1,603 research outputs found

    Performance enhancement of the soft robotic segment for a trunk-like arm

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    Introduction: Trunk-like continuum robots have wide applications in manipulation and locomotion. In particular, trunk-like soft arms exhibit high dexterity and adaptability very similar to the creatures of the natural world. However, owing to the continuum and soft bodies, their performance in payload and spatial movements is limited.Methods: In this paper, we investigate the influence of key design parameters on robotic performance. It is verified that a larger workspace, lateral stiffness, payload, and bending moment could be achieved with adjustments to soft materials’ hardness, the height of module segments, and arrayed radius of actuators.Results: Especially, a 55% increase in arrayed radius would enhance the lateral stiffness by 25% and a bending moment by 55%. An 80% increase in segment height would enlarge 112% of the elongation range and 70 % of the bending range. Around 200% and 150% increments in the segment’s lateral stiffness and payload forces, respectively, could be obtained by tuning the hardness of soft materials. These relations enable the design customization of trunk-like soft arms, in which this tapering structure ensures stability via the stocky base for an impact reduction of 50% compared to that of the tip and ensures dexterity of the long tip for a relatively larger bending range of over 400% compared to that of the base.Discussion: The complete methodology of the design concept, analytical models, simulation, and experiments is developed to offer comprehensive guidelines for trunk-like soft robotic design and enable high performance in robotic manipulation

    Surgical Subtask Automation for Intraluminal Procedures using Deep Reinforcement Learning

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    Intraluminal procedures have opened up a new sub-field of minimally invasive surgery that use flexible instruments to navigate through complex luminal structures of the body, resulting in reduced invasiveness and improved patient benefits. One of the major challenges in this field is the accurate and precise control of the instrument inside the human body. Robotics has emerged as a promising solution to this problem. However, to achieve successful robotic intraluminal interventions, the control of the instrument needs to be automated to a large extent. The thesis first examines the state-of-the-art in intraluminal surgical robotics and identifies the key challenges in this field, which include the need for safe and effective tool manipulation, and the ability to adapt to unexpected changes in the luminal environment. To address these challenges, the thesis proposes several levels of autonomy that enable the robotic system to perform individual subtasks autonomously, while still allowing the surgeon to retain overall control of the procedure. The approach facilitates the development of specialized algorithms such as Deep Reinforcement Learning (DRL) for subtasks like navigation and tissue manipulation to produce robust surgical gestures. Additionally, the thesis proposes a safety framework that provides formal guarantees to prevent risky actions. The presented approaches are evaluated through a series of experiments using simulation and robotic platforms. The experiments demonstrate that subtask automation can improve the accuracy and efficiency of tool positioning and tissue manipulation, while also reducing the cognitive load on the surgeon. The results of this research have the potential to improve the reliability and safety of intraluminal surgical interventions, ultimately leading to better outcomes for patients and surgeons

    Electronic Devices for the Combination of Electrically Controlled Drug Release, Electrostimulation, and Optogenetic Stimulation for Nerve Tissue Regeneration

