Human Machine Interface (HMI)
Human Machine Interface (HMI)
New information technology is making it technically possible to supply the driver with virtually unlimited amounts of information and communication.
The purpose is often to help the driver to drive more safely, but there is an obvious risk that the increasing volume of information will pose a threat to safety – in other words, the interplay between man, machine and the traffic environment will be jeopardised.
To ensure that additional information which is designed to aid the driver does not defeat its purpose, it is extremely important that it is presented in a way that matches the driver’s needs and abilities. This is the starting point for Volvo Car Corporation’s research within the field of HMI (Human Machine Interface).
Volvo SCC – a valuable test tool
The Volvo Safety Concept Car (SCC) can be described as a prototype for testing different ways of creating a user-friendly interface. The aim is that the driver should perceive the information as a source of support and not as a burden. As different drivers may have different information needs, they should also be able to cope with the amount of information and the way it is presented.
"Since we presented the Volvo SCC at the Detroit Motor Show in January, I have often been asked whether all this information and warning technology will not be too much for the average driver. My answer? Yes, of course it is possible that there can be too much information. Evaluating this is one of the main challenges for our research," says Christer Gustafsson, safety engineer at Volvo Cars.
Focus on the driver
Volvo Cars’ objective is to find methods for measuring how new information impacts the driver’s ability to drive safely. This research is the base for developing new user interfaces and their implementation.
"In this context, it’s incredibly important not to throw oneself into an unplanned, galloping technology development process. It is not a question of creating what is technologically feasible but of building what is desirable from the point of view of the driver and safety," explains Christer Gustafsson.
What information enhances safety?
The main challenges are to be found in two areas.
How should the information be designed? This includes the design of displays and their position to make them user friendly.
How should the information be sorted? If there is a heavy flow of information, it is reasonable for the car to help the driver by prioritising certain information and delaying other information.
The Volvo SCC distinguishes between different types of information, for example. The information from the car to the driver is shown on a large display in the combined instrument. This includes camera images and warnings related to the driving task, in addition to trip data. The interaction initiated by the driver and not directly related to the driving task, such as controlling the audio unit, RTI and phone, is presented on a display on the upper part of the centre console.
Prioritising information
Prioritising driver information is also the nucleus of another research and development project, IDIM (Intelligent Driver Information Manager).
Using a number of driving parameters such as movement of the steering wheel, throttle and so on, IDIM can sense when the driver has to focus on driving and any distraction, in the form of a phone call, a voice message or an SMS, could lead to the driver being distracted and thus jeopardise driving safety.
IDIM then gives driving safety top priority and delays incoming phone calls or messages so that they are instead presented at a later stage when the driving situation is less demanding
"IDIM is an excellent illustration of the way information can be sorted and prioritised to make driving safer. The system can also improve the potential for the safe use of technology, which is currently being questioned, such as the phone and messaging systems of other kinds. An integrated phone in combination with IDIM creates totally different opportunities for telephony in cars than a phone lying loose on the passenger seat," says Christer Gustafsson.
With IDIM, we have surpassed the simple method of always inhibiting comunication and interaction with in-car systems, while driving. IDIM makes it possible for the driver to fulfil his/her comunication needs while maintaining driving safety.
Techniques for measuring driver distraction
Volvo Cars has also tackled the challenge of measuring the way different kinds of information affect driver attention.
At the present time, several methods are available for measuring mental work load. These methods can be divided into three groups: subjective measurements, performance measurements and physiological measurements.
Peripheral Detection Task (PDT), a performance measurement, has been chosen for further studies. PDT is used to register changes in peripheral vision. Increasing mental work load is associated with a reduction in the driver’s visual field.
An experiment has been performed to examine whether PDT discriminates between different levels of mental work load for the driver. Twenty-four subjects participated in an on-road experiment.
A navigation system was used and the drivers received route information visually, verbally or both visually and verbally. A memorised route was used as baseline. The PDT performance was measured and the results show that it is sensitive to mental work load compared with other measurement methods. This makes PDT promising as an evaluation tool for new in-vehicle information systems.
Ford investing heavily in HMI research
Volvo Cars’ parent company, the Ford Motor Company, has opened a new high-tech USD 10 million driving simulator laboratory (VIRTTEX) to study driver work load and distraction issues related to new in-vehicle electronic devices.
Ford plans to use PDT in the VIRTTEX as one of its evaluation tools.
The new facility allows researchers to measure a driver’s ability to cope with common traffic situations while using cellular phones, navigation systems and other in-car equipment.
This simulator is the Ford Motor Company’s first full-scale, moving-base driving simulator and it is the most capable device of its kind currently owned by any automotive manufacturer in North America.