Towards a deployable satellite gripper based on multisegment dielectric elastomer minimum energy structures

Abstract

Dielectric Elastomer Actuators (DEAs) are an emerging actuation technology which are inherent lightweight and compliant in nature, enabling the development of unique and versatile devices, such as the Dielectric Elastomer Minimum Energy Structure (DEMES). We present the development of a multisegment DEMES actuator for use in a deployable microsatellite gripper. The satellite, called CleanSpace One, will demonstrate active debris removal (ADR) in space using a small cost effective system. The inherent flexibility and lightweight nature of the DEMES actuator enables space efficient storage (e.g. in a rolled configuration) of the gripper prior to deployment. Multisegment DEMES have multiple open sections and are an effective way of amplifying bending deformation. We present the evolution of our DEMES actuator design from initial concepts up until the final design, describing briefly the trade-offs associated with each method. We describe the optimization of our chosen design concept and characterize this design in terms on bending angle as a function of input voltage and gripping force. Prior to the characterization the actuator was stored and subsequently deployed from a rolled state, a capability made possible thanks to the fabrication methodology and materials used. A tip angle change of approximately 60º and a gripping force of 0.8 mN (for small deflections from the actuator tip) were achieved. The prototype actuators (approximately 10 cm in length) weigh a maximum of 0.65 g and are robust and mechanically resilient, demonstrating over 80,000 activation cycles.

Dielectric Elastomer Based “Grippers” for Soft Robotics

“…Previous approaches use prestretched dielectric elastomers which require relatively bulky and stiff frames to maintain structural integrity, causing increase in weight and more importantly reducing the overall flexibility or soft nature of the system. [10,11] The basis of dielectric elastomer actuation is well established and can be summarized as follows. [12] When a voltage is applied to a sheet of elastomer, with thin electrodes on either side, the elastomer becomes thinner in response to the Maxwell stress derived from the electrostatic attraction between the charges on the opposing electrodes.…”

Dielectric Elastomer Actuator for Soft Robotics Applications and Challenges

“…To enhance the practicality of the DEMES gripper, a new design with multi-segment DEMES was presented in 2014 [86,87]. As shown in Figure 7c, this design consists of repetitive DEMES segments with characteristics of a high aspect ratio.…”

Analysis, experiment, and correlation of a petal-shaped actuator based on dielectric elastomer minimum-energy structures

“…DEMES have attracted intensive attention due to its ease of fabrication, intrinsic combination of soft and hard materials, and diversity of configurations that can be realized by exploring mechanical buckling. Typical DEMES devices include gripper [22], oscillator [23], compliant and bistable mechanisms [24,25], and soft robot [26].…”