Working and Application of Pneumatic air Muscles

Working and Applications of Pneumatic Air Muscles Term Paper Report Fundamental of Mechatronics(SE501)

Name: KRISHNA KANHAIYA

Roll No.: 1411MT05

Submitted To : Dr. A. THAKUR

Working and Application of Pneumatic air muscles Page 1

Working and Applications of Pneumatic Air Muscles

Krishna Kanhaiya

Indian Institute Of Technology, Patna-800013

(Mob no.: 7050209693 ; Email: [email protected])

I. Introduction and Literature review

In recent years, there has been a growing interest in biologically inspired actuation. Traditional

electromechanical actuation has long served the robotics community, but as we move into the new millennium, muscle

like actuators, that have higher power to weight ratios, are becoming ever more attractive for their potential ability to

make robots move in life like ways. Because these actuators can deliver high forces in small packages and with minimal

weight, they are ideal for use in handheld devices. Their ability to act as linear actuators without complex transmissions

is also desirable for certain designs [1].

Pneumatic Muscle Actuator [1],[2], also known as the McKibben Pneumatic Artificial Muscle (PAM) [2],

Fluidic Muscle [2] or the Biomimetic Actuator , is a tubelike actuator that is characterized by a decrease in the actuating

length when pressurized. Best known member of this family is the McKibbenMuscle, which was invented in 1950s by

the physician, Joseph L. McKibben and was used as an orthotic appliance for polio patients [2], while the first

commercialization of PAMs has been done by the Bridgestone Rubber Company of Japan in the 1980s. PAMs are

significantly light actuators that are characterized by smooth, accurate and fast response and also are able to produce a

significant force when fully stretched[1],[2].

Typical manufacturing of a PAM can be found as a long synthetic or natural rubber tube, wrapped inside man

made netting, such as Kevlar, at predetermined angle. Protective rubber coating surrounds the fibber wrapping and

appropriate metal fittings are attached

at each end. The PAM converts

pneumatic power to pulling force and

has many advantages over

conventional pneumatic cylinders such

as high force to weight ratio, variable

installation possibilities, no mechanical

parts, lower compressedair

consumption and low cost [1],[2].

When compressed air is applied to the

interior of the rubber tube, it contracts

in length and expands radially. As the

air exits the tube, the inner netting

acts as a spring that restores the tube

in its original form. This actuation

Figure 1, [2] Shows typical Pneumatic air muscles Various types of PAMs:

(a) McKibben Muscle/Braided Muscle, (b) Pleated Muscle, (c) Yarlott

Netted Muscle, (d) ROMAC Muscle and (e) Paynter Hyperboloid Muscle..


reminds the operation of a single acting pneumatic cylinder with a spring return, while this reversible physical

deformation during the contraction and expansion of the muscle results in linear motion. It should be noted that the most

significant advantage of utilizing PAM in control applications, is that for their position control, as only one analog

variable needs to be controlled, while for the same operation with a pneumatic cylinder, two analog variables need to be

controlled (one for each chamber). As a result in the case of a pneumatic cylinder, it is more difficult to find equilibrium

between the two gauge pressures in the chambers, that it is for the case of PAMs. Typical types of PAMs and the

corresponding naming, are depicted in Figure 1.

As Pneumatic air muscles is a new concept so this is a good field of research. Many research papers have been

published on its modeling, mechanical properties, behavior, its characteristics, applications, control, optimization etc..

Various models have been developed to describe mechanical property of PMA. Chou and Hannaford [16] proposed a

famous brief model based on geometrical relationship with several assumptions. Researchers made improvements in

Chous model by accounting for other factors such as non-cylindrical ends, friction between strands, and elastic force

applied by latex bladder. Minh et al. [7] constructed a hysteresis model based on Maxwell-slip theory to improve the

accuracy of the model. Jun Zhong [17], In order to characterize the hysteretic behavior, a novel method using Bouc-Wen

model is adopted to capture the complex hysteresis of PMAs. This new model dissolves the contractile force into linear

component and hysteretic component.

Some important recent papers which has contribution to this field and helped in improving the technology, are tabulated

below:

Author Work Done Year

Andrea Deaconescu,

Tudor Deaconescu

Discusses the performance of a standardizable rotation module, actuated by

pneumatic muscles and adaptable on robotic systems designed for the aid of

disabled persons. Rotation of a cylindrical joint by means of pneumatic muscles is

achieved in a considerably similar way to that generated by human muscles, based

on the agonist vs. antagonist principle, namely as one muscle contracts the other

will relax.

2009

Yong-Lae Park A design of a soft wearable robotic device composed of elastomeric artificial

muscle actuators and soft fabric sleeves, for active assistance of knee motions was

developed.

2014

Marc Doumit

This study evaluated a PAM as an actuator for powered transfemoral prostheses. 2014

Boran Wang PMA as a direct rotary actuator for hand rehabilitation glove 2014

Benjamin K. S.

