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While fluidic elastomer actuators (FEAs) have been widely adopted for soft roboticsapplications showing potential for capabilities not achievable by their rigid counterparts, they have limited stiffness due to their innate compliance and cannot alter stiffness independently of their configuration on their own. Existing methods of combining FEAs with other mechanisms to achieve stiffness tunability limit the flexibility of the actuators and necessitate additional control inputs, or require energy to maintain higher stiffness and need onboard electronics, and may not work in the presence of electromagnetic fields. To address these limitations, this work proposes the use of supercooled liquid (sodium acetate trihydrate solution) as the multifunctional working fluid of FEAs to control both position and stiffness; we hypothesize that such fluid would be capable of both inflating the elastomer chambers while in liquid state and rapidly solidifying and stiffening the actuators. We investigate the mechanical properties of crystallized SAT samples and ways that they can be reinforced. Additionally, we analyze the stiffness of FEAs that use the supercooled SAT solution as their working fluid, highlighting the high degree of stiffness change (increase by 6.56 times) induced by the crystallization of the solution. Furthermore, we demonstrate the multifunctional manipulation and stiffness change of an FEA with minimal control inputs using supercooled SAT solution as the working fluid. The proposed mechanism is a new way to combine the high manipulability of FEAs with stiffness tunability and opens up new possibilities in designing soft robots and manipulators.

Pneumatic actuators are extensively studied in soft robotics as they are facile, low-cost, scalable, robust and exhibit compliance similar to many systems found in nature. The challenge is to harness, high energy density, chemical, and biochemical reactions to generate sufficient pneumatic pressure for controlled and biocompatible actuation of soft systems. This study identifies and proposes a variety of gas evolution reactions (GERs) and gas consumption reactions (GCRs) as reversible power sources for soft robotic actuators. It marks the first successful coupling of both GER and GCR in actuating pneumatic soft actuators while controlling actuation over reaction rates and final pressure for efficient oscillating actuation. Furthermore, the research introduces a catalytic FDM filament with embedded platinum nanopartocles (PtNPs) for enhanced soft pneumatic actuation, improving catalytic activity and reusability compared to commercial and synthesised dispersed nanopowders. The synthesis and characterisation of sub-3 nm PtNPs in a polymeric matrix achieve higher catalytic activity by optimising the surface-to-volume ratio of the nanoparticles. The fabrication of 3D structures with catalytic properties using additive manufacturing enables complex geometries for diverse soft robotic applications. Moreover, an in-depth investigation of the photoreduction mechanism and in-situ generation of PtNPs in a thermoplastic polyurethane (TPU) matrix is conducted, providing insights for further development of catalytic materials. Creating high surface area structures enhances catalytic properties using the direct ink writing (DIW) method, expanding potential applications in soft pneumatic actuators. TPU Ninjaflex 3D-printed bellow-type pneumatic soft actuators demonstrate chemical resistance and mechanical suitability for coupling with the evaluated GERs and GCRs. The thesis highlights significant progress in coupling GERs and GCRs, paving the way for innovative pow

Intrinsically actuated continuum soft robots merge the features of hyper-redundant and soft robots. The soft structure and redundancy allow the robots to conduct tasks in confined or unstructured environments. Extensile fluidic artificial muscles (EFAMs) can be used to construct soft actuated structures that feature large deformation and enable the robots to access large reachable workspaces. However, the soft robots’ low structural stiffness limits their ability to exert force or carry payloads. This dissertation aims to improve the continuum soft robot's spatial and payload-carrying performance. The work seeks to accomplish the following: 1. Compare multi-segment continuum robots to understand how the number of segments and robot geometry affect their spatial performance.2. Experimentally characterize and model EFAMs to close existing knowledge gaps in their axial and bending behaviors. 3. Investigate the impact of radial reinforcement on the payload-carrying ability of an EFAM robot. 4. Propose a modeling approach that captures the deformation of the robot under payloads.

