The Active City Stop system works on the classic radar scheme. In this case, a laser acts as a radiating element. The beam is focused in front of the car at a certain distance. Special sensors capture the reflected signal and convert it into an electronic code, which is processed by the car's on-board computer. At the same time, the system collects vehicle speed data and estimates an approximate stopping distance. After some calculations, a decision is made whether to enable automatic braking or not. According to Ford engineers, the complex allows 100% to prevent accidents when the car is moving at a speed of 15 km/h and to minimize the consequences of a collision when hit at a speed of 30 km/h.
It would seem that there is any sense in such additions, if in theory a person himself can react quickly enough, but how quickly is another matter. It is known that people spend an average of 0.1 to 0.3 seconds to make a decision, but do not forget that these data are correct if the driver is not tired, intoxicated, unwell, or simply does not see the situation ahead. Accordingly, the risk of an accident increases significantly. At the same time, the Active City Stop automatic braking system scans the situation at a speed of 1/50 of a second, plus the same amount of time it takes to make a decision. In total, it turns out that machine intelligence is at least 5 times faster than human intelligence.
Real-time operation of the Active City Stop system
As noted earlier, the ACS electronic analytical complex is designed for operation in the speed range from 15 to 30 km/h. To control the traffic situation above this range, Ford has developed another system - Forward Alert.
Active City-Stop does its job perfectly in the specified mode, however, during operation, the driver does not receive any warning signals: neither sound, nor light, nor tactile - in the form of steering wheel vibration. If you accelerate to a speed of 40 km / h and head towards a stationary obstacle, the system will not react even if you release the accelerator pedal. However, if you approach a car moving at the same speed at a dangerously close distance, the algorithm will first give a warning signal to the driver, and later apply half-strength braking.
Video of how the automatic braking system (ACS) works on a Ford Kuga and Focus car:
Disadvantages of ACS in operation
Since Active City-Stop relies in its work on a smaller amount of data than a person and does not have the same perfect processing algorithm, sometimes the complex does not work correctly. For example, a standard situation: You are heading for a turn. A car drives ahead and begins to maneuver. The distance between you is getting shorter and the ACS system thinks that the danger of a collision has increased too much and gives the command to brake. In fact, there is no real danger. Even if you continue to move at the same speed, then most likely by the next moment the lane in front will already be free.
Another ambiguous situation arises when a car is maneuvering in front of you at low speeds. Here, too, there may be false positives. We also add that for the reliable operation of the system, it is required to keep clean both the laser lens itself and the sensors installed in the front.
In general, it was not supposed to officially equip cars from Ford with the Active City Stop system for residents of Russia. Representatives referred to the fact that many cars in our country drive with dirty license plates and lights, and the complex's radar focuses on these elements. In theory, this made the system more difficult to work, but in fact, it seems more logical that in large cities people are used to driving close to each other due to limited space. Therefore, the automatic braking system in such an environment would constantly slow down and prevent you from continuing to move.
The cost of the automatic braking system
Although the manufacturers claim that you can order the installation of such an add-on for only $500, the Active City-Stop is actually included in the adaptive cruise control kit, which itself is priced at $1320. Those. in the end, you will have to pay almost $ 2,000, and specifically - $ 1,820. The price for this device, as you can see, is not small, but what good it will be is unknown. It will be possible to order the Active City-Stop installation only in the Focus Titanium, Trend Sport (for example -), as well as Sport Limited Edition trim levels.
- Collision Warning with Auto Brake provides automatic braking when a collision with the vehicle in front becomes imminent
- Adaptive Cruise Control and Distance Alert help the driver maintain the required distance from the vehicle in front
Volvo Cars continues to develop technologies that can prevent collisions such as rear-end collisions. Volvo Cars offers Collision Warning with Auto Brake, an advanced driver warning system that allows the car to automatically apply the brakes if the driver does not react to a dangerous approach to a vehicle in front or a stationary vehicle.
"As a result of these systems, instead of serious injuries, people sitting in both cars may receive only minor bruises," says Ingrid Skogsmo, director of the Volvo Cars Safety Centre.
The new system will be installed on the Volvo S80, V70 and XC70 models from the end of 2007.