Woods

This study presents a push-PAM actuator that converts a contractile PAM into an

extensile pneumatic actuator without resorting to gears or pulleys.

2014

Tae-Yong Choi Joint compliance actuated by PM is actively utilized to enhance human safety

during collisions.

2010


II. Working principle and Modeling

The working principle of PAM is very simple, these muscles contract when compressed air is injected and

extends when the air is released. This axial movement is used for various purposes. These muscles are used in pair or

triplets etc.. to replicate different joints and muscle of human body.

When the PAM actuator inflates, D and L change, n and b remain constant, while the expressions for the PAMs length

and diameter can be formulated as:

L b cos, D b sin( n) (1)

where the thread length can be calculated as:

b 2 ( L 2 D 2 n 2 )0.5

(2)

Equation (2) is referred in the literature as the geometric relationship for the PAM, while its volume is provided by:

V = ( 1 / 4 ) D 2 L (3)

V b 3 sin2 cos(4n 2 )

dL the inner surface displacement, and dV, the volume change. The output work (Wout) done when the actuator shortens associated with the volume change, which is,

d Wout = -FdL (4)

where F is the axial tension, and dL, the axial displacement. From the view of energy conservation, the input work should equal

the output work if a system is lossless and without energy storage. Assume the actuator is in ths ideal condition. We can then

use the "virtual work" argument.

dWout = dWin (5)

-FdL = P'dV (6)

Where, P' is the relative pressure. Utilizing the energy conservation principle, now, we can find derivative of V and L w.r.t

and calculate the geometric force F:


F = P ' b 2 ( 3 c o s 2(4 n 2 )

(7)


III. Applications of PAMs

The aim of this article is to provide a detailed survey on the applications of the PAMs that could be utilized as a

basic reference design. The applications will highlight the most successful utilization of the PAMs in the fields of: a)

Bio-robotics, b) Medical, c) Industrial, and d) Aerospace applications. Some of the application of this most promising

technology are shown below in Figure 2.

Figure. 3,[2]. Biorobotic applications of PAMs: (3.1) Shadow biped walker, (3.2) Isac, (3.3) Airbug, (3.4)

Hopping robot, (3.5) Panter leg, (3.6) Ajax, (3.7) Lucy, (3.8) Stumpy, (3.9) Low cost humanoid hand, (3.10)

Pneumatic bicycle, (3.11) Threelegged robot, (3.12) Mowgli, (3.13) Robotic arm, (3.14) Bipedal robot, (3.15) Quadruped robot, (3.16) Pneumatic torso, (3.17) Pneumatic athlete robot, (3.18) Pneumatic climbing robot,

(3.19) Airics arm, (3.20) Aqua Ray, (3.21) Shadow robot leg, (3.22) Robotic eye with pneumatic actuation


IV. Identified Open Research Problems

Actuator Construction The construction can be varied such as in case of Push-PAMs in which a rod is used an it gives

extension without using any of the gears or pulley. These Push-PAMs can be used in several required location and their

performance can be measured.

Industrial safety As PAMs are very much used in industrial automation, models can be prepared for industrial safety

which will avoid collision. These models can done by using three or four joints.

Human joint replication There are many joints which can be modeled using these muscles and can be tested and

improved for the best close possible result.

Bio-Inspired Robots These artificial muscles can be used for modeling special type of bio-inspired movements such as

inchworm movement, and can be analyzed using proper models.

Models for hysteresis The McKibben PAM model lacks the hysteresis effect in calculation of force, this is an

important concern as a proper hysteresis model is a complex mathematical model and to build a proper one needs

research in this field. Although some models are developed but better can be done.

Finite Element Models - By using a finite element model approach, we can estimate the interior stresses and strains of

the McKibben actuator. Knowledge of these details have led to improved actuator designs and also can be used for

comparison with the proposed results and experimental results.

Fatigue Properties - A typical application often requires a significant number of repeated contractions and extensions of

the actuator. This repeated cycling leads to fatigue and failure of the actuator, yielding a specific life span that is an

important design consideration. So, studying the fatigue properties and predicting its failure by some theoretical model or

via experimental results can be a good area for research.

Control As these muscles have highly non-linear characteristics so a proper control system can be developed for

specific system where these are used taking all constrains.

Performance Characteristics - The force generated by a McKibben Artificial Muscle is dependent on the weave

characteristics of the braided shell, the material properties of the elastic tube, the actuation pressure, and the muscle's

length.

Artificial versus Biological Muscle - The force-length properties of the McKibben actuator are reasonably close to

biological muscle. However, the force-velocity properties are not. We can do research in designing a proper hydraulic

or some other damper to operate in parallel with the McKibben actuator to produce the desired results.


V. Problem Statement

Augmentation of muscle has become is a major challenge and it is required that a cheap and best technology is

developed in order to help millions of physically challenged people. During older age many people suffer from joint

problem. The problem is that they do not get sufficient strength from joints and muscles and hence they become

dependent on supports.

