Platooning – safe convoys for trucks.

A present-day platoon. Back in the late 1990s, a forerunner of truck platooning was started as a research project entitled "electronic towbar". Knorr-Bremse was already involved.

Knorr-Bremse is driving forward the vision of the driverless commercial vehicle. One of the next steps along the road toward the fully automated Highway Pilot will be platoons of trucks with ‘electronic towbars.

Tomorrow’s freight transportation should be safer, faster and more reliable than it is today. One of the key roles will be played by (highly) automated driving. In the emergence of a radically transformed logistics ecosystem, platooning is one strategy for minimizing costs, transport times, accident risks, and fuel and energy consumption.

The road to highly automated driving

A highly automated supply chain requires specially developed trucks, and this continuous development process is well under way. It began decades ago with driver assistance systems such as ABS, ESP and traction control. New developments such as autonomous cruise control, lane keeping systems or emergency brake assist take things a step further. In 2016 Knorr-Bremse presented its Autonomous Yard Maneuvering system, in which a prototype truck and trailer rig covered a prescribed course within the enclosed space of a truck yard fully autonomously. Where once the onboard systems simply assisted the driver, now the driver’s responsibilities are being transferred step-by-step to the vehicle.

In the next few years we’re going to see a gradual shift from more and more versatile driver assistance systems to automated driving.

Dr. Peter Laier – Executive Board Member Knorr-Bremse AG, Commercial Vehicles Division

Tests of such platoons are now being conducted in real-world traffic. Several trucks ‘hook up’ electronically, close behind one another, and the drivers of the vehicles following the lead truck can turn their attention to other things. Along with communication between the trucks, vehicle dynamics control plays an important part in ensuring safe and reliable interaction between the trucks in the platoon.

Complex dynamics of commercial vehicles

Commercial vehicle dynamics are far more complex than in the case of cars, partly due to the variety of vehicle models available. The factors that impact their dynamic handling are not restricted to their length, number of axles and whether they are towing a trailer or semitrailer. There is also the number of driven or steered axles, the load distribution, the height of the center of gravity and many other parameters that exert an influence.

Connected braking and steering systems

One of Knorr-Bremse’s core competencies, as a systems supplier, is delivering intelligent, connected braking and steering systems from a single source. These systems coordinate the automated braking and steering processes, providing greater safety particularly in critical situations, not least by means of lateral guidance which keeps the vehicle safely in lane. Knorr-Bremse‘s acquisition of the commercial vehicle steering business of Hitachi Automotive Systems, Ltd. in Japan and Thailand in 2019 will reinforce this strategy and underpin the company’s engineering expertise.

Perception, decision and actuation

Perception, decision and actuation: these are the three dimensions of highly automated driving, and Knorr-Bremse has a sovereign command of all three. One key factor here is the close collaboration between Knorr-Bremse and its strategic partner Continental, where Knorr-Bremse has overall systems responsibility. When developing perception-related automated driving functions, established sensor technology used in cars can be adapted to the requirements of a truck. Similarly, at the decision level of automated mobility, the truck systems build on algorithms already developed by Continental, with Knorr-Bremse handling adaptation to the truck. Actuation along the entire chain of cause and effect is handled by Knorr-Bremse actuators, ensuring fail-safe overall vehicle functionality.

Safety in highly automated driving

With its mastery of the two essential actuators in a vehicle – the brakes and the steering – Knorr-Bremse is able to develop solutions. Take mandatory fallback systems as an example. There is no need to install two of each safety-relevant component, since automatic steering means that the vehicle will remain steerable even if an electronic subsystem fails. In case of a steering malfunction during platooning, selective braking of individual wheels will guide the truck safely around a bend or onto the hard shoulder. Steering by braking ensures that the vehicle remains maneuverable.

The future of automated driving

Knorr-Bremse and Continental have joined forces to develop the Platooning Demonstrator, based on a platoon of three trucks from different manufacturers. Initial test runs and demonstrations to customers have already been conducted at testing grounds. The cooperation partners show with this Platooning Demonstrator what driving functions they can develop, jointly with the vehicle manufacturers, for automated driving. They include the formation of platoons, driving together, the emergency braking function, exiting by individual vehicles and safe splitting up of the entire platoon. During the development work, special attention is being paid to the process for transferring control from the driver to the vehicle. The experience gained during development of the Platooning Demonstrator forms, for both Continental and Knorr-Bremse, the basis for tackling the technology’s next major application – the Highway Pilot, for highly automated driving of individual trucks on the highway.

The cooperation of Knorr-Bremse and Continental includes all functions for driver assistance and highly automated driving.
Knorr-Bremse and Continental are collaborating on the highly automated driving of commercial vehicles. Together they are testing automated driving in convoy (platooning) with a prototype.
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