Rear-end collisions are the third most common type of traffic accident. In more than 50 percent of cases, the driver does not even have time to press the brake pedal.
The new Collision Warning System with Automatic Braking (CWAB) first warns the driver and prepares the braking system for emergency braking. The brake system is automatically activated if the driver fails to react to a situation where a collision with a vehicle in front or a parked vehicle is imminent.
The Collision Warning System with Auto Brake is an advanced technology compared to the Collision Warning System with Brake Assist, which was first introduced in 2006.
Complete solution: radar and camera
Whereas the previous system on the Volvo S80 only included radar, Collision Warning with Auto Brake uses not only radar but also a camera to determine the position of the vehicle in front. Radar with a range of up to 150 meters works with a camera that monitors the area in front of the car at a distance of up to 55 meters.
The system uses data comparison technology (Data Fusion) coming from the radar and camera, which has increased the efficiency of the system.
"The system uses data from both radar and camera, so automatic braking will only be applied when a collision becomes imminent. The system is programmed so that autonomous braking can only take place when radar and camera data indicate that a collision is imminent." , says Jonas Tisell, technical project manager for Collision Warning with Auto Brake at Volvo Cars.
One of the main advantages of the camera is the ability to recognize parked vehicles and warn the driver, while the system has a low false alarm rate.
"According to statistics, in 50 percent of collisions, a collision occurs with a vehicle in front. Therefore, Collision Warning with Auto Brake is twice as effective as the current Collision Warning with Brake Assist," explains Jonas Tizel.
The system offers several levels of sensitivity adjustment, allowing it to be adapted to different driving conditions and driving styles. The vehicle menu provides a choice of three levels of sensitivity.
The first stage is the prevention and preparation of the brakes
If the vehicle is approaching another vehicle from behind and the driver does not react, the system will activate a red warning light that is reflected on the windshield. At the same time, a beep sounds. This helps the driver to take the necessary action and in most cases the driver is able to avoid a collision.
"The reflected signal is very effective. The red light appears on the windshield in front of the driver's eyes - it's like the brake lights of the car in front," says Jonas Tizel.
If, despite the warning, the risk of a collision only increases, the brake assist function is activated. The brake pads are closer to the brake discs to shorten the reaction time. The hydraulic system increases pressure to maintain braking force, so even if the driver does not apply enough force on the brake pedal, the car will provide effective braking.
Automatic braking reduces the effect of speed
If the driver does not brake and the system determines that a collision is imminent, forced braking is activated.
Automatic braking is designed to reduce the effect of speed as much as possible, thereby minimizing the risk of injury to the occupants of both vehicles.
"Reducing the speed in a collision from 60 km/h to 50 km/h reduces the impact energy by about 30 percent. This means that the occupants of the vehicles may not suffer serious injuries, but minor injuries. Depending on the conditions, the Auto Brake System may prevent a collision altogether ", adds Jonas Tizel.
Adaptive Cruise Control (ACC)
To make driving more convenient, Volvo Cars has developed Adaptive Cruise Control (ACC). ACC helps the driver maintain the required distance from the vehicle in front. This control system allows the driver to relieve the pressure behind the wheel, even if you have to drive in unevenly moving traffic.
The adaptive cruise control includes a radar that constantly measures the distance to the vehicles in front. The system automatically adjusts the speed to maintain the set distance.
The driver turns on the cruise control, sets the required maximum speed in the range from 30 to 200 km/h and selects the time interval to the vehicle in front. There is a choice of five time intervals from 1 to 2.6 seconds.
If the radar detects that the vehicle in front is slowing down, ACC will automatically reduce the speed to match the speed of the vehicle in front. "Adaptive cruise control takes over part of the driving experience so that the driver can focus on the road and continue driving in a safer mode," says Jonas Tizel.
Distance Alert system
Distance Alert is another technology that helps the driver maintain a safe distance from the vehicle in front if the driver has not engaged the Adaptive Cruise Control.
The distance reduction warning system is activated using a button located on the center console. As in the case of ACC, the driver is given a choice of five levels of system settings. If the time interval to the vehicle in front decreases and goes beyond the specified settings, a warning signal is displayed on the lower part of the windshield.
If the Adaptive Cruise Control is turned on while the Distance Warning System is on, the Distance Warning System will be temporarily disabled.
