The armwrestling match between an EAP actuated robotic arm and a human

Description: armwrestlingHigh Resolution image of the armwrestling match graphics (TIFF (10.1 MB))

In 1999, Dr. Yoseph Bar-Cohen, JPL, posed a scientific challenge to the worldwide research and engineering community to develop a robotic arm that is actuated by artificial muscles (moniker for electroactive polymers (EAP)) to win a wrestling match against a human opponent.

Description: W:\www\nasa-nde\lommas\eap\blueball.gifPromote advances towards making EAP actuators that are superior to the performance of human muscles
Description: W:\www\nasa-nde\lommas\eap\blueball.gifIncrease the worldwide visibility and recognition of EAP materials
Description: W:\www\nasa-nde\lommas\eap\blueball.gifAttract interest among potential sponsors and users
Description: W:\www\nasa-nde\lommas\eap\blueball.gifLead to general public awareness since it is hoped that they will be the end users and beneficiaries in many areas including medical, commercial, etc.
Description: W:\www\nasa-nde\lommas\eap\blueball.gifInitially, the challenge is to win against a human (any human) using a simple shape arm and this recent competition was against a high school student who represented the human side.
Description: W:\www\nasa-nde\lommas\eap\blueball.gifThe ultimate goal is to win against the strongest human using as close resemblance of the human arm as possible.

Developing a winning arm will require advances in the EAP field infrastructure including: Analytical tools, materials science, electromechanical tools, sensors, control, feedback, rapid response, larger actuation forces, actuator scalability (use of small and large ones), enhanced actuation efficiency, etc.

Rules for the EAP Armwrestling Contest as of 2008

The intent of the armwrestling contest is to challenge and encourage advances in development of EAP materials.  As progress is being in the field of EAP "the bar will be raised" on the challenge so that eventually the competing arms will need to act very similar to a human arm.  Therefore, in future wrestling contests during the SPIE’s EAP-in-Action Session only the following definition for EAP will be accepted for the actuators that will drive the participating wrestling arms.

EAP is only a material or combination of materials that is primarily composed of a polymer that convert(s) electric to mechanical energy for which the presence of the polymer is a key to the generated force and displacement.  The response should be reversible, namely, the actuated robotic arm should be able to use the same actuation mechanism to return to the starting position.

  • No actuators that involve input of gases, liquids or chemicals will be accepted (e.g., actuated by pneumatic, hydraulic, or use of acid/base).
  • An exception will be given to the use of polymers that are indirectly driven by electric current or field but they will need to be identified as being so.  For example, thermally actuated polymer materials will be accepted if they use embedded electrical heating elements.


2006 - The EAP Armwrestling Contest

The 2006 competition was held during the SPIE’s EAPAD Conf. on Feb. 27, 2006 at 5:00 PM and involved measuring the arms capability and comparing the data of the competing arms.  Each competing EAP actuated arm pulled on a cable that has a force gauge on its other end and was supported by the wrestling fixture (see Figure 1). A schematic diagram with the fixture dimensions is shown on the right of Figure 1.  This fixture was strapped to the table (see Figure 2) and the EAP actuated arms were tested for speed and pulling force capability.  To simulate a wrestling action a 0.5-kg weight that was mounted on the cable had to be lifted to the top of the fixture (shown in the photo – see Figure 1) and the time to reach the top was measured.  In case the arms could not lift the weight to the full height of 9.78” an adjustable base was used to place the weight at a higher starting level.



FIGURE 1: Photos and drawing of the fixture that was used to test the force and speed of the EAP actuated robotic arms


FIGURE 2: An example of the table that will be used to support the test fixture.  The table dimensions are:  Length: 244 cm (96") x Width: 76 cm (30") x Height: 76 cm (30") and Thickness: 2.5 cm (1"). 



Upon pulling on the cable the time was gauged to determine the speed and once the weight reached the top, the cable was stretched and the force was measured by the gauge.  To establish a baseline for performance comparison, Panna Felsen’s capability was the first to be measured and then the three participating robotic arms were tested.  The rules of the contest are on  The results of the contest this year were as follows (the participants are listed below the table):



Lifted height

Force (lbf)

Speed (in/sec)


Panna Felsen





VT - Eng. Sci. & Mech. (lead Cotton/ Josh)    

~8.78" (started from bottom level)





ERI (Shahinpoor)

~3.28"  (started from 6” height)





VT - Mech. Eng. (lead Barbar/Jaime)

Upon activation actuators failure occurred



1.      Environmental Robots Incorporated (ERI), Albuquerque, New Mexico, USA, under the lead of Mohsen Shahinpoor.  ERI used its EWA-3 wrestling robotic arm that was actuated by polymeric muscle consisting of a proprietary blend of  IPMC's and SMP's. It is electrically activated and its actuation mechanism is based on contraction and expansion.



2.      Virginia Tech, USA: : Senior Students under the lead of Barbar Akle, Nakhiah Goulbourne and Don Leo at the Mechanical Engineering Department, including Jaime Schmieg (Team Leader), Dave Griffiths, Heath Folmsbee, Anthony Ribaudo, Erin Lucas, Charley Sessoms and Josh Leong.  This group used dielectric elastomer EAP for the actuation of the arm.




