Audi wireless charging
Audi is working flat out on the future of ‘electromobility' - on its e-tron models and their technology. The brand with the four-ring badge pursues a comprehensive concept that includes every aspect of the task, including recharging the traction battery. In this area, automatic and contactless charging is an especially interesting prospect: Audi's name for this is Audi wireless charging.
Project Leader Dr. Björn Elias says: "We aim to offer our customers a premium-standard recharging method - easy to use and fully automatic, with no mechanical contacts. It uses the induction principle, which is already well known from various products, from the electric toothbrush through the induction cooker hotplate. We are now using it to recharge cars."
Dr. Elias is in charge of the Audi wireless charging pre-development project at Audi Electronics Venture GmbH (AEV), an AUDI AG subsidiary. Within the scope of pre-development in the area of Audi electronics, AEV has the task of identifying new trends in the vehicle electronics environment, checking their suitability and bringing them up to series-production readiness, if necessary in cooperation with outside companies.
An important partner in the area of wireless charging is the WiTricity Corporation from Watertown, near Boston. The American company supplies technical components which are integrated into the vehicle's complete system, in particular the coil systems that are integrated into the plates. The primary coil is normally located at the roadside or on a parking lot; the secondary coil is on the underside of the Audi e-tron vehicle.
When the Audi e-tron or some other suitably equipped electric vehicle is driven to a point above the primary coil in the road surface, the battery charging process starts automatically. Alternating current in the primary coil generates an alternating magnetic field that crosses the air gap and induces an alternating voltage in the secondary coil on the car. This voltage is rectified and fed to the car's traction battery. The process is terminated when the battery is fully charged or if the recharging process is interrupted by driving the car away or switching it off manually.
The primary coil - for instance in the car owner's garage - can be flat on the floor or even under the surface. It is unaffected by rain, ice or snow, and since the alternating magnetic field is only built up when a vehicle is above it, there is no risk to human beings or animals.
This charging technology can be integrated into the traffic infrastructure wherever needed, for instance as garage parking equipment or on housing estates. Dr. Elias outlines a medium-term scenario: "Imagine you drive to work in your Audi e-tron, and on the way home you stop off at the store. Wherever you park the car, its battery will be recharged - perhaps even at traffic signals. These short recharging cycles are ideal for the battery: the smaller the difference between the values before and after recharging, the longer the battery's potential operating life."
Much more work will be necessary before countrywide recharging infrastructures can be built up. Audi is playing an active part as a member of the expert workgroups in Germany and America that are aiming for a uniform public standard. Dr. Elias expects automatic wireless charging technology to go into series production in a few years' time. With it, electromobility has the potential to take a further big step forward.
Project Leader Dr. Björn Elias says: "We aim to offer our customers a premium-standard recharging method - easy to use and fully automatic, with no mechanical contacts. It uses the induction principle, which is already well known from various products, from the electric toothbrush through the induction cooker hotplate. We are now using it to recharge cars."
Dr. Elias is in charge of the Audi wireless charging pre-development project at Audi Electronics Venture GmbH (AEV), an AUDI AG subsidiary. Within the scope of pre-development in the area of Audi electronics, AEV has the task of identifying new trends in the vehicle electronics environment, checking their suitability and bringing them up to series-production readiness, if necessary in cooperation with outside companies.
An important partner in the area of wireless charging is the WiTricity Corporation from Watertown, near Boston. The American company supplies technical components which are integrated into the vehicle's complete system, in particular the coil systems that are integrated into the plates. The primary coil is normally located at the roadside or on a parking lot; the secondary coil is on the underside of the Audi e-tron vehicle.
When the Audi e-tron or some other suitably equipped electric vehicle is driven to a point above the primary coil in the road surface, the battery charging process starts automatically. Alternating current in the primary coil generates an alternating magnetic field that crosses the air gap and induces an alternating voltage in the secondary coil on the car. This voltage is rectified and fed to the car's traction battery. The process is terminated when the battery is fully charged or if the recharging process is interrupted by driving the car away or switching it off manually.
The primary coil - for instance in the car owner's garage - can be flat on the floor or even under the surface. It is unaffected by rain, ice or snow, and since the alternating magnetic field is only built up when a vehicle is above it, there is no risk to human beings or animals.
This charging technology can be integrated into the traffic infrastructure wherever needed, for instance as garage parking equipment or on housing estates. Dr. Elias outlines a medium-term scenario: "Imagine you drive to work in your Audi e-tron, and on the way home you stop off at the store. Wherever you park the car, its battery will be recharged - perhaps even at traffic signals. These short recharging cycles are ideal for the battery: the smaller the difference between the values before and after recharging, the longer the battery's potential operating life."
Much more work will be necessary before countrywide recharging infrastructures can be built up. Audi is playing an active part as a member of the expert workgroups in Germany and America that are aiming for a uniform public standard. Dr. Elias expects automatic wireless charging technology to go into series production in a few years' time. With it, electromobility has the potential to take a further big step forward.
Garage Parking Pilot
Cars that move without the driver taking any action - this still sounds like an idea that has strayed from science fiction. But Audi is bringing it step by step closer to reality. The parking assistant that helps to steer various Audi models such as the Audi A4 and Audi A6 into a parking bay has been in production for some time, and new technologies for ‘piloted parking' are now being developed. The visionary motto is: "If I don't want to drive, I'll let the car take over. If I enjoy driving, for instance on an attractive country road, then I'll take over myself!"