Both systems - Adaptive Cruise Control and Distance Alert - are designed to help the driver and make it easier to drive in accordance with national regulations governing the maintenance of the required distance from the vehicle in front.
System Limits
The capabilities of the described systems depend on the quantity and quality of visible road markings. The camera must clearly distinguish the dividing line between the traffic lanes. Poor lighting, fog, snow, or adverse weather conditions may prevent the system from functioning.
| |The use of cars is ongoing. Some systems are already mandatory in new cars. The collision warning system has not yet been recognized as a mandatory element in manufactured cars, but it is quite popular.
Getting to the bottom of the system
By name, the essence of this innovation is already becoming clear - preventing a collision with an object that is in front. It is implemented by means of forced braking at the moment when the system considers the situation dangerous and a collision is inevitable. If adaptive cruise control is also added to the work, then the car will always be at a safe distance from the next traffic participant in front.
Existing variants of the anti-collision system
Many automotive manufacturers have developed their own versions of this unique technology that can prevent accidents and save lives. But the essence remains the same: the brakes are automatically applied in the car if the driver does not react to a dangerous approach to an object that is in motion or is standing with the engine turned off.
Previously, another system was practiced, which was far from perfect. She assumed the use, and this could not provide high efficiency. The new development is based not only on the radar, but also involves the use of a camera. It is the last element that fixes the position of the nearby car. The range of the radar is 150 meters, and the cameras - 55 meters. This means that the system monitors all objects that fall within the range of the camera. The information coming from these two elements is processed and compared using modern Data Fusion technology, which also improved the efficiency of the system.
Automakers have gone to great lengths to make sure their developments only kick in when a collision is imminent. This factor is very important in a large city, on the roads of which there is a dense movement of vehicles. The low false alert rate is an important and rather rare benefit of collision avoidance technology.
It is convenient for the user to change the settings and select the operating mode, thus adapting the system to the conditions of movement.
Scheme of work
Since we have begun to consider one of the security systems, it is worth considering in detail the principle of its operation. It consists of several stages, which are activated sequentially.
- If the driver does not react to the reduction in the distance between his car and the object in front, a red light starts flashing on the windshield. At the same time, an audible alert is activated. All this is aimed at attracting the attention of the driver, who must respond to the situation properly.
- The system begins to prepare the car for future braking (the pads approach the discs, the pressure in the hydraulics rises). Due to this preparation, braking will be effective even with light pressure on the brake pedal.
- If there is no further action from the driver, the system automatically starts to activate the brakes.
There are several cases to which the system will respond with a decrease in speed:
- dangerous shortening of the distance;
- rebuilding in front of the next car in your lane;
- car leaving its lane without turning on the turn at high speed;
- sudden appearance in front of the car of another road user.
It is not always necessary to hope for a complete stop of the car, but even with a slight decrease in speed, the risk of injury is significantly reduced.
Additional functions
The effectiveness of collision avoidance can be improved by using additional systems.
Adaptive cruise control ACC
The forward collision warning system must work in conjunction with the ACC adaptive cruise control. This development monitors the observance of a safe distance between your car and the one in front. This feature is very handy while on the move.
Radar is constantly working, which measures the distance to each car. The system processes this information and calculates the speed at which critical approach will be impossible. Adds convenience to the user, the ability to set their own parameters, within which the adaptive cruise control will work.
The system monitors the speed of the neighboring vehicle and quickly reacts to its decrease. Thus, the driver can not keep himself in constant tension and entrust some part of the control to auto electronics.
Distance warning
Driving in heavy traffic is facilitated by a system that monitors the reduction in distance and alerts the driver in case of a dangerous situation. This feature is called Distance Alert and can serve as an alternative to adaptive cruise control. If the latter system is inactive, then Distance Alert performs road control.
The driver's attention is attracted by the warning signal, which is located at the bottom of the windshield - just in line of sight.
Pedestrian Detection Technology
All the features that have been described above are related only to cars. But after all, a car can collide not only with its own kind, but also with pedestrians. A separate system has been developed, which is aimed at detecting people near the car. When a nearby person is detected, the car forcibly reduces speed.
