Soft robots based on dielectric elastomer actuators: a review

Abstract

Conventional robots are mainly made of rigid materials, such as steel and aluminum. Recently there has been a surge in the popularity of soft robots owing to their inherent compliance, strong adaptability and capability to work effectively in unstructured environments. Of the multitude of soft actuation technologies, dielectric elastomer actuators (DEAs), also nicknamed ‘artificial muscles’, exhibit fast response, large deformation and high energy density, and can simply be actuated with electric voltage. In this paper, we will discuss applications of DEAs to soft robots, including robotic grippers, terrestrial robots, underwater robots, aerial robots and humanoid robots. We will survey the state of the art regarding these interesting applications and outline the challenges and perspectives. As we know, there have been extensive studies on dielectric elastomer technology in the aspects of materials, mechanics, design, fabrication and controls. To enable practical applications, efforts are underway to decrease operational voltages, improve reliability, and impart new functionalities. Key challenges include the development of freestanding actuators, untethered operation, smart/electronics free actuators, solid and stretchable electrodes, miniaturization, combination of synergistic actuation technologies to impart novel functionalities, development of effective control strategies, etc. We hope that this review can facilitate and enhance applications of dielectric elastomer technology to soft robots.

Dielectric Elastomer Actuator for Soft Robotics Applications and Challenges

“…This uncertainty must be solved to guarantee a stable actuation system. As of now, methods of increasing the breakdown strength through prestretching, liquid dielectric immersion [158][159][160], or predicting the material's breakdown strength are being researched [160,161].…”

Multi-Trigger Thermo-Electro-Mechanical Soft Actuators under Large Deformations

“…DEAs as a class of actuators can generate strains higher than 100% in response to an electric field [16]. Furthermore, DEAs due to their unique features such as light-weight, high energy density, low cost, silent operation, and compliance are well-suited for artificial muscle applications, underwater robots, flexible displays, as well as in dielectric elastomer oscillators [17][18][19][20][21]. Dielectric elastomer oscillators enable distributed, autonomous signal generation, that can be controlled in a wide range by external signals or mechanical stimuli [22].…”

Simulation and Experiment Study on Deformation Characteristics of the Water Hydraulic Flexible Actuator Used for the Underwater Gripper

“…In addition, the experiment results showed that it took only 0.25 seconds for the gripper to grasp the table tennis ball. All of DEAs can be driven by electrostatic force to meet the needs of artificial muscles [8,9], however they require a rigid frame to prestretch the high elastomer, the preparation process is relatively complex, the reliability of the flexible electrode needs to be further improved, and a higher voltage is needed. Ge et al [10] developed a flexible gripper with preprogramming function by using a variety of new materials and 4D multi-material printing technology.…”