"Parking garages and underground car parks are typical examples," says Stefan Stümper. He works for the Audi Electronics Venture, an Audi subsidiary for pre-development in the area of electronics. Not every driver feels happy when driving around looking for an empty parking bay. It takes time to find one, insert the car carefully into it and take it out again later. Our Garage Parking Pilot project assists the driver in performing these tasks."
Stümper explains this technology by taking an Audi driver who wants to see a movie one evening as an example. Using the car's online link while driving into town he checks with the garage's management system whether there is an unoccupied piloted parking bay. This information appears on the car's MMI screen; the driver selects the most suitable garage and the navigation system guides him to it.
At the entrance the driver stops briefly to select any other services he needs on the MMI screen, for instance automatic wireless charging of the battery if he is driving an Audi e-tron model. He then gets out of the car, locks it and uses his smartphone to issue a ‘park' signal to the system.
In the garage a central control unit manages the piloted parking process. It makes WLAN contact with the car at the entrance and calls up the principal data, from which it learns the car's size. The central computer then locates the nearest suitable parking bay and transmits a schematic route map to the car.
This ‘digital thread' operates the Audi's electromechanical steering as it moves through the garage at a speed of between five and ten kilometers an hour. This aim of the project is to perform the parking function reliably without the car having to be upgraded technically. The Audi therefore uses existing series-production sensors to identify its position. An intelligent computer algorithm compiles a complete picture of the surrounding area and compares it with the garage's route map.
If there is the slightest risk of a collision, the Audi comes to a halt. The same applies if radio contact with the central computer is lost. The garage control unit monitors all the car's movements with highly accurate laser scanners. According to pre-development engineer Stümper: The equipment is accurate to the nearest centimeter, but the true challenge is not achieving reliability in the individual modules but in getting all the necessary sensor and control modules to work together as a single, complex overall concept."
After the driver has enjoyed his movie, he calls the garage parking computer by smartphone and instructs it to send the car to the exit point - assuming that he didn't already ask for it to be returned at a specific time. The Audi then re-appears and the parking fee is debited automatically.
"This scenario is only the beginning," says Stefan Stümper. "Our first step would be to equip separate areas in the garages for piloted parking. The central computer would control all the vehicle movements there for maximum speed and safety. Since there are no people in these areas, the ceilings can be lower, the parking bays smaller and the lighting less powerful, to save space and reduce energy consumption. We can also install automated car wash and refueling systems - and of course recharging points for e-tron models."
Science fiction? Not any more - though of course liability questions are very important, and will have to be solved before these systems go into large-scale production. Audi is taking aviation as a guideline: the ‘automatic pilot' has been commonplace for many years, but the final responsibility still rests with the human pilot. The same will apply to the automobile. This is why Audi speaks about ‘piloted driving'. The garage parking pilot is a firm element in the new networked mobility that Audi has named ‘Audi connect'. This term covers all applications and developments that form links between Audi automobiles and their owners, with the Internet, with the infrastructure and with other vehicles - to serve and benefit the customer.
OLED Technology
Cars that move without the driver taking any action - this still sounds like an idea that has strayed from science fiction. But Audi is bringing it step by step closer to reality. The parking assistant that helps to steer various Audi models such as the Audi A4 and Audi A6 into a parking bay has been in production for some time, and new technologies for ‘piloted parking' are now being developed. The visionary motto is: "If I don't want to drive, I'll let the car take over. If I enjoy driving, for instance on an attractive country road, then I'll take over myself!"
"Parking garages and underground car parks are typical examples," says Stefan Stümper. He works for the Audi Electronics Venture, an Audi subsidiary for pre-development in the area of electronics. Not every driver feels happy when driving around looking for an empty parking bay. It takes time to find one, insert the car carefully into it and take it out again later. Our Garage Parking Pilot project assists the driver in performing these tasks."
Stümper explains this technology by taking an Audi driver who wants to see a movie one evening as an example. Using the car's online link while driving into town he checks with the garage's management system whether there is an unoccupied piloted parking bay. This information appears on the car's MMI screen; the driver selects the most suitable garage and the navigation system guides him to it.
At the entrance the driver stops briefly to select any other services he needs on the MMI screen, for instance automatic wireless charging of the battery if he is driving an Audi e-tron model. He then gets out of the car, locks it and uses his smartphone to issue a ‘park' signal to the system.
In the garage a central control unit manages the piloted parking process. It makes WLAN contact with the car at the entrance and calls up the principal data, from which it learns the car's size. The central computer then locates the nearest suitable parking bay and transmits a schematic route map to the car.
This ‘digital thread' operates the Audi's electromechanical steering as it moves through the garage at a speed of between five and ten kilometers an hour. This aim of the project is to perform the parking function reliably without the car having to be upgraded technically. The Audi therefore uses existing series-production sensors to identify its position. An intelligent computer algorithm compiles a complete picture of the surrounding area and compares it with the garage's route map.
If there is the slightest risk of a collision, the Audi comes to a halt. The same applies if radio contact with the central computer is lost. The garage control unit monitors all the car's movements with highly accurate laser scanners. According to pre-development engineer Stümper: The equipment is accurate to the nearest centimeter, but the true challenge is not achieving reliability in the individual modules but in getting all the necessary sensor and control modules to work together as a single, complex overall concept."
After the driver has enjoyed his movie, he calls the garage parking computer by smartphone and instructs it to send the car to the exit point - assuming that he didn't already ask for it to be returned at a specific time. The Audi then re-appears and the parking fee is debited automatically.
"This scenario is only the beginning," says Stefan Stümper. "Our first step would be to equip separate areas in the garages for piloted parking. The central computer would control all the vehicle movements there for maximum speed and safety. Since there are no people in these areas, the ceilings can be lower, the parking bays smaller and the lighting less powerful, to save space and reduce energy consumption. We can also install automated car wash and refueling systems - and of course recharging points for e-tron models."