As a result of the work of this technology, it is possible to reduce the impact force or completely avoid a collision with a pedestrian. Studies have shown that the use of a pedestrian detection system reduces accident deaths, reduces the likelihood of serious injuries and reduces the number of collisions.
The possibilities of this technological development are impressive. It works great in a big city, tracks several pedestrians at once, who can move in different directions, and identifies people with umbrellas in rainy weather.
The system will help prevent a collision with a pedestrian Flaws
The experts still have work to do. Collision avoidance technologies do not work well in bad weather and at night. Road markings, their quantity and quality also affect the quality of work. If the camera does not distinguish dividing lines well enough, then the performance of the system is reduced. As well as during dense fog, insufficient lighting, snowfall and other adverse conditions.
It is foolish to rely entirely on electronics. In any case, the driver is responsible for the lives of people and the safety of property. These systems should be perceived as insurance and assistance, and not to shift all the work of the driver to them.
Have you tried at least once not to brake when your car flies into an obstacle? A sober person would never think of such a thing. Why, then, are there so many incidental collisions - as they say, out of the blue? Carelessness! I thought about it, looked around, reached for the phone ... And, according to the law of meanness, it was at that moment that the car in front suddenly slowed down. A blow, a crumpled bumper, broken headlights - this is at best.
To reduce such accidents to a minimum, several years ago, automakers began to develop preventive safety systems that are ready to stop the car instead of the driver - in automatic mode. At first, they began to equip expensive cars, but after the Ford Focus was gifted with a hitchhiker last year, it became clear: technology went to the people! It turns out that the time has come for serious tests.
In Russia, no one has conducted such tests, and therefore there are no methods or tools. So let's create it ourselves!
We have been preparing for the test for several months. Most of the time was spent on the manufacture of the test setup. We polished the test methodology, filled out more than one stack of papers, filling out applications, travel sheets, memos. We also caught the weather - in the middle of spring it often brings surprises that complicate both measurements and photography. The human factor also interfered. Obeying the instinct of self-preservation, the hands themselves turn the steering wheel at the last moment, and the legs press the brake - it is very scary to hit an obstacle!
If only you knew what it cost me to overcome reflexes that were harmful to my work… After that, I dreamed about the blue poop of our test bully at night. When the preparations were completed, we assembled nine cars at the Dmitrovsky auto training ground that can brake themselves: relatively inexpensive Ford Focus and Volkswagen Golf, Volvo S60, Infiniti Q50 and Hyundai Genesis sedans, as well as crossovers of all stripes - Opel Insignia Country Tourer, Land Rover Discovery Sport, BMW X4 and Cadillac SRX.
FROM METAL AND FOAM
The idea of checking the performance of electronic assistants to avoid accidents did not come to us today. Five years ago, on a Volvo XC60 crossover, we covered the radars and sensors with mud (SR, 2010, No. 5) in order to check whether the electronic active safety systems would work. Some assistants resigned, but the rest, even in such difficult conditions (by the way, typical for Russia), continued to conscientiously fulfill their duties. And last year (ZR, 2014, No. 10) Mikhail Kuleshov, without fear or reproach, went one on one with a Ford Focus hatchback, which moved without a driver at all! Equipped with an automatic braking system, the Focus stopped right in front of the fearless Mikhail. All these were just attempts to get close to serious tests that would allow a comprehensive assessment of the operation of automatic braking systems and their role in active safety.Obviously, cars must respond not only to a static object, but also to a moving one - it is necessary to simulate braking in a traffic jam or slowing down in a highway mode. How to implement this idea? Hitting a car with a car? It will be expensive! Therefore, Valery Zharinov and Gennady Emelkin, specialists of the Za Rulem technical center, set about building a unique experimental facility that allows all types of tests to be carried out. For a whole month they were designing, arguing - and building, adjusting, redrawing. As a result, from the gates of our technical center, they rolled out a model of the rear of the car, capable of moving at speeds up to 80 km/h. Naturally, not independently: the installation is pulled by a tractor - a passenger car with a towbar. The installation is placed on rails that serve as guides: in the event of a collision, it drives away from the ram car along them. This saves his front end from damage, and the driver from a possible airbag impact. "Booth" soft-bodied. A thick layer of foam rubber under the protective cover takes the first hit and gently dampens part of the energy transmitted during impact. And since the pattern on the cover is very reminiscent of the well-known Volkswagen Transporter, we nicknamed our installation “bully”.