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    [ES] La capacidad de las células madre para proliferar formando distintas células especializadas les otorga la potencialidad de servir de base para terapias efectivas para patologías cuyo tratamiento era inimaginable hasta hace apenas dos décadas. Sin embargo, esta capacidad se encuentra mediada por estímulos fisiológicos, químicos, y eléctricos, específicos y complejos, que dificultan su traslación a la rutina clínica. Por ello, las células madre representan un campo de estudio en el que se invierten amplios esfuerzos por parte de la comunidad científica. En el ámbito de la regeneración nerviosa, para modular su desarrollo y diferenciación el tratamiento farmacológico, la electroestimulación, y la estimulación optogenética son técnicas que están consiguiendo prometedores resultados. Es por ello por lo que en la presente tesis se ha desarrollado un conjunto de sistemas electrónicos para permitir la aplicación combinada de estas técnicas in vitro, con perspectiva a su aplicación in vivo. Hemos diseñado una novedosa tecnología para la liberación eléctricamente controlada de fármacos. Esta tecnología está basada en nanopartículas de sílice mesoporosa y puertas moleculares de bipiridina-heparina. Las puertas moleculares son electroquímicamente reactivas, y encierran los fármacos en el interior de las nanopartículas, liberándolos ante un estímulo eléctrico. Hemos caracterizado esta tecnología, y la hemos validado mediante la liberación controlada de rodamina en cultivos celulares de HeLa. Para la combinación de liberación controlada de fármacos y electroestimulación hemos desarrollado dispositivos que permiten aplicar los estímulos eléctricos de forma configurable desde una interfaz gráfica de usuario. Además, hemos diseñado un módulo de expansión que permite multiplexar las señales eléctricas a diferentes cultivos celulares. Además, hemos diseñado un dispositivo de estimulación optogenética. Este tipo de estimulación consiste en la modificación genética de las células para que sean sensibles a la radiación lumínica de determinada longitud de onda. En el ámbito de la regeneración de tejido mediante células precursoras neurales, es de interés poder inducir ondas de calcio, favoreciendo su diferenciación en neuronas y la formación de circuitos sinápticos. El dispositivo diseñado permite obtener imágenes en tiempo real mediante microscopía confocal de las respuestas transitorias de las células al ser irradiadas. El dispositivo se ha validado irradiando neuronas modificadas con luz pulsada de 100 ms. También hemos diseñado un dispositivo electrónico complementario de medida de irradiancia con el doble fin de permitir la calibración del equipo de irradiancia y medir la irradiancia en tiempo real durante los experimentos in vitro. Los resultados del uso de los bioactuadores en procesos complejos y dinámicos, como la regeneración de tejido nervioso, son limitados en lazo abierto. Uno de los principales aspectos analizados es el desarrollo de biosensores que permitiesen la cuantización de ciertas biomoléculas para ajustar la estimulación suministrada en tiempo real. Por ejemplo, la segregación de serotonina es una respuesta identificada en la elongación de células precursoras neurales, pero hay otras biomoléculas de interés para la implementación de un control en lazo cerrado. Entre las tecnologías en el estado del arte, los biosensores basados en transistores de efecto de campo (FET) funcionalizados con aptámeros son realmente prometedores para esta aplicación. Sin embargo, esta tecnología no permitía la medición simultánea de más de una biomolécula objetivo en un volumen reducido debido a las interferencias entre los distintos FETs, cuyos terminales se encuentran inmersos en la solución. Por ello, hemos desarrollado instrumentación electrónica capaz de medir simultáneamente varios de estos biosensores, y la hemos validado mediante la medición simultánea de pH y la detección preliminar de serotonina y glutamato.[CA] La capacitat de les cèl·lules mare per a proliferar formant diferents cèl·lules especialitzades els atorga la potencialitat de servir de base per a teràpies efectives per a patologies el tractament de les quals era inimaginable fins fa a penes dues dècades. No obstant això, aquesta capacitat es troba mediada per estímuls fisiològics, químics, i elèctrics, específics i complexos, que dificulten la seua translació a la rutina clínica. Per això, les cèl·lules mare representen un camp d'estudi en el qual s'inverteixen amplis esforços per part de la comunitat científica. En l'àmbit de la regeneració nerviosa, per a modular el seu desenvolupament i diferenciació el tractament farmacològic, l'electroestimulació, i l'estimulació optogenética són tècniques que estan aconseguint prometedors resultats. És per això que en la present tesi s'ha desenvolupat un conjunt de sistemes electrònics per a permetre l'aplicació combinada d'aquestes tècniques in vitro, amb perspectiva a la seua aplicació in vivo. Hem dissenyat una nova tecnologia per a l'alliberament elèctricament controlat de fàrmacs. Aquesta tecnologia està basada en nanopartícules de sílice mesoporosa i portes moleculars de bipiridina-heparina. Les portes moleculars són electroquímicament reactives, i tanquen els fàrmacs a l'interior de les nanopartícules, alliberant-los davant un estímul elèctric. Hem caracteritzat aquesta tecnologia, i l'hem validada mitjançant l'alliberament controlat de rodamina en cultius cel·lulars de HeLa. Per a la combinació d'alliberament controlat de fàrmacs i electroestimulació hem desenvolupat dispositius que permeten aplicar els estímuls elèctrics de manera configurable des d'una interfície gràfica d'usuari. A més, hem dissenyat un mòdul d'expansió que permet multiplexar els senyals elèctrics a diferents cultius cel·lulars. A més, hem dissenyat