#MissiontotheMoon - With the quattro technology to a successful Mision to the Moon

The next level of quattro

Whether by sunshine, in rain or on snow – quattro has been Audi’s reliable for-wheel drive system for all street conditions and over 35 years. Now quattro will help the Part-Time Scientists to conquer the next condition and successfully complete the Mission to the Moon.
After 384,400 kilometres of orbital spaceflight, the Audi lunar quattro will land on the moon.

Its mission: explore the lunar body and fulfil the tasks of the Google Lunar XPRIZE: land safely on the moon, drive 500 metres, send pictures back to Earth. Maximum traction is essential.

“The first version of our Asimov Rover stood the test very well during a drive through the volcanic crater landscape on the island of Tenerife,” explains Karsten Becker from Part-Time Scientists.

Karsten manoeuvred the rover like a remote-controlled car across the  volcanic rock, always with an eye on the vehicle. During the drive on the moon, Karsten won’t be standing next to the Audi lunar quattro. He will be controlling it from Earth – with a time delay of three seconds. The route is pre-calculated – but still: the rover will be driving more or less blind.

The quattro drivetrain detects wheelspin on a shaft and transfers more torque to another axle, which then ensures more torque on the ground.

A small crater, a somewhat larger rock – any unexpected obstacle could bring it to a halt.

At the moment, the rover’s four wheels are each driven by an own motor and can be turned 360 degrees. Should the rover’s front right wheel come against a stone, for instance, it can be turned at any angle needed so that it can drive around the obstacle – in a slanted position, sideways or backwards.


But what happens on a slope? The sand from the lunar rock, known as lunar regolith, is a thousand times finer than quartz sand. Moving across this moon dust is a huge challenge for the vehicle. If too much moon dust gathers at a single spot in the moon’s landscape, for a turning wheel it is like being stuck in a hole filled with quicksand.


During a tilting test at the German Aerospace Center (DLR), the Part-Time Scientists’s rover managed a nine-degree slope on loose lava stone. But then the wheels began to dig into the dust. They spun, did not have a grip anymore and sank in.


It’s because the rover steers all four wheels with the same power. Currently no one can say if one of the wheels has wheelspin, which can lead to reduced traction, spinning wheels in general and, in the worst case, also to one or more of the wheels digging completely into the dust.


Michael Schöffmann: Head of Transmission Development for Audi and coordinator of development with Part-Time Scientists.

But this is exactly the problem of the rover which the Audi’s quattro
drivetrain solves. It detects wheelspin on a shaft and transfers more torque to another axle, which then ensures more torque on the ground.


That’s why Audi engineers are working on optimising the Rover’s drivetrain with the Part-Time Scientists to develop an intelligent all-wheel transfer for the Audi lunar quattro.


Because, before the rover has to free itself out of a deadlocked situation on a far-away planet, the idea, of course, is to avoid such a situation from the beginning. That means: when the Audi lunar quattro explores an area with slopes and a wheel’s traction reaches its limit in moon dust, a sensor detects the threatening loss in traction. Software then regulates the drivetrain away from the wheel losing its grip and distributes it to the wheels on the axles which continue to deliver stable drive power.


In this way, the lunar quattro remains in driving order and Karsten Becker can steer it back to safe territory. Worst case averted. Mission saved.


Michael Schöffmann, Head of Transmission Development for Audi and coordinator of development with Part-Time Scientists: “The Audi quattro drivetrain is robust, instantaneous and absolutely reliable. The permanent all-wheel drive is distributed to all four wheels when the situation calls for it to completely prevent wheelspin.”


This has been the case for 35 years for cars on Earth – and now for vehicles on the moon too.

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