BEAT HURRY, BUT CAREFULLY
Each car from our mighty nine went through a test cycle, including exercises in statics and dynamics. More precisely, the subject is always on the move, but the “bully” first stands still in the hope that the car approaching him will stop at a safe distance, and then moves, overtaken by the test car. We start our acquaintance with races at low speed. Depending on the first results, we decide whether it is worth driving the subject through the entire program or whether it is better to stop testing until the firewood is messed up. "In the Standing"(Fig. 1) - stop in front of a stationary object. "Bully" is standing, the car is moving. The initial speed of 15 km / h - at first glance, trifling. But in the event of a real accident, body repairs will already be required! Then, with each attempt, increase the speed by 5 km / h. We finish the races when the car in braking touches the bully. Due to the unstable operation of the electronics, it was sometimes necessary to duplicate attempts in order to unambiguously establish when the limit of the control electronics comes. "Give me a sign"(fig. 2) - test of the collision warning system. The driver directs the car into a "bully" at low (20 km/h), medium (50 km/h), high (90 km/h) speeds - and carefully follows the prompts of the electronics: at the first warning, he presses the brake and evaluates (subjectively, of course), whether the electronics gave a signal in a timely manner. It happened that the assistants were treacherously silent and the driver had to dodge the bully at the last moment in order to avoid being hit at high speed. If you can’t dodge it, you will smash the test rig, damage the car, and even get hurt yourself, because at speeds over 50 km / h, with sufficiently hard contact, even with a soft and movable rig, airbags can work. "Catchers"- dynamic tests, when both the bully and the car overtaking it are moving. This is a simulation of the most common traffic situations. For example, a typical case for a city is a “bully” traveling at a speed of 20 km/h, and a car overtaking it at a speed of 50 km/h (Fig. 3). Then we play catch-up at the track pace: the bully keeps 50 km / h, and the speed of the car is 90 km / h. "Slow down"- braking in front of the cork tail. The Bully and the car are moving at a speed of 60 km/h. The Bully starts to slow down and the car overtakes him (Fig. 4). The task of the automatic braking system in all exercises is obvious - to prevent contact. Objective assessments received by cars based on the results of the races, we have summarized in a table. But, as is often the case in such complex tasks, a priori dry scores cannot give a complete picture of how the heroes of our test performed. On different machines - systems of different levels, others are very capricious, and therefore one cannot do without a detailed story about each of them. We will share our impressions not in chronological order, but, for ease of perception, we will go from the less successful test participants to its leaders.ZERO ZERO
- Package contents: 2.2D HSE Luxury
- Test car price: 3,516,000 rubles
- The AEB emergency braking system is available as a separate option (12,100 rubles) in all trim levels or as part of the “Extended Driver Assistance Systems Package” (49,000 rubles).
CONCLUSION
The system operates in a very narrow range of speeds, with a minimum difference between the speeds of the car and the obstacle, and therefore is ineffective. When developing a next generation system, the manufacturer has room for improvement.
BETTER THAN NOTHING
- Package contents: 1.6 Titanium
- Test car price: 1,222,000 rubles
- The Active City Stop emergency braking system and the Forward Alert warning system are not available as separate options and are offered only in the Technology package (15,600 rubles) for cars equipped with Titanium.
CONCLUSION
Active City Stop is an example of an inexpensive anti-crash system that is worth the money. But a small budget limits the possibilities: you can count on ACS only when driving at low speeds - for example, in city traffic jams.
BETWEEN HEAVEN AND EARTH
- Trim: 2.0 CDTi
- Test car price: 1,780,000 rubles
- The emergency braking system is offered in any configuration in the Driver Assistant 2 package (40,000 rubles).
CONCLUSION
Opel can do more than Ford, but it doesn't have the system talents of more expensive cars.
CORRECT COURSE
HYUNDAI GENESIS- Trim: 3.8 V6 GDI Sport
- Test car price: 3,319,000 rubles
- The Autonomous Emergency Braking (AEB) system is included in the equipment of cars in the Luxury and Sport trim levels.
CONCLUSION
The system works, but is not without flaws. First of all, she lacks stability.
