Airbag technology for autonomous vehicles

13 February 2020

(Excerpt)

Automotive industry's focus on active safety technologies―such as antilock-braking system (ABS), electronic stability control (ESC) and traction control system (TCS)―has increased significantly in the past two decades. Automakers are also offering new vehicles with rising number of advanced driver assistance systems (ADAS) such as adaptive cruise control (ACC), lane departure warning (LDW), blind spot detection (BSD) and automatic emergency braking (AEB), which help drivers in reducing the possibility of accidents. Some of these technologies, such as AEB, can even take corrective action like applying brakes if the driver fails to respond in time to avoid accidents.

While active safety systems and ADAS can help reduce accidents, they cannot completely eliminate the possibility of accidents. In an event when accidents are unavoidable, passive safety systems such as airbags and seatbelts continue to play a vital role in reducing the impact of such accidents. Being a passive safety technology, airbags spring into action as soon as a vehicle's sensors detect an accident, reducing occupant injuries and saving lives. According to the National Highway Traffic Safety Administration (NHTSA) data, frontal airbags saved 50,457 lives in the United States between 1987 and 2017. Globally, the contribution of airbags to saving lives and reducing injuries after accidents will be several times more.

Over the years, the number of airbags per vehicle has gone up significantly; many mass market models now come equipped with six airbags as standard. Some automakers are equipping their select model vehicles with even more airbags as part of their strategy to improve occupant safety. Apart from widely used driver-side airbags and passenger-side airbags, some modern vehicles feature knee airbags, side airbags, curtain side airbags, center airbags, rear curtain airbags and seat cushion airbags. Some suppliers are now developing external airbags which will deploy outside the vehicle. Last year, ZF presented a prototype of its pre-crash external side airbag that can deploy before a collision. The German OEM claimed its new airbag can help reduce occupant injury severity for side impact collisions by up to 40%.

Higher global light vehicle production, regulations and safety rating mechanisms like the New Car Assessment Program (NCAP), continue to drive demand for airbag modules. IHS Markit forecasts linear growth in demand for airbag modules over the next six years, from 413.8 million in 2019 to 478 million in 2025, at a CAGR of 2.4%.

Airbags in autonomous vehicles

Airbags, together with seatbelts, have worked effectively when occupants in a vehicle sit in a forward-facing upright position. However, this is set to change in automated driving vehicles. Autonomous driving aims to reduce or completely eliminate a human driver's role in driving a vehicle in order to drastically reduce accidents. Vehicles, featuring SAE Level 3+ automated driving capability, will be able to take control of driving, allowing drivers to spend their time in other activities, such as talking to other occupants, listening to song, podcasts or watching videos. When not driving, the drivers may relax by reclining their seats or talking to fellow passengers by swiveling their seat. In fully autonomous (Level 5) vehicles, self-driving system will take full control of driving.

Autonomous driving is expected to herald new use cases for vehicle interior, including the seating layout, which has remained the same for many decades. The higher the level of automation, the greater the likelihood of unusual interior concept and seat configuration. However, any change in the current seating arrangement in a vehicle will require a higher level of occupant safety. For example, in a highly automated vehicle, a conventional steering wheel airbag may not be that effective if the driver has turned his seat by, say 90%, to talk to a co-passenger. The same also applies to autonomous vehicles, where the steering wheel folds away in autonomous driving mode or where there is no steering wheel.

Airbag suppliers are bracing themselves for these changes through intensifying focus on research and new product development. Autoliv has developed a new protective airbag system called 'Life Cell' that is designed to protect the occupants without being impacted by their seating position, including the seat orientation in proximity to the steering wheel, and the recline angle either pitched forward or leaning backwards. Once it is fully activated together with a steering wheel airbag deployment, the Life Cell airbag resembles a protective cocoon. Life Cell allows for unique vehicle interior styling configurations while still providing head protection. Life Cell's design also enables far-side protection for the occupant and can counteract the velocity impact of free-flying objects, such as unbuckled backseat occupants or loose items not secured in the vehicle, from further injuring the driver.