A soft quadruped robot is being developed at the Department of Machine Design and Department of Production Engineering at KTH. The legs of the robot consist of four continuum actuators that can achieve complex movements. In order to efficiently develop gaits for the robot, reinforcement learning will be used. The learning process will use data from simulation instead of directly from the real robot to save time and resources. However, it is significantly more computationally expensive to simulate soft robotics than rigid, because the physical laws of flexible materials are inherently complex. Because of this, soft robot simulations tend to be slower which limits their usability for reinforcement learning. This thesis explores simulation modelling options in Matlab Simscape for the soft quadruped robot, that can be used in reinforcement learning. Four simulation models of the soft actuator were implemented in order to be tested and compared. Two actuation methods and two build options were chosen based on the literature study and related works, and were then permuted for the different combinations. The tested combinations are: lumped-parameter method actuated by internal force, flexible beam actuated by internal force, lumped-parameter method actuated by cable/pulley network and flexible beam actuated by cable/pulley network. The four actuators were built and tested separately. Computational time and simulation-to-reality gap were used for evaluating the modeling methods. The results show that the best option when modelling the soft actuator for reinforcement learning in Matlab Simscape is to use the lumped-parameter method in combination with a cable and pulley network. High accuracy level can still be achieved despite not keeping the true number of attachment points between the cable and actuator. The number of pulleys in the model is linearly correlated to the time cost required to simulate the model., En mjuk fyrbent robot är under utveckling vid institutionen för maskinkonstruktion och institutionen för industriell produktion på KTH. Robotens ben består av fyra kontinuerligt deformerbara ställdon som kan åstadkomma komplexa rörelser. För att effektivt utveckla gångstilar till roboten kommer förstärkt inlärning att användas. Inlärningsprocessen kommer att använda data från simulering istället för från den fysiska roboten för att spara tid och resurser. Det är dock betydligt dyrare beräkningsmässigt att simulera mjuk robotik än styv, eftersom flexibla material är mer komplexa. På grund av detta tenderar simuleringar av mjuka robotar att vara långsammare, vilket begränsar deras användbarhet för förstärkt inlärning. Detta examensarbete utforskar därför alternativ för modellering och simulering av den mjuka fyrbenta roboten i Matlab Simscape, med målet att den ska kunna användas med förstärkt inlärning. Fyra olika simuleringsmodeller av det mjuka ställdonet implementerades för att testas och jämföras. Två aktiveringsmetoder och två konstruktionsalternativ valdes baserat på litteraturstudien och relaterade arbeten, och permuterades sedan till möjliga versioner. De testade versionerna är således: klumpparametermetod som aktiveras av intern kraft, flexibel balk som aktiveras av intern kraft, klumpparametermetod som aktiveras av kabelnätverk och flexibel balk som aktiveras av kabelnätverk. De fyra ställdonen byggdes och testades separat. Beräkningstid och grad av verklighetstrogenhet, användes för att jämföra resultaten av dessa tester. Resultaten visar att det bästa alternativet vid modellering av det mjuka ställdonet för förstärkt inlärning i Matlab Simscape är att använda klumpparametermetoden i kombination med ett kabelnätverk. Hög noggrannhetsnivå kan uppnås trots att man inte bibehåller det verkliga antalet fästpunkter mellan kabeln och ställdonet. Antalet fästpunkter för kabeln i modellen är linjärt korrelerat till den tidskostnad som krävs för att simulera modell

A soft quadruped robot is being developed at the Department of Machine Design and Department of Production Engineering at KTH. The legs of the robot consist of four continuum actuators that can achieve complex movements. In order to efficiently develop gaits for the robot, reinforcement learning will be used. The learning process will use data from simulation instead of directly from the real robot to save time and resources. However, it is significantly more computationally expensive to simulate soft robotics than rigid, because the physical laws of flexible materials are inherently complex. Because of this, soft robot simulations tend to be slower which limits their usability for reinforcement learning. This thesis explores simulation modelling options in Matlab Simscape for the soft quadruped robot, that can be used in reinforcement learning. Four simulation models of the soft actuator were implemented in order to be tested and compared. Two actuation methods and two build options were chosen based on the literature study and related works, and were then permuted for the different combinations. The tested combinations are: lumped-parameter method actuated by internal force, flexible beam actuated by internal force, lumped-parameter method actuated by cable/pulley network and flexible beam actuated by cable/pulley network. The four actuators were built and tested separately. Computational time and simulation-to-reality gap were used for evaluating the modeling methods. The results show that the best option when modelling the soft actuator for reinforcement learning in Matlab Simscape is to use the lumped-parameter method in combination with a cable and pulley network. High accuracy level can still be achieved despite not keeping the true number of attachment points between the cable and actuator. The number of pulleys in the model is linearly correlated to the time cost required to simulate the model., En mjuk fyrbent robot är under utveckling vid institutionen för maskinkonstruktion och institutionen för industriell produktion på KTH. Robotens ben består av fyra kontinuerligt deformerbara ställdon som kan åstadkomma komplexa rörelser. För att effektivt utveckla gångstilar till roboten kommer förstärkt inlärning att användas. Inlärningsprocessen kommer att använda data från simulering istället för från den fysiska roboten för att spara tid och resurser. Det är dock betydligt dyrare beräkningsmässigt att simulera mjuk robotik än styv, eftersom flexibla material är mer komplexa. På grund av detta tenderar simuleringar av mjuka robotar att vara långsammare, vilket begränsar deras användbarhet för förstärkt inlärning. Detta examensarbete utforskar därför alternativ för modellering och simulering av den mjuka fyrbenta roboten i Matlab Simscape, med målet att den ska kunna användas med förstärkt inlärning. Fyra olika simuleringsmodeller av det mjuka ställdonet implementerades för att testas och jämföras. Två aktiveringsmetoder och två konstruktionsalternativ valdes baserat på litteraturstudien och relaterade arbeten, och permuterades sedan till möjliga versioner. De testade versionerna är således: klumpparametermetod som aktiveras av intern kraft, flexibel balk som aktiveras av intern kraft, klumpparametermetod som aktiveras av kabelnätverk och flexibel balk som aktiveras av kabelnätverk. De fyra ställdonen byggdes och testades separat. Beräkningstid och grad av verklighetstrogenhet, användes för att jämföra resultaten av dessa tester. Resultaten visar att det bästa alternativet vid modellering av det mjuka ställdonet för förstärkt inlärning i Matlab Simscape är att använda klumpparametermetoden i kombination med ett kabelnätverk. Hög noggrannhetsnivå kan uppnås trots att man inte bibehåller det verkliga antalet fästpunkter mellan kabeln och ställdonet. Antalet fästpunkter för kabeln i modellen är linjärt korrelerat till den tidskostnad som krävs för att simulera modell