un dispositiu d'estimulació optogenètica. Aquest tipus d'estimulació consisteix en la modificació genètica de les cèl·lules perquè siguen sensibles a la radiació lumínica de determinada longitud d'ona. En l'àmbit de la regeneració de teixit mitjançant cèl·lules precursores neurals, és d'interés poder induir ones de calci, afavorint la seua diferenciació en neurones i la formació de circuits sinàptics. El dispositiu dissenyat permet obtindré imatges en temps real mitjançant microscòpia confocal de les respostes transitòries de les cèl·lules en ser irradiades. El dispositiu s'ha validat irradiant neurones modificades amb llum polsada de 100 ms. També hem dissenyat un dispositiu electrònic complementari de mesura d'irradiància amb el doble fi de permetre el calibratge de l'equip d'irradiància i mesurar la irradiància en temps real durant els experiments in vitro. Els resultats de l'ús dels bioactuadors en processos complexos i dinàmics, com la regeneració de teixit nerviós, són limitats en llaç obert. Un dels principals aspectes analitzats és el desenvolupament de biosensors que permeteren la quantització de certes biomolècules per a ajustar l'estimulació subministrada en temps real. Per exemple, la segregació de serotonina és una resposta identificada amb l'elongació de les cèl·lules precursores neurals, però hi ha altres biomolècules d'interés per a la implementació d'un control en llaç tancat. Entre les tecnologies en l'estat de l'art, els biosensors basats en transistors d'efecte de camp (FET) funcionalitzats amb aptàmers són realment prometedors per a aquesta aplicació. No obstant això, aquesta tecnologia no permetia el mesurament simultani de més d'una biomolècula objectiu en un volum reduït a causa de les interferències entre els diferents FETs, els terminals dels quals es troben immersos en la solució. Per això, hem desenvolupat instrumentació electrònica capaç de mesurar simultàniament diversos d'aquests biosensors i els hem validat amb mesurament simultani del pH i la detecció preliminar de serotonina i glutamat.[EN] The stem cells' ability to proliferate to form different specialized cells gives them the potential to serve as the basis for effective therapies for pathologies whose treatment was unimaginable until just two decades ago. However, this capacity is mediated by specific and complex physiological, chemical, and electrical stimuli that complicate their translation to clinical routine. For this reason, stem cells represent a field of study in which the scientific community is investing a great deal of effort. In the field of nerve regeneration, to modulate their development and differentiation, pharmacological treatment, electrostimulation, and optogenetic stimulation are techniques that are achieving promising results. For this reason, we have developed a set of electronic systems to allow the combined application of these techniques in vitro, with a view to their application in vivo. We have designed a novel technology for the electrically controlled release of drugs. This technology is based on mesoporous silica nanoparticles and bipyridine-heparin molecular gates. The molecular gates are electrochemically reactive and entrap the drugs inside the nanoparticles, releasing them upon electrical stimulus. We have characterized this technology and validated it by controlled release of rhodamine in HeLa cell cultures. For combining electrostimulation and controlled drug release we have developed devices that allow applying the different electrical stimuli in a configurable way from a graphical user interface. In addition, we have designed an expansion module that allows multiplexing electrical signals to different cell cultures. In addition, we have designed an optogenetic stimulation device. This type of stimulation consists of genetically modifying cells to make them sensitive to light radiation of a specific wavelength. In tissue regeneration using neural precursor cells, it is interesting to be able to induce calcium waves, favoring the cell differentiation into neurons and the formation of synaptic circuits. The designed device enable the obtention of real-time images through confocal microscopy of the transient responses of cells upon irradiation. The device has been validated by irradiating modified neurons with 100 ms pulsed light stimulation. We have also designed a complementary electronic irradiance measurement device to allow calibration of the irradiator equipment and measuring irradiance in real time during in vitro experiments. The results of using bioactuators in complex and dynamic processes, such as nerve tissue regeneration, are limited in an open loop. One of the main aspects analyzed is the development of biosensors that would allow quantifying of specific biomolecules to adjust the stimulation provided in real time. For instance, serotonin secretion is an identified response of neural precursor cells elongation, among other biomolecules of interest for the implementation of a closed-loop control. Among the state-of-the-art technologies, biosensors based on field effect transistors (FETs) functionalized with aptamers are promising for this application. However, this technology did not allow the simultaneous measurement of more than one target biomolecule in a small volume due to interferences between the different FETs, whose terminals are immersed in the solution. This is why we have developed electronic instrumentation capable of simultaneously measuring several of these biosensors, and we have validated it with the simultaneous pH measurement and the preliminary detection of serotonin and glutamate.Monreal Trigo, J. (2023). Electronic Devices for the Combination of Electrically Controlled Drug Release, Electrostimulation, and Optogenetic Stimulation for Nerve Tissue Regeneration [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19384

