The SAFE-UP project defines future safety-critical scenarios involving high-automated vehicles (HAV) and also propose solutions to protect both vehicle occupants and vulnerable road users in the event of a possible collision in rural, highway and urban environment. In future HAV long journeys, the driver is likely to spent time performing non-driving activities, which will demand new interior designs promoting more comfort, and more relaxed seating positions will be introduced. SAFE-UP aims to proactively address these upcoming safety challenges by developing innovative technologies, testing and assessment methods, which will aim to reduce the overall number of road fatalities through crash avoidance and mitigation of injuries. Current restraint systems are made for standard upright positions and their development is limited by legislation, which does not consider to be used in reclined positions. In this context, this paper summarizes the performance of sled tests activities with a THOR-50M, which has been adapted to be tested in reclined positions (THOR-reclined), with the objective of demonstrate the optimization of restraint systems carried out in simulation activities, as well as to demonstrate the reduction of occupant’s injuries when this optimized configuration is used. Sled testing activities were defined, planned and executed considering relevant parameters and reproducing a representative crash scenario with an occupant in a reclined seating position surrounded by a generic environment. These tests were conducted using a sled platform which allowed the assembly of all involved components to evaluate passive safety systems involved in a crash. In order to carry out the final tests with the THOR-reclined, a validation of the components and the generic environment had to be carried out to ensure its robustness and stability during the sled tests. This generic environment manufactured by IDIADA, consisted of a seat backrest, the steering column assembly, a steering wheel, a footrest, knee bolster and a semi-rigid seat, manufactured by CEESAR (Uriot J. , et al., 2015). A total of 6 sled tests were performed, in which injuries of the THOR-reclined, with a seat backrest tilted at 45º, were evaluated by carrying out 2 tests with traditional restraint systems, and 4 tests by using optimized restraint systems. Both tests performed with traditional restraint systems followed a quite similar trend, obtaining injury critical values in several body regions. It could be observed how through the use of optimized restraint systems, there was an improvement as these injury values were reduced in different body areas of the THOR-reclined. The diameter of the airbag’s venthole had an influence on head injury values. Furthermore, a difference in the load on the femurs could also be confirmed by changing the knee bolster density. The sled tests have been performed only with a THOR-reclined, which is one of the very few specimens in the world that have been adapted for these positions. Further analysis with other adapted ATD’s would serve to complement this work and to be able to compare it with results on the THOR-reclined. In addition, other seating postures involving a higher reclined position would be interesting to be studied which would define other pre-crash scenarios. As a conclusion, it can be stated that traditional restraint systems might not be suitable for HAV future crash scenarios, giving evidence of the need to use innovative passive safety systems that would be appropriate for relaxed and reclined seating positions. The optimization performed in simulation activities proved to be effective with the physical demonstration by carrying out sled testing activities with a THOR-reclined. Finally, considering an optimized restraint system configuration resulted in an improvement in the occupant’s injury risks in different body regions of the THOR-reclined.
Mr. Carles Vidal Aguado, R&D Project Engineer, Applus IDIADA