Stress urinary incontinence refers to the unintentional leakage of urine, which is caused by weakening of, or damage to, urethral sphincters or pelvic floor muscles. Not only do the symptoms lead to physical discomfort or pain, but also the embarrassment and inconvenience significantly affects the quality of life, including social, familial, occupational, and sexual aspects. The use of inherently compliant and stretchable materials in soft robotics has driven a new class of biomedical devices which exhibit safe human interaction and embodied intelligent responses. This thesis focuses on the potential solutions for addressing the lack of occlusive pressure adaption in artificial urinary sphincter by employing soft robotic technologies. The research problem is decomposed into three different engineering topics: sensing, actuation, and control, which can correspond to receptors, muscles and the spinal cord or brain, respectively, in terms of human nervous system. For sensing, a stretchable sensor that can wirelessly measure various types of strain is developed, which can be used to remotely monitor physiological activities such as bladder volume or urethral pressure and provide essential information for feedback control. Regarding actuation, a new design of artificial urinary sphincter is proposed. It allows local urethral tissue to relax and potentially avoid ischemia, erosion or atrophy resulting from long-term compression. For control, a new approach of soft control and computing using liquid metal is investigated. The transformation from fluidic to electrical signals allows the device to respond to any sudden intra-abdominal pressure change and give extra support to the mid-urethra. In addition to the active modalities of sensing, actuation and control, an elastic artificial bladder is created which is more physically and physiologically similar to the proximal portion of the lower urinary tract system compared to the rigid funnel specified in the ISO stan

Soft materials are attracting much attention for the development of biostructures able to mimic the movement of natural systems by remote actuation. Multi-sensitive hydrogels are among the best materials for obtaining dynamic and biocompatible soft structures for soft actuators and related biomedical devices. Nevertheless, bioinks based on naturally occurring and stimuli responsive hydrogels able to be 3D printed continues being a challenge for advanced applications. In this work 3D printable electrically and magnetically responsive, non-cytotoxic, hybrid hydrogels based on alginate and zero monovalent iron nanoparticles (NPs) are presented. The effect of NPs addition on the physico-chemical properties of the hydrogels is addressed, together with its effect on the functional electroactive and magnetoactive response. NPs concentration up to 10 % do not affect the mechanical stability of the gels, while promoting an increase actuation response.

Stress urinary incontinence refers to the unintentional leakage of urine, which is caused by weakening of, or damage to, urethral sphincters or pelvic floor muscles. Not only do the symptoms lead to physical discomfort or pain, but also the embarrassment and inconvenience significantly affects the quality of life, including social, familial, occupational, and sexual aspects. The use of inherently compliant and stretchable materials in soft robotics has driven a new class of biomedical devices which exhibit safe human interaction and embodied intelligent responses. This thesis focuses on the potential solutions for addressing the lack of occlusive pressure adaption in artificial urinary sphincter by employing soft robotic technologies. The research problem is decomposed into three different engineering topics: sensing, actuation, and control, which can correspond to receptors, muscles and the spinal cord or brain, respectively, in terms of human nervous system. For sensing, a stretchable sensor that can wirelessly measure various types of strain is developed, which can be used to remotely monitor physiological activities such as bladder volume or urethral pressure and provide essential information for feedback control. Regarding actuation, a new design of artificial urinary sphincter is proposed. It allows local urethral tissue to relax and potentially avoid ischemia, erosion or atrophy resulting from long-term compression. For control, a new approach of soft control and computing using liquid metal is investigated. The transformation from fluidic to electrical signals allows the device to respond to any sudden intra-abdominal pressure change and give extra support to the mid-urethra. In addition to the active modalities of sensing, actuation and control, an elastic artificial bladder is created which is more physically and physiologically similar to the proximal portion of the lower urinary tract system compared to the rigid funnel specified in the ISO stan

Finger rehabilitation robots are developed to assist therapists in performing rehabilitation processes on patients. The repetitive flexion and extension have shown positive outcome in improving functionality of fingers among post-stroke patients. However, these robots are made of rigid structures and actuators such as pulleys and motors which pose danger to the delicate human fingers. This paper proposes a bidirectional bending fibre-reinforced soft actuator as an alternative actuator for fingers rehabilitation robots. The developed bidirectional bending soft actuator successfully achieved bending angle of 269.5Ëš at 70 kPa input air pressure. Shrinking electrical tubes were attached to the bidirectional bending soft actuator to produce bending motion which mimic the motion of finger. The modified bidirectional bending soft actuator was used to construct finger rehabilitation glove and achieved bending angle of 98.5Ëš at 90 kPa for flexion motion.

