Modern vehicle seats feature a multitude of functions, some linked to active vehicle safety systems, which require the use of seat occupancy mats, so-called ‘passive occupant detection systems’ (PODS).
Depending on what weight (an adult, child, shopping bag, or nothing at all) is currently on the seat cushion of the front passenger seat, the PODS sensor activates systems such as the seat belt tensioner and controls the activation of the front passenger airbag in the event of an accident.
The seat occupancy mat consists of a gel-filled cushion, pressure sensors and an electronic control unit. The fact that the car seat has thus become an important and safety-relevant factor in the vehicle presents manufacturers with numerous challenges. Occupancy mats must be calibrated and tested, which is why German specialist Berghof Testing has developed its Seat Function Tester (SFT) and the Force Application Machine (FAM).
According to the company, the FAM helps manufacturers ensure that only functioning and properly calibrated seats will leave their plants. By applying various forces and using control unit communication, it quickly and precisely performs mechanical end-of-line function testing and calibration of the seats without compressed air needed – and in doing so it is a reliable tool of quality assurance of vehicle seats and occupancy mats.
The system tests and calibrates the seat occupancy mat with fast, controlled and high-precision force control. The FAM covers three different tasks: calibration of seat occupancy mats, seatbelt reminder testing as well as body sense testing. It is also possible to combine all three processes in mixed operation with a single unit.
Flexible calibration of different seat variants and series in production is also made possible thanks to variant-related parameterization of the pressure forces and pressure positions on the seat. The entire testing procedure takes approximately 50 seconds in total, meaning laborious and slow testing procedures, such as those using weights, are a thing of the past.
Complementing seat calibration using the FAM is the SFT, available either as a separate system – or together with SFT as a combined system. SFT assumes the task of testing the proper function of all motors, control knobs and seat memory controls installed in the seat – such as pressure-sensitive passenger detection systems (passenger detection, seatbelt reminder), seat adjusters, seat heaters and massage mats, belt buckles and tensioners, foot compartment and ambient lighting, as well as the crash-activated headrest.
The intelligent test system enables cycle time-optimized, efficient and safe testing of individual seats as well as pairs of seats. It logs results, events and errors and integration of the tester into an existing production line is easily possible.
