jiahui liang - nfpa · 10/3/2015 · jiahui liang1 matthew heinrich 2, courtney mattson , matthew...

Jiahui Liang1

Matthew Heinrich2, Courtney Mattson2, Matthew Ramuta2, Jacob Stock2

Martin J. Morris, PhD2, Steven R. Tippett, PhD3, Elizabeth T. Hsiao-Wecksler, PhD1, Jacqueline Henderson, PhD1

1Dept Mechanical Science & Engineering, Univ of Illinois at Urbana-Champaign, Urbana, IL

2Dept Mechanical Engineering, 3Dept Physical Therapy, Bradley University, Peoria, IL

1. Background & Motivation

2. Mechanical Design

3. Controls

4. Testing

5. Conclusion

22015 Fluid Power Innovation & Research Conference

Pneumatic Spasticity and Rigidity Simulator

Photo Credit: Bradley Senior Design Project AY 14-15

2015 Fluid Power Innovation & Research Conference 3


● Hypertonic Muscle Behavior

o Brain or spinal cord injuries1

o Involuntary muscle movement1,2

● Spasticity

o Speed-dependent behavior2

o Affect ~12M people worldwide3

● Rigidity

o Position-dependent behavior2

o Lead-Pipe, Cogwheel

o Affect ~7M people worldwide4

Demonstration of Cogwheel Rigidity

Video Credit: Dr. Yasser Metwally

Spasticity Evaluation

1 Mukherjee et al., 2010 2 Lee et al., 20023 www.aans.org 4 www.medtronic.eu

http://www.aans.org/

http://www.medtronic.eu/


● Clinical Evaluation

o In-person assessment using qualitative scales5,6

o Poor reliability and inconsistency5,6,7

o Consistency improves with experience5

● Problems in Training

o Patient availability5

o Muscle tone changes with

multiple stretching5

Demonstration of Spasticity Assessment During Clinical Training

Photo Credit: Stanford university

5 Pandyan et al., 1999 6 Bohannon et al., 19877 Brokaw, 2014


● Bradley Univ Mech Engr Senior Design Project

o Simulator for clinical training

o One-year long design project

o U Illinois – Mechanical Engr., Bradley – Physical

Therapy, and Bradley – Mechanical Engr.

● Project Goals

o Utilize fluid power

o Replicate spasticity, lead-pipe rigidity and

cogwheel rigidity at the elbow joint during flexion


Requirement Approach

Fluid Powered Pneumatic Actuator

Operational Range Force Analysis

Replicate Spasticity Pneumatic Damper

Replicate Lead-Pipe &

Cogwheel Rigidity

Pneumatic Switch

Flexion Only Actuator Mounting


Concept 1 Concept 2

Concept 3 Concept 4

Preliminary Design Concepts


Rolling Contact


● Relationship between force experienced by user and

pressure inside the pneumatic actuator

Force Analysis of the System


Bore Size: 1.5”


● Simple metal framework with one degree of freedom

● Rotary potentiometer and proportional valve for

feedback control

Potentiometer

Pneumatic Actuator

Metal Stand

Bracketing System

Final Mechanical Design


Forearm

Upper Arm

Proportional Valve

Micro-controller


● Closed-loop control using Arduino

o Spasticity – adjustable pneumatic damper

o Rigidity – pneumatic switch

● Utilize real time position/velocity data for valve control

Electronics used to execute control algorithmsWiring schematic of the electrical components



Spasticity


Lead Pipe

Rigidity


Cogwheel Rigidity


● Air freely flowing through tubing to the opposite side of

the cylinder

Schematic showing flow through the pneumatic cylinder


CylinderPiston

Valve

Tubing

F


● Air freely flowing through tubing to the opposite side of

the cylinder

CylinderPiston

Valve

Tubing



F


● If position threshold is met, signal sent to valve causing

it to close off, preventing free flow

CylinderPiston

Valve

Tubing



F


● Pressure increase on one side, pressure decrease on

other side

CylinderPiston

Valve

Tubing



F


● Motion ceases when differential pressure is equal to

pressure resulting from input force

CylinderPiston

Valve

Tubing



F


● ¾ turn 10 kΩ potentiometer

● Test Range: 180 deg

● Regression analysis

o R squared: 0.997

o Adjusted R: 0.996

● Total error: +/- 5% Position (deg)

Vo

lta

ge

(V

)

0 100 200

0

2

4

Test Setup for Angular Position



● Used motion tracking

software “Tracker”8

● Compared serial output

to motion tracking

analysis from high

speed video at 120 fpsTime (ms)

An

gu

lar

Ve

loc

ity (

rad

/s)

Test Setup for Angular Velocity


8 www.cabrillo.edu

http://www.cabrillo.edu/


● Differentiation of three

muscle behaviors:

spasticity,

lead-pipe rigidity, and

cogwheel rigidity

Pneumatic Spasticity and Rigidity Simulator



● Observation

o Low system torque output

o High gas compressibility

o Limitation of controller frequency (Arduino)

● Conclusion

o Simulation of spasticity and two forms of rigidity

o Received initial feedback for design improvement

o Moving on: Hydraulic design


● Bradley Student Team

o Matthew Heinrich

o Courtney Mattson

o Matthew Ramuta

o Jacob Stock

● This project is funded by Bradley University Mechanical

Engineering and Physical Therapy departments.

Bradley Senior Design – Team 6

Photo Credit: Dr. Jacqueline Henderson


[1] Mukherjee, A., and A. Chakravarty. Frontiers in Neurology 1 (2010): 149.

[2] Lee, H-M, Y-Z Huang, J-J Chen, and I-S Huang. J Neurol Neurosurg

Psychiatry. May 2002; 72(5):621‐629.

[3] American Association of Neurological Surgeons. “Spasticity”.

http://www.aans.org/.Web. Accessed Oct 5, 2015

[4] Medtronic. ”About Parkinson’s Disease”. http://www.medtronic.eu/. Web.

Accessed Oct 5, 2015

[5] Pandyan AD, Johnson GR, Price CI, Curless RH, Barnes MP, Rodgers H.

Clin Rehabil. Oct 1999;13(5):373‐383.

[6] Bohannon RW, Smith MB. Phys Ther. Feb 1987;67(2):206‐207.

[7] Brokaw EB. Engineering in Medicine and Biology Annual Meeting 2014;

Chicago, IL.

[8] Brown, D. "Tracker Video Analysis and Modeling Tool for Physics Education."

https://www.cabrillo.edu/~dbrown/tracker/. Web. Accessed Oct 5, 2015.

jiahui liang - nfpa · 10/3/2015 · jiahui liang1 matthew heinrich 2, courtney mattson , matthew...

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