Extensile fluidic artificial muscles (EFAMs) are soft actuators known for their large ranges of extension, low weight, and blocked forces comparable to those of pneumatic cylinders. EFAMs have yet to be studied in a way that thoroughly focuses on their manufacturing, experimental characterization, and modeling. A fabrication method was developed for production of two EFAMs. The quasi-static axial force response of EFAMs to varying displacement was measured by testing two specimens under isobaric conditions over a pressure range of 103.4–517.1 kPa (15–75 psi) with 103.4 kPa (15 psi) increments. The muscles were characterized by a blocked force of 280 N and a maximum stroke of 98% at 517.1 kPa (75 psi). A force-balance model was used to analyze EFAM response. Prior work employing the force-balance approach used hyper-elastic constitutive models based on polynomial expressions. In this study, these models are validated for EFAMs, and new constitutive models are proposed that better represent the measured stress values of rubber as a function of strain. These constitutive models are compared in terms of accuracy when estimating pressure-dependent stress–strain relationships of the bladder material. The analysis demonstrates that the new hyper-elastic stress models have an error 5% smaller than models previously employed for EFAMs for the same number of coefficients. Finally, the analysis suggests that the new stress functions have smaller errors than the polynomial stress model with the same number of coefficients, guarantee material stability, and are more conservative about the stress values for strains outside of the testing range.

Shape-changing interfaces are promising for users to change the physical properties of common objects. However, prevailing approaches of actuation devices require either professional equipment or materials that are not commonly accessible to non-professional users. In this work, we focus on the controllable soft actuators with inflatable structures because they are soft thus safe for human computer interaction. We propose a soft actuator design, called xBalloon, that is workable, inexpensive and easy-to-fabricate. It consists of daily materials including balloons and plastics and can realize bending actuation very effectively. For characterization, we fabricated xBalloon samples with different geometrical parameters and tested them regarding the bending performance and found the analytical model describing the relationship between the shape and the bending width. We then used xBalloons to animate a series of common objects and all can work satisfactorily. We further verified the user experience about the the fabrication and found that even those with no prior robotic knowledge can fabricate xBalloons with ease and confidence. Given all these advantages, we believe that xBalloon is an ideal platform for interaction design and entertainment applications., ACM International Conference Proceeding Series, Open Access, 27 May 2021, Article number 3460933, 12th Augmented Human International Conference, AH 2021, Geneva, 27 May 2021 through 28 May 2021, Code 169187, identifier:https://dspace.jaist.ac.jp/dspace/handle/10119/17559

Strategies for enhancement of redox-driven deformation of a hydrogel, viologen pendant poly-L-Lysine based glutaraldehyde cross-linked hydrogel (PLLV-GA-gel), were pursued. To surpass the previously reported fastest reductive contraction, a 93 % volume decrease within 100 s on dithionite reduction, and to accelerate expansion on oxidation, we examined the pendant rate dependence and the effect of the addition of conductive fillers or an anionic polymer, poly(styrene sulfonate) (PSS). In testing deformation of water-floated PLLV-GA-gels, the contraction of a 25 % pendant rate gel was greater and faster than others. The initial rate of reductive contraction of the gels with fillers was in the order of graphene nano-platelet (GNP) > gold nanoparticle > carbon nanotube (CNT) > no-filler. The initial rates of swelling of GNP and CNT gels on oxidation were faster than the no-filler gel. PSS incorporation enhanced the swelling rate and amplitude but slowed down the contraction. All the PLLV-based samples on a Au electrode showed largely diffusion-controlled redox reactions of viologen in voltammograms and radical cation dimer rich light-absorption features in electroreflectance spectra. The guide for the choice of conductive filler and coexistence of anionic polymer described herein should be applicable to enhance the deformation of many redox-driven hydrogel actuators., Sensors and Actuators B: Chemical, 331, art. no. 129359; 2021

