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Acceptance of Vehicle Innovations Depends on Human-Machine Interface

Feb 23, 2010

The in-car human-machine interface (HMI) is gaining in importance and making ever deeper inroads into the vehicle. No longer confined to displays and pushbuttons, the impact of HMI now extends beyond domain borders. New approaches by Continental.

Babenhausen/Germany, February 23, 2010. Ever since cars first saw the light of day, those behind the wheel have needed information about the vehicles they are driving and the situation all around them. A prime example of this is the speedometer, which makes up for our own species’ deficient sense of speed. Lateral speed and driving dynamics are a different matter. For generations of drivers, these sources of information proved sufficient, with HMI amounting more or less to a glance at the speedometer, one’s own perception and the right button pressed. Vehicle ergonomics consisted mainly of making sure that the displays were easy to read and that the buttons felt right and were wisely positioned in the cockpit.

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Today the HMI extends well into the vehicle concept – and is likely to advance even deeper in the future. An example for this is the interaction of driver information and driver assistance. The growing possibilities of the electronic assistance systems and the vehicle’s connectivity with its surroundings – by Internet, for example – have defined new tasks for HMI. For one thing, the amount of feedback from the vehicle is growing steadily (in the form of switch point recommendations, for instance). Another thing is that already today drivers can configure more and more functions to their own liking. Admittedly, few car owners make the most of the setting options available to them. One of the main reasons apparently being that operating them seems simply too complicated. The question, then, is how to obtain maximum user friendliness within the context of a particular vehicle's overall setup?

For the leading international automotive supplier Continental it is clear that designing the displays and controls will, in future, only comprise a part of the HMI development process. What is demanded is a holistic understanding of the system that focuses on driver information and driver assistance and keeps in mind that the driving task is by no means always the same. It makes a difference whether one is driving at night, bumper-to-bumper or on a quiet, lightly traveled country road. Ideally a uniform HMI concept ties together all communication between the driver and the vehicle, adapting this to the drive purpose at the time. Here, at the very latest, it is clear that while the ergonomic design of specific switches continues to play an important role, such has long ceased to be anywhere near the full story.

The central mechanical feature of the AFFP® is an electric motor which is linked to the accelerator and which can generate a haptic signal

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At Continental, a holistic understanding of HMI aims also at ensuring that the driver remains optimally relaxed and attentive for as much of the time spent behind the wheel as possible. Helping to maintain the relaxing normal driving condition is timely updated HMI feedback (among other things via visual displays – cluster or head-up displays, for example – or in the form of haptic feedback – via the gas pedal, for instance – or acoustic signals). The following strategies apply for information management as long as the driver still has a chance to intervene:

- Firstly, appropriate information should be provided for the job and situation at hand. To provide targeted support for an optimal train of action, the information can, for example, be shown in the immediate vicinity of the outside mirror, provided this figures into the driver's natural visual sequence.

- Secondly, selecting the optimum information modality is important. A lane departure warning (LDW) on the steering wheel is effective because it warns drivers just where they have direct contact to the appropriate actuator. The accelerator force feedback pedal (AFFP) offers the same advantage because it delivers haptic feedback at the very point where the driver has to intervene in the vehicle’s longitudinal dynamics. Studies have shown a logical link like this to be the best solution ergonomically and one that yields high acceptance values.

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Possibilities and usage – new approaches

To minimize the gap between what drivers can do – based on the technical possibilities the vehicle offers – and what they do do, the sundry driver convenience systems have to be user-friendly. In the real world that is not currently the case. At present, many drivers aren’t even aware of the existence of certain systems, to say nothing of what settings can be variably adjusted to suit their preferences. Unacquainted with the functioning of an automatic start-top system, a driver might, for example, be thrown into panic when it kicks in at the traffic lights. And another point: With a rise in the number of in-car functions, the need for user-friendly individualization of HMI also grows. For that reason solutions are required that can easily be personalized.