In order to eliminate this partial disability an idea should be given in order to deal with this situation where the

augmentation of muscle power takes place. The power should be enough to make the person walk easily without any

support. The advanced design may consider the variation of power based on the demand.

The power generated must be transferred through a proper mechanism in order to make the consumer walk

smoothly, although this can be done by some previously available expensive system. But how to do it in a cheap and best

way that it is available to people easily.

VI. Solution

As we know that Push PAMs are recent development by ASME which just converts the compression of the PAM

into extension of the rod which is inside it. We can use this expansion of the rod and can use a suitable mechanism for

forward movement of the leg.

The body of the PAM can be fixed with the person leg and then the only free path for the rod will be to extend

outwards, this extension can be used for the desired purpose.

The frequency of walk can be matched for a particular person and accordingly the air can be supplied at that

frequency using simple control system.


VII. Validation

The solution is very simple as when the body gets fixed, the only DOF for the rod remains is the extension. This

process does not require much costly equipment, it uses a compressed gas cylinder and only one or maximum two Push

PAM.

VIII. Limitation of Proposed Apporach

We do not know the exact behavior of the Push PAMs. As there me chances of leakage as a rod and then air is

filled, there may be wear also due to the extension and contraction. The exact modeling of a human joint is tedious and

complex, so if properly not executed then this may lead to sudden accident. So it is required that the system must be

accurate and must pass all standards.


References

[1] http://bdml.stanford.edu/twiki/pub/Rise/AaronSummerblog/CompiledArtificialMuscle

[2] Georgios Andrikopoulos, Georgios Nikolakopoulos and Stamatis Manesis A Survey on Applications of Pneumatic

Artificial Muscles, 19th Mediterranean Conference on Control and Automation Aquis Corfu Holiday Palace, Corfu,

Greece June 20-23, 2011

[3] Andrea Deaconescu, Tudor Deaconescu, Performance of a Pneumatic Muscle Actuated Rotation Module,

Proceedings of the World Congress on Engineering 2009 Vol II CE 2009, July 1 - 3, 2009, London, U.K.

[4] Bong-Soo Kang1, Curt S. Kothera2, Benjamin K. S. Woods3, and Norman M. Wereley,, Dynamic Modeling of

Mckibben Pneumatic Artificial Muscles for Antagonistic Actuation, 2009 IEEE International Conference on Robotics

and Automation Kobe International Conference Center Kobe, Japan, May 12-17, 2009

[5] Shameek Ganguly, Akash Garg, Akshay Pasricha, S.K. Dwivedy Control of pneumatic artificial muscle system

through experimental modeling, 2011

[6] Kanchana Crishan Wickramatunge, Thananchai Leephakpreeda, Study on mechanical behaviors of pneumatic

artificial muscle, 2010

[7] Tri Vo Minh, Tegoeh Tjahjowidodo, Herman Ramon, Hendrik Van Brussel, Cascade position control of a single

pneumatic artificial musclemass system with hysteresis compensation, 2010

[8] Xiangrong Shen, Nonlinear model-based control of pneumatic artificial muscle servo systems, 2010

[9] Tae-Yong Choi and Ju-Jang Lee, Control of Manipulator Using Pneumatic Muscles for Enhanced Safety, IEEE

TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 57, NO. 8, AUGUST 2010

[10] Andrea Deaconescu and Tudor Deaconescu, Bio-Inspired Pneumatic Muscle Actuated Robotic System

[11] Dennis Majoe, Lars Widmer and Juerg Gutknecht, Pneumatic Air Muscle and Pneumatic Sources for Light Weight

Autonomous Robots, 2011 IEEE International Conference on Robotics and Automation Shanghai International

Conference Center May 9-13, 2011, Shanghai, China

[12] Doruk Senkal, Hakan Gurocak, Haptic joystick with hybrid actuator using air muscles and spherical MR-brake,

2011

[13] Jzsef Srosi, Sndor Csiks, Istvn Asztalos, Jnos Gyeviki and Antal Vha, Accurate Positioning of Spring

Returned Pneumatic Artificial Muscle Using Sliding-mode Control, 1st Regional Conference - Mechatronics in Practice

and Education MECH - CONF 2011

[14] Liu Xiaomin Wang Yiqiang Geng Dexu, Mechanical Characteristics Analysis on PAM with Elongation and

Torsion, International Conference on Mechatronic Science, Electric Engineering and Computer August 19-22, 2011,

Jilin, China

[15] www.shadow.org.uk/products/airmuscles

[16] Ching-Ping Chou and Blake Hannaford, Member, IEEE , Pneumatic Artificial Muscles, IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION, VOL. 12, NO. 1, FEBRUARY 1996

[17] Jun Zhong, Jizhuang Fan, Yanhe Zhu, Jie Zhao, andWenjie Zhai, One Nonlinear PID Control to Improve the Control Performance of a Manipulator Actuated by a Pneumatic Muscle Actuator, May 2014 [18] Contractile Pneumatic Artificial Muscle Configured to Generate Extension, ASME 2014

Working and Application of Pneumatic air Muscles

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