17-01-2011, 08:04 PM
[b]VIRTUAL REALITY IN AUTOMOBILE PRODUCTION
AJOSH ABRAHAM
Govt.Rajiv Gandhi Institute of Technology
AJOSH ABRAHAM
Govt.Rajiv Gandhi Institute of Technology
[attachment=8272]
CONTENTS
1. INTRODUCTION
2. A VEHICLE BECOMES VIRTUAL REALITY
3. STEREO VISION
4. V.R SYSTEMS & INTERFACING DEVICES
1. HMD-Head Mounted Display
2. BOOM-Binocular Omni Orientation Monitor
3. CAVE-Cave Automated Virtual Environment
4. ImmersaDesks
5. Position Tracking
6. Data Gloves
7. Wand
8. Other input devices
5. ADVANTAGES
6. DRAW BACKS
7. EXAMPLE FOR V.R IMPLEMENTED PRODUCTION
8. OTHER USES & FUTURE OF V.R
1. Military purpose
2. Educational purpose
3. A.R-Augmented reality
9. CONCLUSION
CHAPTER-1
INTRODUCTION
The term Virtual Reality (VR) is used by different people with many meanings. There are some people to whom VR is a specific collection of technologies that is a Head Mounted Display, Glove Input Device and Audio. Some other people stretch the term to include conventional books, movies or pure fantasy and imagination..
Virtual reality known as VR for short is also referred
to as “reality simulated by the computer” or as an “artificial world”. To create this world, high-performance computers convert huge amounts of data into spatial three-dimensional images, giving the observer the same sensory perception as in reality – the virtual world looks “real”. Indeed, such a virtual world is able to replace “real life” in many areas and applications, particularly if it serves to simulate only a precisely defined excerpt of reality.
The virtual future of the automobile has already begun.
The cyberspace world has already developed from simple games to a very serious and meaningful industrial tool. The user is able to move around in a virtual environment interacting with and ultimately even shaping the “world” around him. Modern VR studios have what is commonly called a Cave Automated Virtual Environment or CAVE for short – an “electronic cave in which the observer is surrounded by up to six walls presenting pictures projected in real time. Wearing special glasses, the user then receives a spatial, three dimensional impression of his virtual environment
From the initial idea to the series product – faster
and more efficient than ever before.
Virtual simulation is indispensable today also in the automotive industry. While several prototypes had to be built in the past to test components in advance, planners, designers and engineers now work on one and the same digital model, optimizing this model on the screen and, if necessary, transmitting model data via data lines simultaneously to locations all over the world. This reduces the cost of development and in particular, speeds up the development process, providing faster time to market. A further advantage of VR is that the user is able to assess different variants at an extremely early point in time – even the very first data-set presenting a new design concept can be shown in virtual reality, offering the foundation for virtual tests. Consistent use of such computer-aided simulation was one of the technical prerequisites for the BMW Group in shortening the development period required for a new model from 6 years in the past to just 2 1/2 years today.
In this paper I am trying to describe in what ways virtual reality is helping automobile production, its advantages, drawbacks, and its future developments.
CHAPTER-2
A VEHICLE BECOMES VIRTUAL REALITY
In order to test new vehicle designs and concepts, the
VR engineer takes data saved in the computer and calculates the first 3D model on this basis. In the process the computer subdivides the vehicle into a multitude of triangles referred to as polygons. In other words, the computer superimposes a virtual network describing the geometry of the vehicle on to the underlying design and configuration. Then specific colours and surface features are allocated to the individual components according to their actual characteristics and properties. The last step, finally, is to present the highly realistic result to the observer in real time from individual angles and perspectives.
NOMENCLATURE
CWEFS Crashworthiness Effects Files
DLL Dynamic Link Library
dVISE Software for VR
Dyn2VR
ML
Software for files conversion
FE Finite Element
FEA Finite Element Analysis
LS-DYNA Finite Impact Element Code
PDL Program Design Language
UCF University of Central Florida
VR Virtual Reality
VRV Virtual reality Visualization
VRML Virtual Reality Multi Language
LS-DYNA & VRV SYSTEM
LS-DYNA is used to model the crash scenarios for different contact angles.Theoutput files generated from the analysis are converted to CrashworthinessEffectsFiles (CEFS) capable of VRV. The trainee is then able to observe the impact process simulation as if he/she were actually inside the automobile.
