Pedestrian Headforms

Used for pedestrian safety testing, Diversified Technical Systems’ (Seal Beach, CA) pedestrian headforms (which emulate a human head) embedded data acquisition solution are instrumented with a triaxial accelerometer and miniature SLICE NANO data recorder inside and then launched at a vehicle’s hood and windshield to test for potential injuries that may be sustained by pedestrians. DTS’ three-channel SLICE NANO miniature data recorder with 16 GB flash memory offers a cable-free solution for both the 4.5 kg (9.9 lb) “adult” and the 3.5 kg (7.7 lb) “child” headform. The mounting block also houses a DTS ACC3 PRO triaxial accelerometer, which has a mass of 2000 g (70 oz), that measures the linear acceleration and impact forces. Options are also available for other sensor models. “The DAS and sensors are all inside so there are no cables to get tangled up when it’s launched at the car. That also helps with repeatability—something that’s especially important for regulation testing,” said Scott Pruitt, DTS president and co-founder.

Features pedestrian facility include:

  • Equipment and software developed in-house for targeting and aligning the headform which ensures every impact is exactly where it is supposed to be, well within the permitted tolerance.
  • An accurate independent measurement of the headform velocity before impact, for every test, using a laser-based system.
  • Lower-leg tests conducted using a long acceleration distance to ensure the foam at the rear of the leg is not compressed before the impact on the vehicle

A complete suite of impactors, gives capability to perform any type of testing:

  • Headforms Adult (4.8kg) Small Adult (3.5kg) and Child (2.5kg)
  • Euro NCAP / Japan / GTR 4.5kg Adult headform
  • Upper Leg WG17 / EC / Euro NCAP
  • Lower Leg WG17 / EC / Euro NCAP

The WG17 Headform impactors from Humanetics were developed with the Netherlands Organisation for Applied Scientific Research (TNO) in Delft and partners in the Working Group 17 from the European Enhanced Vehicle-safety Committee (EEVC). These headform impactors have been incorporated in a EEVC proposal for a Directive for Pedestrian Safety Tests of passenger cars for the European Commission. The design of the headform is based on the current WG10 headforms, which are currently used as the tool in pedestrian safety evaluations in the European New Car Assessment Program (EuroNCAP).

In June 1997, the European Enhanced Vehicle-safety Committee (EEVC) decided to set up a Pedestrian Safety working group: WG17. The main task of EEVC Working Group 17 was to review EEVC Working Group 10 pedestrian protection test methods from 1994 and to propose possible revisions, taking into account new data in the field of accident statistics, biomechanics and test results. The EEVC WG17 report has been finalized in December 1998. Several improvements in test conditions, requirements and tools (i.e. impactors) have been included. The new EEVC pedestrian protection test methods will be used by the European Commission for further development of regulations in this field.

Since 1994, the subsystem impactors described in the EEVC test methods have been further evaluated and improved. EEVC WG17 has included new impactor specifications in the EEVC test methods:

  • Improvement of the leg-form impactor with a damper in order to avoid vibrations.
  • Alteration of headform impactor material to improve production and durability.
  • Improvement of the dynamic certification procedure of the leg-form and headform impactors in order to better reflect actual use in bumper and bonnet tests.
  • Enhanced durability and repeatability of the headform impactors.
To improve durability and repeatability EEVC WG17 decided to change to a more Hybrid-like head- form, i.e. an aluminium sphere covered with a PVC skin. The headform specifications have been updated in this respect. The outer diameter and mass of the headforms are unchanged. The Humanetics WG17 Headform impactors meet the original certification requirement, which was developed on the basis of a drop test. Meeting this biofidelity requirement meant that the EEVC WG17 subsequently approved the Humanetics WG17 Headform impactor design.
The original headform certification speed obtained from a drop test was only 20-25% of the impact speed on the car bonnet. EEVC WG17 has now developed a new dynamic certification procedure, which better reflects the actual use of headform impactors in bonnet tests.
In 2009 Euro NCAP has introduced a new overall vehicle rating that will put growing emphasis on pedestrian protection in the years to come.  This new rating system was implemented in February 2010.  At the same time, a new European Commission regulation on the pedestrian protection, (EC) No. 78/2009, has been published, which repeals and replaces the previous EC directives 2003/102/EEC and 2005/66/EC.