Fiber - a primitive yet ubiquitous form of material - intertwines with our bodies and surroundings, from constructing our fibrous muscles that enable our movement, to forming fabrics that intimately interface with our skin. In soft robotics and advanced materials science research, actuated fibers are gaining interest as thin, flexible materials that can morph in response to external stimuli. In this paper, we build on fluidic artificial muscles research to develop OmniFiber - a soft, line-based material system for designing movement-based interactions. We devised actuated thin (øouter < 1.8 mm) fluidic fibers with integrated soft sensors that exhibit perceivably strong forces, up to 19 N at 0.5 MPa, and a high speed of linear actuation peaking at 150mm/s. These allow to flexibly weave them into everyday tangible interactions; including on-body haptic devices for embodied learning, synchronized tangible interfaces for remote communication, and robotic crafting for expressivity. The design of such interactive capabilities is supported by OmniFiber's design space, accessible fabrication pipeline, and a fluidic I/O control system to bring omni-functional fluidic fibers to the HCI toolbox of interactive morphing materials., QC 20220524Part of proceedings: ISBN 978-145038635-7

The field of soft actuators is dominated by elastomers that experience mechanical deformations in response to external stimuli. In this context, magnetic stimuli attract considerable interest because of their easy application, tunability, fast response, remote actuation, and safe penetration in biological environments. Since very recently, research interests in the field are being redirected towards hydrogels, which could virtually replace elastomers, overcoming their limitations and expanding the field of application of soft actuators. The mechanical actuation of hydrogels is a nascent field full of challenges, such as achieving reliable and significant responsiveness. Here we demonstrate that the combination of a physical polymer hydrogel with a dispersed phase consisting of clusters of magnetic particles, results in magnetic hydrogel composites that exhibit high and reversible elongation in response to magnetic stimuli. Our analyses show that this response is strongly dependent on the matrix elasticity, the concentration of magnetic particles, and the particle distribution within the network of polymer nanofibres. Our strategy for the maximization of the response of magnetic hydrogels should be a catalyst for the development of novel applications of composite hydrogels, such as a valve remotely actuated by a magnetic field that we also present here as a proof-of-concept. © 2021 The Author(s).

Altres ajuts: ICN2 is funded by the CERCA programme/Generalitat de Catalunya., New multi-stimuli responsive materials are required in smart systems applications to overcome current limitations in remote actuation and to achieve versatile operation in inaccessible environments. The incorporation of detection mechanisms to quantify in real time the response to external stimuli is crucial for the development of automated systems. Here, we present the first wireless opto-magnetic actuator with mechanochromic response. The device, based on a nanostructured-iron (Fe) layer transferred onto suspended elastomer structures with a periodically corrugated backside, can be actuated both optically (in a broadband spectral range) and magnetically. The combined opto-magnetic stimulus can accurately modulate the mechanical response (strength and direction) of the device. The structural coloration generated at the corrugated back surface enables to easily map and quantify, in 2D, the mechanical deflections by analyzing in real time the hue changes of images taken using a conventional RGB smartphone camera, with a precision of 0.05°. We demonstrate the independent and synergetic optical and magnetic actuation and detection with a detection limit of 1.8 mW·cm -2 and 0.34 mT, respectively. The simple operation, versatility, and cost-effectiveness of the wireless multiactuated device with highly sensitive mechanochromic mapping paves the way to a new generation of wirelessly controlled smart systems.

New multi-stimuli responsive materials are required in smart systems applications to overcome current limitations in remote actuation and to achieve versatile operation in inaccessible environments. The incorporation of detection mechanisms to quantify in real time the response to external stimuli is crucial for the development of automated systems. Here, we present the first wireless opto-magnetic actuator with mechanochromic response. The device, based on a nanostructured-iron (Fe) layer transferred onto suspended elastomer structures with a periodically corrugated backside, can be actuated both optically (in a broadband spectral range) and magnetically. The combined opto-magnetic stimulus can accurately modulate the mechanical response (strength and direction) of the device. The structural coloration generated at the corrugated back surface enables to easily map and quantify, in 2D, the mechanical deflections by analyzing in real time the hue changes of images taken using a conventional RGB smartphone camera, with a precision of 0.05°. We demonstrate the independent and synergetic optical and magnetic actuation and detection with a detection limit of 1.8 mW·cm-2 and 0.34 mT, respectively. The simple operation, versatility, and cost-effectiveness of the wireless multiactuated device with highly sensitive mechanochromic mapping paves the way to a new generation of wirelessly controlled smart systems.

Acting at high speed enables creatures to survive in their harsh natural environments. They developed strategies for fast actuation that inspire technological embodiments like soft robots. Here, we demonstrate a series of simulation-guided lightweight, durable, and untethered soft-bodied robots performing large-degree deformations at unprecedentedly high frequencies of up to 200 Hz, driven at very low magnetic fields down to 0.5 mT, and exhibit a record high specific energy density of 10.8 kJ/m3/mT. Unforeseen nonlinear behavior of our robots is observed in experiments and analyzed by simulation, guiding future designs of soft-bodied robots. Our robots walk, swim, levitate, transport cargo, and can even catch a living fly unharmed. Such ultrafast soft robots with high-frequency oscillations can rapidly adapt to varying environmental conditions, inspire biomedical applications in confined environment, and serve as model systems to develop complex movements inspired by nature.

In nature, tip-localized growth allows navigation in tightly confined environments and creation of structures. Recently, this form of movement has been artificially realized through pressure-driven eversion of flexible, thin-walled tubes. Here we review recent work on robots that "grow" via pressure-driven eversion, referred to as "everting vine robots," due to a movement pattern that is similar to that of natural vines. We break this work into four categories. First, we examine the design of everting vine robots, highlighting tradeoffs in material selection, actuation methods, and placement of sensors and tools. These tradeoffs have led to application-specific implementations. Second, we describe the state of and need for modeling everting vine robots. Quasi-static models of growth and retraction and kinematic and force-balance models of steering and environment interaction have been developed that use simplifying assumptions and limit the involved degrees of freedom. Third, we report on everting vine robot control and planning techniques that have been developed to move the robot tip to a target, using a variety of modalities to provide reference inputs to the robot. Fourth, we highlight the benefits and challenges of using this paradigm of movement for various applications. Everting vine robot applications to date include deploying and reconfiguring structures, navigating confined spaces, and applying forces on the environment. We conclude by identifying gaps in the state of the art and discussing opportunities for future research to advance everting vine robots and their usefulness in the field.

Soft robots, made of soft materials such as di-electric elastomer or shape memory polymers, have receivedtremendous attentions due to its dexterousness, flexibility andsafety compared with rigid robots. However, wider applicationof soft robots is limited due to their complex fabrication processand poor controllability. Here, we introduce a closed loopcontrolled soft actuator that is fully 3D printed with flexiblematerial. The structure of the soft actuator is optimized withFinite Element Method (FEM) to acquire shortest fabricationtime and highest deformation for same stimulus input. A desk-top Fused Deposition Modeling (FDM) 3D printer is used forlow-cost fabrication of such actuators. A webcamera is used forthe image feedback which offers the real time shape monitoringof the soft actuator. An output feedback Proportional IntegralDerivative (PID) controller with lowpass filter is developed withpole placement design method based on a data-driven modelof the 3D printed soft actuator. The controller is implementedto regulate the input air pressure to ensure a fast-response, precise and robust shape changing for any work environments., Part of proceedings ISBNQC 20201216

In nature, tip-localized growth allows navigation in tightly confined environments and creation of structures. Recently, this form of movement has been artificially realized through pressure-driven eversion of flexible, thin-walled tubes. Here we review recent work on robots that "grow" via pressure-driven eversion, referred to as "everting vine robots," due to a movement pattern that is similar to that of natural vines. We break this work into four categories. First, we examine the design of everting vine robots, highlighting tradeoffs in material selection, actuation methods, and placement of sensors and tools. These tradeoffs have led to application-specific implementations. Second, we describe the state of and need for modeling everting vine robots. Quasi-static models of growth and retraction and kinematic and force-balance models of steering and environment interaction have been developed that use simplifying assumptions and limit the involved degrees of freedom. Third, we report on everting vine robot control and planning techniques that have been developed to move the robot tip to a target, using a variety of modalities to provide reference inputs to the robot. Fourth, we highlight the benefits and challenges of using this paradigm of movement for various applications. Everting vine robot applications to date include deploying and reconfiguring structures, navigating confined spaces, and applying forces on the environment. We conclude by identifying gaps in the state of the art and discussing opportunities for future research to advance everting vine robots and their usefulness in the field.

We present a high-displacement pneumatic artificial muscle made of textiles or plastics that can include integrated electronics to sense its pressure and displacement. Compared to traditional pneumatic muscle actuators such as the McKibben actuator and other more recent soft actuators, the actuator described in this paper can produce a much higher (40~65%) contraction ratio. In this paper, we describe the design, fabrication, and evaluation of the actuator, as well as the manufacturing process used to create it. We demonstrate the actuator design with several examples that produce 120 and 300 N at pressures of 35 and 105 kPa, respectively, and have contraction ratios of 40-65%. © 2019 Yang, Greczek and Asbeck.

A new type of soft actuator was developed by using hydrogel materials and three-dimensional (3D) printing technology, attracting the attention of researchers in the soft robotics field. Due to parametric uncertainties of such actuators, which originate in both a custom design nature of 3D printing as well as time and voltage variant characteristics of polyelectrolyte actuators, a sophisticated model to estimate their behaviour is required. This paper presents a practical modeling approach for the deflection of a 3D printed soft actuator. The suggested model is composed of electrical and mechanical dynamic models while the earlier version describes the actuator as a resistive-capacitive (RC) circuit. The latter model relates the ionic charges to the bending of an actuator. The experimental results were acquired to estimate the transfer function parameters of the developed model incorporating Takagi-Sugeno (T-S) fuzzy sets. The proposed model was successful in estimating the end-point trajectory of the actuator, especially in response to a broad range of input voltage variation. With some modifications in the electromechanical aspects of the model, the proposed modelling method can be used with other 3D printed soft actuators.

We present a high-displacement pneumatic artificial muscle made of textiles or plastics that can include integrated electronics to sense its pressure and displacement. Compared to traditional pneumatic muscle actuators such as the McKibben actuator and other more recent soft actuators, the actuator described in this paper can produce a much higher (40~65%) contraction ratio. In this paper, we describe the design, fabrication, and evaluation of the actuator, as well as the manufacturing process used to create it. We demonstrate the actuator design with several examples that produce 120 and 300 N at pressures of 35 and 105 kPa, respectively, and have contraction ratios of 40-65%. © 2019 Yang, Greczek and Asbeck.

We present a high-displacement pneumatic artificial muscle made of textiles or plastics that can include integrated electronics to sense its pressure and displacement. Compared to traditional pneumatic muscle actuators such as the McKibben actuator and other more recent soft actuators, the actuator described in this paper can produce a much higher (40~65%) contraction ratio. In this paper, we describe the design, fabrication, and evaluation of the actuator, as well as the manufacturing process used to create it. We demonstrate the actuator design with several examples that produce 120 and 300 N at pressures of 35 and 105 kPa, respectively, and have contraction ratios of 40-65%. © 2019 Yang, Greczek and Asbeck.

We present a high-displacement pneumatic artificial muscle made of textiles or plastics that can include integrated electronics to sense its pressure and displacement. Compared to traditional pneumatic muscle actuators such as the McKibben actuator and other more recent soft actuators, the actuator described in this paper can produce a much higher (40~65%) contraction ratio. In this paper, we describe the design, fabrication, and evaluation of the actuator, as well as the manufacturing process used to create it. We demonstrate the actuator design with several examples that produce 120 and 300 N at pressures of 35 and 105 kPa, respectively, and have contraction ratios of 40-65%. © 2019 Yang, Greczek and Asbeck.

type:Journal Article, A mechanically induced current (MIC) in a polypyrrole/Au-coated membrane (PPy/Au-membrane) composite with various surface morphologies was investigated, and the electrolyte conditions were determined in an electrochemical cell. A MIC was induced on porous PPy/Au-membranes with a thin layer of PPy. Conversely, relatively small MICs were observed in non-highly porous films such as freestanding films and PPy/Au-membranes with thick PPy deposits. A MIC smaller by one order of magnitude was also observed in a Au-membrane without PPy. These results indicated that the MICs was due to a charging phenomenon in both the redox and the double layer capacitances. The MIC also varied with supporting electrolyte and their concentration. The MIC was strongly reduced in solutions with diluted electrolytes and with bulky cationic electrolytes, indicating that the number and the penetration speed of mobile ions limited the magnitude of the MIC. These characteristics indicated that the MIC was essentially a diffusion limited current. A two-electrode MIC cell was also configured to investigate a power generation film in a normal saline solution, which can possibly be utilized for biomedical applications., source:https://doi.org/10.1016/j.electacta.2011.02.089

This article presents a soft pneumatic bending actuator using a magnetically assisted bilayer composite composed of silicone polymer and ferromagnetic particles. Bilayer composites were fabricated by mixing ferromagnetic particles to a prepolymer state of silicone in a mold and asymmetrically distributed them by applying a strong non-uniform magnetic field to one side of the mold during the curing process. The biased magnetic field induces sedimentation of the ferromagnetic particles toward one side of the structure. The nonhomogeneous distribution of the particles induces bending of the structure when inflated, as a result of asymmetric stiffness of the composite. The bilayer composites were then characterized with a scanning electron microscopy and thermogravimetric analysis. The bending performance and the axial expansion of the actuator were discussed for manipulation applications in soft robotics and bioengineering. The magnetically assisted manufacturing process for the soft bending actuator is a promising technique for various applications in soft robotics., Novel Aerospace Materials

This article presents a soft pneumatic bending actuator using a magnetically assisted bilayer composite composed of silicone polymer and ferromagnetic particles. Bilayer composites were fabricated by mixing ferromagnetic particles to a prepolymer state of silicone in a mold and asymmetrically distributed them by applying a strong non-uniform magnetic field to one side of the mold during the curing process. The biased magnetic field induces sedimentation of the ferromagnetic particles toward one side of the structure. The nonhomogeneous distribution of the particles induces bending of the structure when inflated, as a result of asymmetric stiffness of the composite. The bilayer composites were then characterized with a scanning electron microscopy and thermogravimetric analysis. The bending performance and the axial expansion of the actuator were discussed for manipulation applications in soft robotics and bioengineering. The magnetically assisted manufacturing process for the soft bending actuator is a promising technique for various applications in soft robotics., Novel Aerospace Materials