Communication between finite element files and virtual reality visualization
Dyn2VRML is the prototype of a fully integrated, user-friendly windows based
application. It translates the ASCII output files from LS-DYNA into VRML files.
The application is written in FORTRAN90. All subroutines are compiled into
DLL to be used by the windows–driven graphical interface.
3. VIRTUAL REALITY VISUALIZATION
3.1 Octant Concept
The main intent for this system is training of a large number of personnel. SinceLS-DYNA simulation cannot be performed in real-time for purposes of
visualization (due to the large elapsed time for the numerical solution), thenotion of creating a library of possible zones of crash scenarios were adopted. Figure shows the concept of an octant region for different impact angles. For the sake of ‘proof of principle’, the crash zones are described as octants in a two dimensional space. Figure represents the octant concept used to build the library.
Once the user defines a zone, the closest damage result or scenario, previously solved and stored in the library, is shown according to the angle and velocity of impact between the two vehicles.
The octant concept considerably enhances the time response of the VRVsystem.
Figure 4 shows the concept on how the libraries are being built using the finite
element analysis from LS-DYNA.
As a starting point, small libraries already exist with five simulations for each
octant retrieved, resulting in a total of forty simulations. The following libraries
are : a) a car impacting a car and b)a car impacting a light truck The construction of further libraries would involve different impact velocities, different car models and different initial conditions. The numerical results are compared with actual test data involving two cars and involving a light truck with a passenger car.
4.1 Car colliding with another Car
Figure represents the first scenario with two cars colliding. This model has close to 10,000 elements including beam, shell and solid elements. The impact velocity is 55mph (left car only) and the angle between the cars symmetry axes is 130 degrees.
5. NUMERICAL SIMULATIONS
5.1 Fiesta models colliding at frontal impact – Region I
The numerical simulation performed on the model in this particular case is based on Figure 5. Figure 7 shows the numerical result at an intermediate
step.
Figure – Intermediate step.
It is important to emphasize that the visualization procedure proposed in this
work is not a 2-D screen seen on a regular monitor screen or the picture in this
1 2
paper. The 3 -D environment is achieved with the head mounted display. Once in
use, the analysis can be easily done from outside the car (as a witness that
sees the crash) or from inside the car (as the driver or as a passenger).
Figure 8 shows the final step of the simulation with some internal details. This
feature is obtained by removing some of the components from the postprocessor
(visually only). Figure 9 depicts a zoom image from Figure 8. The
different views permit a better understanding base on the internal behavior of
the different parts inside the hood.
Figure – Final step with internal details.
Figure 9 – Final step with internal details and zoom
Similar procedures are performed for all the others impact regions, i.e., other
Octants (II, VIII).
CHAPTER-4
V.R SYSTEMS AND INTERFACING DEVICES
The main V.R systems and interfacing devices used are
1. HMD-Head Mounted Display
2. BOOM-Binocular Omni Orientation Monitor
3. CAVE-Cave Automated Virtual Environment
4. Data glove
5.Wand
6. Other input devices
1 .HMD
Looking like oversized motorcycle helmets, head-mounted displays are actually portable viewing screens that add depth to otherwise flat images. If you look inside the helmet you will see two lenses through which you look at a viewing screen. As a simulation begins, the computer projects two slightly different images on the screen: one presenting the object as it would be seen through your right eye, the other, through your left. These two stereo images are then fused by your brain into one 3D image.
To track your movements, a device on top of the helmet signals your head movements relative to a stationary tracking device. As you move your head forwards, backwards, or sideways, or look in a different direction, a computer continually updates the simulation to reflect your new perspective.
Because head-mounted displays block out the surrounding environment, they are favored by VR operators who want the wearers to feel absorbed in the virtual environment, such as in flight simulators. And as you might expect, these displays also are popular with the entertainment industry. The cost of a little escapism, however, can be an aching neck. Most head-mounted displays weigh several pounds.
