For fine-tuning of the parameters of algorithms used for activation of deployable pedestrian protection safety systems, quite a number of impact tests have to be performed on real vehicles. The impactors used for these purposes comprise misuse-objects, hardest-to-detect pedestrian impactors, but also impactors that represent larger pedestrians, such as the WG17 legform or the FlexPLI. Such tests are performed with impact speeds up to 55 kph and at ambient temperatures between −35 °C and 90 °C. Especially for the more complex FlexPLI there is a high risk of damage to the impactor under such conditions. Additionally, the required calibration procedures after such test series and an obligatory exchange of parts (e.g. ligaments) after each test are a source for further costs.
Therefore, the aim of this study was the development of an impactor surrogate that correctly represents all relevant impact properties of the FlexPLI for sensor testing, but being much more robust, offering the simplest possible structure and therefore being also suited for repeated tests with impact speeds of up to 55 kph, without the need for replacement parts. Finally, it could be demonstrated that a simple impactor design, even without a knee joint, could fulfill these requirements very well.
It is also shown in this study, how a fully parametrized impactor model has been used together with the optimization tool LS-OPT, to efficiently support the development process of such an impactor surrogate.