Robotic systems are increasingly being utilized in applications that require interaction with humans. In order to enable safe physical human-robot interaction, light weight and compliant manipulation are desirable. These requirements are problematic for many conventional actuation systems, which are often heavy, and typically use high stiffness to achieve high performance, leading to large impact forces upon collision. However, pneumatic artificial muscles (PAMs) are actuators that can satisfy these safety requirements while offering power-to-weight ratios comparable to those of conventional actuators. PAMs are extremely lightweight actuators that produce force in response to pressurization. These muscles demonstrate natural compliance, but have a nonlinear force-contraction profile that complicates modeling and control. This body of research presents solutions to the challenges associated with the implementation of PAMs as actuators in robotic manipulators, particularly with regard to modeling, design, and control. An existing PAM force balance model was modified to incorporate elliptic end geometry and a hyper-elastic constitutive relationship, dramatically improving predictions of PAM behavior at high contraction. Utilizing this improved model, two proof-of-concept PAM-driven manipulators were designed and constructed; design features included parallel placement of actuators and a tendon-link joint design. Genetic algorithm search heuristics were employed to determine an optimal joint geometry; allowing a manipulator to achieve a desired torque profile while minimizing the required PAM pressure. Performance of the manipulators was evaluated in both simulation and experiment employing various linear and nonlinear control strategies. These included output feedback techniques, such as proportional-integral-derivative (PID) and fuzzy logic, a model-based control for computed torque, and more advanced controllers, such as sliding mode, adaptive sliding mode, and adapt

Open Access - Förlagets fulltext: https://dl.acm.org/doi/10.1145/3472749.3474802

Práce obsahuje seznam vybraných nových nekonvenčních pohonů, které se objevily za posledních 10 let, matematicko-fyzikální model 3D-Elastomerového pohonu, jeho konstrukci a testování. Seznam je rozdělen podle principu a typu na 6 kategorií a sice pohony pneumatické, hydraulické, měkké, piezoelektrické, mikro/nano a s tvarovou pamětí. Konstrukce pohonu využívá 3D tisknu a odlévání silikonu k sestrojení měkkého pneumatického pohonu se třemi stupni volnosti ohybu. Pohon je následně testován na ohyb a prodloužení., This report contains a list of new chosen uncommon actuators that emerged in the last 10 years, mathematical model of 3D-Elastomer actuator, construction and testing of 3D-Elastomer actuator. The list is divided by the priciple and the type to 6 categories, which are pneumatic actuators, hydraulic actuators, soft actuators, piezoelectric actuators, micro/nano actuators and shape memory actuators. The construction of actuator is using 3D printing technology and silicone molding to build soft pneumatic actuator with three degrees of freedom of bending. Actuator is then tested for its elongation and bending parametres.

Práce obsahuje seznam vybraných nových nekonvenčních pohonů, které se objevily za posledních 10 let, matematicko-fyzikální model 3D-Elastomerového pohonu, jeho konstrukci a testování. Seznam je rozdělen podle principu a typu na 6 kategorií a sice pohony pneumatické, hydraulické, měkké, piezoelektrické, mikro/nano a s tvarovou pamětí. Konstrukce pohonu využívá 3D tisknu a odlévání silikonu k sestrojení měkkého pneumatického pohonu se třemi stupni volnosti ohybu. Pohon je následně testován na ohyb a prodloužení., This report contains a list of new chosen uncommon actuators that emerged in the last 10 years, mathematical model of 3D-Elastomer actuator, construction and testing of 3D-Elastomer actuator. The list is divided by the priciple and the type to 6 categories, which are pneumatic actuators, hydraulic actuators, soft actuators, piezoelectric actuators, micro/nano actuators and shape memory actuators. The construction of actuator is using 3D printing technology and silicone molding to build soft pneumatic actuator with three degrees of freedom of bending. Actuator is then tested for its elongation and bending parametres.

Práce obsahuje seznam vybraných nových nekonvenčních pohonů, které se objevily za posledních 10 let, matematicko-fyzikální model 3D-Elastomerového pohonu, jeho konstrukci a testování. Seznam je rozdělen podle principu a typu na 6 kategorií a sice pohony pneumatické, hydraulické, měkké, piezoelektrické, mikro/nano a s tvarovou pamětí. Konstrukce pohonu využívá 3D tisknu a odlévání silikonu k sestrojení měkkého pneumatického pohonu se třemi stupni volnosti ohybu. Pohon je následně testován na ohyb a prodloužení., This report contains a list of new chosen uncommon actuators that emerged in the last 10 years, mathematical model of 3D-Elastomer actuator, construction and testing of 3D-Elastomer actuator. The list is divided by the priciple and the type to 6 categories, which are pneumatic actuators, hydraulic actuators, soft actuators, piezoelectric actuators, micro/nano actuators and shape memory actuators. The construction of actuator is using 3D printing technology and silicone molding to build soft pneumatic actuator with three degrees of freedom of bending. Actuator is then tested for its elongation and bending parametres.