3.      Virginia Tech, USA: : Senior Students under the lead of John Cotton at the Department of Engineering Science and Mechanics, including Joseph Ash, Matthew Degner, Sara Jasin, Jordan Milford, Kevin Nash, Josh Oechslin (Team Leader), Catherine Ross, and Brandon Shue.  This arm was based on the same mechanism that was used by the VT students in 2005.





The wrestling fixture (Figure 1) was drawn by Ayoola K Olorunsola, JPL, constructed by Qibing Pie and his students from UCLA, and finalized by Chris Jones, JPL.


Considering participation in the 2007 armwrestling contest

1.      DSO National Laboratories, Defense Medical & Environmental Research Institute, Centre for Human Performance, Singapore, under the lead of Kelvin Hau-Kong Chan, Chan Hau Kong, and Lee Vee Sin Peter

2.      Swiss Federal Laboratories for Materials Testing and Research, EMPA, Dubendorf, Switzerland

2005 - The EAP/Human Armwrestling Match

The first competition was held on March 7, 2005 at 5:00 PM in San Diego, California and the 17-year old student human opponent won against all the three robotic arms that participated. These arms were made by:
1. Environmental Robots Incorporated (ERI), Albuquerque, New Mexico, USA.
2. Swiss Federal Laboratories for Materials Testing and Research, EMPA, Dubendorf, Switzerland
3. Virginia Tech - Steven Deso, Stephen Ros, Noah P. Papas, Senior Students in the Engineering Science and Mechanics Dept.

The longest to hold against the student has been the arm from ERI and it lasted for 26-seconds. To get a prospective to this major milestone for the field of EAP one may want to be aware that the first flight of the Wright Brothers before over hundred years lasted only 12-seconds.

The following photos of the three arms where taken during the competition:



Description: ChampionsAlso, a video of the competition is available on the Discovery channel's Daily Planet, March 15, 2005.

Current status
Description: W:\www\nasa-nde\lommas\eap\blueball.gifThe first Armwrestling Match of EAP Robotic Arm against Human (AMERAH) was held on March 7, 2005 at 5:00 PM during the International Society for Optical Engineering (SPIE) Annual International EAPAD (EAP Actuators & Devices) Conference.
Description: W:\www\nasa-nde\lommas\eap\blueball.gifThe 1st AMERAH was coordinated with the United States ArmSports.
Description: W:\www\nasa-nde\lommas\eap\blueball.gifOn March 15, 2004, John Brzenk (the World Wrestling Champion per Guinness Book of Records), John Woolsey (ABC Wide World of Sports Wrist-wrestling Champion) and Harold Ryden (California State Champion) attended the EAP-in-Action Session and they were introduced to the EAPAD Conference attendees to give them an idea about the toughness of this challenge. These Champions participation was arranged thanks to Mr. Marvin Alex Cohen, who was the Technical Advisor to Warner Bros Motion Pictures in the movie "Over The Top" that is stared by Sylvester Stallone. Mr. Cohen participated under the banner "Fox Sports Net".

RULES for the Armwrestling competition in 2005 - A website was formed for the AMERAH Armwrestling Competition Rules.

The Human Opponent

The human opponent was Panna Felsen, who is a straight A high school student from the San Diego School District.

The Table for the Armwrestling Competition

A standard Armwrestling table was brought to the competition by Dave Devoto who is a pioneer and leading representative of the United States ArmSports

AMERAH Competition Judges

The following are the members of the AMERAH organization Committee and the Competition Judges.
CHAIR: Yoseph Bar-Cohen, Senior Research Scientist and Group Leader, JPL's NDEAA Lab.
Description: W:\www\nasa-nde\lommas\eap\blueball.gifDave Devoto - Pioneer and leading representative of the United States ArmSports
Description: W:\www\nasa-nde\lommas\eap\blueball.gifRichard Landon - from Stan Winston Studio (SWS designed and created the robots and makeups for Spielbergs movie AI). Mr. Landon wrote chapter 6 in the Biologically Inspired Intelligent Robots book
Description: W:\www\nasa-nde\lommas\eap\blueball.gifJohn D. Madden -Univ. of British Columbia (Canada), Co-chair of the 2005 EAPAD Conference
Description: W:\www\nasa-nde\lommas\eap\blueball.gifJoanne Pransky - World's First Robotic Psychiatrist
Description: W:\www\nasa-nde\lommas\eap\blueball.gifBrian Thomas - Senior Event Manager, SPIE-- The International Society for Optical Engineering

The Armwrestling - Support Organizations

Description: W:\www\nasa-nde\lommas\eap\blueball.gifThe hosting and logistics of the competition was done by SPIE as part of the EAP-in-Action Session of the annual EAPAD Conference, San Diego, CA, USA
Description: W:\www\nasa-nde\lommas\eap\blueball.gifThe United States ArmSports is an umbrella organization representing armwrestlers, armwrestling organizations and tournaments in the United States of America and around the World. ArmSports is a relatively new term encompassing the ancient sport known as Armwrestling, Arm Wrestling, Arm-Wrestling, Wrist-wrestling, Indian wrestling etc. United States ArmSports is the exclusive American member of the World Armwrestling Federation (WAF).

To return to:
Description: W:\www\nasa-nde\lommas\eap\blueball.gifNDEAA Webhub or to the
Description: W:\www\nasa-nde\lommas\eap\blueball.gifWorldWide Electroactive Polymers (WW-EAP) Webhub