Science fiction? Not any more - though of course liability questions are very important, and will have to be solved before these systems go into large-scale production. Audi is taking aviation as a guideline: the ‘automatic pilot' has been commonplace for many years, but the final responsibility still rests with the human pilot. The same will apply to the automobile. This is why Audi speaks about ‘piloted driving'. The garage parking pilot is a firm element in the new networked mobility that Audi has named ‘Audi connect'. This term covers all applications and developments that form links between Audi automobiles and their owners, with the Internet, with the infrastructure and with other vehicles - to serve and benefit the customer.
OLED Technology
The ‘tunnel of light' in the basement of the Audi Electronics Center in Ingolstadt is a rather dark place - until it comes to casting light on the situation. The floor is gray, the curtains have black drapes and only in the middle there are three specimens brightly lit in various shades of yellow and red. The room is like the stage of a theater, with Stephan Berlitz, Head of Innovations Lighting/ Lighting Electronics at Audi, as the stage manager.
Berlitz is one of the development engineers who have helped put Audi in the lead in modern automobile lighting technology. LED daytime running lights and headlights are development milestones; the next step forward will be OLED. Displays using this technique have already reached series production maturity in the electronic industry. Berlitz and his team cooperate closely with Audi Design on utilizing OLEDs as exterior lighting for the automobile.
OLED stands for "organic light emitting diode". Unlike LEDs, which consist of semiconductor crystals, they are organic polymers with the properties of semiconductors. Only a few nanometers thick, the paste-like material occupies the space between an anode and a cathode. These both have an electrically conductive coating. Because they are only a few thousandths of a millimeter thick, all these materials can be transparent if necessary.
Two glass plates with a flat polished surface enclose the assembly and make it air- and water-tight. The resulting sandwich, just over a millimeter thick, is held in a metal frame. If a low voltage is applied, photons are emitted in the electrical field and the surface is illuminated. The thinner the layer, the greater the brightness. Various polymers can be used to obtain different colors.
Several OLEDs can be placed one behind the other for mixed color effects, since they are transparent. White light is obtained by adding the colors together.
Stephan Berlitz demonstrates a rear light that his team has built up for the Audi Q7. Inside it, the light comes from four small red OLED plates aligned next to one another. Eight flat segments make up the curved yellow strip for the flashing turn indicator.
"This homogeneous visual effect would not be possible with today's LEDs," Berlitz explains. "These are individual points of light that need additional optical devices - reflectors, optical conductors or scatter optics. OLED surfaces are themselves the source of light, and the thin plates also look attractive. They weigh little, light up extremely fast, develop only a small amount of heat, last for several tens of thousand hours and don't consume any more energy than conventional light-emitting diodes. OLEDs suit Audi perfectly because they combine high-end technology, maximum precision and super design!"
The Audi roadmap for introducing OLEDs to series production will take several years to put into effect. At the current level of development, the new diodes only withstand low currents and the acceptable temperature range ends at about 80 degrees Celsius. OLEDs will make an appearance as rear lights in the relatively near future; for brake lights, which have to be about five times brighter, a few more years will elapse. But Berlitz can also visualize white OLEDs being used for daytime running lights and side lights.
The biggest target of all - especially for Audi's designers - are three-dimensional OLEDs. The first prototypes are now appearing as part of a project with public support. They are fascinating: delicate, almost weightless ring-shaped sources of light, installed on various levels in the rear light units of an Audi TT.
Free forms can perhaps be obtained by means of an intermediate solution - arranging the small plates three-dimensionally. Clusters of this kind could be located anywhere on the body, as seen on a model of the future Audi R8 OLED concept. It has strips consisting of hundreds of triangular OLEDs on its sides, back and inside the car. "My design department colleagues have transformed the entire car into a source of light!" says Berlitz. This will permit the car to be identified in a whole series of ways that can be constantly varied."
The ‘swarm' - the third exhibit in the tunnel of light, is another scenario for the future. The rear end of the car is transformed into a large illuminated surface, with innumerable small points of light flickering like a swarm of fish and following the car's movements. When the driver turns right, the swarm moves in the same direction, when he or she applies the brakes, the ‘fish' rush forward, and the faster the car is driven, the more hectic the swarm's movements. In this way the OLEDs tell the driver behind actively just what the car is doing.
The ‘swarm' uses OLEDs in a technical display, with a matrix made up of a large number of pixel-size units that can be energized separately. The OLED swarm too combines the attractive with the practical, or as Berlitz puts it: "It looks sensational but it's also a definite safety feature!"
Hybrid Body Materials
Major breakthroughs mostly begin in a small way. At first glance, the exhibits presented by Benjamin Bender seem to have nothing spectacular about them: narrow strips of aluminum with a thin layer of carbon-fiber reinforced plastic (CFRP) on the back.
In fact this advanced development project, which postgraduate Bender is undertaking in the Audi Lightweight Design Center (ALZ) at the Neckarsulm plant, has great future potential. At a later date, when the new hybrid metal and CFRP structures go into series production, they will represent another step forward in ultra-lightweight construction at Audi.
The Audi brand became a leader in lightweight vehicle construction some years ago with its aluminum bodies. Using the ASF (Audi Space Frame) construction principle on the Audi A8, Audi R8 and Audi TT models reduced the weight of their bodies by as much as 40 percent compared with conventional steel structures. Now Audi is launching the next stage in the process: the Multimaterial Space Frame, which combines aluminum, steel and fiber-reinforced components.
