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
Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH
To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
25.04.2017 | Physics and Astronomy
25.04.2017 | Materials Sciences
25.04.2017 | Life Sciences