Autonomous driving has long been far from science fiction at Daimler. Autonomous driving with long-distance trucks will be a reality in ten years time. The Mercedes-Benz Future Truck 2025 study, which is close to reality, has already absolved this stage. It is technologically based on the 2014 Mercedes-Benz Actros. It demonstrates the future-proof concept of Europe's leading long-distance truck, which has set the standard for cost-effectiveness, safety and ease of operation since its market launch in 2011.
The Mercedes-Benz Actros - basis for the near-series study
The technological basis for the Future Truck 2025 with "Highway Pilot" is the Mercedes-Benz Actros 1845. Its engine develops 330 kW (449 hp) and a maximum torque of 2200 newton metres. Power is transferred by the fully automated 12-speed Mercedes PowerShift 3 transmission, which is standard equipment.
Its unusual semitrailer already provides a visual outlook on the near future. Mercedes-Benz presented the Aerodynamics Trailer two years ago, as a world premiere at the International Commercial Vehicle Show (IAA). Aerodynamically optimised, it is able to reduce the fuel consumption of the complete semitrailer combination by up to five percent. The overall package consisting of the Mercedes-Benz Future Truck 2025 and Mercedes-Benz Aerodynamics Trailer allows the advantages of both to be perfectly combined into the semitrailer combination of tomorrow.
Still veiled in secrecy
For demonstration drives on the roads, the Future Truck 2025 is still disguised – it is clad in black-and-white adhesive foil to obscure the exterior contours. In the interior, a protective shroud conceals the cockpit from inquisitive glances. However, additional monitors already give an advance indication that this is the workplace of the combined driver and transport manager in the truck of the future. The new Actros already makes a visual distinction between the driving and living areas. In the future the cab will also include a comfortable and functional working area for autonomous driving phases.
Moreover, the coming EU length restriction for trailer and semitrailer combinations allows additional aerodynamic improvement measures. The Aerodynamics Trailer will benefit from this. As will the Future Truck 2025 in its final and spectacular version. It will celebrate its world premiere in September, at the International Commercial Vehicle Show (IAA).
Eyes front: radar sensors and a camera scan the road ahead
The technical features are decisive for the outstanding capabilities of the Mercedes-Benz Future Truck 2025 as an autonomous vehicle. A radar sensor in the lower area of the front end scans the road ahead at long and short range. The front radar sensor has a range of 250 m and scans an 18-degree segment. The short-range sensor has a range of 70 m and scans a 130-degree segment. The radar sensor is the basis for the Proximity Control Assist and Emergency Braking Assist already available today.
The area ahead of the truck is also scanned by a stereo camera located above the dash support behind the windscreen. This is currently the location of a mono-camera if the optional Lane Keeping Assist is ordered. The range of the stereo camera is 100 m, and it scans an area of 45 degrees horizontally and 27 degrees vertically.
The stereo camera of the Mercedes-Benz Future Truck 2025 identifies single- and double-lanes, pedestrians, moving and stationary objects, all objects within the monitored area and also the condition of the road surface. The camera recognises everything that contrasts with the background, and is therefore also able to measure clearances precisely. The front stereo camera also registers the information on traffic signs.
In addition to object and distance recognition, the stereo camera recognises lane markings as a major function for autonomous track guidance.
The road surface to the left and right of the truck is monitored by radar sensors installed in the sides. They are located on the left and right, ahead of the tractor unit's rear axle. The sensors have a range of 60 m and cover an angle of 170 degrees.
Multisensor fusion: fusion of the data from all sensors
The sensors are networked (multisensor fusion), and provide a complete image of the surroundings. All moving and stationary objects in the truck's vicinity are registered. Fusion of the data from the front radar sensor, side radar sensors and front camera by a high-performance multi-core processor in the central computer provides a continuous view of the entire area in front of and beside the truck. For comparison, the human eye has a 150-degree angle of vision, but its focal area is merely a fraction of this.
The sensor system of the Mercedes-Benz Future Truck 2025 already comes from the next generation of this technology. The sensors work so precisely that they can not only recognise the road edge by the marker lines, but even identify the course of the road surface by the roadside features (e.g. guard rails or vegetation).
The sensor and camera technology is active throughout the speed range from standstill to the legally permitted maximum truck speed of 80 km/h. By intervening in the steering, it automatically keeps the truck safely in the centre of its lane. The system also includes a three-dimensional digital map, which is already used for the assistance system Predictive Powertrain Control (PPC). This means that the truck is always fully aware of the road's course and topography.
In addition the digital map and the information from multisensor fusion are used to determine the truck's own position.
V2V – vehicle-to-vehicle communication
The "Highway Pilot" is ideally partnered with V2V and V2I networking. Every vehicle equipped with this in the near future will transmit continuous information to its surroundings, the CAM (Corporate Awareness Message). The vehicle uses this to announce its presence. The information content includes vehicle position and model, dimensions, direction of travel and speed, any acceleration and braking manoeuvres and the bend radii negotiated.
The frequency of information transfer depends on the vehicle speed and the intensity of any changes in its movement. It varies between one message per second when cruising to ten times that interval when changes are significant.
Transmission is via WLAN technology, using the standard, Europe-wide G5 frequency of 5.9 gigahertz. The basis is the ITS Vehicle Station (Intelligent Transport Systems and Services) on board the vehicle. Communication between vehicles is also standardised following an agreement between a consortium of automobile manufacturers, suppliers, public organisations and research institutions.
Predictive driving – fast reactions
The range of these continuous messages is a radius of around 500 m. The vehicles inform each other about their movements, so that they can respond to them immediately in advance. This includes e.g. reacting to vehicles joining a motorway, or when approaching the end of a traffic tailback. Each of these messages certified to prevent misuse. Transmission to this distance also works in unfavourable weather conditions.
If necessary the continuous reports are overlaid with DEN messages (Decentralized Environmental Notification). These give a warning of unusual events, for example emergency braking, activation of the hazard warning system or switching on fog lamps.
V2I – communication between the truck and infrastructure
V2I means that all these messages and signals are also sent to external recipients such as traffic control centres. These are then able to respond flexibly, for example by changing the speed limit or opening up additional lanes. Messages can also be sent to the vehicles, for example about daytime or temporary roadworks.
If the next relay station for V2I is out of direct range, the information is relayed via other vehicles in the form of a transmission chain. If there is no WLAN network, transmission is by mobile technologies such as UMTS and GPRS.
All these data inform the driver or the onboard computer about events happening outside the range of vision in good time. The driver and vehicle are therefore aware of problems in advance, before they can become a hazard.
Anti-tailback measures: road traffic as a self-learning system
The Mercedes-Benz Future Truck 2025 is therefore not on the road in isolation, but constantly communicates with its environment, unnoticed by the driver. Just as it sends information about its own movements and journey to other vehicles, it receives signals showing the movements of other trucks and any other vehicles. The result is real-time communication between the networked vehicles that cannot be matched by even the most precise radio traffic reports.
In this way information about sluggish and slow-moving traffic is passed between vehicles in advance, also data on tailbacks and their length and duration, or on roadworks – the data are available to all road users. As the networked vehicles respond automatically, a steady traffic flow and efficient use of the limited infrastructure are ensured, better than even the most sophisticated traffic management systems can currently achieve. In the event of major problems, early information is provided about automatically initiated route changes to the destination or recommended diversions. In combination with autonomous driving, road traffic will develop into a self-learning system.
The average transport speed will be increased by the improved traffic flow alone, without raising the speed limit, and at the same time the smoother flow will save fuel. This benefits all parties involved in the goods transport sector: the transport operators and their drivers, dispatchers and customers.