Dynamic Characterization of a Pneumatic Muscle Actuator and Its Application to a Resistive ...

219 Pages·2016·8.69 MB·English

by  Jennifer L. Serres

WWrriigghhtt SSttaattee UUnniivveerrssiittyy
CCOORREE SScchhoollaarr
Browse all Theses and Dissertations Theses and Dissertations
2008
DDyynnaammiicc CChhaarraacctteerriizzaattiioonn ooff aa PPnneeuummaattiicc MMuussccllee AAccttuuaattoorr aanndd IIttss
AApppplliiccaattiioonn ttoo aa RReessiissttiivvee TTrraaiinniinngg DDeevviiccee
Jennifer L. Serres
Wright State University
Follow this and additional works at: https://corescholar.libraries.wright.edu/etd_all
Part of the Engineering Commons
RReeppoossiittoorryy CCiittaattiioonn
Serres, Jennifer L., "Dynamic Characterization of a Pneumatic Muscle Actuator and Its Application to a
Resistive Training Device" (2008). Browse all Theses and Dissertations. 882.
https://corescholar.libraries.wright.edu/etd_all/882
This Dissertation is brought to you for free and open access by the Theses and Dissertations at CORE Scholar. It
has been accepted for inclusion in Browse all Theses and Dissertations by an authorized administrator of CORE
Scholar. For more information, please contact [email protected].
DYNAMIC CHARACTERIZATION OF A PNEUMATIC
MUSCLE ACTUATOR AND ITS APPLICATION TO A
RESISTIVE TRAINING DEVICE

A dissertation submitted in partial fulfillment of the
Requirements for the degree of
Doctor of Philosophy

By

JENNIFER L. SERRES
M.S., Wright State University, 2006
B.S., Wright State University, 2005

__________________________

2008
Wright State University
COPYRIGHT BY

JENNIFER LYNN SERRES

2008
WRIGHT STATE UNIVERSITY

SCHOOL OF GRADUATE STUDIES

November 10, 2008
I HEREBY RECOMMEND THAT THE DISSERTATION PREPARED UNDER MY
SUPERVISION BY Jennifer Lynn Serres ENTITLED Dynamic Characterization of a
Pneumatic Muscle Actuator and Its Application to a Resistive Training Device BE
ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF Doctor of Philosophy.

_____________________________
David B. Reynolds, Ph.D.
Dissertation Director

_____________________________
Ramana V. Grandi, Ph.D.
Director, Ph.D. in Engineering Program

_____________________________
Joseph F. Thomas, Jr., Ph. D.
Dean, School of Graduate Studies

Committee on Final Examination:

__________________________
David B. Reynolds, Ph.D.

__________________________
Chandler A. Phillips, M.D., P.E.

__________________________
Raymond Hill, Ph.D.

__________________________
Stanley R. Mohler, M.D.

__________________________
Dana Rogers, Ph.D.
ABSTRACT

Serres, Jennifer Lynn, Ph.D., Department of Biomedical, Industrial, and Human Factors
Engineering, Wright State University, 2008. Dynamic Characterization of a Pneumatic
Muscle Actuator and Its Application to a Resistive Training Device.

Research described in this dissertation expands the use of a biomechanical
phenomenological model to a commercially available pneumatic muscle actuator (PMA).
Due to the nonlinearities of the device, achieving accurate control is challenging.
Experiments have been conducted that define boundaries of operation where linear
approximations can be used to describe the dynamics of the PMA. Empirical data
presented in this dissertation show that nonlinearities exist more prevalently at higher
loads (on average >70% contractile force value). When the PMA is under high loads,
low displacement occurs. Therefore, these regions are of less interest to design engineers.
Once conditions of nonlinearities were defined, operational areas of interest were
characterized.
Open-loop linear systems analysis utilized the characterization profiles for the
PMA in combination with a model for the D.C. servo motor to develop a system transfer
function describing the dynamics of the overall plant. A Tustin (bilinear) transform was
applied to the transfer function to generate a discrete time recursion equation. This
equation describes the interaction of the PMA and the D.C. servo motor. It was then used
to generate motor voltage profiles to demonstrate various tasks on the system.
Finally, this dissertation describes a new concept of using PMAs as an antagonist
in a resistive training device. One such application is in a microgravity environment
(prolonged space flight). The characterization analysis presents a method to demonstrate
iv
this task on the Dynamic Test Station (DTS). In this demonstration the PMA acts as an
antagonist generating a resistive load, which the D.C. servo motor, representing the
human operator, works against. A 90o isokinetic (constant velocity) rotation of the D.C.
servo motor pulley is achieved at eight PMA pressures each of which generates a
different resistive load.

