A new kind of remotely-controlled towing tractor that contains drive technology from Siemens is an environmentally friendly solution for taking aircraft from the gate to the take-off position.
Until now, airplanes have had to use their own turbines to cover this stretch. However, this is very uneconomical, as taxiing consumes up to one metric ton of fuel, depending on the airplane’s size and the distance covered. It is much more efficient to use a diesel-electric towing tractor that attaches itself to the nose wheel and pulls the airplane to the runway. As a result, an aircraft doesn’t have to turn on its engines until after it arrives at the runway.
After conducting extensive tests, Lufthansa now regularly uses such taxiing robots or TaxiBots at Frankfurt International Airport. According to the airline, the tractors enable it to save around 11,000 metric tons of fuel each year at Frankfurt Airport alone. TaxiBots are the result of a joint project between Siemens, the French TLD Group, Israel Aerospace Industries, and Lufthansa LEOS.
TaxiBots not only cut fuel consumption and emissions, they also reduce the strain on aircraft engines, thus extending their maintenance intervals. In addition, they aren’t as noisy as jet turbines. Current TaxiBots tow narrow-body (i.e. single-aisle) airliners such as the Airbus A320 and the Boeing 737. These tractors create only half as much noise as a taxiing airplane.
Including its own energy consumption, a Narrow-Body TaxiBot can save up to 150 kilograms of fuel on each taxiing mission. Trials with Wide-Body TaxiBots for airliners with two aisles, such as the Airbus A380 and the Boeing 747-400, are scheduled to begin soon at Chateauroux Airport in France. One such TaxiBot can save up to one metric ton of fuel when it tows a wide-body jet, which can weigh up to 600 metric tons.
Tractors Powered by Diesel-Electric Hybrid Drives
TaxiBots are real powerhouses — the narrow-body model has around 500 kilowatts of drive output (approximately 800 hp), while a Wide-Body model generates about 1 megawatt (over 1,350 hp). The TaxiBot’s four wheel pairs — for a Narrow-Bodyvehicle — or six wheel pairs — for a Wide-Bodyvehicle— is driven by electric motors. Every individual wheel of the Wide-Body model has its own drive motor.
Siemens supplies the tractors with powertrains, which consist of generators, electric motors, converters, electronics, and software. Although many of the components are based on those of the ELFA hybrid drive system for buses, they were specially developed or adapted for the needs of TaxiBots, which, among other things, require high torques and short response times.
For safety reasons, the system has a redundant design, which means that two diesel engines drive two generators for electricity production. The converters turn the electricity into a form usable by the electric motors. Depending on the model in question, a tractor can be equipped with either six or 16 converters. Wide-Body TaxiBot systems can even be separated into three pieces in the event of a fault. This ensures that two thirds of the drive system will work. In case of a fault such as a short circuit, the electronics developed by Siemens automatically switch off one third of the drive system.
The wheel module that contains the motors for each wheel pair is also a completely new development. Moreover, Siemens engineers have optimized Wide-Body TaxiBot technology by using permanent-magnet electric motors, which operate even more efficiently than conventional asynchronous machines. What’s more, the motors are completely integrated into the wheel module housings. Another new feature is that a TaxiBot can control the electric motor of each of its wheels separately.
This is an advantage when the vehicle turns in place or travels slowly, for example, because a great deal of force is required to turn the wheels under an airliner’s massive load. To achieve this, the Wide-Body TaxiBot can apply different amounts of force to the two wheels of a pair or drive them in opposite directions.
An important consideration during the development of TaxiBots was that pilots would continue to have sole control over an airplane, as required by law. For example, a tractor would be unable to properly brake a moving airliner weighing hundreds of tons.
When a pilot brakes an airplane via its main landing gear, the TaxiBot responds within 130 milliseconds and brakes as well so that the nose wheel isn’t subject to any strain. A plane’s nose wheel is attached to a TaxiBot by means of a special interface mechanism that registers all of the pilot’s steering and braking maneuvers, which it translates into commands for the tractor’s wheels. The software for controlling the wheels also comes from Siemens.
Mr. Dr Norbert Aschenbrenner
Mr. Florian Martini
Dr. Norbert Aschenbrenner | Siemens Pictures of the Future
Multiregional brain on a chip
16.01.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
Researchers develop environmentally friendly soy air filter
16.01.2017 | Washington State University
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction