Adaptive Texture and Shape Modulation of a Soft Skin from Bio-inspired Coiled Actuators
Abstract
Self-morphing abilities of muscles and soft tissues play a fundamental role in the swimming performance and efficiency of a great variety of underwater living organisms. As an example, cephalopods are able to expose their dermal erectors (i.e., papillae) to match their surroundings and then rapidly retract them to swim away from predators with minimal hydrodynamic drag. Such shape and texture modulation functionalities are extremely attractive for the development of efficient and dexterous underwater vehicles and robots. These topics are highly relevant for the U.S. Navy and scientific progress in the naval research field. The current technologies of shape and texture modulation are mostly based on shape memory materials or pneumatic systems and can only offer a limited number of output shapes/textures (usually one or two). A significant improvement of the state of the art on this topic is truly needed, and the proposed research aims to reduce the gap between biological and synthetic self-morphing systems. The research idea proposed herein aims to develop a soft, lightweight, stretchable, and adaptive device, able to perform high-resolution texture modulation. The device will require low input voltage for actuation (<1V/mm) and it will be able to provide surface roughness in the micronscentimeters range. The high resolution of the texture modulation (in the range of 1 mm) will allow at the same time 3D shape modulation, with a potentially unlimited number of complex target shapes. The inspiration for the proposed device comes from cephalopods. Texture and shape modulation in cephalopods are performed by dermal erector muscles (known as papillae), that contract and push the overlying tissue upward and away from the mantle surface. The proposed research aims to emulate this mechanism by embedding electrically-actuated artificial muscles inside a soft matrix. The artificial muscles consist of twisted and coiled actuators with an initialflat spiral shape. When an electrical input is applied, they change their geometry to a conical shape and push the soft matrix upward. The final length of each actuator can be tailored using a specific electrical input. In this project, scalable manufacturing and assembly techniques will be developed to incorporate the actuators on large areas of the soft matrix and a theoretical model will be proposed to relate the input energy to the density work provided by the device. The ability of the device to regulate the hydrodynamic drag underwater will be also demonstrated. A similar technology will pave the way for the development of wearable smart materials for the artificial camouflage of soldiers, vehicles, and equipment. Moreover, the application of the proposed smart skin on the surface of boats~ hulls could prevent or reduce the hull fouling phenomenon, a well-known problem affecting boats trading in warm water ports. A periodical fast actuation of the embedded artificial muscles could cause fouling agents to become detached or even avoid their deposition.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 25, 2019
- Source ID
- N000141912136
Entities
People
- Caterina Lamuta
Organizations
- Office of Naval Research
- United States Navy
- University of Iowa