb=2.6s warning the driver; when Tb=1.6s the vehicle model get-4m/s2 deceleration; when Tb=1.6s it is-8m/s2. Finally based on the Bosch middle range radar system, conduct some preliminary research about AEB system. Expound the test scenarios, test equipments, test condition, and the stationary/moving object when conducting the experiment about the AEB system. Considering the security problem, when the experiments is doing set when Tb = 1.2 s the deceleration is-5 m/s2. And do simulation also at the strategy. Compare the test result and simulation result, and analyzes the reason causing the difference.Test scenario:?test vehicle speed is 40km/h, target is stand. ?test vehicle speed is 50km/h and the target speed is 20km/h. Select the duration of time of the maximal deceleration, the minimum distance between the test vehicle and target, and whether can avoid collisions, as indicators to compare the test results and simulation results. Scenario? : The test results are 1.92 s, 0.54 m and avoidance collision; simulation results are 2.18 s, 0.58 m and avoidance collision. Scenario?: The test results are 1.42 s, 1.07 m and avoidance collision; simulation results are 2.25 s, 2.74 m and avoidance collision. So the test results and simulation results are very close. The simulation results of E-NCAP scenarios show, when approaching stand target, the speed is over 65km/h collision cannot be avoided, when approaching slow moving and regular break target collision can be avoided, when approaching emergency brake target collision cannot be avoided when the initial distance is 12 m.In conclusion, the simulation results show some certain guiding for the parameter tuning when practical application. In addition, this paper carried primary research on experiment of AEB system. This has certain reference value on further research on it.