JPL Electroactive (EAP) as Artificial Muscles

Yoseph Bar-Cohen JPL, 8 18-354-2610, [email protected] http://ndeaa.j pl.nasa.gov/

February 2 1-22,2002 von Karman Auditorium Lecture Series ,-

Nature as a model for engineering

V Helicopter Glider (Tipuana tipu) (Alsomitra macrocarpa) Aerodynamic dispersion of seeds I - (Courtesy of Wayne's Word) --T1imbleweed Ref: http://waynesword.palom.edu/plfeb99.htm#helicopters

Some octopuses can change their Courtesy of William M. Mer, of North Carolina color according to their mood Octopus adaptive shape, texture and camouflage Ref: http://www.pbs.org/wnet/nature/octopus/ 2 .* Six Million Dollar Man Ref.: http://web.ukonline.co.uk/craig.pierce2/six.ht1iil

The series started in 1974, Lee Majors took the role of Col. Steve Austin, quite a switch from a cowboy in the wild west series Big Valley.

In the early episodes Steve Austin was portrayed as a man in complete rejection of his situation, he couldn't come to terms with the fact that he had lost the sight in his left eye, and had his right arm and both legs amputated, in the pilot episode he tried to commit suicide, but was stopped by a nurse (Barbara Anderson), this form of Human emotion by the character of Steve Austin led to critical acclaim for the series.

When Steve is told that there is a chance that he can be fitted with new limbs and shown them, he is shocked, but the Doctor explains these are very special and once fitted he would be able to hold a woman's hand and she wouldn't be able to tell that it was bionic, the skin texture, heat, hairs would all match his own original arm.

The surgery goes ahead for many hours and after, the surgical team wait in his room for him to recover. Then success he wakes and attempts to lift his new and approved arm, which as you can see he does, and then the long re-hab road can start.

The Six Million Dollar Man is based on the Martin Caidin novel "The Cyborg". 3 rzi

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0 m I 0 Jim Henson’s Creature Shop, Walt Disney Imagineering “Haunted animatronic creature with skin Mansion0 Disney” at Disneyland

7 Robot that responds to human expressions Cynthia Breazeal, MIT, and her robot Kismet

8 Background Most conventional mechanisms are driven by requiring gears, bearings, and other complex components.

Emulating biological muscles can enable various novel manipulation capabilities that are impossible today.

Electroactive polymers (EAP) are emerging with capability that can mimic muscles to actuate biologically inspired mechanisms.

EAP are resilient, fracture tolerant, noiseless actuators that can be made miniature, low , inexpensive and consume low .

EAP can potentially be used to construct 3-D systems, such as robotics, which can only be imagined as science fiction using current capabilities.

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Historical prospective Roentgen [ 18801 is credited for the first experiment with EAP electro- activating rubber-band to move a cantilever with mass attached to the free-end Sacerdote [ 18991 formulated the strain response of polymers to activation Eguchi [ 19251 discovery of * marks the first developed EAP - Obtained when carnauba wax, and beeswax are solidified by cooling while subjected to DC bias field. Another important milestone is Kawai [1969] observation of a substantial piezoelectric activity in PVF2. - PVF2 films were applied as , miniature actuators and speakers.

Since the early 70’s the list of new EAP materials has grown considerably, but the most progress was made after 1990.

* Electrets are dielectric materials that can store charges for long times and produce field variation in reaction to pressure.

10 .. Non-Electro Active Polymers (NEAP)

Conductive and Photonic Polymers

Smart Structures and Materials

Deformable Polymers - Chemically Activated - Shape Memory Polymers

- Inflatable Structures - Light Activated Polymers - Magnetically Activated Polymers

11 Non-Electrical Mechanically Activated Polymers

Shape klemory Polymers Heat/pressure activation (W. McKibben Artificial Laser Illuminated Sokolowski, JPL) -Muscles Light activation (H. Misawa, Japan ) Air Pressure activation (Hannaford, B.U. Washington)

Ionic Polymers Ferrogel Smart Structures Chemical transduction (P. Magnetic Activation (M. Zrinyi, Polymers with Stable shapes Calvert, UA) Hungary) (S. Poland, Luna Innovations, VA ) 12 Comparison between EAP and widely used transducing actuators

