ZF on tomorrow’s occupant safety systems

By Matthew Beecham | 29 May 2018

András Tóth

András Tóth

Continuing just-auto/QUBE's series of interviews with tier 1 suppliers, we caught up with András Tóth, Vice President Product Planning & Strategy, Global Occupant Safety Systems, ZF Active and Passive Safety Technology Division. Here, we learn about how ZF is pushing back the technical boundaries of airbags and preparing passive safety systems for autonomous vehicles.

In terms of passive safety systems, what will tomorrow's car feature?

Generally, passive safety technology has evolved in the past in terms of restraint performance (e.g. by adaptivity and pre-crash features) and will continue to do so driven by increasing safety regulation and rating requirements.

The trend towards higher levels of assisted or even automated driving has the potential to allow new degrees of freedom for vehicle operators such as non-driving tasks, conversing with other occupants in newly configured, more convenient seating positions. This, of course, presents a whole new paradigm shift for occupant safety which today is based on regulations for occupants in [fixed] seating positions.    

In what ways do you see the autonomous vehicle (Level 5 as defined by the SAE) change passive safety technologies?

While speculation has been offered that fully autonomous vehicles will one day eliminate the need for occupant safety systems, that potential reality is still far into the future and it will be decades before most vehicles are fully autonomous.

When Level 5 vehicles do exist, at first they will share the road mainly with non or partially-automated vehicles and thus will require at least an equal level of occupant protection. With the aforementioned potential cockpit configurations and seating positions, we believe this will require an increase in seat-integrated restraints where an occupant-centric protection system is able to move with the occupant. Restraints will also need to be increasingly adaptive to new occupant positions such as the increased space granted between the instrument panel and the occupant.  

Airbags are a mature technology. How much potential is there for further development?

Although interior airbags have already experienced a huge progression from both a technical and content perspective, there are still a number of real world accident types that are driving the need for further airbag technologies. For example, interaction bags that help to protect occupants in far side crashes and in particular are designed to help prevent head strikes between front seat occupants.

We are developing adaptive rear seat airbags.

The rear seat is another area where airbags have not traditionally been present and we are developing adaptive rear seat airbags that can adjust depending on how close the front seats are positioned in relation to the rear seat occupants.

Adding the challenges presented by new possibilities for autonomous driving interiors remains significant expectations for passive safety development.

Could you give us an idea on the ways in which ZF is pushing back the technical boundaries of airbags?

Another innovative airbag example is the development of external pre-crash airbag concepts. This pre-crash external airbag deploys from the external side structure of the vehicle to help protect passengers in the event of a side impact crash.  The airbag design utilises a high volume 3D bag with internal tethers.  The external bag is triggered pre-crash when information from environmental sensors such as cameras or radars indicate that an impact is imminent. Testing studies have shown that this technology can help to reduce impact energy and vehicle intrusion by up to 20-30 percent. The system could be production ready in the 2020 timeframe.  Similar pre-crash capable, seat-integrated side airbags inside the vehicle are envisioned to add further crash severity protection for sensor enhanced vehicles.

We believe that airbags can be deployed before a crash based on sensor data from radar and camera system. Is this an area ZF is developing?

As the above example demonstrates, utilising internal and external sensor data from advanced driver assist systems such as camera, radar, LiDAR, etc., and other on-board sensors that record vehicle speed, occupant presence and position, etc. through the car's safety electronic control unit (ECU) can allow numerous systems to react accordingly in a coordinated way. Seatbelts and seats can adjust, and airbag deployment can be adapted to the predicted type, direction and severity of an imminent crash. For example, in a particularly severe side crash, a tether mechanism within the side airbag can close the inflator vent, maintaining pressure in the bag for longer. By combining the information from these sensors, we can potentially generate additional critical milliseconds in scenarios such as side impact where there is even less time to react to an impact. These systems have been in development for some time and are near to production readiness.

We understand that the term 'integrated safety' refers to how active safety and passive safety are seen as less distinct from one another. Is that correct and what does it mean for ZF?

We have more than a thousand engineers looking at how seatbelt systems can play an active role in occupant protection.

As more advanced technologies in both the active and passive safety realms find their way into today's vehicles, our engineers and researchers are constantly looking for ways to enhance safety by avoiding accidents or mitigating their effects. Seatbelt systems are a great example of a technology that most people would think of as a passive restraint, but we have more than a thousand engineers that look at how these systems can play an active role in occupant protection. The active control retractor (ACR) motorised seatbelt was one of the first examples of integrating active and passive safety and we are now introducing the third generation of this product and making further enhancements such as the active buckle lifter that can also help to reduce seatbelt slack in anticipation of an accident, to load limiting options that help manage occupant energy prior to or in a crash.

We appreciate that a passive safety system on an electric vehicle looks similar to that found on an ICE powered car. Yet are there any differences at all due to their power generation?

The restraint systems would not tend to look that different on the surface, but may need to be customised quite differently because the crash pulse of the vehicle would be altered due to the structural differences of large battery packs and where they are placed in the vehicle. So, the restraint systems would need to take this into account in helping to protect the occupant.

We have seen some consolidation in the occupant restraints market over the past decade. Do you see more to come?

This is hard to predict but when considering the general global megatrends toward automated driving, advanced safety and electrification of the powertrain understanding the intricacies of how these complex trends affect occupant safety favours larger more integrated system solution suppliers. How this may or may not impact market players of the future, shall remain in the realm of individual speculation.