Daimler SLK - the electronic roadster

March 24, 2011 // By Christoph Hammerschmidt
This week, Daimler starts delivery of its new SLK roadster model to the dealer's showrooms. Buyers will get a car with an unusual plethora of electronic assistant systems.

Daimler points out that safety was the Leitmotiv for the combination of many different assistant systems; some of them are used for the first time in such a vehicle. For example, the roadster is equipped with a novel drowsiness detection system.

Unlike other systems, it does not watch the driver with a camera and evaluates the activities of his eyes. Instead, the system detects drowsiness and increasing inattentiveness by considering the style of driving. At the beginning of every ride, the system determines an individual profile of the driver's behaviour. Throughout the travel, this profile is continuously compared against current activities and reaction times. In order to do so, it processes data from steering movements, reaction times and control usage. Other factors taken into account are speed, lateral acceleration / deceleration, side wind, road condition, time of the day and duration of the trip. If the system detects typical indicators for driver's fatigue, it issues an optical and acoustical warning.

The Speed Limit Assist utilizes a camera on the inside of the windscreen to detect speed limit signs. The system makes use of image processing algorithms; if it "sees" such a road sign, it indicates the speed limit in the instrument cluster or central display.

An advanced adaptive cruise control system utilizes three radar systems, acting at different ranges (30m, 60m, 200m). It works at speeds of up to 200 km/h and warns the driver if the distance to the vehicle in front decreases too fast and too far. If the system figures that a collision is highly probably it computers the brake pressure necessary to prevent the accident. 1.6 seconds before the computed impact time it applies 40 percent of the brake power; issues a haptic warning to the driver and triggers the Pre-safe function. 0.5 seconds before the impact it applies maximum braking power.

The 'Pre-safe' functions are intended to mitigate the consequences of an imminent accident. The