25 research outputs found
Investigations and simulations of magneto elastomer materials (MSE) influenced by static magnetic fields for soft robotics applications
Magneto-sensitive Elastomere sind Verbundwerkstoffe, die hauptsächlich aus einer Elastomermatrix bestehen, in der magnetischen Partikeln dispergiert sind. Ein ins magnetosensitive Elastomer eingreifende Magnetfeld bewirkt Änderungen der Eigenschaften dieses Materials. Diese Qualität macht die MSE zu einer Option mit hohem Potenzial für Soft Robotics- Anwendungen. Für die Realisierung dieser Masterarbeit wurden MSE-Proben aus einer Elastomermatrix, Silikonöl und Carbonyleisenpartikeln hergestellt.
Tests wurden durchgeführt, um Verbesserungen zu entwickeln, die sich auf Soft-Robot- Anwendungen konzentrieren, insbesondere bei Endeffektoren. In dieser Arbeit wurden die
Eigenschaften von magneto-sensitive Elastomerproben in Abwesenheit und Gegenwart eines Magnetfeldes experimentell untersucht. Die untersuchungen wurden mittels eines Magnetfeldes realisiert, dass durch einen Permanentmagneten induziert wurde. Um die Intensität zu varriieren, wurde der Permanetmagent in unterschiedlichen Abständen zur Probe positioniert. Die experimentell erhaltenen Ergebnisse wurden verwendet, um den Einfluss der MF über der MSE zu verstehen und ein geeignetes Materialmodell unter Verwendung der Finite-Elemente-Methode zu entwickeln.Magneto-sensitive elastomers are composite materials made mainly of an elastomer matrix, in which magnetic particles are dispersed. A magnetic field applied in the magneto sensitive elastomers achieves changes in the properties of this material. This quality turns the magneto-sensitive elastomers in an option with high potential in soft robotics applications. In the present thesis, samples of magneto-sensitive elastomers containing an elastomeric matrix, silicone oil and carbonyl iron particles were produced.
Tests were performed in order to develop improvements focused on soft robotic applications, particularly in end effectors. In this thesis, the properties of magneto-sensitive elastomers samples have been experimentally studied in the absence and presence of a magnetic field. The magnetic field was induced by a permanent magnet that was moved at different distances from the sample to change the intensity of the magnetic field. The results obtained by experiments were used to understand the influence of the magnetic field on the magneto-sensitive elastomer and to obtain a suitable material model using finite element method.Los elastómeros magneto-sensibles son materiales compuestos hechos principalmente de una matriz de elastómero, en la que se dispersan las partículas magnéticas. Un campo magnético aplicado en los elastómeros magneto-sensibles logra cambios en las propiedades de este material. Esta cualidad convierte los elastómeros magneto-sensibles en una opción con alto potencial en aplicaciones de robótica blanda. En la presente tesis, se fabricaron muestras de elastómeros magneto-sensibles que contenían una matriz elastomérica, aceite de silicona y partículas de hierro carbonilo.
Se realizaron pruebas para desarrollar mejoras enfocadas en aplicaciones de robótica blanda, particularmente en efectores finales. En esta tesis, las propiedades de las muestras de elastómeros magneto-sensibles han sido estudiadas experimentalmente en ausencia y presencia de un campo magnético. El campo magnético fue inducido por un imán permanente que se movió a diferentes distancias de la muestra para cambiar la intensidad de este campo magnético. Los resultados obtenidos por experimentos se utilizaron para comprender la influencia del campo magnético en el elastómero magneto sensible y para obtener un modelo de material adecuado utilizando el método de elementos finitos.Tesi
Development of microstructures for application on a controllable bioinspired adhesive mechanism for gripping system in pick-n-place task
Dissertação de mestrado integrado em Engenharia MecânicaA natureza oferece uma variedade de ideias para uma adesão transitória e reversível a
diferentes substratos. Até agora, os soft dry adhesives (SDAs) bioinspirados mais estudados
são superfícies com matrizes de micropilares. A inspiração veio de espécies terrestres, como
as osgas, cujas almofadas dos pés são cobertas por intrincadas fibrilhas que permitem uma
forte adesão (que se deve a forças intermoleculares) bem como uma fácil libertação.
