TECHNICAL REPORT. NADS MiniSim Driving Simulator. Document ID: N Author(s): Yefei He Date: September 2006

Transcription

1 TECHNICAL REPORT NADS MiniSim Driving Simulator Document ID: N Author(s): Yefei He Date: September 2006 National Advanced Driving Simulator 2401 Oakdale Blvd. Iowa City, IA Fax (319) Copyright 2006 by the National Advanced Driving Simulator, The University of Iowa. All rights reserved.

2 TABLE OF CONTENTS Table of Contents... i 1 Introduction Architecture MiniSim Components Real-time Core Simulation Control Front End GUI Driving Control Feel and Instrumentation Vehicle Dynamics Scenario Control Visual Rendering Audio Engine Driving Data Collection and Analysis Motion System Subsystem Structure Sample Applications IDC Corvette Simulator John Deere Tractor Simulator Xperience Driving Simulator NADS Driving Kiosk Caterpillar Wheel Loader Mini-Simulator... 7 APPENDIX A: MiniSim Configurations... 9 Basic Features... 9 Intermediate Features... 9 Advanced Features... 9 Appendix B: MiniSim Sample Environments i

3 1 INTRODUCTION The NADS MiniSim driving simulator is a highly flexible PC-based driving simulation system. It uses the same advanced technologies built into the more sophisticated large NADS simulators, at a fraction of the cost to build and operate, and is easy to customize for specific applications. The configuration data for the virtual environment are in the same format as those used by the large NADS simulators; therefore, studies designed for the MiniSim can be easily carried out on the latter when simulation in higher fidelity is necessary. 1

4 2 ARCHITECTURE 2.1 MiniSim Components A complete MiniSim driving simulator contains the following components: Real-Time Core Simulation Control Front-End GUI Driving Control Feel and Instrumentation Vehicle Dynamics Scenario Control Visual Rendering Audio Engine Driving Data Collection and Analysis Motion System Real-time Core The real-time core is the underlying engine that coordinates the execution of the various functionalities of the simulator and provides the real-time data communication mechanism among components, either through shared memory on the same computer, or through a local TCP/IP connection between different computers. The other components are built on top of the real-time core Simulation Control Front End GUI The front-end GUI for the MiniSim provides control to the driving simulation process and to data collection and analysis. The operator can start, stop, and replay drives, select different scenarios, play presentations, and collect and analyze driving data through the front-end GUI. Typically, the GUI is displayed on a small touchpad screen Driving Control Feel and Instrumentation The driving control feel and instrumentation component reads the driver s control input via the steering wheel and foot pedals, and passes it to the vehicle dynamics component. It also takes the vehicle data such as speed and engine RPM and renders them to the instruments. Active force feedback can be built into the steering wheel and pedals. Depending on the cab hardware, special-purpose D/A and A/D converters may need to be installed on the PC that hosts the component. The instruments can be either physical or simulated on the main display(s) Vehicle Dynamics The vehicle dynamics components provide a physics-based passenger vehicle model that simulates the car the subjects drive during the runs. It is identical to the corresponding component in the large NADS simulators. By changing input data, the same software can be used to simulate different types of vehicles. For further customization for example, to simulate tracked vehicles, vehicles with hydraulic systems, or vehicles with high 2

5 fidelity tire/soil models different vehicle dynamics components with the same interfaces can be swapped in with minimal modification to other parts of the simulator Scenario Control The scenario control component is responsible for simulating the behavior of other vehicles and objects in the virtual environment. It is identical to the scenario control component in the large NADS simulators and takes the same scenario configuration files as input Visual Rendering The visual rendering component renders the visual scene to the main display(s) of the driving simulator. One or more PC(s) with high-performance graphics cards run the visual rendering component. If there are multiple visual channels, they will be synchronized either via hardware or software. The renderer is built on top of an OpenGLbased open-source graphics library, which is maintained and supported by an active community and easily accessible for NADS staff to add their own enhancements for specific demands Audio Engine The audio engine provides audio cues to the driver. The component produces sounds from the own vehicle including engine, powertrain, and tires, as well as sounds from the surrounding environment. The PC that hosts the audio engine is equipped with a PC audio card and connected to a set of surround-sound speakers Driving Data Collection and Analysis The driving data are collected at the same frequency that the MiniSim runs. The set of data that can be collected include driving control inputs, own vehicle states, and scenario data. All data are stored on file for replay and future reference. During the drive, the data can go through a real-time analysis, and the results can be shown to the operator or the driver. After the drive, a more comprehensive analysis of the data can be performed Motion System The motion system can be a small fixed platform that provides movement to the cab, or it may consist of devices that provide vibration feel to the cab or the seats. It can also be a miniscule motion base independent to the cab that illustrates motion, even a virtual one, i.e., one simulated on a monitor screen. 2.2 Subsystem Structure Some applications do not require all of the functionalities provided by a full system. Therefore, the system is designed to be highly modularized so that a specific driving simulator can be built with only selected components. In its implementation, the MiniSim simulator is made up of subsystems that are separate executables and run independently while communicating through the data communication layer in the real-time core. Some components may be combined together into one subsystem for efficiency. Subsystems are 3