Audi engineers have in-depth competency in working with all these materials. They are not forced to work with a single material; instead, their motto is ‘the right material in the right place for outstanding performance'.
The new bodies, by combining the advantages of the various materials, will be much lighter than conventional metal structures.
Benjamin Bender's project takes the multimaterial concept a step further, by making the individual components into ‘hybrids'. If a metal element in the body structure - a B-post or a sill - is systematically reinforced with CFRP, its properties are enhanced, for instance its strength or its deformation behavior in a crash. Yet at the same time it weighs less, because the comparatively heavy metal - steel or aluminum - has been partly replaced by much lighter CFRP.
At the Audi Lightweight Design Center in Neckarsulm about 180 specialists work on the future of Audi vehicle bodies. Benjamin Bender has to find answers to a number of questions. How should the metal and CFRP be combined in order to obtain optimal properties in each component? At which points does the reinforcement have its maximum effect? And what do practical tests tell us about the components' crash performance or resistance to corrosion?
The method used to join the two materials is another central topic. This is normally done with rivets, screws or technical adhesives. The new project adopts a more ingenious approach: the synthetic resin needed to produce a component entirely in CFRP acts here as the connecting medium.
Bender is currently investigating whether RTM (resin transfer molding) can be used to bond the two materials together. The RTM process is suitable for higher production volumes and is one of the key technologies at the Audi Lightweight Design Center.
"Even if development work goes according to plan, it will take several more years," says Bender, "and we will still need some time before it's ready for series production." Audi knows very well that major breakthroughs often take a bit longer - in ultra-lightweight construction too.
FRP Coil Springs
For Audi, ultra-lightweight vehicle design is more than engineering competency alone. It's an attitude of mind that exists throughout the company. The brand's engineers fight determinedly to avoid every scrap of unnecessary weight - not only in the body but also in every component and assembly that goes to make up the complete automobile.
Ultra-lightweight design is especially interesting in the chassis and suspension area. Every reduction in unsprung mass improves ride comfort and handling. Joachim Schmitt's pre-development project is in this technological area. It is devoted to a component which is nothing special to look at, but has to withstand severe loads. A component which one might think could scarcely be improved any more: the coil spring. The project takes a different view, however, and aims to replace the steel spring with a spring made from fiberglass reinforced plastic (FRP).
The FRP coil spring, which Schmitt has developed jointly with the patent holder SOGEFI, is very different from a conventional steel spring. It's bright green in color, the so-called wire is thicker, the spring's overall diameter is greater and the number of turns is lower. Above all, this type of spring is much lighter in weight. Project engineer Schmitt has the facts: "Each of the steel springs in the A4 model's front suspension weighs 2.66 kilograms. The FRP spring weighs only 1.53 kilograms, more than 40 percent less, but performs just as well."
A helix made from fiberglass reinforced plastic is capable of absorbing torsional loads extremely well if it is designed with this purpose in mind. The core of the spring consists of long glass fibers twisted together and impregnated with epoxy resin. A machine wraps additional fibers around this core, which is only a few millimeters in diameter, at alternating angles of plus and minus 45 degrees to the longitudinal axis. These layers support each other and act in either compression or tension. Torsional loads across the component are converted in the fibers into tensile and compressive loads.
The next production stage is for the ‘wire', while it is still wet and soft, to be wound onto a metal alloy core with a low melting point; this core is the negative form of the finished spring. The FRP material is then hardened in an oven at more than 100 degrees, so that the core melts. This is the process currently used to manufacture the prototypes. Later it will be very much faster and more efficient: a pilot batch will be made first, followed by the start of high-volume production: a million springs annually.
The new FRP suspension springs will make their debut before the end of 2012 in the electrically propelled Audi R8 e-tron model. In 2013 they will be introduced step by step in greater volume for Audi midsize and large luxury models. Long-term road trials are taking place at the moment, accompanied by marathon test cycles on special rigs, each of which imposes loads on the spring equal to about 300,000 kilometers of driving by the average customer.
"In the early days many of my colleagues were not convinced that the project would be a success," Joachim Schmitt recalls. "But from the very start FRP proved to be an excellent choice of material. It is absolutely immune to corrosion, even if struck by stones flung up from the road surface, and effectively resistant to chemicals such as wheel cleaning products. Manufacturing FRP springs consumes less energy than for steel springs, and they reduce the weight of a car such as the current Audi A4 by about four kilograms - a notable step forward."
Schmitt and his colleagues are already able to tune their FRP springs to suit the chassis engineers' wishes, taking the car, its axle loads and its ride comfort and handling characteristics into account. All they have to do is vary the length of the wire, its diameter and the number of turns. In a few years' time the engineers expect improved production methods to increase the load capacity of the FRP material, so that the space needed for the springs is no larger than for today's steel springs.
Which just leaves the unusual bright green color - but Audi's development engineers have tackled this as well. Joachim Schmitt: "If we add a certain amount of graphite to the mixture for the FRP springs, they are dyed black right through. And for enthusiastic drivers we're already working on red and blue springs!"
Multitouch Controls
The driving simulator in the basement of the Audi Electronics Center in Ingolstadt is not just a bodyshell with seats in it, but an almost complete car - an Audi A8 with only the front end and the engine missing. Above its roof is a tall structure containing four large film projectors. Their images are shown on a curved wall that surrounds the car in a 240-degree segment of a circle. To complete the 360-degree image, two further projectors are aimed at a screen behind the car.
On this particular day the big picture is a four-lane highway with only light traffic on it. "Our test candidate will be asked to follow the car ahead," says Kristin Dettmer, whose responsibility in the Development Operating Concept department is the ‘touchpad'. "The occupant of the front passenger seat will then ask him to perform certain tasks: dialing a telephone number, choosing a new destination on the navigation system or playing a selection from the media list.
