Overview

Objective

Background

Data Collection

CODAmotion Model

Equation Design

LabVIEW™

Results

Discussion

Conclusion

Objective

To analyze force and

moment data using inverse

dynamics to correlate

ground reaction forces to

forces at the back of the

horse that could be

transferred to a rider.

This could potentially be

used to match horses to

riders based on their

physical abilities

Backgroundo Therapeutic riding, or

hippotherapy, is an alternative to traditional physical therapy. o To treat: Cerebral Palsy, Autism, &

Muscular Dystrophy.

o Previous studies indicate that horseback riding can positively affect the mental state of riders.

o No previous scientific research proving the physical benefits of therapeutic riding exists.

o In order to verify and optimize any physical benefits, force data at the horse’s back is needed to design physical therapy exercises.

Data Collection

o Previously collected by Dr. Lopez and her graduate student

o What we had to work with:o Force plate

o Marker position

o Video verification

o Basic physical characteristics of the test horse

o Our project’s objective is to: design a way to analyze this information

Data Collection

o Started with approximately 70 trials

o Determined valid trials based on: o One hoof on force plate at a

time

o That hoof must be the horse’s left side of the body

o Checked for typical ground reaction force plot

o Verified using CODAmotion software

o Deemed four trials valid

Vertical Direction

Lateral Direction

CODAmotion Modelo Able to import

information from force plate and photodiode markers

o Created Virtual Markers

o Able to export numerical data including:o Forces

o Accelerations

o Velocities

o Marker position

o Angles

Biomechanicso Inverse Dynamics: A mathematical

process that uses ground reaction forces to determine the moments and forces at joint.

o Requires some assumptions:o Joints are frictionless pin-joints.

o Segments are rigid with mass concentrated at a constant center of mass.

o Treat the distance between markers as the “beam” or segment

o Ignore internal forces due to muscles – no way to measure this with the given data

o Basic Steps:o Starting with the terminal segment apply the weight

of the segment to center of gravity

o Find the net force for that segment

o Transfer that force to the next segment and repeat the process

Dynamic Equations

• Using these equations on each individual free-body diagram:

• Fx=max , Fy=may , Fz=maz, M=Iα

• Here are some of the equations we came up with:

• Fx=Rgfx-Maaax–Mbabx-Mcacx-Mdadx-Meaex-Mfafx

◦ Fy= Rgfx-Wa-Maaax–Wb-Mbabx-Wc-Mcacx-Wd-Mdadx-We-Meaex-Wf-Mfafx

Equation Formation

The values given by CODAmotion are the vector

position, acceleration and angular acceleration at each

marker. Also, the angles between segments can are given.

Treated the bones in the horse’s body as segments in a

framed structure to calculate our resultant values.

The length of segments can be found by subtracting the

position of one vector from another. The weight of each

bone was found previously as a percentage of total

weight.

The equations were converted into Microsoft Excel

spreadsheets to verify our LabVIEW coding results.

Purpose: To create a user interface

Insert Equations into Software

Use Mealy Machine Logic

Input: Weight, Height, Gait

Output: Forces and Moments at different gaits + visual representation of resultant angle.

LabVIEW™

Image of user interface

Results

We developed a software program to model

a horse’s gait in such a way as to compute

the forces that would be exerted at it’s back.

For our test horse (weight: 395N; height:,)

resulting values were:

Gait Force (N) Mx (Nm) My (Nm) Mz (Nm)

Walk 840.5 -616.4 -460.3 934.6

Trot 22343 771.8 -1196.4 4503.3

Discussion Results compared to a research paper from

Cambridge University.

Measured the pressure at a horse’s back during a trot.

One trial horse was reported to be 163cm tall and 300kg in mass.

Pressure values were converted to force values and found to be 17,064N.

This horse’s stats were input into our software program; a force of 16,920N was found.

Percent error: 0.85%.

Conclusion

We met our objective by creating a

software program to analyze raw data and

calculate the forces and moments exerted at

a horse’s back.

Our results are valid when compared to

published works. Further work must be

done to validate the program and apply it to

the human body.

Acknowledgments

Dr. Mandi Lopez

Dr. Marybeth Lima

LSU Agricultural Center

LSU SVM

BAE Department

LabVIEW®

CODAmotion®

Thank you!

Questions?