6 usually distributed to several PCs, some with specific hardware required by residing subsystems. Figure 1 shows an illustration of a sample MiniSim simulator architecture with a custom subsystem. As mentioned above, the MiniSim driving simulator is highly modularized. Each component can be individually customized. For example, instruments can be physical or virtual; control inputs can be off-the-shelf steering wheels and pedals, a custom-built cab that uses parts from real cars, or simply keyboard and mouse controls; vehicle dynamics can be built to simulate different vehicles; the number of visual channels is configurable depending on needs. Some components can be absent from the simulator. The configuration of subsystems is also flexible and is done through a subsystem configuration file. The simulator can be configured to run only some of the subsystems present, and the subsystems can be redistributed among the PCs of the simulator system, subject to hardware and software limitations. For data communication, a master file lists all the data elements to be published in the communication layer. Each subsystem registers some of them as input data and others as output data. For example, the driving control feel subsystem registers steering angle as an output, and the vehicle dynamics subsystem registers it as an input. Conceivably, a custom subsystem can register the steering angle as an input, perform real-time processing on it, and generate a modulated steering angle as output, while the vehicle dynamics subsystem registers the modulated steering angle as its input source for dynamics computation instead. 4

7 SCNVIF AUDIO Visuals Scenario Control R/T Scheduler Comm. Layer Comm. Layer R/T Scheduler Audio Engine DAQ Data Collection MOTION Data Analysis Motion Washout FRONT-END Simulation State/Mode Control R/T Scheduler Hard Disk R/T Scheduler Motion Base R/T Scheduler Touchpad Screen Comm. Layer Comm. Layer Comm. Layer Local Ethernet/Shared Memory SteerAngle SteerAngle* DYNA Comm. Layer CUSTOM Comm. Layer CFS Comm. Layer R/T Scheduler R/T Scheduler R/T Scheduler Vehicle Dynamics Custom Functions Ctrl Inputs/Fdbk Instrumentation Steering Instruments &Pedals Figure 1. Sample MiniSim Architecture with a Custom Subsystem and Data Flow 5

8 3 SAMPLE APPLICATIONS NADS has built several small driving simulators based on the MiniSim architecture. They vary in build cost, and their uses are diverse. 3.1 IDC Corvette Simulator The IDC Corvette Simulator is a three-channel driving simulator with a cab built from a genuine Corvette car and Corvette vehicle dynamics, without scenarios and motion. It is built to fit into a trailer to educate teenagers about driving safety. 3.2 John Deere Tractor Simulator The John Deere Tractor Simulator is a single-channel driving simulator with a John Deere tractor cab and corresponding dynamics, sitting on a fixed-base hexapod platform, with no scenarios. The visuals are a customized pre-distorted circular image projected to a half dome using a fisheye projector. The system is built for vehicle design testing. 3.3 Xperience Driving Simulator The Xperience Driving Simulator is a single-channel driving simulator with a single scenario. It has a quarter cab built from a genuine Ford Focus car, but the steering wheel and pedals are slightly modified from an off-theshelf product for lower cost. It has drive playback and performance analysis. The simulator is built to demonstrate the effect of certain medicines on driving performance. 3.4 NADS Driving Kiosk The NADS Driving Kiosk is a low-cost single-channel driving simulator with multiple scenarios, with off-the-shelf steering wheel and pedals and virtual instrumentation, and a miniscule motion base. It is built to be placed in a kiosk in a shopping mall to introduce NADS to the public and to recruit drivers for NADS studies. 6

9 3.5 Caterpillar Wheel Loader Mini-Simulator The Caterpillar Wheel Loader Mini-Simulator is a singlechannel driving simulator with a single scenario, Caterpillar wheel loader dynamics, a miniscule motion base, and interchangeable control input and instrumentation subsystems a cab built from a real wheel loader and an offthe-shelf steering wheel and pedal with keyboard and virtual instruments. It is built to test and improve the vehicle dynamics subsystem based on libraries provided by Caterpillar, in order to prepare for studies run on the large NADS simulator. 7

10 8

11 APPENDIX A: MINISIM CONFIGURATIONS Basic Features Standard table mounted steering wheel and pedals (ECS) Single display plasma based visuals Surround sound audio GUI, touchscreen based simulator control panel Realistic vehicle dynamics model for the driver's vehicle Scenario control for traffic and dynamic elements A suite of (5) scenarios and road networks 100 hours of technical support Compatibility with the NADS family of simulators Intermediate Features Same as Basic with the following updates and additions: Validated vehicle dynamics model for driver A suite of (10) scenarios and road networks A data acquisition module that collects real-time information about various aspects of the simulation ISAT scenario control authoring tool Advanced Features Same as Intermediate with the following updates and additions: Forced feedback steering and brake controls A 3 display plasma based visuals Customized instrumented cabs 9

12 10

13 APPENDIX B: MINISIM SAMPLE ENVIRONMENTS Rural: deer in a night scene Rural: dusk lighting 11

14 Highway: random traffic Highway: lead vehicle braking 12

15 Town: 3-way intersection Rural: sudden pull-out 13