Driving On Six Legs
The driver takes her foot off the gas pedal. She wants to turn left. About 60 feet before the corner, the Head-up Display gives the driver a warning by showing a red triangle with a car and a left turn arrow in its center.
The woman takes about a second to react, then steps on the brake. The car comes to a stop just before the middle of the crossroads, its wheels already turned left. At almost the same moment, an oncoming, fast-moving car shoots past. It was a near miss. However, even if there had been a collision, no harm would have come to the driver or her BMW 5 Series.
The dangerous traffic incident just described took place in BMW’s new dynamic driving simulator. This test, a part of the PREVENTT project, was performed several times a day, every day, for six weeks, with different test subjects and under varying conditions. PREVENT is a project co-funded by the European Union that aims to reduce road accident rates by developing innovative safety technologies.
The BMW simulator was being used to test a left-turn assistant, which is a step in the direction of a future hazard-alert system. These tests focused on the optimal timing and delivery of the warning, along with drivers’ reactions to the system. Do they get annoyed if the turn assistant is overly cautious? Are they frustrated if the alert comes too late? Should a warning for oncoming traffic be given at every crossroads or only when the driver informs the system – for example, by using the directional indicator – that she intends to turn left?
The list of questions is long and the success of any future system depends on whether the right answers have been found. “By taking into account psychological data of this kind from driving simulation tests, we can be sure that new assist systems actually do the job they are designed for, and that drivers are willing to accept them,” says engineer Dr. Alexander Huesmann, BMW Project Manager of Driving Simulation. “Assist systems must not try to take over for the driver or relieve him of responsibility.
They are there only to provide support and help reduce stress – the less obtrusively, the better.” At this stage, testing the left-turn assistant with real cars on real roads would have been far too dangerous. In the driving simulator, on the other hand, the most extreme driving situations can be created and varied endlessly, and repeated again and again. This is also much more convenient, efficient and environmentally friendly than testing with real cars.
Tests can be performed at any time of day or night and in any kind of weather. Above all, there is virtually no risk at all. BMW has been using driving simulation in the development and testing of driver-assist systems since the early 1990s.
During that time, both hardware and software have been continuously refined and improved. Today, half a dozen driving simulators, controlled from 90 different workstations, occupy an entire building at BMW’s Research and Innovation Center in Munich.
They include a new state-of-the-art, high-tech dynamic driving simulator – one of the most powerful in the car industry. Here, a real BMW model is mounted on a platform inside the projection dome, which is about 22 feet in diameter and 15 feet high. At a rate of 60 images per second, computers generate realistic traffic scenes onto the dome’s semicircular screen.
The simulator’s database contains some 20 miles of highway, another 20 miles of city streets, and a variety of country roads, along with crossroads, traffic signs, curves, houses, pedestrians – not to mention any number of preceding, following and oncoming vehicles.
Sunshine, dense fog and darkness can also be simulated. The computers control the instruments inside the car and react in real time to all driving maneuvers. Realistic sound effects, ranging from different engine noises at different speeds to tire squeals, are also reproduced. But the most outstanding feature of this dynamic driving simulator is its amazing maneuverability. The platform stands on six adjustable, telescoping legs. This hexapod system allows movement about all three axes.
During a simulated drive, the dome almost appears to be dancing. Bobbing and weaving with effortless grace, it tilts and rotates up to 30 degrees, takes a bow, goes down on one knee, wiggles its hips, jumps up or sways in all directions. Every movement of the dome is the result of an action by the driver inside the car. The various movements give the driver a real feeling of acceleration, deceleration or cornering. Gravity affects the driver’s sense of balance, making the feeling of the virtual drive highly realistic.
“This is important because we want drivers to behave in the simulator exactly as they would in everyday life,” explains Huesmann. The testing of new systems at BMW even includes the use of eye-tracking technology, with infrared cameras recording where the driver looks, and for how long.
This has shown, for example, that when a Head-up Display conveys important information, such as speed and navigation instructions, the frequency with which drivers look away from the road to instruments on the dashboard is reduced by up to 90 percent.
The first results of the PREVENT project will be presented to the public this autumn. The left-turn assistant tested by BMW is just one of a number of new safety systems being tested by PREVENT. It is a big step towards an ambitious goal: to cut the number of road accidents in Europe in half by the year 2012.
Source: BMW Magazine