v
TABLE OF CONTENTS

1. INTRODUCTION AND BACKGROUND 1
1.1. Overview of the Problem 1
1.2. Background and Review of Literature 2
1.2.1. Pneumatic Muscle Actuators (PMAs) 2
1.2.1.1. PMA Basic Operation 2
1.2.1.2. Comparison of Actuators 3
1.2.1.3. Comparison of PMAs to Biological Muscle 5
1.2.1.4. Commercially Available Pneumatic Muscle
Actuators 6

1.2.2. Overview of PMA Modeling Techniques 7
1.2.2.1. Geometric Modeling 8
1.2.2.2. Biomimetic Modeling 14
1.2.2.3. Phenomenological Modeling 15
1.2.3. PMA Applications 16
1.2.3.1. Low Force Applications 17
1.2.3.2. High Force Applications 17
1.2.4. Physiological Effects of Long-term Spaceflight 19
1.2.4.1. Current Countermeasures: Exercise 20
1.2.4.2. Current Countermeasures: Passive Stretching 21
vi
TABLE OF CONTENTS (Continued)

1.2.4.3. Current Countermeasures: Nutritional Supplements 21
1.3. Research Goals and Objectives 22
1.3.1. Research Goals 22
1.3.2. Research Objectives 22
1.3.2.1. Objective 1 22
1.3.2.2. Objective 2 22
1.3.2.3. Objective 3 23
1.3.2.4. Objective 4 23
2. PMA DYNAMIC TEST STATION 25
2.1. Mechanical System 27
2.1.1. Sensors 28
2.1.1.1. Linear Variable Differential Transducer 28
2.1.1.2. Pressure Transducer 29
2.1.1.3. Load Cell 30
2.1.1.4. Rotational Potentiometer 31
2.1.2. Additional System Components 32
2.1.2.1. Pneumatic Muscle Actuator 32
2.1.2.2. D.C. Servo Motor 33
2.1.2.3. Proportional Pressure Regulator 34
2.2. Operating System 35
2.3. Electrical System 37
3. THEORY 40
vii
TABLE OF CONTENTS (Continued)

3.1. Characterization of a Phenomenological Model for Commercial
Pneumatic Muscle Actuators 40

3.2. Characterization of a Pneumatic Muscle Test Station with Two
Dynamic Plants in Cascade 43

3.2.1. Development of D.C. Servo Motor Transfer Function 43
3.2.2. Development of PMA Transfer Function 45
3.2.3. Combination of PMA and D.C. Servo Motor Transfer Functions 46
3.3. Lower Extremity Resistive Exercise Device Utilizing an Antagonist
Pneumatic Muscle Actuator 48

4. METHODS 50
4.1. Characterization of a Phenomenological Model for Commercial
Pneumatic Muscle Actuators 50

4.1.1. Experimental Methods for Static Loading Study 50
4.1.2. Experimental Methods for Preliminary Contraction Study 51
4.1.3. Experimental Methods for Contraction Study 52
4.1.4. Experimental Methods for Relaxation Study 53
4.1.5. Experimental Methods for Validation Study 53
4.1.6. Statistical Methods for PMA Characterization Study 53
4.2. Characterization of a Pneumatic Muscle Test Station with Two
Dynamic Plants in Cascade 54

4.2.1. Mathematical Methods of Tustin Transform 54
4.2.2. Experimental Methods for DTS Limitation Study 56
4.2.3. Experimental Methods for Isokinetic Displacement Study 56
4.2.4. Statistical Methods for System Characterization Study 58
viii
TABLE OF CONTENTS (Continued)

4.3. Lower Extremity Resistive Exercise Device Utilizing an Antagonist
Pneumatic Muscle Actuator 59

4.3.1. Experimental Methods for Isokinetic Rotation Study 59
4.3.2. Statistical Methods for Isokinetic Rotation Study 59
5. RESULTS 61
5.1. Characterization of a Phenomenological Model for Commercial
Pneumatic Muscle Actuators 61

5.1.1. Static Loading Study 61
5.1.2. Preliminary Contraction Study 63
5.1.3. Contraction Study 64
5.1.4. Relaxation Study 69
5.1.5. Validation Study 71
5.2. Characterization of a Pneumatic Muscle Test Station with Two
Dynamic Plants in Cascade 73

5.2.1. DTS Limitation Study 73
5.2.2. Isokinetic Displacement Study 76
5.3. Lower Extremity Resistive Exercise Device Utilizing an Antagonist
Pneumatic Muscle Actuator 82

5.3.1. Isokinetic Rotation Study 82
6. DISCUSSION 94
6.1. Characterization of a Phenomenological Model for Commercial
Pneumatic Muscle Actuators 94

6.2. Characterization of a Pneumatic Muscle Test Station with Two
Dynamic Plants in Cascade 96

ix