The NADS simulation center is best known for its high-fidelity ground vehicle driving simulator, NADS-1. This simulator is comprised of a 13 degree-of-freedom motion base with the largest motion envelope of any existing driving simulator.
The motion system’s unique capabilities set it apart from other simulators, thus enabling NADS-1 to accurately reproduce motion cues for sustained acceleration and braking maneuvers, movement across multiple lanes of traffic, and interaction with varying road surfaces. Realistic reproduction of these combined maneuvers is not possible in fixed-base or limited lateral movement simulators. Motion cues for NADS-1 are correlated with other sensory stimuli, providing the highest fidelity real-time driving experience in a simulated environment.
From the driver’s standpoint, the simulator consists of an entire car, sport utility vehicle, or truck cab located inside a 24-foot dome. Each vehicle cab is equipped with full instrumentation specific to its make and model.
Accelerator and brake pedals utilize software-controlled electrical motors to provide feedback, thus allowing unlimited flexibility in programming specific pedal feedback mechanisms. The steering wheel is similarly designed to allow customized steering response to each vehicle type.
All dashboard indicators are operational, and the majority of control switches are instrumented. Multiple in-vehicle cameras provide customized views of the cab environment.
Inside the dome, the cab is mounted to the floor through four hydraulic actuators that produce vibrations emulating road feel. The whole dome is mounted on a yaw ring that can rotate the dome about its vertical axis by 330 degrees in each direction. The yaw ring assembly is mounted on top of a traditional hydraulic hexapod, which in turn is mounted on two belt-driven beams that can move independently along the X and Y axes. The X-Y assembly produces lateral and longitudinal accelerations by moving about a 64-foot by 64-foot bay.
The motion system is capable of providing high-fidelity acceleration cues by blending the hexapod‐induced accelerations with the yaw ring and X-Y assembly accelerations.
The visual system consists of eight Liquid Crystal Display (LCD) projectors that project visual imagery inside of the dome. The driver is immersed in a 360-degree photorealistic virtual environment. Higher resolution is used in the forward field-of-view to accommodate better feature recognition and reduce eye fatigue. All scenery is updated and displayed 60 times per second. NADS staff have developed a rich set of tiles that can be combined to create a wide variety of complex virtual environments, ranging from urban to rural landscapes. When necessary, additional tiles can be developed to meet project‐specific requirements.
The audio system provides sounds that emulate wind, tire, engine, and other vehicle noise, as well as special effects such as tire blowouts that are correlated with the dynamic behavior of the vehicle. Additional sounds produced by surrounding traffic are blended with the ambient sounds to produce an immersive experience.
|Why is fidelity important?|
As fidelity increases, so too does the transfer of training and the accuracy of assessment, particularly among experienced or expert drivers.
Lower fidelity simulation can be used for preparation and development of scenarios or study protocols without incurring the cost of high-fidelity simulation platforms. Lower fidelity simulation is also ideal for new driver training where full immersion is not necessary.