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Determining Rider-Vehicle Dynamics

Utilizing an ATV Simulator

Charles Jennissen, MD

Gerene Denning, PhDDepartment of Emergency Medicine,

University of Iowa Carver College of Medicine

Salam Rahmatalla, PhD

Environment and Civil Engineering,

Jonathan DeShaw, MSEBiomedical Engineering

University of Iowa College of Engineering

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Background

University of Iowa and the College of Engineering has very strong computer modeling and simulator programs.

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Virtual Soldier

Santos, a high fidelity avatar

Biomechanical musculoskeletal modeling along with predicative dynamics technology

Can deliver feedback on how a certain type of task or combination of movements will impact a human's level of fatigue, speed, strength and torque over a period of time.

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Center for Computer Aided Design

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Hank Virtual Environments Lab

Focuses on using virtual environments to study human perception and action.

Understand how children and adults negotiate traffic-filled intersections in our virtual environment.

Understand how people perceive and adapt to virtual environments.

Factors that put children at risk for getting hit by motor vehicles when crossing intersections

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National Advanced Driving Simulator (NADS)

One of the two most sophisticated driving simulators in the world.

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MiniSim

Harnesses the technological sophistication of NADS in a compact, customizable configuration.

Can be rapidly deployed for off-site or multi-sited research, population-specific assessment, or driver training.

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NADS

Looking at the role of cognitive development in safe tractor operation.

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3D Bio-Motion Research Lab

Performs applied and basic research in human motion and biomechanics.

Moog ECU-624-1800 Electric Motion System

A tilt/vibration platform that is capable of acceleration of up to 15 m/s² in the longitudinal, lateral, and vertical directions. (Simulate Speed)

Can generate angular motion of at least 20 degrees in the roll, pitch and yaw directions. (Simulate Sloped Terrain)

Can vary vibration frequncies. (Simulate Rough Terrain)

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3D Bio-Motion Research Lab

Moog Electric Motion System

State of the art motion tracking equipment including a Vicon system with 12 SV cameras and a Motion Analysis system with 16 Eagle-4 cameras.

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ATV simulator

Bought a non-functioning Yamaha Bruin 4x4 ATV.

Stripped the tires and modified it so that the ATV could be secured to the motion platform.

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ATV simulator

Created a padded protective structure around the ATV that could be secured to the motion platform.

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Objective

Determine inter-individual variability in the biomechanical parameters of experienced adult operators with regards to operator/vehicle dynamics using an adult sized ATV simulator

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Subjects

6 adult males

18-45 years of age

Within one standard deviation of mean height and weight for an average adult male

≥100 hours of ATV operating experience

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Methods

Reflective markers were placed on the subjects (24) and on the vehicle (4).

Accelerometers placed on helmet and at C7

A series of seven programs were performed by each participant with changes at a variety of accelerations.

2 identical pitch programs (incline/decline)

2 identical roll programs (side hill/side to side)

2 identical vertical change programs (hole/bump)

1 program with all elements

Small vibrational motion in 6 degrees of freedom used as physical distraction and to mimic normal vehicle vibration

Movie of ATV riding through wooded area used as mental distraction

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Methods

Subjects were video recorded from the back and side.

Vicon motion capture system recorded motion of the subject from the pelvis and above

Motion data analyzed with Visual 3D™Software which is NIH approved

Pitching Motion - Video

Pitching Motion – Motion Capture

Pitching Motion – Motion Capture

Pitching – At Time of Largest Motion

Subject 1 & Repeat Subject 2 & Repeat Subject 3 & Repeat

Pitching – At Time of Largest Motion

Subject 4 & Repeat Subject 5 & Repeat Subject 6 & Repeat

Pitching – Angle Between Torso and ATV

Side View

0 50 100 150 200 250 300 350 4000

10

20

30

40

50

60

70

80AVERAGE 4 Point: C7 to Pelvis to 4 Wheeler Angle

Cycle, Time = 2 Seconds

Angle

- (

Degre

es)

Sub1

Sub1 Repeat

Sub 2

Sub 2 Repeat

Sub3

Sub3 Repeat

Sub 4

Sub 4 Repeat

Sub5

Sub5 Repeat

Sub 6

Sub 6 Repeat

Rolling Motion - Video

Rolling Motion – Motion Capture

Rolling Motion – Motion Capture

Rolling – At Time of Largest Motion

Subject 1 & Repeat Subject 2 & Repeat Subject 3 & Repeat

Rolling – At Time of Largest Motion

Subject 4 & Repeat Subject 5 & Repeat Subject 6 & Repeat

Rolling – Angle Between Torso and ATV

Front View Back View

*Measured degrees from verticalAngle from C7 to the center of the pelvis to

the ATV0 50 100 150 200 250 300 350 400

-30

-20

-10

0

10

20

30

40AVERAGE 4 Point: C7 to Pelvis to 4 Wheeler Angle

Cycle, Time = 2 Seconds

Angle

- (

Degre

es)

Sub1

Sub1 Repeat

Sub 2

Sub 2 Repeat

Sub3

Sub3 Repeat

Sub 4

Sub 4 Repeat

Sub5

Sub5 Repeat

Sub 6

Sub 6 Repeat

Roll Motion – Accelerations at C7

Roll Motion – Change of Force at C7

Future Studies

Will add pressure sensors on the handle grips, seat, and footrests to provide additional biomechanical measurements.

Conclusions

Our preliminary data provides proof-of-principle for using our simulator to study “active riding.”

Future studies include determining how factors such as gender, age, inexperience, and passengers influence rider-vehicle dynamics.

Simulator-based technology is a powerful and safe tool to address research questions related to ATV operation that cannot be tested using other methods.