Assistance systems – up close and personal

Assistance systems – up close and personal

You’re sitting at the wheel of your stationary car. In the rearview mirror you see another car approaching at high speed. Alarmed, you wait for it to hit you. Suddenly your seat belt tightens and your open windows close all by themselves.

8. 8. 2023 Škoda World

Thankfully, there is no collision: the test driver avoided the stationary car at the last moment and passed you. Your body, which had braced itself in anticipation of the impact, relaxes again. The simulated demonstration of the Škoda’s Crew Protect Assist (which is what tightened the seat belt and closed the stationary car’s windows) is over.

Simulation of Škoda’s Crew Protect Assist during a workshop at the test polygon

The scenario might be frightening, but in the conditions of the Škoda test polygon it’s perfectly safe. In real traffic, however, rear-end collisions with stationary cars are fairly common. And that’s why this is one of a number of situations that the developers at Škoda are focusing on. Current Škoda models are among the safest in their classes. This is thanks in part to a host of assistance systems that have been and are being intensively developed and tested by the Czech carmaker. In a workshop on the test polygon, they revealed how they go about it.

Robot drivers

For a modern car to be safe, proven and properly certified, for example in Euro NCAP tests, its assistance systems and other active safety features have to undergo a series of tests. These require not only a high degree of accuracy but also repeatability. “Euro NCAP, for example, requires us to test around 100 different emergency braking system scenarios in front of pedestrians and other vulnerable road users,” explains Lukáš Eis from Škoda. These are scenarios where the car is supposed to brake automatically when a pedestrian (adult or child), cyclist or motorcyclist is at risk of being hit at lower speeds (typically up to 60, sometimes up to 85 km/h). The scenarios apply different approach speeds and angles at which a collision might occur. The purpose of the assistance system is then to detect the imminent collision and apply the brakes to avoid the accident if possible, or at least to ensure that the speed at the time of the collision is as low as possible.

Emergency braking in front of a pedestrian

“Of course, we also fine-tune the system to make sure that it works as well as possible in normal traffic, without disturbing the driver but protecting inattentive road users. But because of the degree of precision and repeatability required, we test the functionality on the polygon using robot technology,” Lukáš explains. As part of the demonstration, a Škoda Enyaq driven entirely by a robot is propelled towards a collision with a dummy pedestrian. Even though test driver Martin Najman is behind the wheel, he doesn’t actually control the car. “I start the car, but then I just hold a kill switch. Because of the requirement that the interaction between car and pedestrian must be accurate to within 5 centimetres, everything is controlled by the robot using differential GPS,” Martin explains. It can take over six weeks to test all scenarios for one such safety system (testing also has to be done at night using artificial light, for example).

Robotic system driving a car using differential GPS

Active assistance

For emergency braking in front of vulnerable road users, cars use both radar and camera signals, as do other active safety systems. Sometimes they have to evaluate several inputs at the same time. That applies to the scenario depicted in the introduction, where a car approaches a stationary or slower-moving car from behind. Ideally, an emergency braking function would be activated in the car approaching from behind. “In this case, the car is able to apply the brakes when there is a difference in speed between the cars of up to about 60 kilometres per hour,” explains Petr Dudík, another developer of assistance systems.

Emergency braking in a situation where a car approaches another stationary or slow-moving car

However, Škoda cars also have a function that helps with evasive manoeuvres in cases like this. “If the driver’s movement of the steering wheel indicates that he wants to avoid an obstacle, the car will assess whether there is a risk of collision with anyone or anything nearby and, if there is no risk of collision, the system will help the driver manage this manoeuvre,” Petr explains. The system also makes sure that the manoeuvre is not too sloppy and that the driver does not end up off the road.

In this case, the car evaluates data from sensors and other systems, including the Lane Assist system. In Škoda cars, this uses a camera to detect not only white and yellow lines, but also roadsides with asphalt-gravel or asphalt-grass transitions, curbs, concrete barriers, bollards and so on. Lane assist works at speeds above 65 km/h. “For the system to be triggered, the camera only needs to see the lane boundary on one side, and it uses that boundary to guide the driver,” says Ondřej Smetana.

During the demonstration, a monitor showed how Lane Assist lets a car “see” lane boundaries

According to Ondřej, the system detects the distance between the car and the lane boundary, evaluates how fast the car is approaching the boundary and adjusts the steering accordingly. “The system is not active at lower speeds and it doesn’t work on sharp corners with lateral acceleration of 3 m/s or more. In addition, the system also detects the driver’s activity via the steering wheel, but the driver still has to drive,” Ondřej explains. On gentler curves, though, the system allows the driver to “cut” the curve, i.e. to get as close as possible to its inner edge. Similarly, the system does not intervene when the turn signals are used (unless a car is detected in the driver’s blind spot). “The driver can always override the assist system by exerting force, though,” Ondřej adds.

A real emergency

The car’s smart sensors and some of the features mentioned above are also used by the Emergency Assist. This can stop the car if it detects that the driver is inactive. First, though, it uses several warnings; a warning sound is heard and a prompt appears on the display; this is followed by a “tap” on the brakes. “This is an intervention that can perhaps wake up a driver who has fallen asleep,” explains Jiří Splítek.

Smart sensors and safety systems can even stop the car if it recognises that the driver is completely inactive.

If the driver still does not actively take charge of the wheel, the car continues through further warning stages, for example with an audible signal. “If the driver remains inactive even after that, the car prepares for impact, rolls up the windows to 55 mm, closes the sunroof, and tightens the seat belts. The car then flashes its lights, honks its horn and is brought to a stop. The car unlocks when it stops and the interior lights come on. If the driver doesn’t react, after 15 seconds the emergency services are called,” Jiří says. Lane Assist or Travel Assist must be switched on for this system to work. “Our Emergency Assist starts the whole procedure at the moment when one of these systems should be deactivated. This is after 25 seconds of inactivity with Travel Assist, and after two steering inputs with Lane Assist,” Jiří explains.

The carmaker’s developers are tasked not only with fine-tuning the functionality of these assistance systems, which are designed to help the driver in an emergency situation, but also with developing additional functions based on those already in use. The new Superb, for example, will have an improved Driver Fatigue Recognition system, while Škoda cars will also get a new Cornering Assistant. Another brand new area is cyber security for cars in accordance with the UNECE regulation. These requirements are intended to ensure that assistance systems function reliably and to make it difficult or impossible for hackers to take control of them.