Press Release
Page 1: Developing the concept
Page 2: Design
Page 3: Simulation and computing
Page 4: The "Strake"; Wind tunnel
Page 5: Electronics
Page 6: Test-driving; suspension
Page 7: A car for the senses
Page 8: Quality assurance
Virtual worlds: simulation and computing
Among these employees were many who were closely involved in the car’s progress, its appearance and its design long before they were able to handle a single component “in the flesh�. Never before had such intensive use been made of computer-aided simulation tools from the virtual world. Never before had so many of the Audi Q7’s characteristics been portrayed with the aid of bits and bytes, and never before had so few actual prototypes been built and, at the same time, such a high level of production maturity attained.
The advantages are obvious: everything than can be designed, destroyed, tested, modified and displayed on a screen in the virtual world of the computer only needs to be confirmed when actual hardware – culminating in the “real car� – becomes available. This not only cuts development time and cost but also boosts quality, since any conflicts of objective affecting the car can be eliminated even more accurately and efficiently.
This is the world in which terms such as Computer Aided Design (CAD), Computer Aided Engineering (CAE), Digital Mock-Up (DMU), Finite Element Method (FEM) or Virtual Reality (VR) are bandied about all the time in conversation among the technical specialists. They work with super-computers, microprocessors, power walls, gigantic volumes of data and the very latest software technologies. This is where the classic skills of mechanical engineering and vehicle design come together with advanced mathematics, lattice structures suitable for input to the computer and complex differential equations. There is very little that the computer cannot calculate and simulate.
The list of areas in which simulation technology is used in motor-vehicle manufacturing is a long one: body rigidity, strength and operating life, avoidance of unpleasant vibration, doors, lids, occupant protection, interior components, joining techniques and crash performance can all be displayed by these methods, as can driving dynamics, ride comfort, fuel consumption, sensor operation, aerodynamics and aero-acoustics, heating, ventilation and air conditioning, headlights, suspension characteristics or the actual combustion process in the engine. Many others could be mentioned too: Audi Technical Development currently uses some 250 simulation methods in production areas.
Even in the early vehicle development phase, colleagues from the Toolmaking, Production or Test Construction departments participate actively: as elements in the “digital factory�, they can simulate how certain sheet-metal parts can best be made (or if they are suitable for production in their initial form).
In an imaginary production shop, the spot welds to be produced by the robots are decided upon, and the robots’ own positions determined so that they keep clear of each other while performing the necessary movements.
In the “Cave�, as it is called, an engineer from Test Construction wearing 3D goggles extends a fully movable “virtual hand� into the Audi Q7’s body. He is using this authentic three-dimensional environment to check whether an employee on the assembly line will later be able to install, for example, a seat designed on the computer or the vehicle’s roof lining easily without any collisions with other components occurring. Nor should we forget that all this happens at a time when neither the car itself nor any of its components have been built.
At the power wall, a back-projection screen about 6 metres wide and 2.5 metres high, everyone involved in the development process, from technicians to members of the Board of Management, can view a virtual picture of the Audi Q7. Almost every detail can be displayed, even the surface texture of materials used inside the car.
With a single mouse-click, the car can be turned for viewing from every possible perspective, or the observer can make a circular flight all around it or through the interior. Various paint finishes and equipment specifications, as well as left- or right-hand-drive versions, can all be conjured up within a matter of seconds. The development engineers can even blend the real and virtual worlds together on the power wall, for example by displaying the virtual Audi Q7 in a real setting to see what effect is created when it is seen on the road.
Dr. Ulrich Widmann is Head of Functional Design at Audi. He knows the reasons why simulation technologies have now become indispensable: “A model such as the Audi Q7 is a highly complex combination of many different components and assemblies, with any number of different characteristics.
To develop it and determine its performance by means of genuine tests would be totally impracticable. Such a mammoth task can only be tackled successfully by means of a vast number of virtual-world simulations.�
Even in the Audi Q7 concept phase, computing and optimising the design ratings of the vehicle package is a particularly important task. There are tools that permit the modular vehicle concept to be described by just a few different parameters – about 1,000 in all, each of which can be changed interactively. Adjacent design areas that are influenced by these changes are then modified automatically. For example, the complete B-post can be moved rearwards by five centimetres within a matter of minutes.
The volume of data necessitated by such a change is immense: for a crash analysis on a modern car, up to a million elements are now involved when calculating the results within a period of 150 milliseconds. To calculate the effects of a frontal collision, the super-computer with its eight processors needs about 22 hours.
When Audi Q7 development is complete, some 2,000 virtual frontal crash tests will have been carried out, compared with just over 40 on actual vehicles. Dr. Widmann: “Our forecast accuracy from these simulations is already 90 % or higher!� An important aspect of such processes is for all the departments taking part to be networked together at an early stage, so that all of them have access to the latest design data.
Widmann: “For the Audi Q7, we used an “Engineering Portal� for the first time that our suppliers were able to access directly as well.�
The experts’ term for this kind of closely interlocked development work that takes place in parallel is “Simultaneous Engineering� (SE).
“We never worked as intensively as this before in the virtual world. Together with an actual concept car to act as a basis for package decisions and convey a sense of space, we were able to reach the series-production development phase more rapidly�, says Dr. Widmann.
