An arm wrestling robot driven by dielectric elastomer actuators

The first arm wrestling match between a human arm and a robotic arm driven by electroactive polymers (EAP) was held at the EAPAD conference in 2005. The primary objective was to demonstrate the potential of the EAP actuator technology for applications in the field of robotics and bioengineering. The Swiss Federal Laboratories for Materials Testing and Research (Empa) was one of the three organizations participating in this competition. The robot presented by Empa was driven by a system of rolled dielectric elastomer (DE) actuators. Based on the calculated stress condition in the rolled actuator, a low number of pre-strained DE film wrappings were found to be preferential for achieving the best actuator performance. Because of the limited space inside the robot body, more than 250 rolled actuators with small diameters were arranged in two groups according to the human agonist–antagonist muscle configuration in order to achieve an arm-like bidirectional rotation movement. The robot was powered by a computer-controlled high voltage amplifier. The rotary motion of the arm was activated and deactivated electrically by corresponding actuator groups. The entire development process of the robot is presented in this paper where the design of the DE actuators is of primary interest. Although the robot lost the arm wrestling contest against the human opponent, the DE actuators have demonstrated very promising performance as artificial muscles. The scientific knowledge gained during the development process of the robot has pointed out the challenges to be addressed for future improvement in the performance of rolled dielectric elastomer actuators.

[1]  Steve Nadis,et al.  The cells that rule the seas. , 2003, Scientific American.

[2]  Q. Pei,et al.  Electroelastomer rolls and their application for biomimetic walking robots , 2003 .

[3]  D. De Rossi,et al.  Electromechanical characterisation of dielectric elastomer planar actuators: comparative evaluation of different electrode materials and different counterloads , 2003 .

[4]  R. Pelrine,et al.  DESIGN AND PERFORMANCE OF AN ELECTROSTRICTIVE-POLYMER-FILM ACOUSTIC ACTUATOR , 1998 .

[5]  Ron Pelrine,et al.  Dielectric elastomer artificial muscle actuators: toward biomimetic motion , 2002, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[6]  Ron Pelrine,et al.  New high-performance electroelastomer based on interpenetrating polymer networks , 2006, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[7]  R. Pelrine,et al.  Electrostriction of polymer dielectrics with compliant electrodes as a means of actuation , 1998 .

[8]  Q. Pei,et al.  High-speed electrically actuated elastomers with strain greater than 100% , 2000, Science.

[9]  Patrick E. Phelan,et al.  Investigation of electrostrictive polymers as actuators for mesoscale devices , 2004 .

[10]  Yoseph Bar-Cohen,et al.  Electroactive Polymer (EAP) Actuators as Artificial Muscles: Reality, Potential, and Challenges, Second Edition , 2004 .

[11]  Ron Pelrine,et al.  Mechatronic system of dielectric elastomer actuators addressed by thin film photoconductors on plastic , 2004 .

[12]  Ron Pelrine,et al.  Multiple-degrees-of-freedom electroelastomer roll actuators , 2004 .

[13]  Peter Sommer-Larsen,et al.  Performance of dielectric elastomer actuators and materials , 2002, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[14]  R. Pelrine,et al.  Actuation Response of Polyacrylate Dielectric Elastomers , 2003 .