MAJOR TYPES OF HEAD MOUNTED DISPLAYS
LCD display HMD
Projected HMD
Small CRT HMD
Single Column LED HMD
2. BOOM
The Binocular Omni Orientation Monitor, or BOOM, is similar to a head-mount except that there's no fussing with a helmet. The BOOM's viewing box is suspended from a two-part, rotating arm. Simply place your forehead against the BOOM's two eyeglasses and you're in the virtual world. To change your perspective on an image, grab the handles on the side of the viewing box and move around the image in the same way you would if it were real: Bend down to look at it from below; walk around it to see it from behind. Control buttons on the BOOM handles usually serve as the interface.
3. CAVE
CAVE is the short form for cave automated virtual environment
The cyberspace world has already developed from simple games to a very serious and meaningful industrial tool. The user is able to move around in a virtual environment, interacting with and ultimately even shaping the “world” around him. Modern VR studios have what is commonly called a Cave Automated Virtual Environment or CAVE for short – an “electronic cave “in which the observer is surrounded by up to six walls presenting pictures projected in real time. Wearing special glasses, the user then receives a spatial, threedimensional impression of his virtual environment.
According to Thomas DeFanti, co-developer of the CAVE and director, University of Illinois at Chicago "In the CAVE, you are no longer on the outside looking in but on the inside looking out."
One of the newest, most "immersive" virtual environments is the CAVE. Stepping into this 10 x 10 x 9-foot darkened cubicle is like jumping into the viewing box of the BOOM or climbing into your computer screen. No longer are you observing data through portals or just a flat screen; rather, the display enables you to experience the sensation of being "inside" the data.
This greater sense of being inside or immersed in, the data results from two advantages the CAVE has over other virtual environments. The first advantage is unencumbered movement. No clunky helmets or viewing boxes are needed here. The only required gears are a pair of glasses and a wand. The second advantage of the CAVE is its large field of view. In the CAVE, data are projected in stereoscopic images onto the walls and floor of the CAVE so that they fill the cubicle. In a simulated aquarium, fish not only swim in front of you or on your left and right but below and behind you as well.
To get a 3D effect, the computer projects stereoscopic images in rapid, alternating succession while it controls the lenses in the viewing glasses in synchronization with the images being flashed on the screen. The undetectably fast shuttering produces the stereo vision. A tracking device attached to the glasses relays the viewer's position to the computer that then recomputes the image to reflect the viewer's new perspective at a rate of 10 frames per second. Wands are the most commonly-used interface devices.
Because the 3D images can be seen by anyone wearing the CrystalEyes shuttering glasses, the CAVE is ideal for collaborative work. One or several people can simultaneously observe and analyze a simulation, though only from the perspective of whomever is wearing the tracking device. For now, everyone must be in the same CAVE .
Some images are accompanied by sounds mapped to the same data driving the imagery. A virtual trip to the beach is so much more compelling when you can hear the sound of waves crashing on the shore and the cry of seagulls. But beyond providing ambiance, sounds can reveal fine features in data not easily captured in images, such as speed and frequency. How easy it is to hear the subtle swirls and eddies of air as it flows across the surface of jet! A bang can tell you when two molecules connect. A beep emitted as a beacon can guide you home to Earth from your explorations in a vi rtual galaxy.
Working in the virtual “CAVE”, engineers with 3D glasses “see” the interior of a car on the walls and floor of the CAVE in a genuine three-dimensional experience
adjusting to their movements.(about the picture above)
4. ImmersaDesks
VR technology clearly is evolving toward smaller, cheaper, more flexible systems with greater resolution. ImmersaDesks, for instance, will serve as streamlined versions of the CAVE bringing 3D, immersible technology into the office at a fraction of the cost. About the size of a drafting table, Immersadesks are portable yet large enough to fill the field of view of the person sitting in front of it (thus giving the illusion of immersion). Images are viewed with the same lightweight stereoscopic glasses used in the CAVE. Scientists will be able to design applications for the CAVE on Immersadesks in their offices. Architects will design buildings in 3D, then switch modes, and escort their clients on a virtual walk-through of the model.
