The Driving Simulator
Driving Simulator | Truck Simulator | Ford Econoline Van | Computers | Eye Trackers
There are some 20 mid-level driving simulators currently in existence around the world (Weir and Clark, 1995). The University of Massachusetts has purchased one of the mid-level Real Drive simulators manufactured by Illusion Technologies, Inc. Four such simulators, including ours, are now installed and fully operational. Two are located in Melbourne, Australia. They are being used by the Victoria Transport Accident Commission (TAC) both to train younger drivers and to undertake research into the attributes of younger drivers that contribute to their over involvement in accidents. The third Real Drive simulator has already toured the major transportation research centers in Europe and the United states in the summer and fall of 1994. This tour included the University of Massachusetts campus. That simulator is now owned by The University of Washington. Our simulator, the fourth such simulator manufactured by Illusion Technologies, was delivered in December of 1995 and has been fully operational now since January of 1996. The simulator was upgraded in the spring of 2000, including increases in the number of screens, additions of new computers, and upgrades to all the software.
Hardware. The vehicle cab in the University of Massachusetts Driving Simulator is an actual Saturn sedan. A driver operates the controls of the Saturn just as he or she would on the road. The visual world is displayed on three screens, one in front of the car and two on each side. Each screen subtends 60 degrees in the horizontal direction and 30 degrees in the vertical direction. As the driver turns the wheel, brakes or accelerates, the roadway that is visible to the driver changes appropriately. The images themselves are updated 60 times a second using state of the art Silicon Graphics computers (a Silicon Graphics Infinite Reality Engine, an O2 and two Indy). The image resolution on each screen can be as high as 1024 X 768. The sound system for the simulator consists of three speakers, two located on the left and right sides of the car and one, a sub-woofer, located in front of the car. The system provides realistic road, wind and other vehicle noises with appropriate direction, intensity and Doppler shift.
Software. A visual database modeling tool (Designer's Workbench, Coryphaeus Software) was provided by Illusion Technologies with the initial delivery of the system. We can and do build visual databases which include freeway, rural and suburban sections as well as intersections, parking lots, and other roadway geometries. Buildings can be efficiently represented by only those surfaces that would be visible to the subject while operating on an adjacent roadway. The database software lets us model seasonal variation (so as to examine the effects of vegetation on traffic signing) as well as dawn, day, twilight and night. Objects in the database are properly occluded and cast shadows according to the time of day being simulated. Similarly, tree lines and forests need only be represented as they would appear to the subject while in the simulator. Additionally, Illusion Technologies has supplied a basic library of objects with the visual database modeling software which includes passenger vehicles, trucks and delivery vans, motorcycles, bicyclists, pedestrians, and domestic animals. These basic objects are modifiable using the software as to color and some minor physical arrangements to produce vehicles that visually differ from each other.
Frequently, in addition to populating the visual database with static objects (buildings, signs, etc.), it is useful to program the movement of a test vehicle or to coordinate the movement of other vehicles and pedestrians with the movement of the driver's vehicle. To do such, we have software, Real Drive Scenario Builder (Monterey Technologies), which greatly facilitates the coordination. Vehicles can be programmed to move along road surfaces at a normal speed (1-120 M/Hr) under computer or workstation control or be "transported" - i.e., moved instantly to any set of coordinates in the database. This last capability is an important one for eye contingent displays. Additionally, there are provisions for moving pedestrians. Motorized vehicles have the appropriate number of light points to represent headlights, parking lights, turn signals and stoplights.
Finally, it is necessary to animate the database as a driver maneuvers through it. The animation of the visual data base is under the control of EasyScene (Coryphaeus Software). EasyScene can be used in stand alone mode to animate a particular database, in combination with RDSB to watch a fully programmed scenario unwind, or with a real driver and RDSB to record the driver's responses as well as coordinate the movement of other vehicles with the driver's responses.
The truck simulator sits in a separate facility. The overall system was designed by Systems Technology Incorporated. A single screen sits in front of a mock up of a truck cab. Full size mirrors are mounted on the left and right hand sides. An image is displayed on both side mirrors as well as on the front screen. A remote heads free eye tracker can be used to monitor the position of the eyes on the road ahead.