    Model Based Control of Soft Robots: A Survey of the State of the Art and Open Challenges

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    Continuum soft robots are mechanical systems entirely made of continuously deformable elements. This design solution aims to bring robots closer to invertebrate animals and soft appendices of vertebrate animals (e.g., an elephant's trunk, a monkey's tail). This work aims to introduce the control theorist perspective to this novel development in robotics. We aim to remove the barriers to entry into this field by presenting existing results and future challenges using a unified language and within a coherent framework. Indeed, the main difficulty in entering this field is the wide variability of terminology and scientific backgrounds, making it quite hard to acquire a comprehensive view on the topic. Another limiting factor is that it is not obvious where to draw a clear line between the limitations imposed by the technology not being mature yet and the challenges intrinsic to this class of robots. In this work, we argue that the intrinsic effects are the continuum or multi-body dynamics, the presence of a non-negligible elastic potential field, and the variability in sensing and actuation strategies.Comment: 69 pages, 13 figure

    Evaluating footwear “in the wild”: Examining wrap and lace trail shoe closures during trail running

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    Trail running participation has grown over the last two decades. As a result, there have been an increasing number of studies examining the sport. Despite these increases, there is a lack of understanding regarding the effects of footwear on trail running biomechanics in ecologically valid conditions. The purpose of our study was to evaluate how a Wrap vs. Lace closure (on the same shoe) impacts running biomechanics on a trail. Thirty subjects ran a trail loop in each shoe while wearing a global positioning system (GPS) watch, heart rate monitor, inertial measurement units (IMUs), and plantar pressure insoles. The Wrap closure reduced peak foot eversion velocity (measured via IMU), which has been associated with fit. The Wrap closure also increased heel contact area, which is also associated with fit. This increase may be associated with the subjective preference for the Wrap. Lastly, runners had a small but significant increase in running speed in the Wrap shoe with no differences in heart rate nor subjective exertion. In total, the Wrap closure fit better than the Lace closure on a variety of terrain. This study demonstrates the feasibility of detecting meaningful biomechanical differences between footwear features in the wild using statistical tools and study design. Evaluating footwear in ecologically valid environments often creates additional variance in the data. This variance should not be treated as noise; instead, it is critical to capture this additional variance and challenges of ecologically valid terrain if we hope to use biomechanics to impact the development of new products

    Exploring Animal Behavior Through Sound: Volume 1

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    This open-access book empowers its readers to explore the acoustic world of animals. By listening to the sounds of nature, we can study animal behavior, distribution, and demographics; their habitat characteristics and needs; and the effects of noise. Sound recording is an efficient and affordable tool, independent of daylight and weather; and recorders may be left in place for many months at a time, continuously collecting data on animals and their environment. This book builds the skills and knowledge necessary to collect and interpret acoustic data from terrestrial and marine environments. Beginning with a history of sound recording, the chapters provide an overview of off-the-shelf recording equipment and analysis tools (including automated signal detectors and statistical methods); audiometric methods; acoustic terminology, quantities, and units; sound propagation in air and under water; soundscapes of terrestrial and marine habitats; animal acoustic and vibrational communication; echolocation; and the effects of noise. This book will be useful to students and researchers of animal ecology who wish to add acoustics to their toolbox, as well as to environmental managers in industry and government

