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# Dielectric Elastomer actuator

Smart materials respond to external stimulus like temperature, pressure, pH, electric field, magnetic field etc., by changing one or more of their properties in a controllable manner. Dielectric elastomer (DE) is a type of smart material which produces large strains with the application of voltage. Due to this properties DE can be used as actuators where large strains are required.

The conventional actuators like hydraulic, pneumatic, electro-mechanical actuators are expensive, heavy, complex and have high power consumption which cannot be used in MEMS (micro electro mechanical systems), DIELECTRIC ELASTOMER ACTUATORS (DEA) can be termed as an alternative. Also future robotics applications require devices that are simple, robust and lightweight. For future robotics a suggested solution is binary actuation. Binary actuation can be thought as mechanical analogy for digital electronics. The actuator changes or flips between two states in binary actuation. Commercially DE material is available in form of tape under the brand name of 3M.

## Applications of Dielectric Elastomer

The actuators based on DE are more suitable for MEMS (micro electro-mechanical systems) and for producing large actuation, where traditional actuators based on hydraulic, pneumatic and electro-mechanical might not work [1].

One of the actuation based on DE which is being made is spring-roll actuator. The preparation of spring-roll DEA and its potential applications are discussed in [2],[3].

One of the applications where Dielectric elastomer actuators are used is discussed in [2]. In this an arm wrestling match between a robotic arm powered by DEA and a human arm is discussed. The DEA used in this paper are spring-roll actuators.

The actuators based on DE can be operated in systems that are entirely soft [4] i.e. no rigid object is present in that system. Therefore DEA have the ability to function as actively deformable systems capable of large-scale changes in conformation i.e. shape shifting robotics [4].

Another application of DE is Diamond actuator. The design and the possible applications of diamond actuator are discussed in [5]. The diamond shape provides a uniform stress state during actuator deformation. Therefore the film is loaded uniformly everywhere and thus the entire films mass contribute equally and optimally to work output production [5]. Diamond actuators exploit the large deformation capabilities of elastomer VHB 4905/4910. The use of diamond actuator as a binary actuator is discussed in [5].

#### Reference:

[1] Raj Kumar Sahu, Munshi Imran Hossain, Karali Patra and Shovan Bhaumik, Dielectric elastomers: materials for future actuators", 10th National Conference on Industrial Problems on Machines and Mechanisms (IPRoMM 2010), MNIT, Jaipur (Rajsthan) December 17-18, 2010.
[2] Gabor Kovacs, Patrick Lochmatter and Michael Wissler, An arm wrestling robot driven by dielectric elastomer actuators", Smart Materials and Structures, S306-S317, IOP publishing, 2007.
[3] Rui Zhang, Andreas Kunz, Patrick Lochmatter and Gabor Kovacs, Dielectric Elastomer Spring Roll Actuators for a Portable Force Feedback Device", Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 347-353, USA, 2006.
[4] Michael T. Petralia and Robert J. Wood, Fabrication and analysis of dielectric-elastomer minimum-energy structures for highly-deformable soft robotic systems", The 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems, Taipei, Taiwan, October 18-22, 2010.
[5] Jean-Sebastian Plante, Dielecetric Elastomer Actuators for Binary Robotics and Mechatronics", PhD Thesis, Massachusetts Institute of Technology, 2006 .