Abstract
The aim of this study was to develop the computer simulation model for the pedestrian detection sensor with the pressure tube. Pedestrian sensing system is an important component of the active system such as an active bon-net or a pedestrian protection airbag system. The pedestrian sensing system has to have the ability to detect a range of pedestrian statures and to recognize the animal or the small object. Computer simulations provide a powerful tool for optimizing the sensor system’s ability and the sensor integration parameters.
A new simulation methodology that adopts the multi-chamber airbag simulation method and the virtual vent was developed for the pressure tube type pedestrian detection sensor. In this study the impact tests with various bumper foam design were conducted in order to investigate the pressure output characteristics of the pressure tube type pedestrian detection sensor. The pressure peak at the end of the tube and the time delay between both ends of the tube were recorded. Based on this information, computer simulations are carried out to get the reliable pressure tube model. The simulation model development focused on the pressure peak, the rising time and the time delay of the pressure. The efficiency of permeability between control volumes and the time delay of the pressure propagation were used for reproducing the result of the physical tests.
The results showed that the computer simulation model using the multi-chamber airbag and the virtual vent produced pressure peak and pressure propagation in the pressure tube during the impact. Some aspects of the pressure characteristics in the tests using the various sensor integration parameters were in good agreement with the model.
The uniform pressure method is the fast simulation method but not for the wave propagation in the airbag. In case of the impact location is near the end of the tube, the model has the limitation for providing both pressure magnitude and time delay. The efficiency of permeability and the time delay of the virtual vent were can be used alternately for provide the accurate information.
The pressure response of the pressure tube model using multi-chamber airbag and virtual vent presented in this paper is new and comparable with that in corresponding impact tests in terms of the pressure peak, the rising time and the time delay of the pressure. The more accurate investigation into the various pedestrian detection scenarios and the bumper foam design for the sensor integration can be made to improve the discrimination of the sensor output signal using the developed simulation method.
New computer simulation method for the pedestrian detection sensor with pressure tube has been developed. Main aspects of the pressure response in the model due to the various bumper foam designs were in good agreement with tests.
KEYWORDS – Pedestrian Detection Sensor, Pressure Tube, Multi-chamber Airbag, Virtual Vent, Uniform Pressure Method