Attachment J.4_HDS System Description.pdf

FEDERAL HIGHWAY ADMINISTRATION’S

HIGHWAY DRIVING

SIMULATOR

SYSTEM DESCRIPTION

1.1 SCOPE

The Federal Highway Administration’s (FHWA) Highway Driving Simulator (HDS) is designed to meet the needs of Turner-Fairbank Highway Research Center’s (TFHRC) Human Centered Systems (HCS) safety research program. HDS is a fully interactive driving simulator used by HCS for human factors research in highway safety and highway operations. The HDS provides a platform to study driver performance over a broad spectrum of driving situations as defined by varying highway designs and traffic control devices. An example of this is evaluating the effectiveness of various safety countermeasures developed as a result of identified driver performance problems or driver behavior (Figure 1). The HDS is also used for developing and testing new roadway designs. HDS’s capabilities are highly responsive to the increasing scope, complexity, and requirements of the FHWA’s research program. Recently, automated vehicle features and automated vehicle traffic have been introduced into the HDS system to accommodate the requirements of the current research. This document describes the HDS system capabilities and its use for highway driving research.

Figure 1 Simulated Roadway Scene with Various Safety Related Traffic Control Devices

1.2 SYSTEM DESCRIPTION

The current upgrade configuration focused on increasing the capabilities of the system as well as lowering the life cycle support cost of the system. The major components that support the HDS are the Graphics Workstations, HDS Interactive System and the Test/Preparation station. Figure 2 shows the physical system layout. Note all major components including the TFHRC facility are tied together through a gigabit Local Area Network. Local area network controls exist to isolate or communicate with each of the major components including the TFHRC facility.

Figure 2 HDS Physical System Plan

1.3 DEVELOPMENT WORKSTATION

There are development workstations for modeling, software, audio and graphics development. These workstations have an associated server for configuration management of archive data, software development, scenario models, and completed simulations. The workstations are equipped with essential application software for the development of software, modeling, configuration control, and rendering.

There is also a workbench and workstation area for the simulator maintenance technician.

1.4 HDS INTERACTIVE SYSTEM

The HDS system includes the following subsystems: an operator’s control station, audio subsystem, scene projection subsystem, and the car cab (vehicle) control subsystem.

1.4.1 HDS SYSTEM – OPERATOR’S CONTROL STATION

The Operator’s Control Station (Figure 3) provides a central control point for initiating, operating, and monitoring an experiment. The researcher and operator can monitor simulator operations from the multiple displays at the console. The experimenter and staff can also verify that the experiment is progressing according to plan, observe the driver and the roadway scene, communicate with the driver and check to ensure the experimental data is being collected and recorded. The station allows the experimenter to continuously monitor the participants performance. Status indicators for major HDS components are located at the operator's control station.

The Operator’s Control Station contains seven monitors, one for each projector, a Database Server PC, an Audio PC, a Vehicle Dynamics I/O control PC and Operator Control PC. The Operator Control PC provides system power control via commercial of the shelf digital I/O hardware and scenario management control. The audio PC provides aural cues for the driver. The Vehicle Dynamics PC provides motion equations and provides the dynamic control of moving objects in the simulated environment (including the motion base).

Figure 3 Operator’s Control Station

1.4.2 HDS SYSTEM – AUDIO SUBSYSTEM

The sound effects are provided by a six-channel system. Multiple speakers and subwoofer are used to simulate real time engine noise, road noise, wind noise, tire squeal, and other roadway vibrations.

1.4.3 HDS SYSTEM – SCENE PROJECTION SUBSYSTEM

The scene projection subsystem, as seen in Figure 4, consists of seven JVC 4K laser projectors that are driven by seven custom image generating PCs, each containing Nvidia A6000 graphics cards. The PCs are mounted over the vehicle on a projector support structure that was custom designed and built for the HDS. The multiple projectors allow the full use of the 240-degree cylindrical screen. Two side-view mirrors and one center rear-view mirror are simulated using liquid crystal display monitors.

Figure 4 HDS System

1.4.4 HDS SYSTEM – FORD VEHICLE CONTROL SUBSYSTEM

The central feature of HDS is the Ford Focus sedan vehicle. Apart from the engine and drive train, fuel tank and lines; the vehicle is complete. Volunteer research participants get in and “drive” the otherwise intact vehicle. Digital and Analog I/O signals from the vehicle are relayed to the Dynamic I/O PC. These signals include steering wheel position, accelerator position, and the brake pedal position, etc. The steering, the accelerator pedal and the brakes provide realistic feedback to the driving participants.

Figure 5 View from Behind the Simulator Vehicle on 6DOF Motion Base

The HDS vehicle is mounted to an electronically actuated motion base that is state-sensed and controlled through the data in-out subsystem of the Dynamics in-out PC. The motion base has six degrees-of-freedom (X, Y, Z, roll, pitch and yaw). The HDS vehicle dynamics software provides the calculated data to drive the motion base. Vehicle dynamics data comes from the driver’s interaction with the vehicle controls (accelerator, brake, steering, etc.) while reacting to the 3-dimensional visual scenes designed for a particular study. The motion base has the capability to move ±8 inches in the x, y or z axis or ±15˚ in roll, pitch or yaw. This system, under computer control, is used to generate car cab pitch under positive or negative acceleration, car body roll during cornering maneuvers and responds to roadway elevation and geometries.

1.4.5 HDS EYE TRACKING SYSTEM

An eye tracking system allows data to be collected about where participants are looking, primarily focused on gaze behavior outside of the vehicle. The eye tracker uses a quad SmartEye AB camera system and is integrated with the eyesDx MAPPS real time recording and analysis application for synchronization of the eye tracking data along with the visual environment.

The eye tracker (Figure 6) consists of 4 cameras mounted on the vehicle dashboard and focused on the driver’s eyes. The tracker is fully calibrated and allows for approximately 1.5 degrees accuracy of tracking eye glances to viewed objects. While the driver experiences the simulated scene the eye tracker data is recorded by the MAPPS application for later analysis by the research team.

Figure 6 Eye Tracking System, 3 of 4 Cameras Shown

1.4.6 TEST/PREPARATION STATION

The Test/Preparation station consists of multiple PCs and monitors to provide a means to continue HDS software development work and checkout while the HDS simulator is being used for experiments.

1.5 SOFTWARE ARCHITECTURE DESCRIPTION OF THE HDS

The HDS system is driven by an evolving software engine which uses a PC cluster architecture to allow for multi-channel graphics rendering and distributed processing of real time dynamics and scene content control. The PCs are interconnected through a 10 Gigabit LAN. The distribution of PCs within the system architecture optimizes the graphics and computational capability of each PC by distributing the software processing and to minimize LAN data traffic. This software architecture allows for a scalable system which can be configured as a single channel, single computer desk top system or to a larger multi-channel configuration using multiple computers to run each aspect of the simulation, thus allowing for much larger simulations with more dynamic scene content.

1.5 SOFTWARE ARCHITECTURE DESCRIPTION OF THE HDS