Um dos objetivos atuais dos esforços da investigação é transferir a solução da natureza
para estruturas artificiais que possam um dia encontrar aplicações tecnológicas. Este trabalho
visa replicar os comportamentos de agarra e libertação das osgas, utilizando como base as
suas estruturas fibrilares pegajosas. Para este objetivo, serão utilizadas várias técnicas de
fabrico e ensaios experimentais para determinar o melhor protocolo para a criação de
microestruturas. Foram estudados micropilares cilíndricos lisos e micropilares com forma de
cogumelo, tendo sido escolhidos estes últimos dado que aderem melhor aos substratos lisos
em comparação com pilares cilíndricos.
O presente trabalho começou por delinear o estado de arte, no qual se investiga o
desenvolvimento de SDAs bioinspirados e as suas qualidades adesivas. Além disso, também
foram abordados os fundamentos de adesão fibrilar. Prosseguiu-se para o desenvolvimento
de amostras em polidimetilsiloxano (PDMS) com o objetivo de caracterizar este material num
equipamento de ensaio universal (UTM).
Neste trabalho foram examinadas várias técnicas de microfabricação. Tendo em
consideração a dimensão das micropartículas utilizadas, foram produzidas microestruturas
utilizando uma metodologia de baixo custo. Foram utilizados e testados vários tipos de
métodos para fabricar os moldes, ou seja, para produzir pilares cilíndricos lisos foi utilizada
fresagem e para produzir micropilares em forma de cogumelo foi utilizada impressão 3D.
Devido à sua forma, os micropilares em forma de cogumelo requerem uma dupla moldagem,
com um molde intermediário constituído por um material altamente flexível.
Finalmente, com o auxílio do UTM para realizar testes de aderência, foi avaliada a
eficiência das microestruturas.Nature offers a variety of ideas for transient and reversible adhesion to different
substrates. Geckos and insects use hairy structures whose adhesion is due to intermolecular
forces. So far, the most widely studied SDAs are surfaces with arrays of micropillars. The
inspiration came from terrestrial species including lizards and geckos whose toe pads are
covered by intricate fibrils that enable strong attachment as well as easy release.
The current goal of research and development efforts is to transfer nature's solution
into artificial structures that might someday be applied in different technologies. Hence, this
work aims to replicate the grasping and releasing behaviors of geckos using their fibrillar sticky
structures as a basis. In order to achieve this goal, different kinds of designs, fabrications, and
testing will be used to determine the best protocol for creating microstructures. Smooth
cylindrical and mushroom-shaped micropillars were studied. The latter were chosen because
they adhere to smooth substrates better than cylindrical micropillars.
This work began by outlining the state of the art on the development of soft dry
adhesives (SDAs) with natural inspiration and an examination of their dry adhesive properties.
Additionally, the fundamentals of fibrillar adhesion were also covered. The work then
proceeded to the development of polydimethylsiloxane (PDMS) specimens with the goal of
characterizing this material in a universal testing machine (UTM).
A number of microfabrication techniques were examined. Based on the size of the
employed microparticles, microstructures were produced applying a low-cost method.
Different methods were employed depending on the shape of the molds, i. e., to produce
cylindrical flat pillars, it was used a CNC milling machine whereas to produce mushroom
shaped micropillars, it was used 3D printing. Due to their design, the micropillars with the
mushroom shape required double molding with an intermediary mold made of a highly
flexible material.
