Fluidic Fabric Muscle Sheets for Wearable and Soft Robotics

Conformable robotic systems are attractive for applications in which they can be used to actuate structures with large surface areas, to provide forces through wearable garments, or to realize autonomous robotic systems. We present a new family of soft actuators that we refer to as Fluidic Fabric Muscle Sheets (FFMS). They are composite fabric structures that integrate fluidic transmissions based on arrays of elastic tubes. These sheet-like actuators can strain, squeeze, bend, and conform to hard or soft objects of arbitrary shapes or sizes, including the human body. We show how to design and fabricate FFMS actuators via facile apparel engineering methods, including computerized sewing techniques. Together, these determine the distributions of stresses and strains that can be generated by the FFMS. We present a simple mathematical model that proves effective for predicting their performance. FFMS can operate at frequencies of 5 Hertz or more, achieve engineering strains exceeding 100%, and exert forces greater than 115 times their own weight. They can be safely used in intimate contact with the human body even when delivering stresses exceeding 10$^\text{6}$ Pascals. We demonstrate their versatility for actuating a variety of bodies or structures, and in configurations that perform multi-axis actuation, including bending and shape change. As we also show, FFMS can be used to exert forces on body tissues for wearable and biomedical applications. We demonstrate several potential use cases, including a miniature steerable robot, a glove for grasp assistance, garments for applying compression to the extremities, and devices for actuating small body regions or tissues via localized skin stretch.Comment: 32 pages, 10 figure

Analysis of the motion of soft animals (Gastropods)

Terrestrial gastropods crawl by means of a train of pedal waves produced by the contraction and relaxation of the muscles in their ventral foot. The areas between two consecutive pedal waves are known as interwave regions and they remain stationary to the substrate while crawling happens. Adhesive locomotion of terrestrial gastropods involves the secretion of a non-Newtonian yield-stress mucus that communicates the stress of the ventral foot to the ground. This project puts forward a theoretical model in which the only source of adhesive locomotion is the geometry of the pedal waves, rather than the rheological properties of the mucus. The model is based on the proven existence of small vertical displacements in the ventral surface of terrestrial gastropods and provides a region where any combination of values for the pedal wavelength and the lag between the horizontal and vertical pedal waves allows locomotion to happen. In order to validate this theoretical model, the images taken during a set of experiments performed by Universidad Carlos III in collaboration with the University of California and Stanford University in 2010, have been analyzed through a Digital Particle Image Velocimetry technique. In summary, the aim of this project is to answer the following question: can a biomimetic robot crawl using a Newtonian mucus? The results show that for three out of the four experiments analyzed, the values obtained fit in the region proposed by the model. Even if three experiments are not conclusive enough to validate the calculations, this project opens the doors to the development of biomimetic robots capable of mimicking terrestrial gastropod’s adhesive locomotion using substances exhibiting a Newtonian behavior.Ingeniería Biomédic