5. DATA GLOVES
Data gloves offer a simple means of gesturing commands to the computer. Rather than punching in commands on a keyboard, which can be tricky if you're wearing a head-mounted display or are operating the BOOM, you program the computer to change modes in response to the gestures you make with the data gloves. Pointing upwards may mean zoom in; pointing down, zoom out. A shake of your fist may signal the computer to end the program. Some people program the computer to mimic their hand movements in the simulation; for instance, to see their hands while conducting a virtual symphony. One type of dataglove has a web of fiber optic cables along its back. Changes in the amount of light transmitted to the computer by the cables signal how the joints of your fingers are bent. Once the dataglove has been calibrated to your hand, your gestures trigger pre-programmed commands. Other gloves use strain sensors over the joints to detect movement. Yet others rely on mechanical sensors to measure your hand movements For interaction with small objects in a virtual world, the user can use one of several gloves designed to give feedback on the characteristics of the object. This can be done with pneumatic pistons which are mounted on the palm of the glove. When a virtual object is placed in the virtual hand, the users hand can close around it. When the fingers would meet resistance from the object in reality the pressure in the pistons is increased, giving the sensation of resistance from the virtual object
6. Wands
Wands, the simplest of the interface devices, come in all shapes and variations. Most incorporate on-off buttons to control variables in a simulation or in the display of data. Others have knobs, dials, or joy sticks. Their design and manner of response a re tailored to the application. For example, biologists sometimes use wands like scalpels to slice tissue samples from virtual brains. Most wands operate with six degrees of freedom; that is, by pointing a wand at an object, you can change its position and orientation in any of six directions: forward or backward, up or down, or left or right. This versatility coupled with simplicity is the reasons for the wand's popularity.
7. OTHER INPUT DEVICES
Almost anything can be converted into a sensing device for simulation in virtual reality. Researchers have converted a trampoline into a pseudo surf board. Caterpillar, Inc. attached sensors to a mock tractor cab, complete with steering wheel and pedals, and used this environment to simulate test drives of its new line of backhoe loaders.
Stair steppers are an example of the limitless manifestations of interface devices. As part of a simulated battlefield terrain, engineers from an army research lab outfitted a stair stepper with sensing devices to detect the speed, direction, and intensity of a soldier's movements in response to the battlefield scenes projected onto a head-mounted display. The stair stepper provided feedback to the soldier by making the stairs easier or more difficult to climb.
Via glasses and a data glove, the movements of the VR master (left) are transmitted to the computer for subsequent calculation and optimization of the electronic simulation process (right).
CHAPTER-3
STEREO VISION
Stereo vision is often included in a VR system. This is accomplished by creating two different images of the world, one for each eye. The images are computed with the viewpoints offset by the equivalent distance between the eyes. There are a large number of technologies for presenting these two images. The images can be placed side-by-side and the viewer asked (or assisted) to cross their eyes. The images can be projected through differently polarized filters, with corresponding filters placed in front of the eyes.
The two images can be displayed sequentially on a conventional monitor or projection display. Liquid Crystal shutter glasses are then used to shut off alternate eyes in synchronization with the display. When the brain receives the images in rapid enough succession, it fuses the images into a single scene and perceives depth. A fairly high display swapping rate (min. 60 Hz) is required to avoid perceived flicker. A number of companies made low cost LC shutter glasses for use with TVs (Sega, Nintendo, Toshiba, etc.). However, locating the glasses themselves is getting difficult as none are still being made or sold for their original use. Stereo graphics sells a very nice commercial LC shutter system called CrystalEyes.
Another alternative method for creating stereo imagery on a computer is to use one of several split screen methods. These divide the monitor into two parts and display left and right images at the same time. One method places the images side by side and conventionally oriented. It may not use the full screen or may otherwise alter the normal display aspect ratio. A special hood viewer is placed against the monitor which helps the position the eyes correctly and may contain a divider so each eye e sees only its own image. An alternative split screen method orients the images so the top of each points out the side of the monitor. A special hood containing mirrors is used to correctly orient the images.
