SENIOR DESIGN 2015-2016
SMARTSPECIALIZED MOBILIZATION AND REHABILITATION
TEAM
Outline
• Background• Justification• Goals• Methods• Analysis• Force Sensor Sub-Team• Budget• Key Dates
1
Disability Prevalence
• 1500 children born per year with spina bifida [1]
• 1 in 323 children born with cerebral palsy [2]
• 16.5% of 7-11 year olds have sensory processing disorder [3]
[1] S. E. Parker et al., “Updated National Birth Prevalence estimates for selected birth defects in the United States, 2004-2006,”
[2] D. Christensen et al., “Prevalence of cerebral palsy, co-occurring autism spectrum disorders, and motor functioning - Autism and Developmental Disabilities Monitoring Network, USA, 2008,”
[3] A. Ben-Sasson et al., “Sensory Over-Responsivity in Elementary School: Prevalence and Social-Emotional Correlates,”
3
Physical Therapy
• The AmTryke is a hand and foot tricycle• Therapeutic effects on musculoskeletal control not quantified
• Methods to quantify musculoskeletal activity using:• Kinematic data• Kinetic data• Electromyographic data
4
INSERT PICTURE OF AMTRYKE HERE
Overall Objective
•Quantify the therapeutic effects of AmTyke exercise:
•Perform initial study using kinematic data and gross motor function measure (GMFM)
•Improve kinematic measurement process•Develop force sensors for future use in kinetic data gathering
5
High Level Deliverables
Force Sensor Team• Two working handlebar force sensors• Documentation, SolidWorks model, and electrical
schematic of the sensor and circuit for future work
BME• Journal manuscript on the kinematic analysis of
AmTryke rehabilitation
6
SMART Members
Data Analysis• Amerz Chek• Daniella Guerrero• Allen Hill (Lead)• Wei Shu
Modeling• Alana Alston• Immanuel Phiri• Alexia Thomas (Sub-
Lead)
Load Cell• Ellie Blow (Sub-
Lead)• Aaron Jones• Johannus Smith 7
Functional Diagram
Data Acquisition
Data Processing
Model Scaling
Kinematic Representation Data Analysis
Processing Team
Modeling Team
Load CellDesign
Test
Working Load Cell
Load Cell Team
8
Methods: Experiment
• 6 subjects• Age: 2-7 years old• Disabilities: Cerebral palsy,
spina bifida, SPD, prenatal drug exposure
• Before and after motion capture
• 3-month interval
9
10
11
12
Data Processing
13
Data Analysis
14
0 30 60 90 120 150 180 210 240 270 300 330 360
30
40
50
60
70
80
90
100
110
120
130Old Right Elbow Flexion (deg) vs. Handlebar Angle (deg)
Handlebar Angle (deg)
Rig
ht E
lbow
Fle
xion
(deg
)
Average Std = 15.9918
0 30 60 90 120 150 180 210 240 270 300 330 360
30
40
50
60
70
80
90
100
110
120
130New Right Elbow Flexion (deg) vs. Handlebar Angle (deg)
Handlebar Angle (deg)
Rig
ht E
lbow
Fle
xion
(deg
)
Average Std = 6.9423
0 30 60 90 120 150 180 210 240 270 300 330 360
-50
-40
-30
-20
-10
0
10
20
30
40
Handlebar Angle (deg)
Rig
ht E
lbow
Fle
xion
(deg
)
Right Elbow Flexion (deg) vs. Handlebar Angle (deg)
Old Average Std = 15.99175New Average Std = 6.94228
0 30 60 90 120 150 180 210 240 270 300 330 360-115
-110
-105
-100
-95
-90
-85
-80
-75Right Knee Angle (deg)
Handlebar Angle (deg)
Rig
ht K
nee
Ang
le (d
eg) (
deg)
LeftRightCcnorm = 0.974468
0 30 60 90 120 150 180 210 240 270 300 330 360-115
-110
-105
-100
-95
-90
-85
-80
-75Right Knee Angle (deg)
Handlebar Angle (deg)
Rig
ht K
nee
Ang
le (d
eg) (
deg)
LeftRightCcnorm = 0.973816
0 30 60 90 120 150 180 210 240 270 300 330 360-5
0
5
10Old Knee Angle vs. Handlebar Angle (deg)
Handlebar Angle (deg)
Kne
e A
ngle
(per
cent
)
Average Std = 2.1794
0 30 60 90 120 150 180 210 240 270 300 330 360-5
0
5
10New Knee Angle vs. Handlebar Angle (deg)
Handlebar Angle (deg)
Kne
e A
ngle
(per
cent
)
Average Std = 2.3439
Alana Alston, Immanuel Phiri, Alexia Thomas
Modeling
Process Improvement
Model simplification•Simple vs. Complex
Marker set reduction•What is vital?
16
Experiment Setup
Initial Capture:•38 markers •Specifically modeled upper limb movement in a bicycling motion
Control Inverse Kinematics:•OpenSim was used to scale and run inverse kinematics •An average RMS error was calculated for the model as a whole from the individual markers
18
Angle Comparisons
3 117 231 345 459 573 687 801 915 1029114312571371148515991713182719412055216922832397251126252739285329670
10
20
30
40
50
60
70
Shoulder Flexion
Complex Simple
Time (sec)
Ang
le (d
eg)
Angle comparisons
3 117 231 345 459 573 687 801 915 102911431257137114851599171318271941205521692283239725112625273928532967-40
-35
-30
-25
-20
-15
-10
-5
0
Shoulder Adduction
Complex Simple
Time (sec)
Ang
le (d
eg)
Angle comparisons
3 117 231 345 459 573 687 801 915 1029114312571371148515991713182719412055216922832397251126252739285329670
10
20
30
40
50
60
Shoulder Rotation
Complex Simple
Time (sec)
Ang
le (d
eg)
Marker Removal and IK Generation
Marker Removal:•Focused on scapula and lateral elbow markers in this order:•L&R Scap1, L&R TriSpn, L&R Shoulder, L&R ElbowMed
IK Data Generation:•New .mot files were generated each time a marker was removed along with new RMS values.