    Back-support exoskeletons in industrial tasks - Effects and side-effects on physical stress and strain

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    Exoskeletons are wearable, mechanical structures supporting the musculoskeletal system (e.g., in physical work) by generating torques which act on the human body. Recently, they have been introduced as a new prevention approach for work-related musculoskeletal disorders (WMSDs), receiving growing interest in various occupational areas and in research. However, their effectiveness on musculoskeletal health has not been proven, and possible negative effects impacting the musculoskeletal system have not been sufficiently investigated. Therefore, the aim of this doctoral thesis was to investigate the effects of using back-support exoskeletons (BSEs) on physical stress and strain during industrial tasks. Herein, the back, as the main target area, and other unsupported areas (e.g., the legs, shoulders, abdomen) are focused. The thesis begins with a systematic review with several meta-analyses (Bär et al., 2021) outlining the effects of occupational exoskeletons on biomechanical, physiological, and subjectively perceived stress and strain. The meta-analyses revealed that using a BSE can potentially reduce the acute stress or strain in the back area during industrial tasks. Negative side-effects were not identified by the analyses for the BSEs, but occur occasionally. However, there is still not enough research on this aspect. Overall, research following high methodological standards and evaluating various health-relevant aspects is thoroughly lacking. In response to the findings of Bär et al. (2021), an exploratory laboratory experiment was conducted to determine the influence of the commercially available passive BSE Laevo® V2.56 on physical stress and strain during simulated industrial tasks. Specifically, we investigated the effects of using the device on muscle activity in various body areas, spine and lower limb postures, and heart rate, focusing on a sorting task holding a static forward bent posture (including different trunk orientations; Bär et al., 2022a), and on a dynamic lifting task (including different lifting styles and trunk orientations; Luger et al., 2021b). Finally, Bär et al. (2022b) presents the exoskeleton’s effects on vertical and horizontal (anteroposterior) tibiofemoral joint forces during the static and the dynamic work tasks. In Bär et al. (2022a) and Luger et al. (2021b) we found that using the Laevo® in simulated industrial tasks resulted in only minor, reductions of the back extensor muscle activity (the erector spinae), but moderate support for hip extension (the biceps femoris). Meanwhile, minor changes in spinal posture and muscle activity in unsupported body areas occurred, and hip and knee flexion moderately increased. Thereby, the individual task executions (lifting style, trunk orientation) influenced the effects. Heart rate slightly decreased when using the Laevo® across all task executions (Bär et al., 2022a; Luger et al., 2021b). The vertical tibiofemoral joint forces generally increased with using the Laevo® without interacting with the task executions, while the device’s effects on the horizonal (anteroposterior) tibiofemoral joint forces varied across the individual experimental conditions (Bär et al., 2022b). This research shows that using a BSE may support either the back or hip extension and reduce acute stress or strain in target areas. However, changes of only single parameters (e.g., muscle activity) without monitoring associated musculoskeletal structures and functions (e.g., joint postures and forces) may prevent correct interpretations behind possible changes. Furthermore, negative side-effects may occur when using a BSE, which are insufficiently examined or not yet identified. The detection and further exclusion of negative side-effects is essential for the safe application of occupational exoskeletons. Various other factors may also codetermine any effects (either desired or undesired) associated with the use of occupational BSEs, e.g., individual work tasks and executions, mechanical characteristics of the device, and human individualities. Therefore, implementations of occupational exoskeletons at work should be preceded by individual assessments of the devices, with particular consideration of the various influencing factors. Overall, definitive conclusions in relation to musculoskeletal health is still beyond this dissertation and the current literature. Randomized controlled intervention studies in the field are critical for detecting long-term effects related to WMSD risk. They must include a well-thought selection and combination of various outcome parameters and body areas (e.g., relate various interacting stress and strain parameters, and include several interrelated musculoskeletal structures) and consider adherence to high methodological quality standards
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