You Drive Me Crazy

Highly automated driving under SAE Level 4 is casting its shadows. In the future, vehicles without steeringwheels and pedals will need new input devices that will enable a human driver to take control whenever necessary. In addition, highly automated driving functions demand high-performance steering systems to provide reserves for potential handover scenarios. IAV has examined both of these aspects in studies.

Although highly automated SAE Level 4 vehicles will be able to decide for themselves in most situations, this will not apply in every case. This is why it may sometimes be necessary for a human driver to take control. In future, this could require completely new control input devices. After all, vehicles will no longer need any steering wheel or pedals. Then, even a large windscreen for forward vision will no longer be an absolute necessity. As a result, new concepts are called for that will make it possible for a human driver to take over quickly and control the vehicle intuitively.

"The battle of the senses"

In the study “The battle of the senses: application of future control devices as a fallback solution for highly automated driving”, IAV examined precisely what this might look like. “To get a view of the road, we use a pair of first-person-view glasses that are quickly at hand in the event of hazard and deliver an image from a camera pointing in the direction of travel,” explains Christian Dreher, Technical Consultant at IAV. The advantage is that the view seen through these glasses provides relevant information on the traffic situation if there is poor forward visibility or the driver is sitting with his or her face looking towards the side or rear – a highly probable scenario in tomorrow’s vehicles with their completely restructured passenger compartments.

Once steering wheels and pedals are obviated in highly automated vehicles, it will be necessary to integrate alternative input devices. Existing components, such as the knobs or joysticks from the infotainment system, can be used. Both enable a steering and driving functionality.

For their study, IAV’s experts tested their ideas on alternative input devices with test persons. These involved the use of RC cars that are equipped with a front view camera. Questionnaires provided the basis for recording participants’ subjective assessment, for example, which input device made it possible to remain in control of the driving situation more quickly. Also objectively evaluated was the performance of participants in various driving exercises, e.g. how reliably they were able to keep in lane or drive through a gate. The next step will be to validate these findings in a real-world SEAT Ateca on IAV’s test track in Gifhorn.

“Control indicator” for manual driver torque request

In a further study (“You drive me crazy: enhance the driving ability of professional drivers to improve controllability judgement of hazardous situations”), IAV investigated how the driving ability of test drivers can be adapted to provide a better assessment of controllability in hazardous driving situations. Four controllability classifications are defined for this purpose in ISO standard 26262 (C0: controllable in general; C1: simply controllable; C2: normally controllable; C3: difficult to control or uncontrollable).

The case in hand involves developing steering systems that need to be verified and validated several times by professional test drivers on test tracks in an early phase of the development process. The aim is to enable later consumers to retain good control over the vehicle even in potentially critical driving situations. The correlation between the C classifications for controllability and steering is established on the basis of the manual driver torque required for intervening in steering. To this end, IAV has drawn up a proposal based on scientific data.

“The challenge is that test drivers are very well trained and can easily apply a higher level of manual steering torque than the average driver in critical situations,” says Dr. Marcus Perner, Technical Consultant at IAV. “In certain instances, calibration of the steering system’s safety functions may be too conservative, resulting in an unnecessarily high safety margin. Therefore, it is our aim to obtain assessments that come as close as possible to actual consumer driving behavior at an early stage in the development process”.

IAV sees the potential for implementing additional complex functionalities for the steering system. To obtain an objective assessment of current manual driver torque e.g. while circling IAV has developed a type of “control indicator”. In a similar way to audio devices, it consists of green, yellow and red LEDs that display the current value in an intuitive manner. This allows test drivers to calibrate the system in such a way that they can complete the driving exercise with minimum manual steering torque. This opens up more capability for automated driving functions.

In the study, 20 test drivers assessed the device in a positive light, commenting that the criticality of a situation was instantly evident at all times. In the next step, IAV’s experts are planning a larger study involving around 100 test drivers. Moreover, IAV experts will examine additional influences on the controllability of the situations due to further vehicle dynamic parameters. In the meantime, the control indicator is already providing valuable
assistance in projects.

The article was published in automotion 02/2019, the automotive engineering magazine of IAV. Here you can order the autmotion free of charge.