•Ex. 1.mot: Scap1•Ex. 2.mot: TriSpn•Ex. 3.mot: Scap1 + TriSpn
RMS Values
RMS Values•A MATLAB program was used to calculated the RMS errors of the comparison between the base model and new generated models
Aimed for the following values:•0 < RMS < 5 degrees – for markers on segments with rotations•0 < RMS < 1 cm - for makers on thorax and Pelvis regions •Markers were picked based on their RMS value
Final Marker set
Final Marker set
Force SensorEllie Blow, Johannus Smith, Aaron Jones
Background Research
•Previous Multiaxial Force Sensors•Liu’s Model
• Side-centered Support Beams• 7 cm X 7 cm• 20 strain gages
•Kim’s Model• Corner Support Beams and Central Support Beam• 9 cm X 9 cm• 24 strain gages
Selection
•Liu’s Model, and shrink it down to a 4 cm by 4 cm piece
•Reasons•Easier geometry to produce•Fewer strain gages to measure the same forces and moments
•Closer to the desired size
Prototype•Made of 7075-T6 Aluminum•Hand-milled at the MTDL (18 hours)•Fitted with the Fz Bridge•5 cm X 5 cm•Used to develop a testing procedure for use with the final sensor•Used to validate linearity of responses
Attachment to the AmTryke•Cut off the original handlebar to retain the threading that connects to the bicycle•Slide the baseplate over the cut handlebar and use a nut so that it freely rotates.•Use four 4-40 screws to attach the baseplate to the sensor housing•Attach the handlebar to the housing using a 7/16-20 bolt
Sensor Circuit: Instrumentation Amp
•Gain of 1 •1 ohm resistors are placeholders•Boosts the signal to mitigate noise
Sensor Circuit: Notch Filter
•4 pull notch filter •Focused at 60 HZ to reduce room noise•Leads into final gain phase (R9 resistor)
Sensor Circuit: Final Amp
•Gain of 5•Outputs to the Vicon system•Used to amplify the filtered signal to a level that the Vicon system can work with
Sensor Calibration Testing•Isolate each force and moment by applying along/around the respective axis•Create a input(lbf or lbf*in) vs output(mV) plot to find the voltage increase per lbf or lbf*in for each bridge for each force•This results in a 6X6 matrix
Sensor Calibration w/ Circuit•Comparable results with similar linearity•Proves the response of the circuit tracks with the force applied
Project Budget
Items Expected ActualRaw Materials $75 $122
Strain Gages $900 $285
Manufacturing $400 $781
Electronics $125 $100
Lab and Testing Supplies $250 $250
Total $1750 $1538
36
Key Dates
10/20
12/20
01/21
03/07
09/03
04/22Force Sensor BME
Planning Literature compilation ResearchPhase 1 Design Pilot DataPhase 2 Basic Prototyping/Testing Initial DataPhase 3 Rescaling/Manufacturing Final DataFinalization Final Modifications Documentation
Force Sensor
BME
37
References
[1] S. E. Parker, C. T. Mai, M. A. Canfield, R. Rickard, Y. Wang, R. E. Meyer, P. Anderson, C. A. Mason, J. S. Collins, R. S. Kirby, A. Correa, and National Birth Defects Prevention Network, “Updated National Birth Prevalence estimates for selected birth defects in the United States, 2004-2006,” Birth Defects Res. Part A Clin. Mol. Teratol., vol. 88, no. 12, pp. 1008–1016, Dec. 2010.
[2] D. Christensen, K. Van Naarden Braun, N. S. Doernberg, M. J. Maenner, C. L. Arneson, M. S. Durkin, R. E. Benedict, R. S. Kirby, M. S. Wingate, R. Fitzgerald, and M. Yeargin-Allsopp, “Prevalence of cerebral palsy, co-occurring autism spectrum disorders, and motor functioning - Autism and Developmental Disabilities Monitoring Network, USA, 2008,” Dev Med Child Neurol, vol. 56, no. 1, pp. 59–65, Jan. 2014.
[3] A. Ben-Sasson, A. S. Carter, and M. J. Briggs-Gowan, “Sensory Over-Responsivity in Elementary School: Prevalence and Social-Emotional Correlates,” J Abnorm Child Psychol, vol. 37, no. 5, pp. 705–716, Jan. 2009.
38
References
[4] S. A. Liu and H. L. Tzo, “A Novel Six-Component Force Sensor of Good Measurement Isotropy and Sensitivities,” Sensors and Actuators A: Physical, vol. 100, no. 2–3, pp. 223–230, Sep. 2002.
39
40
Strain Gage Placement
41
Housing
42
Dimensions: Top View
43
Dimensions: Side View
44
Future Work
• Four (4) force sensors for kinetic analysis
• Develop interactive app for AmTryke users
45
Handlebar Angle Calculations
• PCA on marker data to extract axis of rotation
• LMS for outlier detection
• Inverse tangent to calculate angle
Y.-S. Liu and K. Ramani, “Robust principal axes
determination for point-based shapes using least median
of squares,” Computer-Aided Design, vol. 41, no. 4, pp.
293–305, Apr. 2009.
46
Symmetry Analysis
47
Gap Filling
•Interpolation algorithms:•Spline Fill•Pattern Fill•Rigid Body Fill•Kinematic Fill
48