The technical developments of the past and the present are making fully automated driving possible one step at a time. These technologies will make it possible to drive on the freeway and in cities with increasing degrees of automation and in increasingly complex situations. In order for the systems to be accepted by drivers, they must have impressive functions and be easy to use. The behavior of the functions must be understood just as intuitively as their limits.
The trend toward automated driving poses new technical challenges with regard to surround sensors, actuators and the electrical/electronic architecture in the vehicle. The communication protocols for data exchange between vehicles must also be standardized.
What is happening around the vehicle? An important core technology for automated driving is reliable and precise detection of the vehicle’s surroundings. As the vehicle has to move independently in real traffic, it must be able to detect all relevant road users around the vehicle (360 degrees), and reliably assign them to the correct lanes. To do so, multiple sensors with differing measurement principles monitor every area of the vehicle’s surroundings. Using redundant sensors increases the reliability and robustness of the information. The surround sensors must provide a real, completely reliable, and constantly available 3D image of the vehicle's surroundings. The majority of the sensors required for this are already in production.
The traditional combination of radar, video and ultrasonic technology is not capable of covering all use cases. For this reason, Bosch is working on new sensor technologies that fulfill the complex requirements for detection of the vehicle's surroundings. The data supplied by the individual sensors is fused and processed to produce a complete environmental model. All static and dynamic objects are represented in this model. Completely new hardware and software technologies and algorithms are used for this calculation. Using digital maps and relative positioning (localization), the detected objects are then allocated precisely to the appropriate lanes. Thus, the system can interpret the situation, detect drivable areas, and deduce a driving strategy.
Highly and fully automated functions have to keep an eye not only on the vehicle’s surroundings, but on the driver, too. This is because, with certain functions in place, the driver no longer has to monitor the system and can hand full control over to the system, at least for a certain amount of time or in specific cases. The system then prompts the driver to assume responsibility for driving – but the vehicle must be able to detect whether or not the driver is able to do so.
The transfer of control between the vehicle system and the driver currently remains a challenge for developers. How long can and should the transfer take? What happens if the driver does not take control? A possible scenario: if the driver does not take control when approaching a specified freeway exit, for example, the automated vehicle will automatically pull over onto the shoulder and make an emergency call.
For automated driving, localization must be available, robust, and accurate to within an inch at all times. A sensor alone is unable to meet these requirements. Therefore, data is combined from satellite navigation, landmarks (lane markings and roadside structures), and a highly precise digital map. In addition to all lanes and roadside structures, this dynamic map also contains information about curves. The map is constantly informed of current speed limits, changes to the road network, and even short-term road construction via a mobile network.
Automated vehicles must calculate a preview of the vehicle’s surroundings that goes far beyond such near-range sensor technology as radar or video sensors. This preview is referred to as the “electronic horizon.” For this calculation, positioning is precisely determined in real time using the Global Navigation Satellite System (GNSS). Using the information obtained in this way and a comparison with current vehicle parameters, the system is able to plan a driving strategy, such as a lane-changing maneuver, for example.
Highly precise, dynamic position determination in real time is absolutely essential for automated driving. It is crucial in order to guide the vehicle with incredible precision, and thus to avoid negatively affecting other road users.
Slider to the right: Accuracy of the GPS position determination
Slider to the left: Accuracy of the position determination for automated driving using GPS, cloud data, inertial sensors and digital maps.
The driving strategy regulates how the automated vehicle should behave in road traffic, and determines the values required for vehicle control. The vehicle must also be able to take on tasks that are already a challenge for drivers. For example, it must decide for itself where to drive to and when to accelerate, brake, and steer – and all this on the basis of information that changes extremely quickly. The system must, therefore, calculate the route with proper attention to its entire environment, and control the car quickly, safely, and precisely.
If the vehicle takes over the tasks of the driver, safety aspects also become an issue. Although the risk of technological failure is reduced to a minimum, it cannot be eliminated completely. In the event of a system failure, the vehicle must be able to bring itself into a safe state without any driver intervention.
As vehicles gradually take over more and more driving tasks, safety-critical systems such as brakes and steering have to satisfy special requirements. To ensure maximum availability, even in the event that one component fails, there will be a change in vehicle architecture. What is needed is a system architecture with redundancies, one that is still able to control the vehicle in case of failure or, if necessary, passes control back to the driver.
Normally, an electric power steering system steers the vehicle. In the future, this will be designed with redundancy as well. For the brakes, Bosch already has a fallback: the iBooster, an electromechanical brake booster. Both iBooster and the ESP® brake control system are designed to brake the car – independently of each other – without the driver having to intervene.
Modern driver assistance systems help drivers reach their destination in a safer, more relaxed manner. They keep the vehicle in lane, regulate the speed and distance from other vehicles, illuminate the road in the best way possible, warn of traffic jams – and, once you reach your destination, they help you into even the smallest of parking spaces. If required, they can automatically initiate full braking in order to prevent rear-end collisions, or at least reduce the severity of collisions if they occur.
Driver assistance systems form the basis for the automated driving of the future. They have already been in production for several years, and are becoming increasingly popular. We are sure you have one or more of these assistance systems on board your vehicle.
The greatest challenge in the development of automated functions is still inner-city traffic, where an extremely wide range of road users must be considered from all directions. We also need concepts to ensure the correct functioning of the systems so that they work reliably, carefully and appropriately to the situation.
Furthermore, a critical mass of vehicles that can communicate with each other (around 10 percent) is required for standard operation. In addition to the technical challenges, the legal framework must also be adjusted or recreated from scratch in order to pave the way for automated driving. Bosch is taking the next step by implementing solutions for automated and connected parking (automated valet parking).