The 1990 Ford Econoline Van (E150) when donated will have about 16,000 miles on it when it arrives on campus sometime in September of 1998. The equipment available on board makes the van ideal for studying advanced transportation technologies on the road. At the time of delivery, the equipment will include: a) automatic transmission, tinted windows, power windows, four captains chairs, computer table, equipment racks, and 110 V AC power supply control panel; b) an Onan gas generator for 120 VAC power in the rear of the van (the fuel source is one of two of the vehicles dual gas tanks; the Onan has its own battery and charger with hook-up for an invertor; the Onan is controlled and monitored via a control panel inside the Van); c) a fully programmable 94 GHz frequency stepped radar [some of the programmable items are: step size, bandwidth, PRF, range bins, receiver attenuation, AGC option, STC option (the STC pattern is programmable); also, the wave form may be single frequency, stepped frequency, or a combination of both; the radar has a quadrature output and is a coherent system; Millitech built the radar]; d) antenna mounts for a radar on a platform located on the front of the Van (the platform may be adjusted in height and roll; the radar also has two buffered I Q outputs that are connected to an o-scope; the o-scope is critical in that it allows one to monitor the real time signals and is used for system diagnostics; a Tektronics analog 400 MHz scope with 4 inputs was used, but is not part of the donated equipment); e) programmable antenna (it can scan in AZ and/or EL; the AZ max scan is +/-45 degrees and the EL max scan is +/-7.5 degrees; it can be set stationary to any angle within the antennas scan limits; polarity is linear); f) an antenna controller that interfaces the computer to antenna (the controller also has some diagnostic indicators; Millitech built the antenna system); g) a 486 computer and monitor with radar-antenna system control software (all system programmability is done via the system software menu; the computer houses a WAAG III dual A/D; the A/D has a 20 MHz max sample rate; it is used to sample I and Q; a spare A/D card, the WAAG II, is included; the computer houses the necessary I/O cards for system interface; the sample rate of the IQ channels is controlled by a external function generator; the radar response and antenna scan patterns can be stored, played in real time, or played back from storage; some processing software was received with the donation); h) two function generators are required, but were not donated (an HP8112 is used for PRF generation and has a sync output to synchronize the A/D sample clock; the A/D sample clock is an HP8116); i) an Electronics Interface Unit (EIU) interfaces the entire system together (it also monitors radar and antenna temperatures and displays them); j) a Head Down Display, mounted in the front dash (the display is about 6" by 10"; an auxiliary computer monitor is integrated so that the driver's HDD can be seen by the passengers; a video switch box can switch displays); k) and an HDD computer or transputer (multi processor system) [the software and transputer system was contracted to System Computer Services (SCS) in San Diego; this computer is not part of the donation].
The Human Performance Laboratory has four SGI computers, an Onyx Infinite Reality, an Onyx Reality Engine 2 and two Indy's. The Onyx Infinite Reality and Reality Engine 2 utilize a real-time multiprocessor CPU technology to provide fixed frame rate performance. This is achieved through a simulation specific software layer, IRIS PerformerTM which can be utilized to implement real-time database processing. Integrated by the application developed, IRIS PerformerTM provides deterministic performance, flexibility and real-time control of the simulation environment. The Onyx can support frame update rates of up to 72 Hz. It's high polygon throughput and fill rates make it an ideal simulator image generator. The Onyx offers exceptional large screen image quality by providing sub-sampled anti-aliasing. Up to 16 sub-samples per pixel and 64 sub-pixel resolution at high performance ensure that all images generated by the Onyx and subsequently projected onto a screen other than the monitor are smooth. A unique feature of the Onyx is that all anti-aliasing is fully compatible with the system Z buffer. Databases can be modeled and rendered regardless of depth sorting or the use of binary separating planes. This reduces both modeling time and complexity, while increasing the flexibility of the application. Texture capabilities are extensive on the Onyx. Size, efficiency, capacity, performance, configurability, and exceptional image quality are key texture features. A standard 4 megabytes of on-line texture memory enables up to 380 X 128 mip-mapped textures. Maximum texture size is 1024 X 1024. Textures can be redefined freely within the texture memory space. High texture image quality is provided by trilinear mip-mapping, full color (R,G,B,A - with 4, 8 and 12 bits per component) photo realistic texture, texture contouring, texture sharpening, 3D texture, projected texture, and detailed texture enhancement. Anti-aliasing, high quality texture mapping and weather effects are all implemented without affecting performance. The bus and pipeline structure are designed to provide maximum elasticity and throughput, ensuring that the system runs at optimal performance under widely varying loads.
The Human Performance Laboratory has three state of the art eye trackers. One is a head mounted eye tracker which is capable of sampling the position of the eye at 200 Hz. The head is free to move anywhere. The system overlays the eye position on a video of the scene that is being viewed by an individual wearing the eye tracker. The eye tracker was developed by Applied Science Laboratories and delivered to us in December of 1997. The second eye tracker is also a head mounted. However, this eye tracker is coupled with a head tracker which lets us determine exactly at what point on a monitor an individual is fixating. The eye tracker was developed by SensoriMotor Instruments and was delivered in January of 2001. Finally, we have a floor mounted eye tracker that is coupled with a head mounted tracker which allows an individual to move his or her head freely within a cubic foot of space, yielding the world coordinates of the eye position within that space. This eye tracker was developed by Applied Science Laboratories and is part of the truck simulator.