In order to develop fully automated driverless vehicles that can operate in urban environments, you need to have systems equipped with sensors that can reliably detect and recognise objects. Here, cameras, radar, ultrasound, and lidar serve as a vehicle’s “sensory organs.” Each sensory device has a specific talent, so to speak: cameras can recognise colours and using two cameras enables stereoscopic vision. Radar works rapidly and can even “see” underneath cars. It also has a range of up to 250 metres. Ultrasound, on the other hand, is very good for monitoring short distances around the vehicle. Lidar (Light Detection and Ranging) uses a laser beam to create a highly precise 3D measurement of the distance to the object recognised, its position, and its height.
All sensors continually monitor the vehicle’s entire surroundings in real time. The data they produce is put through a sensor fusion process that calculates an extremely exact model of the surrounding environment within milliseconds and precisely plans the vehicle’s route. Daimler and Bosch are jointly developing the algorithms needed for this. Such a system produces a huge amount of data. A stereo video camera alone generates around 100 gigabytes of data for every kilometre driven. The model of the surrounding environment that’s produced meets the stringent safety standards at Daimler and Bosch, which in the opinion of both companies is a basic requirement if fully automated vehicles are to become a reality. In order to ensure maximum reliability, various circuits perform the required computing calculations in parallel.
All data is sent to an automated drive controller (ADC), the central computer in a fully automated driverless vehicle. The ADC makes decisions that it passes on to the motion control unit, which then operates the actuators – i.e. the steering wheel, the gas pedal, and the brakes. Daimler has clear rules for this: all critical actuators and motion sensors in a fully automated Mercedes-Benz must have backups, and this also includes all control devices and the power supply system.
For example, the steering system that’s operated with electric motors not only has two motors but also redundant power electronics. The pneumatic brake booster previously used has been replaced by the electromechanical iBooster from Bosch. The combination of the brake booster and the Electronic Stability Programme (ESP) creates a braking system that allows the vehicle to be stopped safely even if individual components fail.