Adaptability of vehicle safety systems ensures safety for all passengers with consideration to their size, gender, and mobility.
Interview with Dr. Andrew Harrison
German Aerospace Center – Institute of Vehicle Concepts
As highly automated and autonomous vehicles move closer to becoming an everyday reality, the demands on vehicle safety are undergoing a fundamental transformation. One critical area is passive safety, in other words, the technologies and systems designed to protect passengers during accidents. But what does the future of passive safety look like in a world where passengers might travel in new seating configurations or engage in non-driving related tasks?
This is one of the key questions addressed by the EU research project Aware2All. Within this project, adaptive passive safety systems are being researched and developed that dynamically respond to real crash scenarios and the evolving interior designs of future automated and autonomous vehicles. The goal is to create and evaluate passive safety features, such as advanced airbags and seating structures, that ensure the protection of all occupants, regardless of their size, gender, or seating posture, by designing adaptive safety systems that respond dynamically to real-time crash situations in new vehicle interiors.
In the following interview, Dr. Andrew Harrison, Aware2All’s task leader for passive safety and leader of DEMO 1 , explains how passive safety is evolving to meet the demands of new vehicle concepts. He also discusses the challenges involved, and shares insights from the project’s ground-breaking research.
Question 1:
Dr. Harrison, could you please explain what is meant by "passive safety" and why it is so important in vehicle development?
Answer:
‘Passive safety is what protects you when things go wrong.’
Passive safety refers to the design features and systems in a vehicle that protect occupants in the event of an accident. This includes components such as seatbelts, airbags, and the vehicle's structural design. Unlike active safety, which aims to prevent accidents, passive safety works to reduce injuries during and after an accident happens. By effectively managing and mitigating the energy in an accident through crumple zones and load-path management, the impact on passengers is reduced, significantly lowering the risk of injury or death. Basically, it can be said that passive safety is what protects you when things go wrong. This is why passive safety systems play a vital role in saving lives. This is why passive safety systems are crucial not only for saving lives but also for ensuring that vehicles are developed to be as safe as possible for occupants. On top of that, meeting established passive safety standards is a legal requirement for vehicles to be approved for use on public roads.
Figure 1: Cut-model to show passive safety systems considered in Aware2All (highlighted).
Question 2:
How do highly automated vehicles change the requirements for passive safety?
Answer:
Highly automated and autonomous vehicles fundamentally change how we think about and approach passive safety. Since these vehicles take over the driving tasks, the interior design can be drastically different, potentially allowing a ‘living room’ style interior. As result, occupants might not be sitting in the usual upright position or even facing forward for which current passive safety systems are designed. For example, occupants might be reclining, sitting backward, or not paying attention to external events. This requires a complete redesign of traditional safety features like airbags and seatbelts to accommodate various seating positions and configurations. Furthermore, the emerging change in interior configurations, in particular to ‘shuttle’ vehicle designs, often leads to shorter crumple zones to maximise comfort and space. Therefore, as vehicles become more automated, passive safety features must evolve to ensure occupants remain safe, regardless of their seating position or activity inside the vehicle.
Question 3:
Why are adaptive safety systems crucial for the future of mobility?
Answer:
Adaptive safety systems are crucial for the future of mobility because they enable vehicle safety features to adapt to changing designs and how people use vehicles. As we move away from ‘traditional’ layouts, adaptability of vehicle safety systems ensures safety for all passengers with consideration to their size, gender, and mobility. As cars become more automated and people use them in new ways — like shared rides, lying back to relax, or even working while riding — the safety systems need to be smart enough to respond to all those different scenarios. For example, an adaptive system could detect that a passenger is reclining and adjust the airbag or seatbelt to provide optimal protection. In short, adaptive safety systems help ensuring that everyone stays safe, no matter how they’re using the vehicle, which is key as mobility becomes more flexible and automated.
Question 4:
How do you ensure in the Aware2All project that passive safety systems are suitable for a greater variability of passengers and seating postures?