Finally, using the UTM to perform adhesion tests, the efficiency of the microstructure
was evaluated
Design, Actuation, and Functionalization of Untethered Soft Magnetic Robots with Life-Like Motions: A Review
Soft robots have demonstrated superior flexibility and functionality than
conventional rigid robots. These versatile devices can respond to a wide range
of external stimuli (including light, magnetic field, heat, electric field,
etc.), and can perform sophisticated tasks. Notably, soft magnetic robots
exhibit unparalleled advantages among numerous soft robots (such as untethered
control, rapid response, and high safety), and have made remarkable progress in
small-scale manipulation tasks and biomedical applications. Despite the
promising potential, soft magnetic robots are still in their infancy and
require significant advancements in terms of fabrication, design principles,
and functional development to be viable for real-world applications. Recent
progress shows that bionics can serve as an effective tool for developing soft
robots. In light of this, the review is presented with two main goals: (i)
exploring how innovative bioinspired strategies can revolutionize the design
and actuation of soft magnetic robots to realize various life-like motions;
(ii) examining how these bionic systems could benefit practical applications in
small-scale solid/liquid manipulation and therapeutic/diagnostic-related
biomedical fields
Magnetic Hybrid-Materials
Externally tunable properties allow for new applications of suspensions of micro- and nanoparticles in sensors and actuators in technical and medical applications. By means of easy to generate and control magnetic fields, fluids inside of matrices are studied. This monnograph delivers the latest insigths into multi-scale modelling, manufacturing and application of those magnetic hybrid materials
Objekt-Manipulation und Steuerung der Greifkraft durch Verwendung von Taktilen Sensoren
This dissertation describes a new type of tactile sensor and an improved version of the dynamic tactile sensing approach that can provide a regularly updated and accurate estimate of minimum applied forces for use in the control of gripper manipulation. The pre-slip sensing algorithm is proposed and implemented into two-finger robot gripper. An algorithm that can discriminate between types of contact surface and recognize objects at the contact stage is also proposed. A technique for recognizing objects using tactile sensor arrays, and a method based on the quadric surface parameter for classifying grasped objects is described. Tactile arrays can recognize surface types on contact, making it possible for a tactile system to recognize translation, rotation, and scaling of an object independently.Diese Dissertation beschreibt eine neue Art von taktilen Sensoren und einen verbesserten Ansatz zur dynamischen Erfassung von taktilen daten, der in regelmäßigen Zeitabständen eine genaue Bewertung der minimalen Greifkraft liefert, die zur Steuerung des Greifers nötig ist. Ein Berechnungsverfahren zur Voraussage des Schlupfs, das in einen Zwei-Finger-Greifarm eines Roboters eingebaut wurde, wird vorgestellt. Auch ein Algorithmus zur Unterscheidung von verschiedenen Oberflächenarten und zur Erkennung von Objektformen bei der Berührung wird vorgestellt. Ein Verfahren zur Objekterkennung mit Hilfe einer Matrix aus taktilen Sensoren und eine Methode zur Klassifikation ergriffener Objekte, basierend auf den Daten einer rechteckigen Oberfläche, werden beschrieben. Mit Hilfe dieser Matrix können unter schiedliche Arten von Oberflächen bei Berührung erkannt werden, was es für das Tastsystem möglich macht, Verschiebung, Drehung und Größe eines Objektes unabhängig voneinander zu erkennen
Lateral bending liquid crystal elastomer beams for microactuators and microgrippers
With the rapid development of microsystems in the last few decades, there is a
requirement for high precision tools for micromanipulation and transportation of micro-objects, such as microgrippers, for applications in microassembly, microrobotics, life
sciences and biomedicine. Polymer based microgrippers and microrobots executing
various tasks have been of significant interest as an alternative to the traditional silicon
and metal based counterparts due to the advantages of low cost fabrication, low
actuation temperature, biocompatibility, and sensitivity to various stimuli. The
exceptional actuation properties of liquid crystal elastomers (LCE) have made these
materials highly attractive for various emerging applications in the last two decades.
Large programmable deformations and the benefits offered by the elastic, thermal and
optical properties of LCEs are suitable for implementing stimuli-responsive
microgrippers as well as various biomimetic motion in soft robots.
