132 research outputs found
Design and Development of a Soft Robotic Gripper for Fabric Material Handling
Fabric and textile materials are widely used in many industrial applications, especially in automotive, aviation and consumer goods. Currently, there is no semi-automatic or automatic solution for rapid, effective, and reconfigurable pick and place activities for limp, air permeable flexible components in industry. The production of these light-weight flexible textile or composite fiber products highly rely on manual operations, which lead to high production costs, workplace safety issues, and process bottlenecks. As a bio-inspired novel technology, soft robotic grippers provide new opportunities for the automation of fabric handling tasks. In this research, the characteristics of fabric pick and place tasks using the clamping grippers are quantitatively investigated. Experiments on a carbon fiber fabric are performed with a collaborative robot to explore the damage, slippage, draping, and wrinkling during basic pick and place operations. Based on the experimental results, multiple soft robotic gripper configurations are developed, including a compliant glove set that can improve the performance of traditional rigid grippers, an elastomer-based soft gripper, and a linkage-based underactuated gripper. The gripper designs are analyzed and refined based on finite element simulation. Prototypes of the grippers are fabricated using a rapid tooling solution for an overmolding strategy to verify their functionality. Through the research, it is proven feasible to reliably perform flexible fabric handling operations using soft grippers with appropriate toolpath planning. Finite element simulation and additive manufacturing have shown to be useful tools during the gripper design and development procedure, and the methodologies developed and applied in this work should be expanded for more flexible material handling challenges
A Dexterous Tip-extending Robot with Variable-length Shape-locking
Soft, tip-extending "vine" robots offer a unique mode of inspection and
manipulation in highly constrained environments. For practicality, it is
desirable that the distal end of the robot can be manipulated freely, while the
body remains stationary. However, in previous vine robots, either the shape of
the body was fixed after growth with no ability to manipulate the distal end,
or the whole body moved together with the tip. Here, we present a concept for
shape-locking that enables a vine robot to move only its distal tip, while the
body is locked in place. This is achieved using two inextensible, pressurized,
tip-extending, chambers that "grow" along the sides of the robot body,
preserving curvature in the section where they have been deployed. The length
of the locked and free sections can be varied by controlling the extension and
retraction of these chambers. We present models describing this shape-locking
mechanism and workspace of the robot in both free and constrained environments.
We experimentally validate these models, showing an increased dexterous
workspace compared to previous vine robots. Our shape-locking concept allows
improved performance for vine robots, advancing the field of soft robotics for
inspection and manipulation in highly constrained environments.Comment: 7 pages,10 figures. Accepted to IEEE International Conference on
Rootics and Automation (ICRA) 202
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 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
Mechanical Self-Assembly of a Strain-Engineered Flexible Layer: Wrinkling, Rolling, and Twisting
Self-shaping of curved structures, especially those involving flexible thin
layers, has attracted increasing attention because of their broad potential
applications in e.g. nanoelectromechanical/micro-electromechanical systems
(NEMS/MEMS), sensors, artificial skins, stretchable electronics, robotics, and
drug delivery. Here, we provide an overview of recent experimental,
theoretical, and computational studies on the mechanical self-assembly of
strain-engineered thin layers, with an emphasis on systems in which the
competition between bending and stretchingenergy gives rise to a variety
ofdeformations,such as wrinkling, rolling, and twisting. We address the
principle of mechanical instabilities, which is often manifested in wrinkling
or multistability of strain-engineered thin layers. The principles of shape
selection and transition in helical ribbons are also systematically examined.
We hope that a more comprehensive understanding of the mechanical principles
underlying these rich phenomena can foster the development of new techniques
for manufacturing functional three- dimensional structures on demand for a
broad spectrum of engineering applications.Comment: 91 pages, 35 figures, review articl
Significance of designing the filling of an open rapid sand filter when removing impurities from water
Filtration is a mechanical process of squeezing, during which the passage of liquid occurs, in this
paper, specifically water, through a porous layer of material. During that flow, the impurities are
retained within that layer, which is called the filter, and the water is desired quality comes out of
the filtering device. The goal of this work is to demonstrate the importance of dimensioning the
filter itself, so reliably that during the actual filling of the filter, almost all impurities remain in
that layer. There are different types of filters, and also different dimensions for each type. Which
type will be specifically used depends on several factors such as the desired quality of the water
coming out of the filter, the initial state of the water (pollution) coming into the filter, the
amount of water reaching the filter, the speed of the filtration process itself, etc. In this paper,
the importance of dimensioning sand filters, as well as the selection of the filter filling method, is
highlighted
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Mechanics and applications of stretchable serpentine structures
Stretchable structures have been developed for various applications, including expandable coronary stents, deployable sensor networks and stretchable bio-mimetic and bio-integrated electronics. High-performance, stretchable electronics have to utilize high-quality and long-lasting inorganic electronic materials such as silicon, oxide dielectrics and metals, which are intrinsically stiff and often brittle. It is therefore an interdisciplinary challenge to make inorganic electronics stretchable while retaining their electronic functionality. Patterning stiff materials into serpentine-shaped wavy ribbons has become a popular strategy for fabricating stretchable inorganic electronics. However due to a lack of mechanics understanding, design of serpentine structures is still largely empirical, whether for freestanding or substrate supported serpentines. This dissertation systematically investigates the mechanics of serpentine structures with emphasis on the effects of serpentine geometry and substrate stiffness, which involves theoretical analysis, numerical simulation, and experimental validation. Our theory has successfully predicted the stretchability and stiffness of various serpentine shapes and has been applied to the optimization of serpentine designs under practical constraints. We are also the first to point out that not all geometric effects are monotonic and serpentines are not always more stretchable than linear ribbons. To manufacture high quality serpentine ribbons with high throughput and low cost, we have invented a “cut-and-paste” method to fabricate both metallic and ceramic serpentines. As a demonstration of our method, a noninvasive, tattoo-like multifunctional epidermal sensor system has been built for the measurement of electrophysiological signals, skin temperature, skin hydration, and respiratory rate. Engineering of epidermal stretchable antenna for wireless communication is also detailed and rationalized.Mechanical Engineerin
Significance of designing the filling of an open rapid sand filter when removing impurities from water
Filtration is a mechanical process of squeezing, during which the passage of liquid occurs, in this
paper, specifically water, through a porous layer of material. During that flow, the impurities are
retained within that layer, which is called the filter, and the water is desired quality comes out of
the filtering device. The goal of this work is to demonstrate the importance of dimensioning the
filter itself, so reliably that during the actual filling of the filter, almost all impurities remain in
that layer. There are different types of filters, and also different dimensions for each type. Which
type will be specifically used depends on several factors such as the desired quality of the water
coming out of the filter, the initial state of the water (pollution) coming into the filter, the
amount of water reaching the filter, the speed of the filtration process itself, etc. In this paper,
the importance of dimensioning sand filters, as well as the selection of the filter filling method, is
highlighted
Design of a novel long-range inflatable robotic arm: Manufacturing and numerical evaluation of the joints and actuation
The aim of this paper is to present the design of a new long-range robotic arm based on an inflatable structure. Inflatable robotics has potential for improved large payload-to-weight ratios, safe collision, and inspection in areas inaccessible to human beings as in nuclear plants. The robot presented here is intended to operate inspection or maintenance missions in critical installation taking care to not collide with its environment. It is made with innovative inflatable joints and an original actuation system. Prototypes of this inflatable manipulator were constructed using two different manufacturing procedures. Using LS-DYNA nonlinear dynamic finite element modeling we have numerically analyzed the specific geometry and dynamical behavior of the resulting joints. The simulations have given insight into understanding the joint bending process and have revealed guidance for optimizing the conception
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