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Configuring at the press of a button – Simplify your Drive

With its “Simplify your Drive” display and system concept, Continental has developed a new approach to systems networking and HMI. Inspired by the range of options available on digital cameras and the like, the automotive supplier has developed three sample profiles a driver can activate at the press of a button. What has been made to look extremely uncomplicated on the surface actually triggers complex changes within the vehicle. The vehicle configuration varies depending on whether the driver has activated the "Comfort", "Sport" or "Eco" mode. “Simplify your Drive” networks engine management, automatic transmission control (selection of switch points), suspension & damping, certain subordinate convenience functions of driver assist systems, energy management and the human-human interface. The latter affects, for instance, how the AFFP’s behavior is perceived but also the make-up of the user interface. The driving mode selected determines which specific program maps and parameters are activated in the control devices involved. A single vehicle thus becomes three different ones: a vehicle geared to maximum comfort, with a wide scope of driver support and minimal demands made on the driver; a sporty car; or an especially fuel-efficient model. Switching from one profile to another is easily possible – to suit the driver and the mood of the moment, the purpose of the trip etc. Ergonomically it is important that the HMI conform to the respective relative weight assigned a given information or support system in the overall scheme of things – and even go so far as to take into account the psychological aspects of color. In the medium term individual profiles tailored point-for-point to specific drivers are likewise envisaged. The corresponding settings for an individual profile could, for example, be stored in a remote access key, something that previous HMI concepts did not yet allow for. The technical depth of “Simplify Your Drive” is evident from the underlying engineering know-how. Around 200 Continental specialists in the Powertrain, Chassis and Interior divisions have collaborated on development of the demo vehicle. Using that as the yardstick, the all-embracing, freely configurable multiple-function instrument used might very well be the most visible innovation, although it is by no means the most complex one. The cockpit of the “Simplify your Drive” vehicle makes one thing especially clear. Thanks to rigorous simplification of the HMI, the user interface will, in the future, more forcibly leave its mark on the car’s experiential quality.

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Internet in the car – with AutoLinQ

This applies all the more if the car has Internet access. With AutoLinQ, Continental has developed a new solution for rendering Internet services and content useful in cars. The information and benefits the solution provides for are not available only on the road, however. Drivers will also be able to view the state of their vehicles on the home computer or even when out and about. Data and commands can likewise be transmitted to the vehicle worldwide. HMI is at the core of such innovations as well, for Internet services on the road are inevitably different than Internet on the home or office PC. Services and information have to be presented in a form appropriate for the situation. The classic browser interface is not a suitable solution in this case. Only by purposefully optimizing the Internet for in-car use will it be possible to enjoy this experience while circumventing the pitfalls – gain without pain, so to speak. Continental draws on its more than 100-year tradition in the HMI area to render innovative Internet-based applications serviceable in moving vehicles. What is more, Continental also lends developers support with tools and guidelines useful in the design of sensible automotive systems.

Impact on development

Massive changes of the kind currently underway in the HMI area necessarily also have an impact on the development processes themselves. For that reason Continental opts for the user-centered design process in the development of vehicle HMI. In the course of HMI design, concepts are put to the test on the driving simulator. Above all, an HMI detail’s suitability to a specific driving task is painstakingly studied. How great is the acceptance? Is the look and feel right? Continental views it as its duty to offer practice-oriented solutions. While the HMI is, of course, subordinate to the respective OEM’s philosophy, the supplier’s own comprehensive know–how is called upon to implement this philosophy. Alongside ergonomically designed controls, this also increasingly involves the ability to maintain a grip on the interaction of driver assist systems and driver information in the vehicle but also assumes a broad-based understanding of the needs and expectations of completely diverse user types behind the wheel.

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Continental has been pressing ahead with this innovation from its very inception: The technology underlying the eddy current speedometer patented by Otto Schulze in 1902 was not only the standard in motor vehicles for decades but also provided the basis for Continental’s now more than 100-year-long tradition in the HMI domain. The present-day HMI should not only keep drivers informed but also allow them to immediately experience the respectively relevant vehicle technology. After all, acceptance of vehicle innovations increasingly depends on acceptance of the respective HMI.


Enno Pflug

External Communication


Division Interior

Sodener Straße 9

65824 Schwalbach am Taunus

Phone: +49 6196 87-2515

Fax: +49 6196 8779-2515

Nicole Geissler

External Communication


Division Chassis & Safety

Guerickestraße 7

60488 Frankfurt am Main

Phone: +49 69 7603-8492

Fax: +49 69 7603-3945

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