None of these tasks is difficult, but each step in the process calls for a certain degree of concentration. The driver wears glasses into which two miniature cameras are integrated: one of them films the surrounding area, the other the pupil of the driver's eye. Later, the Audi development team analyzes the recorded images with the aid of special software. This gives them detailed information about how long the driver took for each of the steps on the MMI monitor, and how often he looked at the control pad.
Audi attaches great importance to car control. Ten years ago, when the MMI system was first introduced in the Audi A8, the brand led the field in relation to its competitors. In 2010 the touchpad - the ‘MMI touch' - was also premiered in the Audi A8. It was the next major step forward, and has now been combined with the turn-and-push control in the new Audi A3. The aim is to maintain this design leadership: a vast number of new functions are now becoming possible, especially in the infotainment area, and will call for even more intelligent control concepts.
All development work is centered on an unalterable Audi principle: operation of the controls should be so intuitive that the driver's task is made easier, not more complicated. This is the guideline that governs Kristin Dettmer's project too: further development of the touchpad for Multitouch operation using several fingers.
The touchpads available for many current Audi models are intended for single-touch operation and are therefore especially suitable for the input of letters and numerals, using one finger. But Audi plans to use Multitouch technology for future generations of these devices. Using more than one finger opens up entirely new prospects. The system has already been extended to permit two fingers to be used when searching quickly in the navigation map, and three fingers make it quicker to scroll through long media lists. The touchpad measures twelve by eight centimeters, which most users find sufficient.
"For the new control system we have also revised the menu logic and the screen graphics," Kristin Dettmer explains. "Until now they were entirely based on the turn-and-push knob and its rotary movements. Now there is to be greater emphasis on the horizontal and vertical elements, though we don't intend to dispense with the adjusting knob entirely, since it will definitely remain the ideal device for selecting a certain number of functions."
Many test results, especially from the driving simulator, the digital ‘surface table' and an Audi A7 Sportback used for actual road testing, have contributed to the success of this development work, which has been in progress for three years. The question is always: how well do the test candidates cope with the Multitouch control principle?
"The public got to know the principle when the iPad and iPhone were introduced," says Kristin Dettmer. "Of course our test ‘guinea pigs' differ: older people in particular are rather hesitant when invited to operate the controls with several fingers. Our system is therefore basically suitable for single-finger operation as well. Many people start that way, then discover how easy it is to move on to the next levels. It's this ‘joy of use' that we're trying to communicate."
Audi's thinking on future control concepts is going ahead in a number of different directions. One of these focuses on innovative touchpad technology that sends a tactile response back to the user's fingers. Another project concentrates on improving voice control and a third uses innovative gesture control for the head-up displays. Here too the development staff headed by Bernhard Senner is working on a very advanced principle, of which a model already exists.
Driver and front passenger have their own head-up displays, for the front passenger it shows digital journey guide, news and pictures from video telephone calls. There is also a third, central projection visible to all occupants; here too the images appear to be on the windshield.
The driver's side only displays the relevant information in the form of symbols, still images and simple animations. Some of them, for example the navigation arrows, are imaged created by a novel contactless technology, and seem to float directly above the actual surroundings. The passenger's viewing area, on the other hand, has access to all video functions. In this case the image uses the new DLP (digital light processing) technology, which boosts brightness and contrast.
Bernhard Senner has an example that illustrates the idea behind the new technological principle. "If the front passenger finds an interesting destination in his digital travel guide, for instance a restaurant, he can make a simple, rapid ‘wipe' gesture to move the content as a still image into the center zone. If the driver then makes a similar gesture to accept the destination into his own head-up display, he can then input it to the navigation route." A small camera detects the hand movements and transmits the appropriate signals to the system.
Predictive Suspension
Downhill skiing on a mogul piste is great fun, provided that visibility is good. The skier has to be able to find the ideal track, bend and stretch the legs at just the right moments and float rhythmically and in a seemingly effortless way over the peaks and valleys.
"Even today, when a car is driven over an uneven surface, it's like a skier tackling a mogul run in thick fog!" says Dr. Andreas Schindler of Audi's chassis pre-development department. "The skier and the driver don't know what's ahead of them. They can't react until they sense the first movements through the skis or the wheels. Our task is to improve this situation."
Some years ago Audi began to equip its cars with predictive intelligence. Radar- and camera-based assistance systems such as adaptive cruise control und Audi active lane assist support the driver and enhance driving comfort. The technologies that will follow in the next few years will give this trend fresh impetus; examples are the traffic jam assistant, the intersection assistant or predictive suspension.
A year ago Audi announced an innovation that will increase occupant comfort: elimination of lateral forces. A video camera identifies bends as the car approaches them and an active mechanism in the suspension, which consumes only a small amount of energy, tilts the car's body so that the passengers are only aware of a minimum amount of centrifugal force acting on them. Predictive suspension uses a similar principle, but minimizes vertical rather than lateral forces.
The biggest challenge that Audi's pre-development team had to face was locating suitable sensors for their project. These have to respond to changes within an area up to 20 meters long ahead of the car, even in difficult conditions such as wet roads with shiny surfaces, or after dark. Very high-resolution road-surface images are needed so that possible obstacles can be located within a tolerance of a few millimeters - and, for instance, to distinguish potholes in the road from cross-joints or plastic bags.
An algorithm in the system's control unit analyzes information on road surface irregularities and the car's own movements, and supplies the appropriate suspension control signals. Simulations of this area of the project are already operating very reliably, and concept development of the high-resolution sensors is now going ahead rapidly.