In this thesis, a method and the associated processes for fabrication and molecular
alignment in LCE were developed, which enabled new functionality and improved
performance of the LCE based microactuators and microgrippers, providing controlled
response by thermal and remote photothermal actuation, and allowing easy integration
of the LCE end-effectors into robotic systems for automated operation. Lateral bending
actuation has been demonstrated in LCE microbeams of 900 µm of length and 40 µm of
thickness, owing to the new monolithic micromolding technique using vertical patterned
walls for alignment. The effects of parameters such as the beam width, the size of the
microgrooves, and the surface treatment method on the behavior of the microactuators
were studied; the internal alignment pattern of liquid crystals in the structure was
investigated by different microscopy methods. An efficient method for finite element
modeling of the bending LCE actuators was developed and experimentally verified,
based on the gradient of equivalent thermal expansion in the multi-layer structure,
which was able to predict the bending behavior of the actuators in a large range of
thicknesses as well as rolling behavior of the actuators of tapered thickness. The novel
LCE microgripper with in-plane operation showed efficient thermal and photothermal
actuation, achieving the gripping stroke of 64 µm under the light intensity of 239
mW/cm2
for the gripper length of 900 µm, which is more efficient than the typical SU-8
polymer based microgrippers of the same dimensions. The LCE gripper was
successfully demonstrated for the application in manipulation of the objects of tens to
hundreds of micrometers in size. Therefore, the novel LCE microgripper bridges the gap in the LCE-based gripper technologies for typical object size in applications for
systems microassembly, biological and cell micromanipulation. The lateral bending
functionality enabled by the proposed method expands design opportunities for thermal
and photothermal LCE microactuators, providing an effective route toward realization
of new modes of gripping, locomotion, and cargo transportation in soft microrobotics
and micromanipulation
Magnetic Hybrid-Materials
Externally tunable properties allow for new applications of suspensions of micro- and nanoparticles in sensors and actuators in technical and medical applications. By means of easy to generate and control magnetic fields, fluids inside of matrices are studied. This monnograph delivers the latest insigths into multi-scale modelling, manufacturing and application of those magnetic hybrid materials
Recommended from our members
Soft pneumatic actuators: a review of design, fabrication, modeling, sensing, control and applications
Soft robotics is a rapidly evolving field where robots are fabricated using highly deformable materials and usually follow a bioinspired design. Their high dexterity and safety make them ideal for applications such as gripping, locomotion, and biomedical devices, where the environment is highly dynamic and sensitive to physical interaction. Pneumatic actuation remains the dominant technology in soft robotics due to its low cost and mass, fast response time, and easy implementation. Given the significant number of publications in soft robotics over recent years, newcomers and even established researchers may have difficulty assessing the state of the art. To address this issue, this article summarizes the development of soft pneumatic actuators and robots up until the date of publication. The scope of this article includes the design, modeling, fabrication, actuation, characterization, sensing, control, and applications of soft robotic devices. In addition to a historical overview, there is a special emphasis on recent advances such as novel designs, differential simulators, analytical and numerical modeling methods, topology optimization, data-driven modeling and control methods, hardware control boards, and nonlinear estimation and control techniques. Finally, the capabilities and limitations of soft pneumatic actuators and robots are discussed and directions for future research are identified
Advanced Mobile Robotics: Volume 3
Mobile robotics is a challenging field with great potential. It covers disciplines including electrical engineering, mechanical engineering, computer science, cognitive science, and social science. It is essential to the design of automated robots, in combination with artificial intelligence, vision, and sensor technologies. Mobile robots are widely used for surveillance, guidance, transportation and entertainment tasks, as well as medical applications. This Special Issue intends to concentrate on recent developments concerning mobile robots and the research surrounding them to enhance studies on the fundamental problems observed in the robots. Various multidisciplinary approaches and integrative contributions including navigation, learning and adaptation, networked system, biologically inspired robots and cognitive methods are welcome contributions to this Special Issue, both from a research and an application perspective