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STI Driving Simulator
In January 2005, the construction of a high-fidelity driving simulator was completed for use by researchers at the National Older Driver Research and Training Center (NODRTC) at the University of Florida. This simulator is the first of two driving simulators to be used for investigations primarily related to the capabilities and limitations of older drivers; hence it has been referred to as the Early Availability Driving Simulator (EADS).
The Visual Display
This simulator provides a large forward field-of-view (fov) of 180 degrees and displays virtual objects behind the car. The entire scene is computer-generated.
- View of the simulator field of view (including rear view mirror display) and computer workstation.
The wide fov is accomplished by connecting three flat screens with scenes provided by three high intensity projectors (Sanyo, 2000 ANSI Lumens). Although a continuous curvilinear surface would provide a better representation of the forward scene, after a few minutes of practice the process of "perceptual filling" prevails and subjects indicate that they notice no partitioning of the three separate segments. The wide fov allows drivers to make changes in direction at intersections in a very natural way. Overall contrast can be altered to simulate reduced visibility associated with heavy rainfalls or fog.
The Vehicle Configuration
- Junction box that distributes computerized signals to steering wheel, accelerator, brake and retrieves turn-signal indications.
In the 1997 Dodge Neon car, the "driver" operates normal accelerator, brake, and signalizing and steering controls with the corresponding visual scene responding accordingly. Longitudinal and lateral movement allows the driver to speed up or slow down, come to a halt, steer laterally including lane changes and changes of direction at intersections. All changes are controlled by software that interface a junction box under the hood of the vehicle.
The simulator is built on a computerized platform developed by the Systems Technology Inc. (STI) of Hawthorne, CA. The specific configuration is the STISIM Drive Model 500W produced by STI. The vehicle and tire model runs on a dedicated processor that is linked to the simulation via a network. It operates at fast update rates necessary to provide high-fidelity simulation of the vehicle dynamic responses as well as provides proper steering force/feel feedback. Road-feel is also captured via a low-frequency audio woofer and amplifier providing engine, transmission and road noise at varying intensities and frequencies.
Auditory Display and Apparent Motion
Sounds related to vehicle performance and external factors are simulated by the STISIM Drive software. These sounds include engine sound mentioned above, tire screech due to heavy braking or high cornering loads, horn, and the turn indicators. External sounds include a crash sound, siren sound, and tire noise that can discriminate between on and off-road surfaces. We also have the capability of substituting standard sounds provided with the simulator's customized sound files and playing recorded messages at specific locations in the driving scenario.
- Researcher, Dr. Sherrilene Classen, evaluates research participant using the EADS.
A control area situated to the rear of the vehicle overlooks the driver, vehicle and viewing screens. At this workstation the three visual screens are duplicated and a fourth control monitor allows the experimenter to set parameters for each trial and to monitor data being collected. Two-way communication is maintained via speakers and microphones in the vehicle and at the workstation.
Measurement and Performance Recording
The recording software permits the acquisition of up to 40 vehicle, driver and simulation parameters. Specific data recorded depends upon the driving scenario being used and the assessment goals. For our present studies, the parameters below are recorded:
- Elapsed time from beginning of run (sec)
- Total distance traveled from beginning of the run (feet)
- Longitudinal velocity (feet/second)
- Longitudinal acceleration (feet/second²)
- Lateral acceleration (feet/second²)
- Lateral lane position with respect to the roadway dividing line, positive to the right (feet)
- Lateral control during turn (Difference between vehicle and roadway curvature)
- Yaw rate (radians/second)
- Vehicle heading angle (degrees)
- Steering wheel angle input (degrees)
- Brake Actuation
- Left signal
- Right signal
- Current traffic signal light position
- Visual Scanning
- Roadway traffic data
- Vehicle collisions includes: other vehicles, off-road and pedestrians
In addition to these parameters, statistical data such as mean and standard deviation of parameters such as lane deviation, speed, steering angle can be included. An Open Module can also be used to develop additional performance measures such as physiological indices of GSR, EMG, or EEG.