In Aware2All, we have created a digital representation of the DLR Urban Modular Vehicle (UMV) People-Mover for analysis and development of passive safety systems. This acts as a playground to identify critical aspects of an accident and to evaluate and optimise solutions. For example, the digital model has variations with reclined and upright seats with different concepts of seatbelts and airbags. We employ a number of occupant models to represent 50th and 05th male and female, alongside physically disabled variants. In the digital world, we employ Anthropometric Test Devices (as used in regulatory testing) and Human Body Models to satisfy a range of occupant sizes, genders and mobility. The injury and kinematic data is used to inform decisions in the vehicle structure, airbag and seatbelt design.
Image: frontal view of two human body models (VIVA+ 50th percentile Female); left: Standard female model in seated position; right: female model with physical disability (loss of limb).
(Image source: Humanetics Innovative Solutions, Inc. (“Humanetics”). All rights reserved)
(Model source: Viva+ Documentation, https://vivaplus.readthedocs.io, licensed under CC BY 4.0.)
Image: ISO view of two FE-THOR-AV ATDs left: 05th Percentile female FE-ATD in seated position with physical disability (loss of limb).; right: 50th Percentile Male FE-ATD with physical disability (loss of limb).
Image: three human body model positions; Standard upright driving posture, one in upright seated posture for HAV, one in reclined posture within a HAV
(Model source: Viva+ Documentation, https://vivaplus.readthedocs.io, licensed under CC BY 4.0.)
Video: 360-degree rotating view of these two human body models
Question 5:
Can you tell us more about the different use cases you have studied in Aware2All?
Answer:
We wanted to keep the use-cases as close to regulatory and consumer testing as possible whilst still acknowledging critical scenarios. The main two load-cases (cases that represent an accident) are a Full Frontal Rigid Wall impact and the Mobile Progressive Deformable Barrier impact.
Video: load-case Full Frontal Rigid Wall impact
Video: load-case Mobile Progressive Deformable
The load-cases are used in consumer testing and represent potential rear-world and severe accidents, of which the vehicle must pass safety requirements. The load-cases were used to build various “scenarios”. Within the scenarios, we have occupants sitting in forward and rearward orientations and in reclined positions for 50th & 05th percentile passengers, as well as with a physical disability (represented by loss of limb). The scenarios were designed so that we could examine challenges and draw conclusions and results from one scenario and apply it to another. For example, a scenario which presents opposed facing occupancy can be formed in early stages of safety system development by analysis of the rearward and forward-facing use-cases. The use of different passenger models in each load-case and scenario enables critical assessment of the performance of the restraint systems for all passengers, responding to the challenges in restraint system design for a larger occupant to a smaller occupant, or those with a physical disability, for example.
Question 6:
What findings have you made so far, for instance, in the use case of rear-facing seating?
Answer:
Rear-facing occupancy in forward collisions represents a relatively new area of research focused on enhancing occupant safety. Current kinematic studies indicate that, during the initial crash phase, the occupant moves rearward into the seatback, followed by an upward trajectory throughout the initial crash phase. The preliminary outlook from kinematics highlight the neck and pelvis as possible key regions warranting further investigation due to various factors, including the occupant interaction with the seatbelt. The interaction of the seatbelt, with the conventional design, shows that the occupant response significantly changes with belt parameters and potentially lead to elevated injury risk. Initial findings suggest that the 50th percentile male may be at greater risk of pelvic injury compared to the 5th and 50th percentile females when using conventional restraints. These conclusions are based solely on comparative simulations, as accurate injury risk quantification requires extensive data for assessment, verification, and validation. Ongoing efforts by DLR, THI, and Humanetics aim to develop robust evaluation methods, which will support deeper analysis of injury metrics and inform future research in rear-facing occupant protection as well as assessment criteria.
Dr. Harrison, thank you for taking the time to share your fascinating work with us. We wish you and all partner involved in the Aware2All project all the best, and look forward to seeing what comes next. We will be sure to keep our readers updated on future developments.