Automotive Engineering Automotive engineering What are driver assistance systems?
Advanced Driver Assistance Systems, also known as ADAS, have been available in new vehicle models for several years. They not only support drivers but also pave the way for autonomous driving.
Driver assistance systems, also known as advanced driver assistance systems (ADAS), are designed to support drivers of cars and trucks in driving and thus increase road safety. The range of methods is quite broad: there are relatively simple assistance systems such as the parking aid, but also much more complex ones such as a traffic jam pilot. Highly automated and autonomous systems are currently not yet authorized.
Definition Driver Assistance System
Driver assistance systems support the driver of motor vehicles and, in some instances, take over his tasks. The objectives of the use of driver assistance systems are to increase driving safety, enhance driving comfort, and improve efficiency.
To be able to differentiate a large number of driver assistance systems, they are divided into different categories. The classification of the society of automotive engineers (SAE) has become established worldwide. In the SAE document J3016, the different driving modes are divided into six levels.
- Level 0 stands for no automation; this means that the human driver controls the vehicle. Driver assistance systems only provide support through acoustic signals, such as parking assistance or the blind-spot warning system.
- Level 1 already describes the first supporting functions. The driver is actively supported when steering or accelerating or braking. Examples are lane departure warning or an adaptive speed assistant with distance control.
- Level 2 links steering intervention with cruise control, systems in this class can accelerate or brake a vehicle and keep it on track at the same time.
With all the systems mentioned so far, the human operator must keep an eye on the environment. Also, the driver must carry out all remaining aspects of the dynamic driving task - such as changing lanes or overtaking. In levels 3 to 5, the vehicle's systems monitor the environment. Drivers are allowed to turn away from the driving task; for example, they may read, sleep, or watch television. There is a distinctive feature of Level 3: Here, the vehicle's system can request the driver to take over control of the car or truck within a specific time.
- Level 3 is fulfilled by a system when it completely takes over control of the car in a limited situation. An example is the jam pilot. If the traffic jam dissolves, the driver has to retake the wheel.
- Level 4 is for highly automated vehicles. Intervention by the occupants is no longer necessary. However, vehicles in this category still have pedals and a steering wheel that can be used to steer manually if desired.
- Level 5 is identical to Level 4 in terms of the system, but vehicles in this category no longer have a steering wheel and pedals. Therefore the vehicle must be able to drive autonomously wherever it is on the road.
List of selected driver assistance systems
- Anti-lock braking system, ABS
- Autobahn Pilot
- Hill-start assistance
- Parking aid
- Adaptive High Beam Assist
- Adaptive speed control
- Automatic emergency brake assistant
- Automatic windscreen wiper
- Active Lane Keeping Assistant
- Blind Spot Monitoring
- Traffic sign recognition
How are driver assistance systems structured?
In general, a driver assistance system requires different sensors, an electronic control system that evaluates the sensor data. It then sends control signals - either to loudspeakers and displays to warn the driver or to actuators to actively intervene in the vehicle control system.
Current vehicle models, for example, are fitted with ultrasonic sensors that are used for parking assistance. Other sensors include a camera, radar, and lidar. The latter function similarly to radar sensors but emit light (light detection and ranging) in the wavelength range of about one micrometer. Radar waves in modern automotive applications transmit and receive signals with wavelengths of about four millimeters.
Radar and lidar are very well suited for measuring distances between your vehicle and objects in the environment. Also, these sensors can be used to determine relative speeds. The camera has its strength in detecting objects - in other words, the difference between a hedge and a wall.
All sensor data is evaluated in electronic control units. In the most straightforward assistance systems, for example, a beep is generated in case of danger to indicate that a line has been crossed. In some vehicles, the steering wheel can also vibrate briefly, or a warning symbol appears on the speedometer display.
In more complex systems, some actuators intervene directly in the vehicle control system. In the meantime, for example, automatic emergency brake assistance (AEB for automatic emergency braking) has become a legal requirement. The AEB system detects obstacles and automatically initiates emergency braking if the driver does not react in time. Other systems, such as adaptive distance control or active lane departure warning, automatically control a vehicle's speed and the steering angle.
This article was first published in German by Automobil Industrie.