Audi's sensor technology engineers make use of the extensive experience they gain from their work on future driver assistance systems, where extremely varied technologies are being tested, from PMD (photo-mixed detector) sensors through radar-sensors and laser scanners. Stereo cameras are also a promising development in the predictive suspension area. The outcome - which technology will be first across the finishing line - is still undecided, but one thing is certain: Audi will adopt nothing less than a no-compromise solution, as it has in all its development projects.
Berlitz is one of the development engineers who have helped put Audi in the lead in modern automobile lighting technology. LED daytime running lights and headlights are development milestones; the next step forward will be OLED. Displays using this technique have already reached series production maturity in the electronic industry. Berlitz and his team cooperate closely with Audi Design on utilizing OLEDs as exterior lighting for the automobile.
OLED stands for "organic light emitting diode". Unlike LEDs, which consist of semiconductor crystals, they are organic polymers with the properties of semiconductors. Only a few nanometers thick, the paste-like material occupies the space between an anode and a cathode. These both have an electrically conductive coating. Because they are only a few thousandths of a millimeter thick, all these materials can be transparent if necessary.
Two glass plates with a flat polished surface enclose the assembly and make it air- and water-tight. The resulting sandwich, just over a millimeter thick, is held in a metal frame. If a low voltage is applied, photons are emitted in the electrical field and the surface is illuminated. The thinner the layer, the greater the brightness. Various polymers can be used to obtain different colors.
Several OLEDs can be placed one behind the other for mixed color effects, since they are transparent. White light is obtained by adding the colors together.
Stephan Berlitz demonstrates a rear light that his team has built up for the Audi Q7. Inside it, the light comes from four small red OLED plates aligned next to one another. Eight flat segments make up the curved yellow strip for the flashing turn indicator.
"This homogeneous visual effect would not be possible with today's LEDs," Berlitz explains. "These are individual points of light that need additional optical devices - reflectors, optical conductors or scatter optics. OLED surfaces are themselves the source of light, and the thin plates also look attractive. They weigh little, light up extremely fast, develop only a small amount of heat, last for several tens of thousand hours and don't consume any more energy than conventional light-emitting diodes. OLEDs suit Audi perfectly because they combine high-end technology, maximum precision and super design!"
The Audi roadmap for introducing OLEDs to series production will take several years to put into effect. At the current level of development, the new diodes only withstand low currents and the acceptable temperature range ends at about 80 degrees Celsius. OLEDs will make an appearance as rear lights in the relatively near future; for brake lights, which have to be about five times brighter, a few more years will elapse. But Berlitz can also visualize white OLEDs being used for daytime running lights and side lights.
The biggest target of all - especially for Audi's designers - are three-dimensional OLEDs. The first prototypes are now appearing as part of a project with public support. They are fascinating: delicate, almost weightless ring-shaped sources of light, installed on various levels in the rear light units of an Audi TT.
Free forms can perhaps be obtained by means of an intermediate solution - arranging the small plates three-dimensionally. Clusters of this kind could be located anywhere on the body, as seen on a model of the future Audi R8 OLED concept. It has strips consisting of hundreds of triangular OLEDs on its sides, back and inside the car. "My design department colleagues have transformed the entire car into a source of light!" says Berlitz. This will permit the car to be identified in a whole series of ways that can be constantly varied."
The ‘swarm' - the third exhibit in the tunnel of light, is another scenario for the future. The rear end of the car is transformed into a large illuminated surface, with innumerable small points of light flickering like a swarm of fish and following the car's movements. When the driver turns right, the swarm moves in the same direction, when he or she applies the brakes, the ‘fish' rush forward, and the faster the car is driven, the more hectic the swarm's movements. In this way the OLEDs tell the driver behind actively just what the car is doing.
The ‘swarm' uses OLEDs in a technical display, with a matrix made up of a large number of pixel-size units that can be energized separately. The OLED swarm too combines the attractive with the practical, or as Berlitz puts it: "It looks sensational but it's also a definite safety feature!"
Hybrid Body Materials
Major breakthroughs mostly begin in a small way. At first glance, the exhibits presented by Benjamin Bender seem to have nothing spectacular about them: narrow strips of aluminum with a thin layer of carbon-fiber reinforced plastic (CFRP) on the back.
In fact this advanced development project, which postgraduate Bender is undertaking in the Audi Lightweight Design Center (ALZ) at the Neckarsulm plant, has great future potential. At a later date, when the new hybrid metal and CFRP structures go into series production, they will represent another step forward in ultra-lightweight construction at Audi.
The Audi brand became a leader in lightweight vehicle construction some years ago with its aluminum bodies. Using the ASF (Audi Space Frame) construction principle on the Audi A8, Audi R8 and Audi TT models reduced the weight of their bodies by as much as 40 percent compared with conventional steel structures. Now Audi is launching the next stage in the process: the Multimaterial Space Frame, which combines aluminum, steel and fiber-reinforced components.
Audi engineers have in-depth competency in working with all these materials. They are not forced to work with a single material; instead, their motto is ‘the right material in the right place for outstanding performance'.
The new bodies, by combining the advantages of the various materials, will be much lighter than conventional metal structures.
Benjamin Bender's project takes the multimaterial concept a step further, by making the individual components into ‘hybrids'. If a metal element in the body structure - a B-post or a sill - is systematically reinforced with CFRP, its properties are enhanced, for instance its strength or its deformation behavior in a crash. Yet at the same time it weighs less, because the comparatively heavy metal - steel or aluminum - has been partly replaced by much lighter CFRP.
