ADAS simulation technology: keeping drivers ‘in the loop’
05 October 2018
The next generation of vehicles will feature high levels of connectivity. As this piece from Ansible Motion explains, how drivers react to technology intervention will be a crucial element for the acceptance of the connected car...
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Rising use of advanced driver assistance systems (ADAS) presents a fascinating challenge for vehicle verification and testing, perhaps more so than any other aspect of the vehicle, as this is where the interactions of the machine and its human driver become entwined. Human beings are therefore a vital part of the test and verification process for vehicles with ADAS systems.
It is imperative that manufacturers understand how drivers who are stressed, tired or distracted respond to sensor-derived information and/or system interventions – helping determine if it will ever be possible for connected cars to deliver a safe, pleasant and seamless experience on our roads.
Previously, it has been necessary to assess system behaviour with real drivers in real cars. However, this approach is costly as it requires access to vehicles, as well as secure test facilities. Nowadays there are two options: standalone prototype vehicles; or the use of an engineering-class driver-in-the-loop (DIL) simulators, in conjunction with prototypes.
DIL simulation has progressed dramatically in recent years. Legacy, ‘hexapod’ style simulators, adopted by the auto industry from 50-year-old aircraft technology, are now being superseded by what are termed ‘engineering-class simulators’: leaner, meaner variants that can keep up with the needs of modern vehicle testing.
The dynamics of road vehicles are characterised by short, sharp movements – in stark contrast to the lower frequency, large arc movements of aircrafts. Ansible Motion design simulators with road vehicles in mind: its simulators have industry-unique motion systems that are aligned with the six primary movement axes of a vehicle, providing the appropriate control and mechanical stiffness to accurately carry out the desired motions.
The industry-leading ‘stratiform’ motion system is essentially a vehicle cabin placed on top of several layers of sophisticated machinery, rather than simply a set of rolling tires. The first X-Y-Yaw layers give the simulator its ground plane movements, while the subsequent layers generate pitch, roll and ‘bounce’ motions. This results in a simulator with a lower centre of gravity, and a very high level of control fidelity.
Ansible Motion is unique in its ability to create fully immersive experiences through its high-tech DIL simulators, meaning drivers respond as they would in a real car. This enables engineers to recreate real-world scenarios and monitor driver reactions – for example, in autonomous emergency braking (AEB) procedures. DIL simulators that can create convincing illusions for drivers can be very useful tools for human factor studies, vehicle engineering work and/or fundamental automotive research.
Simulators offer vehicle manufacturers tangible benefits over using prototypes alone: first, building fewer development cars to a higher standard (average prototype cost is £1m per vehicle); and second, the ability to test multiple scenarios in a laboratory-like, repeatable environment. DIL laboratories create space for professional and non-professional drivers alike to test and experience realistic and repeatable scenarios in a controlled environment. And nowadays of course, some simulator ‘drivers’ are not human at all.
A successful experiment enables the drivers to engage and interact with virtual vehicles in virtual environments, while making measurable changes on the fly. DIL simulation allows engineers to make changes at the touch of a button – ranging from weather variations to vehicle attributes. New vehicle design features can be thoroughly explored with real-time monitoring and feedback.
DIL simulation can create a valuable margin within the vehicle development cycle (project timelines can be reduced by as much as 70% when simulation is used in conjunction with physical prototypes), giving designers time to conduct further experiments and/or reduce time-to-market.
To suitably test and validate ADAS scenarios (each of which may have many thousands of combinations to be verified), offline simulation tools are essential to tackle the intense number-crunching required at both the early and ongoing development stages. DIL simulation allows vehicle designers to truly understand how drivers may respond to ADAS implementations.
For example, the handover experience from driver to vehicle and back again can be tested with real people, to gather both subjective and objective feedback on the experience. Catching unacceptable interactions early in the development process has the potential to save millions of pounds – not to mention, the vehicle manufacturer’s reputation.
Looking further ahead, DIL simulators can be used to answer questions and solve mysteries around vehicle autonomy. For instance, assessing the root causes of motion sickness: an issue which has been reported in autonomous vehicle testing, and that autonomous advocates are yet to offer a solution to.
If today’s drivers are to become passengers in their cars, thanks to autonomous controls, then their time will naturally become utilised in some other way. The University of Michigan interviewed more than 3,200 people, asking what they would do if they had to no longer pay attention to the road. They found that 36% would engage in visual activities that might increase the incidence of motion sickness, such as reading, working or watching videos.
Other reports, moreover, suggest as many as 66% of passengers might experience mild to moderate motion sickness while being transported by autonomous vehicles. Ansible Motion’s driving simulator technology enables automotive designers to virtually test a multitude of conditions, including road surfaces, sound levels, suspension settings, interior surroundings, and much more.
Designers can experience and truly understand the best combination that gives optimum ride comfort, for example. This means the first physical prototype can already be designed to minimise motion sickness. “The reason for this,” says Phil Morse, international manager at Ansible Motion, “is simple: safety.
“Maintaining the trust of motorists and passengers will be crucial if we’re to transition successfully to autonomous vehicles. But making the switch will be difficult, by its very nature. Cars might be asked to handle autonomous driving on motorways, for instance, and then switch to traditional human control in complex urban environments.
“It’s clear that in the future, all vehicles will be developed and refined in a virtual world, as well as in the real world. The latest engineering-class driving simulators now make it possible to integrate hardware to allow human and non-human drivers to engage, just as they would in a real car.”
People will ultimately decide the success or failure of vehicle features and functions in the marketplace. For example, the point where functions such as electronic stability control (ESC) or AEB should intervene is highly subjective.
DIL testing can advance human interaction and experience dramatically in a vehicle project’s timescale, and can vastly increase the frequency of driver contact with envisioned systems as they are being tuned and developed. One US OEM reported that by pre-qualifying testing on a simulator, a ten-day testing session for ESC was reduced to just three days.
The emerging trends of electrification, connectivity and autonomy require early and frequent feedback from real people, from expert evaluators to everyday drivers and participants – whose behaviour, instincts and interactions are necessarily intertwined with the intervention of autonomous technologies. Driving simulator labs, containing technologies befitting the vehicles that are now being developed inside them, may be the best way to make this happen.
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