|Dr. Nico Kämpchen on an automated test drive. Click to enlarge.|
Engineers at BMW Group Research and Technology are developing advanced automated driver assistance systems for the highway. Researchers have equipped a BMW 5 sedan with intelligent software as well as vision assistance and environment detection systems.
The prototype system can autonomously control acceleration and braking, and it can safely pass slower vehicles. One of the greatest challenges early in the project involved reacting to vehicles merging on to the motorway at exit and access points. The prototype system reacts to the situation by allowing the merging vehicles to join the traffic flow, and it can even change lanes giving the merging vehicles adequate space to enter traffic safely. This is possible up to a speed of 130 km/h (80 mph), but in compliance with current traffic regulations regarding speed limits and such things as prohibited passing zones.
This is an entirely new situation and experience for the driver—it is a strange feeling handing over complete control of the car to an autonomous system. But after a few minutes of experiencing the smooth, sovereign and safe driving style, drivers and passengers begin to relax somewhat and trust the independent system. Nevertheless, the driver is still responsible for the situation at all times and must constantly keep an eye on traffic and the surroundings.—Nico Kämpchen, Project Manager for Highly Automated Driving at BMW Group Research and Technology
To ensure that the automated research vehicle functions smoothly and with agility in real traffic, the car must be endowed with strategies to react appropriately in daily traffic situations. The basis for these strategies consists of two parts: first, pinpointing the position of the vehicle in its own lane; and second, the car must be able to clearly recognize all vehicles and objects in its nearest surroundings.
This is accomplished through the redundant fusion of various sensor technologies such as lidar, radar, ultra sound and video cameras that monitor the environment around the automobile. To ensure that the vehicle situation is precisely assessed, at least two different measurement methods must be used in every direction.
By accessing digital maps, the camera and the localization data of the extremely precise GPS, the automated vehicle prototype can determine its location in its own lane, and it also receives exact information about the characteristics of the route ahead, including the number of lanes that section of the motorway has. This information is supplemented by data from the forward-looking camera integrated in the lane departure warning system. Objects in front of the vehicle are detected by the radar sensors of the adaptive cruise control system with Stop&Go function and by a laser scanner as well. The same is true for objects at the sides or rear of the vehicle.
Precursors and basis: BMW TrackTrainer and the Emergency Stop Assistant. The technology needed for automated driving assistance systems was developed by engineers at BMW Research and Technology in two projects that resulted in the BMW TrackTrainer and the Emergency Stop Assistant.
The BMW TrackTrainer supports autonomous driving on competition race courses. With the precision of the localization a safe and yet very dynamic driving style can be realized. The TrackTrainer is currently used in BMW driver training sessions to give participants a genuine feel for the racing line—they experience it behind the wheel and not from the passenger seat. With merged data from an exact digital map, along with GPS and video data, the TrackTrainer can autonomously guide a vehicle along the racing line of a complete race track for training purposes. The system is already in its second generation, featuring optimized and precise position localization achieved by merging redundant sensors.
The constant comparison of GPS and video data with the digital maps and internal vehicle data was used to automatically guide a vehicle around the legendary North Loop of the Nürburgring on 21 October 2009. On 25 May 2011, the BMW TrackTrainer performed a similar feat at the Laguna Seca Raceway in California, demonstrating that fast and dynamic automated driving is indeed possible.
The main difference between the sessions at the rack track and trials on the motorway is that we are not alone when driving along a public motorway. That is why we were interested in learning about the developments in the Emergency Stop Assistant Project to ensure safety in our own undertaking.—Nico Kämpchen
The emergency stop assistant prototype realized by BMW is part of the SmartSenior Initiative of the Federal Ministry of Education and Research in Germany which was launched in May 2009. The system incorporates technologies for controlling and pinpointing the location of a motor vehicle and analyzing the vehicle environment for added safety.
If a driver loses control of a vehicle—for example due to a health emergency—the emergency stop assistant can detect the situation and autonomously take control of the car and bring it to a safe stop. The system activates the emergency flashers, carefully monitors traffic and guides the vehicle to the right shoulder of the road. Then an emergency call is automatically sent out to inform authorities of the situation, including information for emergency medical teams to ensure a quick and efficient response. This is all based on the Advanced Emergency Call function from BMW ConnectedDrive that is already available as a feature for production automobiles. This project served as the foundation for the environment recognition function that is used in automated motorway driving.
Automated future scenarios: Parking Assistant and Traffic Jam Assistant from BMW ConnectedDrive in the BMW i3 Concept. Research will continue on automated vehicles equipped with advanced driver assistance systems in order to develop innovative assistance functions for the future. Examples are the Parking Assistant and Traffic Jam Assistant in the BMW i3 Concept.
Since the BMW i3 Concept is primarily designed as an urban vehicle, it is equipped with functions that make parking easier and driving in congested traffic less stressful. The park assistant automatically parks the vehicle without any driver intervention. The car accelerates and brakes on its own, and shifts gears from forward to reverse as needed when difficult parking maneuvers are required.
The Traffic Jam Assistant helps drivers in rather monotonous traffic situations and congested areas, taking over so that the driver can relax. It maintains a safe distance between vehicles and automatically controls the speed and steering, and is able to stop the car if necessary. As long as the driver keeps one hand on the steering wheel, the vehicle can provide assistance in keeping the car precisely in its lane at speeds up to 40 km/h (25 mph).
The next thing we want to ‘teach’ our prototype is how to deal with road construction sites and motorway junctions. Construction sites are a big challenge because they take on all kinds of forms, which makes detection, localization and determining the right vehicle response quite difficult.—Nico Kämpchen