CHAPTER-5
ADVANTAGES OF V.R
1. From the initial idea to the series product – faster and more efficient than ever before.
Virtual simulation is indispensable today also in the automotive industry. While several prototypes had to be built in the past to test components in advance, planners, designers and engineers now work on one and the same digital model, optimizing this model on the screen and, if necessary, transmitting model data via data lines simultaneously to locations all over the world. This reduces the cost of development and, in particular, speeds up the development process, providing faster time to market. A further advantage of VR is that the user is able to assess different variants at an extremely early point in time – even the very first data-set presenting a new design concept can be shown in virtual reality, offering the foundation for virtual tests. Consistent use of such computer-aided simulation was one of the technical prerequisites for the BMW Group in shortening the development period required for a new model from 6 years in the past to just 2 1/2 years.
2.Tests can be done anywhere in the world
Since the models are computer generated it can be sent to any part of the world through web. So at a faster rate test drives can done and feedback will come before the launching of the vehicle.
3. In design and analysis
The “walk-in” cockpit: Test persons wearing 3D glasses sitting in front of the power wall assess various new design alternatives. The control unit is at the front right.
Via glasses and a data glove, the movements of the VR master (left) are transmitted to the computer for subsequent calculation and optimization of the electronic simulation process (right).
The complicated approach taken in generating a virtual world serves a definite purpose: To provide a clear overview of what would otherwise be a sheer myriad or maze of data and to create a style of visualization open to human sensory perception. If all this data were printed on paper as a list of numbers and figures, nobody would have any idea of what they are “seeing”. So it is only conversion into spatial, three-dimensional presentation which is able to combine the still unparalleled ability of the human brain to process images
In many areas, however, purely visual presentation is
often not sufficient – for example in judging the acoustics, control functions and safety of a vehicle or its individual components. In such a case everything depends on the material of the component used and its properties. So following thorough analysis, the computer applies huge amounts of information to describe the future vehicle with a high standard of precision. The engineer is able to consider the vehicle in the virtual
world from every angle, “cutting through” the vehicle wherever he wishes, conducting measurements, moving around inside the vehicle, and enlarging or reducing the size of the image. Using appropriate software, he is even able to “drive” the car in virtual reality, checking out the noise and sounds generated in the process.
Designers assess the geometry of specific components, engineers in the Package Department examine how they can use even the last millimeter of space inside the car, and ergonomic requirements are given particular attention in simulating the vehicle’s interior. “Sitting” in the virtual car, real people are able to test whether, say, the cockpit elements are perfectly arranged and whether they are still easy to read under various light conditions (or whether they might possibly reflect the light). Engine development specialists are able to examine weak points in the engine in a process of simulated interaction at a stage in which the engine itself only exists as a set of data.
4. VIRTUAL DUMMIES HELPS TO SAVE LIVES AND COST
VR plays a particularly important role in safety research, allowing the user to simulate processes which would-be too expensive or dangerous to test in reality. Even before the launching of a new car the first time, it has already been “crashed” at least 100 times in all kinds of ways in the virtual world. The computer takes 2 – 4 days to simulate a head-on collision against a wall, operating day and night in the process and subdividing the tenth of a second in actual the impact into increments each lasting just a thousandth of a second. This creates a kind of silent “movie” with the car pushing against the wall in millimeters and being deformed
so gently in the process as if it was made of plastilin. This procedure saves a lot of time, since a “real” prototype car costs up to three-quarters of a million Euro.
By comparison, a computer “crash” of the type described costs only about Euro 400.-, despite the long computer time required. So although development engineers building a new model require more than1,000 virtual test runs, this process is still significantly
less expensive than one single real-life test. A further advantage of simulated tests is that the engineer can check out different variants without the risk of harming human health or damaging material. Real-life safety tests are nevertheless still required by law in order to verify the reliability and accuracy of computer calculation
5. TO TEST TRAFFIC SCENARIOS
Computer simulation even serves these days to realistically test traffic scenarios and try out countermeasures before they are applied on the road. Using realistic simulation models, the tester is able to examine systems which in the real world can either not be examined at all or only with an immense effort.