At the Audi Lightweight Design Center in Neckarsulm about 180 specialists work on the future of Audi vehicle bodies. Benjamin Bender has to find answers to a number of questions. How should the metal and CFRP be combined in order to obtain optimal properties in each component? At which points does the reinforcement have its maximum effect? And what do practical tests tell us about the components' crash performance or resistance to corrosion?
The method used to join the two materials is another central topic. This is normally done with rivets, screws or technical adhesives. The new project adopts a more ingenious approach: the synthetic resin needed to produce a component entirely in CFRP acts here as the connecting medium.
Bender is currently investigating whether RTM (resin transfer molding) can be used to bond the two materials together. The RTM process is suitable for higher production volumes and is one of the key technologies at the Audi Lightweight Design Center.
"Even if development work goes according to plan, it will take several more years," says Bender, "and we will still need some time before it's ready for series production." Audi knows very well that major breakthroughs often take a bit longer - in ultra-lightweight construction too.
FRP Coil Springs
For Audi, ultra-lightweight vehicle design is more than engineering competency alone. It's an attitude of mind that exists throughout the company. The brand's engineers fight determinedly to avoid every scrap of unnecessary weight - not only in the body but also in every component and assembly that goes to make up the complete automobile.
Ultra-lightweight design is especially interesting in the chassis and suspension area. Every reduction in unsprung mass improves ride comfort and handling. Joachim Schmitt's pre-development project is in this technological area. It is devoted to a component which is nothing special to look at, but has to withstand severe loads. A component which one might think could scarcely be improved any more: the coil spring. The project takes a different view, however, and aims to replace the steel spring with a spring made from fiberglass reinforced plastic (FRP).
The FRP coil spring, which Schmitt has developed jointly with the patent holder SOGEFI, is very different from a conventional steel spring. It's bright green in color, the so-called wire is thicker, the spring's overall diameter is greater and the number of turns is lower. Above all, this type of spring is much lighter in weight. Project engineer Schmitt has the facts: "Each of the steel springs in the A4 model's front suspension weighs 2.66 kilograms. The FRP spring weighs only 1.53 kilograms, more than 40 percent less, but performs just as well."
A helix made from fiberglass reinforced plastic is capable of absorbing torsional loads extremely well if it is designed with this purpose in mind. The core of the spring consists of long glass fibers twisted together and impregnated with epoxy resin. A machine wraps additional fibers around this core, which is only a few millimeters in diameter, at alternating angles of plus and minus 45 degrees to the longitudinal axis. These layers support each other and act in either compression or tension. Torsional loads across the component are converted in the fibers into tensile and compressive loads.
The next production stage is for the ‘wire', while it is still wet and soft, to be wound onto a metal alloy core with a low melting point; this core is the negative form of the finished spring. The FRP material is then hardened in an oven at more than 100 degrees, so that the core melts. This is the process currently used to manufacture the prototypes. Later it will be very much faster and more efficient: a pilot batch will be made first, followed by the start of high-volume production: a million springs annually.
The new FRP suspension springs will make their debut before the end of 2012 in the electrically propelled Audi R8 e-tron model. In 2013 they will be introduced step by step in greater volume for Audi midsize and large luxury models. Long-term road trials are taking place at the moment, accompanied by marathon test cycles on special rigs, each of which imposes loads on the spring equal to about 300,000 kilometers of driving by the average customer.
"In the early days many of my colleagues were not convinced that the project would be a success," Joachim Schmitt recalls. "But from the very start FRP proved to be an excellent choice of material. It is absolutely immune to corrosion, even if struck by stones flung up from the road surface, and effectively resistant to chemicals such as wheel cleaning products. Manufacturing FRP springs consumes less energy than for steel springs, and they reduce the weight of a car such as the current Audi A4 by about four kilograms - a notable step forward."
Schmitt and his colleagues are already able to tune their FRP springs to suit the chassis engineers' wishes, taking the car, its axle loads and its ride comfort and handling characteristics into account. All they have to do is vary the length of the wire, its diameter and the number of turns. In a few years' time the engineers expect improved production methods to increase the load capacity of the FRP material, so that the space needed for the springs is no larger than for today's steel springs.
Which just leaves the unusual bright green color - but Audi's development engineers have tackled this as well. Joachim Schmitt: "If we add a certain amount of graphite to the mixture for the FRP springs, they are dyed black right through. And for enthusiastic drivers we're already working on red and blue springs!"
Multitouch Controls
The driving simulator in the basement of the Audi Electronics Center in Ingolstadt is not just a bodyshell with seats in it, but an almost complete car - an Audi A8 with only the front end and the engine missing. Above its roof is a tall structure containing four large film projectors. Their images are shown on a curved wall that surrounds the car in a 240-degree segment of a circle. To complete the 360-degree image, two further projectors are aimed at a screen behind the car.
On this particular day the big picture is a four-lane highway with only light traffic on it. "Our test candidate will be asked to follow the car ahead," says Kristin Dettmer, whose responsibility in the Development Operating Concept department is the ‘touchpad'. "The occupant of the front passenger seat will then ask him to perform certain tasks: dialing a telephone number, choosing a new destination on the navigation system or playing a selection from the media list.
None of these tasks is difficult, but each step in the process calls for a certain degree of concentration. The driver wears glasses into which two miniature cameras are integrated: one of them films the surrounding area, the other the pupil of the driver's eye. Later, the Audi development team analyzes the recorded images with the aid of special software. This gives them detailed information about how long the driver took for each of the steps on the MMI monitor, and how often he looked at the control pad.
