Nowadays, guardian angels have strange names. For example, they are called ESP, ANB, LDW or AMK. However, these abbreviations do not conceal any supernatural beings, but rather highly developed technologies for cars, whose task is usually to prevent traffic accidents and increase driving comfort. Such so-called Driving Assistance Systems become active, for example when the vehicle is at risk of leaving the road or if a collision can no longer be prevented. In future, they will make an ever greater contribution to increasing safety on the roads.
In the Beginning There was ABS
The anti-locking system (ABS), which has long been standard equipment in modern vehicles, is already considered to be a "classic". It prevents the tyres from locking when braking and the driver from thus losing control of his/her car. Speed sensors determine the locking tendency of each wheel and transmit it to the ABS. This continuously evaluates the signals and, in an emergency, triggers two solenoid valves per wheel that reduce the braking pressure and thus the braking force in fractions of a second. This means that the vehicle can still be steered and can manoeuvre past an obstacle.
The so-called engine braking control (MSR) works in a similar way. It controls the wheel slippage when the foot it taken off the accelerator. If the drive wheels lose adhesion during severe load changes, the vehicle becomes unstable. It can no longer be steered and may skid. The MSR detects this tendency by comparing the speed of the drive wheels with that of the free-moving wheels and then accelerates slightly if necessary.
One for Everything – the Electronic Stability Programme
The Electronic Stability Programme (ESP) integrates ABS and MSR and extends them by a higher level stability monitoring. It works like this: a sensor measures the angle at which the driver turns the steering wheel. Together with the speed of travel, the system calculates the course that the driver is specifying. At the same time, two other sensors measure the transverse acceleration and the turning of the car on its vertical axis. If the data deviate from those of the calculate target course, there is a severe risk of skidding and, without any action by the driver, the ESP brakes either the front wheel on the outside of the bend or the back wheel inside the curve – depending on whether the vehicle is over or under steering. In this way, the risk of skidding is reduced by up to 80 per cent.
More recent systems even go a step further and actually execute a full braking manoeuvre in an emergency. The Automatic Emergency Brake (ANB) intervenes as soon as the distance to the vehicle in front reduces so much that a crash is inevitable. The aim of the ANB is to mitigate the consequences of a collision as far as possible. For this purpose, a radar sensor permanently measures the distance to the vehicle in front. The data are transmitted to a computer that calculates the minimum distance that the car needs to come to a standstill in time at the speed in question. If the vehicle comes closer than this distance the system automatically brakes fully to prevent a collision or to greatly reduce the speed of collision. Based on the ANB, Automatic Distance Control (ADR) is already in use in the Phaeton and in the Audi A8. It, too, in conjunction with the F2S system (Follow to Stop) automatically brings the vehicle to a complete standstill, if necessary, behind a car driving ahead. Furthermore, the ADR contains a collision warning and a predictive bend recognition that independently brakes the car if it is travelling too fast.
Staying on Course thanks to Camera Monitoring
Since 18 per cent of all accidents result from the driver leaving the road, Volkswagen Group Research has developed a system that registers at an early stage if the car leaves the lane. Lane Departure Warning (LDW) or Heading Control (HC) is the name of this ultra-modern technology that is already nearing series production. With the help of a camera integrated in the vehicle, the lane markings can be recognised and thus the position of the car within the lane can be permanently detected. If the vehicle deviates too much from the ideal line, the system warns the driver. And independent intervention by the system, where active steering keeps the car automatically in the lane, is possible in theory. However, electronic steering intervention is still banned by law in Europe.
However, the number one cause of accidents is still the driver. If he or she makes a mistake, the consequences are often devastating. Up to 25 per cent of all fatal accidents on the road are due to fatigue. A camera in the cockpit that monitors the driver's eyelids could save lives in future. This Attention Control (AMK) developed by Volkswagen permanently records the duration and frequency of blinking and thus draws conclusions about the current physical state of the driver. At the first signs of fatigue, he/she is immediately warned acoustically and requested to take a break.
Parking Made Easy
Speed limits and their end often change and are easily missed. Volkswagen's Road Sign Display (VZA) makes it easy for drivers to keep an overview. The system registers the current speed limits along the motorway and displays them digitally in the driver's cockpit.
The promise of easy and stress-free parking is held out by an innovative system that either assists the car or automatically manoeuvres it into any parking space. This, too, is the result of highly developed technology: first of all, sensors record the dimensions of the space and any obstacles. Then, the data are evaluated by the system and the computer calculates the ideal route into the parking space. By pressing a button, the driver now activates the parking assistant and the car reverses into the space.
The Vehicle's All-Round Vision
The pinnacle of automated driving could be reached if one day cars errantly "monitor" their entire surroundings and react independently to any conceivable hazardous situation. Volkswagen has taken a first step in this direction with the "surroundings perception" project. The aim is to bring together the entire vehicle surroundings model into a holistic surroundings model using all of the sensor data. Driver assistance systems could thus detect possible hazards all around the vehicle and possibly introduce the relevant measures to prevent an accident. The Enhanced Night Vision system is involved in the project. This is an infrared-supported unit, which recognises pedestrians and their position or their distance from the vehicle and notifies the driver.
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