6. VIRTUAL SHOWROOM
CHAPTER-6
DRAWBACKS
Despite enormous potential practical application, VR, in its current state, has drawbacks. It is still extremely expensive, the graphics are still cartoonish, and there is still a slight, but perceptible time lag between the user's body movements and their translation in Cyberspace. The equipment the user must wear, such as head gear, gloves, and other tools, needs refinement. At this early stage in the development of VR, no one knows what the long-term effect of using head-mounted displays might be on human eyes or what the possible psychological effect might be from spending too much time in Cyberspace. People using VR head gear sometimes complain about chronic fatigue, a lack of initiative, drowsiness, irritability, or nausea after interacting with a environment which is created for a long time.
CHAPTER-7
EXAMPLE FOR V.R IMPLEMENTED PRODUCTION
Not only is the individual vehicle an ideal object for cyberspace technology. On the contrary – BMW’s production specialists now design entire press shops and paintwork facilities in virtual space, presenting and assessing, say, every body panel as well as the tools required for its production in their original size. Engineers in Planning, Development and Production use virtual reality to see how the sheet metal is drawn over and shaped by the virtual tool. Such simulation models are indeed ideal for ongoing analysis and improvement of body panels without having to build elaborate models. Different colours are used to characterize the thickness of the sheet metal tested, enabling the engineer to optimize possibly critical points step by-step
CHAPTER-8
OTHER USES AND FUTURE DEVELOPMENTS OF V.R
IN ENTERTAINMENT INDUSTRY
Sporting 3D glasses. Flying through images. A trip through virtual reality is clearly fun, which is one reason its potential is being explored by the entertainment industry.
IN SCIENCE
Virtual environments are helping researchers decipher the knowledge buried within the mountains of data that are piling up hourly, streaming out of space and earth-based instruments. Soon, scientists separated by a continent w ill simultaneously analyze data and conduct experiments.
IN MEDICINE
Doctors are using virtual environments to treat cancer more safely and effectively. Doctors study 3D images of a patient's body structure to plan radiation therapy so it damages a minimum of healthy tissue as it destroys the cancer. In Georgia, engineers are developing a sophisticated data glove so that one day cancer specialists in Atlanta will "feel" tumors in patients 130 miles away, sensing its size, texture, and pressure.
IN EDUCATION
Virtual environments are bringing exciting new resources into the classroom. Soon, students may stroll amongst digital bookshelves, learn anatomy on a simulated cadaver, or monitor financial trends, all in virtual reality.
VIRTUAL FACTORY
Example for the implementation of V.R given earlier is an example for virtual factory.
MILITARY PURPOSE
For analyzing strategies and to train soldiers now V.R is using.
AUGMENTED REALITY-A.R
Augmented reality is yet a further step in this development process: With this kind of man/machine interaction the user “sees” context-related information derived from the object considered right in front of him in his line of vision. Wearing special glasses, a
mechanic, for example, is able to see information helping him in his work. This may be maintenance and repair instructions as well as the presentation of actual data for a comparison with the related target data. If, say, the mechanic is required to screw in a
bolt, arrows will start to rotate in front of his eyes at exactly the right point. The entire process is controlled by a microphone and voice recognition, a small video camera
on the frame of the user's glasses observing the right position of the components during installation. The image provided by the camera may also be fed to a remote expert able, even from a distance, to give the local user the information he requires in his work.
CHAPTER-10
CONCLUSION
The technology is developing rapidly, and shows considerable potential. The ability of VR to provide realistic simulations of data, objects and environments, with which users can interact and manipulate in an intuitive and realistic manner, opens up a vast wealth of possibilities for work-related applications. Those responsible for work settings should begin thinking now of ways in which VR might be useful.I think test driving a vehicle in cyber space is not at far distance for Indians, especially for keralites because we were the first created stereovision on screens in India.
REFERENCES
1. CAD/CAM-GROOVER
2. bmwgroup.com
3. bmwgroupscienceclub
4. lionhrtpubISR/isr-6-98/interview.html
5. hfmgvrouge/faq.asp
6. industrysearch.com.au/features/virtual.asp
7. nautramedbrain/virtualreality.html
8. lynellenwrite/hcifinal.html
9. ericdigests1996-2/virtual.html