Audi attaches great importance to car control. Ten years ago, when the MMI system was first introduced in the Audi A8, the brand led the field in relation to its competitors. In 2010 the touchpad - the ‘MMI touch' - was also premiered in the Audi A8. It was the next major step forward, and has now been combined with the turn-and-push control in the new Audi A3. The aim is to maintain this design leadership: a vast number of new functions are now becoming possible, especially in the infotainment area, and will call for even more intelligent control concepts.
All development work is centered on an unalterable Audi principle: operation of the controls should be so intuitive that the driver's task is made easier, not more complicated. This is the guideline that governs Kristin Dettmer's project too: further development of the touchpad for Multitouch operation using several fingers.
The touchpads available for many current Audi models are intended for single-touch operation and are therefore especially suitable for the input of letters and numerals, using one finger. But Audi plans to use Multitouch technology for future generations of these devices. Using more than one finger opens up entirely new prospects. The system has already been extended to permit two fingers to be used when searching quickly in the navigation map, and three fingers make it quicker to scroll through long media lists. The touchpad measures twelve by eight centimeters, which most users find sufficient.
"For the new control system we have also revised the menu logic and the screen graphics," Kristin Dettmer explains. "Until now they were entirely based on the turn-and-push knob and its rotary movements. Now there is to be greater emphasis on the horizontal and vertical elements, though we don't intend to dispense with the adjusting knob entirely, since it will definitely remain the ideal device for selecting a certain number of functions."
Many test results, especially from the driving simulator, the digital ‘surface table' and an Audi A7 Sportback used for actual road testing, have contributed to the success of this development work, which has been in progress for three years. The question is always: how well do the test candidates cope with the Multitouch control principle?
"The public got to know the principle when the iPad and iPhone were introduced," says Kristin Dettmer. "Of course our test ‘guinea pigs' differ: older people in particular are rather hesitant when invited to operate the controls with several fingers. Our system is therefore basically suitable for single-finger operation as well. Many people start that way, then discover how easy it is to move on to the next levels. It's this ‘joy of use' that we're trying to communicate."
Audi's thinking on future control concepts is going ahead in a number of different directions. One of these focuses on innovative touchpad technology that sends a tactile response back to the user's fingers. Another project concentrates on improving voice control and a third uses innovative gesture control for the head-up displays. Here too the development staff headed by Bernhard Senner is working on a very advanced principle, of which a model already exists.
Driver and front passenger have their own head-up displays, for the front passenger it shows digital journey guide, news and pictures from video telephone calls. There is also a third, central projection visible to all occupants; here too the images appear to be on the windshield.
The driver's side only displays the relevant information in the form of symbols, still images and simple animations. Some of them, for example the navigation arrows, are imaged created by a novel contactless technology, and seem to float directly above the actual surroundings. The passenger's viewing area, on the other hand, has access to all video functions. In this case the image uses the new DLP (digital light processing) technology, which boosts brightness and contrast.
Bernhard Senner has an example that illustrates the idea behind the new technological principle. "If the front passenger finds an interesting destination in his digital travel guide, for instance a restaurant, he can make a simple, rapid ‘wipe' gesture to move the content as a still image into the center zone. If the driver then makes a similar gesture to accept the destination into his own head-up display, he can then input it to the navigation route." A small camera detects the hand movements and transmits the appropriate signals to the system.
Predictive Suspension
Downhill skiing on a mogul piste is great fun, provided that visibility is good. The skier has to be able to find the ideal track, bend and stretch the legs at just the right moments and float rhythmically and in a seemingly effortless way over the peaks and valleys.
"Even today, when a car is driven over an uneven surface, it's like a skier tackling a mogul run in thick fog!" says Dr. Andreas Schindler of Audi's chassis pre-development department. "The skier and the driver don't know what's ahead of them. They can't react until they sense the first movements through the skis or the wheels. Our task is to improve this situation."
Some years ago Audi began to equip its cars with predictive intelligence. Radar- and camera-based assistance systems such as adaptive cruise control und Audi active lane assist support the driver and enhance driving comfort. The technologies that will follow in the next few years will give this trend fresh impetus; examples are the traffic jam assistant, the intersection assistant or predictive suspension.
A year ago Audi announced an innovation that will increase occupant comfort: elimination of lateral forces. A video camera identifies bends as the car approaches them and an active mechanism in the suspension, which consumes only a small amount of energy, tilts the car's body so that the passengers are only aware of a minimum amount of centrifugal force acting on them. Predictive suspension uses a similar principle, but minimizes vertical rather than lateral forces.
The biggest challenge that Audi's pre-development team had to face was locating suitable sensors for their project. These have to respond to changes within an area up to 20 meters long ahead of the car, even in difficult conditions such as wet roads with shiny surfaces, or after dark. Very high-resolution road-surface images are needed so that possible obstacles can be located within a tolerance of a few millimeters - and, for instance, to distinguish potholes in the road from cross-joints or plastic bags.
An algorithm in the system's control unit analyzes information on road surface irregularities and the car's own movements, and supplies the appropriate suspension control signals. Simulations of this area of the project are already operating very reliably, and concept development of the high-resolution sensors is now going ahead rapidly.
Audi's sensor technology engineers make use of the extensive experience they gain from their work on future driver assistance systems, where extremely varied technologies are being tested, from PMD (photo-mixed detector) sensors through radar-sensors and laser scanners. Stereo cameras are also a promising development in the predictive suspension area. The outcome - which technology will be first across the finishing line - is still undecided, but one thing is certain: Audi will adopt nothing less than a no-compromise solution, as it has in all its development projects.
Comments
Post a Comment