Property EAP EAC SMA 1 Actuation strain 0.1 - 0.3 % 43% short fatigue life IForce (MPa) 0.1 -3 30-40 about 700 I Reaction speed psec to sec psec to sec sec to min 1 Density 1- 2.5 glee 6-8 g/cc 5 - 6 g/cc Drive 2-7Vl 50 - 800 V NA 10-100V/pm I Consumed Power* m-watts watts watts I Fracture toughness resilient, elastic fra gi 1 e elastic

* Note: Power values are compared for documented devices driven by such actuators. 13 m e( m 0E .rl @ d 1 0 en CI) 0 ii aa4 m 0 m *mNE w c, m 0E 0 0 lac@ *L(E c, s 4 A @ 0 0 w H c,a 1 L 0 a4

0E .e( c,z 0 0u R .\ 0 RaJ en -YCL s R E1 Elements of EAP actuated robots

Communication Power

P ropu Is io n/Mo b il ity/ Intelligent control Locomotion Functions Navigation EAP Swimming and/or diving Collision avoidance Walking Auto nom o us pe rfo rm a n ce 1 Hopping and/or flying Microswitching and positioning -. I Sensing EAP actuation sensors Imaging L LOther sensors as needed 1 15 Insects as workhorses and robots

Insects were used by various researchers (e.g., University of Tokyo, Japan) as locomotives to carry backpack of wireless electronics.

EAP offers the potential of making insect-like robot to replace the “rea1 thing”.

a Cricket Spider Cockroach

Reference: http:Nwww.leopard.t.u-tokyo.ac.jp/

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Q) m HE EAP infrastructure

IonicEAP Electronic EAP

I 1-1 I1 1 I I1 I Dielectric EAP material pool loniq Gel IPYC cond;ctive Nanorbes Ferroelectric I 1 I 1 1 polymers 1 1 1 1 EAP I I e laGraft sto me r I 'I 'I

EAP mechanism Nonlinear Material properties Computational chemistry understanding and electromechanical characterization New material synthesis enhancement modeling

Material .Shaping Microlayering Miniaturization EAP Processing (fibers, films, (ISAM & inkjet techniques techniques etc.) printing) I

T 00 lsls u p port e leme nts Sen so rs Actuators MEMS

,t Miniature Robotics General applications and devices Insect-like robots Medical devices D eviceslA pp Iica t io n End effectors Shape control s Manipulators Muscle-like actuators Miniature locomotives Active weaving and haptics 18 4 W

r. h r uE & H J 6) n c, .d GI $ n a 0 Ju4 J c, 2a E' m n 3 J M b 3 8 0 0 z '4 a 8 c/I1 c, J m u ce M 8 2 s Mh a 2 0 w 0 F4 u 'ac, E '0 E 0 m M6) 0 6) 5u 2 & 'rl 0 b 0 0 3 'd 6) 0 cr' w 6) w M M c 0 u m m E u H cl 0E a w...... H 0 Current EAP Advantages and disadvantages EAP type Advantages Disadvantages

Electronic - Can operate in room conditions for a Requires high (- 150 EAP long time Wlm) - Rapid response (mSec levels) - Requires compromise between Can hold strain under DC activation strain and stress Induces relatively large actuation Glass transition temperature is inadequate for low temperature actuation tasks

Ionic EAP * Large bending displacements Except for CPs, ionic EAPs do not Provides mostly bending actuation hold strain under DC voltage (longitudinal mechanisms can be * Slow response (fraction of a second) constructed) - Bending EAPs induce a relatively - Requires low voltage low actuation Except for CPs, it is difficult to produce a consistent material (particularly IPMC) - In aqueous systems the material sustains Electrolysis at H.23-V

20 13 uerr 3 4 03 4 2; n 031 5.

Strain (%) Ionic EAP Turning chemistry to actuation

IPMC [JPL using ONRI, Japan & UNM materials] ElectroRheological Fluids (ERF) [ER Fluids Developments Ltd]

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t =1.1 s

Force* Force* Ionic Gel Carbon-Nan0 tubes [T. Hirai, Shinshu University, Japan] [R. Baughman et al, Honeywell, et all

22 Planetary application considered at JPL

Sample handling robotics Extending EAP lowers a robotic arm, while bending EAP fingers operate as a gripper

23 EAP Dust Wiper Baselined in the MUSES-CN Nanorover

d.

