Laboratory experiments of vehicle crash data from event data recorder and additional CAN bus data

Abstract

Following the EU General Safety Regulations of April 2019, the EU Parliament has proposed and approved a law whereby the Event Data Recorders (EDRs) will become mandatory on the modern vehicle fleet. The inclusion of EDRs is not only beneficial to recover pre and post-crash data which was notoriously difficult to be known by the traditional accident reconstruction methods, but also provides a glimpse of the driver input parameters during pre-crash. The accuracy and validation of the 02EDR (airbag module generation used in this study) that was equipped on a 2007 Toyota Auris was tested in the low-cost and repeatable experimental campaign discussed herein. While everything remains stationary within a confined laboratory environment, emulation of various driving parameters was carried out through LabVIEW and the respective electrical circuits. The emulated parameters were the same parameters that get recorded in the 5-second pre-crash data period of the EDR, being Vehicle Speed, Engine Speed, Accelerator Pedal Position (APP) and Brake Status. Apart from the change in brake status which was programmed to either go ON or OFF, the other emulated driving parameters were simulated to either remain constant or else ramp up and ramp down in a reasonable fashion, similar to a realistic driving behaviour. Messages conveying data of interest transmitted on the test vehicle’s Controller Area Network (CAN) Bus were sniffed (overheard) and deciphered using a sniffer. The respective translational equations as well as different refresh rates of the different CAN messages were catalogued and characterized. A series of small impacts that did not trigger airbag deployment (non-deployment events) were performed to validate the data limitations stated in the EDR report. Meticulous planning for carrying out a deployment event (a bigger impact that triggers airbag deployment) using an Izod setup was also carried out. By varying the impact hardware (to lengthen the deceleration pulse), building electronic circuitry (to capture the airbag deployment pulse) as well as integrating various external reference instrumentation including a rotational potentiometer to track the Izod pendulum’s motion, two accelerometers and an Inertial Measurement Unit (IMU), the setup was prepared to trace and capture the deployment signal upon impact. The deployment data that was acquired from three different acquisition systems, being CAN, LabVIEW and CDR report, was synchronised and is presented.