Case Study Development of Virtual Driving Simulator for Transportation Research M. K. Abdul Jalil, PhD Faculty of Mechanical Engineering Universiti Teknologi.

Case StudyCase Study

Development of Virtual Driving Development of Virtual Driving Simulator for Transportation Simulator for Transportation ResearchResearch

M. K. Abdul Jalil, PhD

Faculty of Mechanical EngineeringUniversiti Teknologi Malaysia

Johor, Malaysia

© Engineering Visualization Research Group (EVRG)

ICPDD ’04, Kota Kinabalu

This presentation…

To share with you our short research experience of developing a static base driving simulator

Basis for vehicle related reach activities in the future

Development of basic research in computational and visualization areas



Introduction

Virtual reality is a technology allows user to feel immersed in a computer-generated environment

A virtual driving simulator is a virtual reality device allows its user to feel a life-like experience of driving an actual vehicle

A driving simulator is cost effective tool to enable analysis on driving characteristics, and interaction between visual database and vehicles

A low cost PC-based static driving simulator can be used to develop VR related system



History of Driving Simulator

Root on flight simulator in early 1900s

Daimler-Benz high-fidelity driving simulator in 1985 with the advent of computer technologies

Advanced driving simulator constructed since 1990s

The most sophisticated driving simulator around the world, NADS in Iowa



Advanced Simulator Capable of simulating the

dynamic motions and scenes of actual vehicle with high fidelity simulation output

Construction cost is very high with consists of a visual system, control feel system, dynamic feedback platform, auditory system and complex full developed vehicle dynamic model

Examples: National Advanced Driving Simulator (NADS), Leeds Advanced Driving Simulator (LADS)



Why Driving Simulator?

Vehicle Prototyping – new vehicle design, ride and handling

Safety Related Issues – DWI, Cellular Phone, Driving endurance, blind spot

Drivers Training – truck simulators, train simulators



Components Visual database - simulation

of surrounding environment, including other vehicles

Vehicle Dynamic Model (VDM) - simulation of the physics of vehicle model and the road surface

‘Driving Cab’ A system that enables the

operator to interpret the state of the model such as visual display

Control devices, such as steering wheel, brake pedal and throttle



Our Research .. Static base simulator PC based, low-cost, with sufficient graphic

quality Components

visual database – audio + visual database VDM Vehicle control – accelerator, steering, brake

As a groundwork and preliminary attempt to develop an advanced driving simulator for vehicle related research



System Architecture



Hardware

3 Potentiometers

CB-68LP, 68-Pin Digital and Trigger I/O Terminal Block

NI PCI 6024E, 200 kS/s, 12-Bit, 16 Analog Input Multifunction DAQ

To PCI slot of Server CPU



Issues … Visual Database Rendering cost

Effective way of producing a detailed image, without using too much computer power

Graphic optimization is implemented – LOD

Simulation Frame-rate & Fidelity of Vehicle Driving Simulator

Large graphical delays mean a great risk of the driver getting dizzy even if the screen has good acuity

Acceptable frame-rate to human user (approx 40 frame/second) Enough quality and temporal response for driving tasks and maneuvers

Real-time Computation of Vehicle Dynamic Model (VDM)

The ability to run in real time depends on the integration time step and the complexity of the vehicle dynamic model

6 DOF VDM is used



Visual Database VR environment is developed using WorldToolKit

(WTK) programming language. All models created using AutoCAD & 3D Studio WTK reads these models into the VR environment

and manage them under Scene Graph WTK universe includes:

Static models – sky, landscape, buildings, road, barriers, lights

Effects – fog, sound Transform node – driver’s view port in VR environment Position information – current position data extraction



Scene Graph Management

Universe

Root Node

Light Node Group NodePosition

Information

Transform Node

Geometry Node

Driver View port



Graphic Construction & Optimisation

Shell Modeling Texture Mapping Visible Facet Foggy Effect Recursion Technique Collision Detection Level of Detail (LOD)



Shell Modeling

Models loaded into WTK are prepared in 3D shell (rather than solid) for polygon reduction.

Shell modelling reduces memory usage in the rendering of model internal parts



Texture Mapping

Texture mapping to improve visual database realism

Real photo images were taken by using digital camera and exported in .jpeg format



Visible Facet

Visible facet of building containing window frames and wall are created using single polygon with wall textures image mapped on the polygon to minimize graphical complexity



Fog Effect

Driver visibility Linear model

used



Collision Detection

Realistic road driving simulation

Against curbs, buildings, etc



Level of Detail (LOD)

Closer objects – good graphics

Far objects – minimal rendering



WTK Virtual Environment



Network Data Transmission

Transmission Control Protocol / Internet Protocol (TCP/IP) was employed as the data transmission protocol between 2 PC’s

TCP is a connection-based protocol designed to ensure smooth data transfer



Vehicle Dynamic Model (VDM)

The vehicle dynamic model is computed using MATLAB-SIMULINK program in the server computer

SIMULINK S-function block constructs a TCP/IP port for data interface with the client computer



Handling Dynamic Model

cosVu sinVv

v

u

Y

X

cossin

sincos

The velocities components and from vehicle velocity, and its sideslip angle, in the equations

Equations of motion of handling system

YNYmVN

YNYmVN

)(

)(

YNYmVN

YNNY

)(Handling Coefficients Corresponds To Velocity

(Courtesy from Motor Vehicle Dynamic, World Scientific)



Handing and Cornering Effect

The view port is from the position of vehicle c.g.



Quarter-Car Model

)( sfluflflsfl ZZkF

)( sfluflSdfl ZZCF

)( uflrfltfltfl ZZkF

)( uflrflStdtfl ZZCF

uflufldtfldflsfltfl ZmFFFF

ufl

dtfldflsfltflufl

m

FFFFZ

Quarter-Car Model

A two-degree of freedom quarter-car model is suitable to examine the forces acting on the suspension system natural frequency up to 30-50Hz

Arrange in the form of Newton’s Second Law, the unsprung mass vertical acceleration is computed



Full-Car Model

B

rrrlfrflb

m

FFFFZ

XX

rrfrrlfl

I

aFF

aFF )

2)(()

2)((

YY

frflrrrl

I

bFF

bFF )

2)(()

2)((

The result obtained from quarter-car model is substituted into Full-car model. The equation of motions of suspension system are

bB ZmF

XXX IM

YYY IM

Hence, the variables of dynamic model is obtained

Full-Car Model



Visualization of Suspension Response

The view port is from the position of vehicle c.g.



Suspension Response of Vehicle

Road Input, [Z]

Vertical Translation, z

Roll angle

Pitch angle



Conclusion

Our first attempt to develop a low-cost static base driving simulator using VR technology is almost completed.

This project provides the groundwork for future development of advanced driving simulator.



Future work

Integration of Motion base Development of traffic simulation Comprehensive database development More efficient computational and graphics

rendering methods – parallel rendering, better approximation methods



Thank You

Contact: [email protected]

Case Study Development of Virtual Driving Simulator for Transportation Research M. K. Abdul Jalil, PhD Faculty of Mechanical Engineering Universiti Teknologi.

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