24 Computational chemistry

Computational chemistry may lead to material design tools using comprehensive modeling to methodically synthesize effective new EAPs

(NASA-LaRC)

25 EAP Material Characterization

Different methods of characterization are needed for the various types of EM. FU N CTI 0N GENE RATOR

Efforts are underway to develop- a database 4 that allows comparing the properties of EAP with other material-base actuators CCD EAP IEW CAMERA

26 Applications Underway or under consideration Mechanisms Medical Applications - Lenses with controlled configuration - EAP for biological muscle augmentation - Mechanical lock or replacement - Noise reduction - Miniature in-vivo EAP robots for - Flight control surfaces/Jet flow control Diagnostics and microsurgery - Anti G-suit - Catheter steering mechanism Robotics, Toys and Animatronics - Tissues growth engineering - Biologically-inspired robots - Interfacing neuron to electronic devices - Toys and Animatronics Using EAP Human-Machine Interfaces - Active bandage - Haptic interfaces Liquid and Gases Flow Control - Tactile interfaces Controlled Weaving - Orientation indicator - Garment and clothing - Smart flighvdiving suits - Artificial nose MEMS - Active Braille display EM Polymer Sensors & Planetary Applications - cleanedwiper - Shape control of gossamer structures 27 MEMICA (MEchanical -MLrroring using -Controlled stiffness and -Actuators)

28 Platforms for EAP Implementation

Android making facial expressions [G. Pioggia, et al, University of Pisa, Italy]

Robotic hand platform for EAP [G. Whiteley, Sheffield Hallam U., UK]

29 Bibliography Books Bar-Cohen Y. (Ed.), “Electroactive Polymer (EAP) Actuators as Artificial Muscles - Reality, Potential and Challenges,” SPIE Press, http://www.spie.org/bookstore/ ISBN: 08 1944054X (200 1) pp. 1-687.

Proceedings Bar-Cohen Y., (Ed.), ”Electro-ActivePolymer (EAP) Actuators and Devices,” Proceedings of the EAPAD Conf., SPIE’s 6thAnnual International Symposium on Smart Structures and Materials, Vol. 3669, ISBN 0-8194-3 143-5, (1999), pp. 1-414. Zhang Q.M., T. Furukawa, Y. Bar-Cohen, and J. Scheinbeim (Ed.), “ElectroactivePolymers (EAP),” ISBN 1-55899-508-0, MRS Symposium Proceedings, Vol. 600, Warrendale, PA, (1999), pp 1-336. Bar-Cohen Y ., (Ed.), “ElectroactivePolymer Actuators and Devices,” Proceedings of the EAPAD Conf., 7th Smart Structures and Materials Symposium, Vol. 3987, ISBN 0-8194- 3605-4 (2000), pp 1-360. Bar-Cohen Y ., (Ed.), “Electroactive Polymer Actuators and Devices,” Proceedings of the EAPAD Conf., 8thSmart Structures and Materials Symposium, Vol. 4329, ISBN 0-8 194- 4015-9 (2001), pp. 1-524. Websites WW-EAP Webhub: http://ndeaa. jpl.nasa. godnasa-nde/lommas/eap/EAP-web.htm 30 The grand challenge for EAP as ARTIFICIAL MUSCLES

31 SUMMARY Artificial technologies (AI, AM, and others) for making biologically inspired devices and instruments are increasingly being commercialized.

- Autonomous robotics, wireless communication, miniature electronics, effective materials, powerful information technology are some of the critical support technologies that have have emerged and enhanced enormously in recent years.

Materials that resemble human and animals are widely used by movie industry and animatronics and they have been advanced to become highly effective.

Electroactive polymers are human made actuators that are the closest to resemble biological muscle potentially enabling unique robotic capabilities.

Technology has advanced to the level that enables biologically inspired robotic applications.

Science fiction ideas are increasingly becoming technology reality. 32