Fishing line artificial muscle|Peltier element|Control device

既存の電動義手には柔軟性に乏しい、駆動音がする、重いといった問題がある。これらの問題を解決する方法としてアクチュエータに人工筋肉を使用するということが考えられる。人工筋肉には様々な種類があるが、近年注目されているのはMITのHainesらのグループが発表した釣り糸人工筋肉である。この人工筋肉は高出力、低コスト、高い量産性を持つが、動作方法についてはまだ確立されていない。本研究ではペルチェ素子を用いた制御装置を製作し、市販されているロボットハンドに釣り糸人工筋肉と制御装置を組み込み、動作検証を行なった。Existing electric prostheses have problems such as poor flexibility, driving noise, and heavy weight.It is conceivable to use artificial muscles instead of electric motors for actuator as a method to solve these problems. Recently, the artificial muscles made by fishing line has attracted attention among the various types of artificial muscles. This artificial muscle has high power, low cost and high productivity, but its operation method has not been established yet. We developed a thermal control device using a peltier element and incorporated a method of twisting fishing lines as artificial muscles.We used it for actuator in robot hand. The thermal control device could control robot hand and we verified its operation

Role of digital supply chain in promoting sustainable supply chain performance: the mediating of supply chain integration and information sharing

AbstractPurposeThe study investigated the relationship between digital supply chain (DSC) and sustainable supply chain performance (SSCP) of small and medium-sized enterprises (SMEs) via the lens of supply chain integration (SCI) and information sharing (IS). This study concentrates more on the mediating role of SCI and IS in the link between DSC and SSCP that no research has mentioned before.Design/methodology/approachThis research figures out how the DSC impacts the performance of the organization and the supply chain. By employing a carefully designed questionnaire to gather data, a quantitative methodology was employed. Managers at the senior and medium levels were the responders who were targeted. There are 467 valid replies gathered from the primary survey. The data results were used in the analysis using partial least squares structural equation modeling (PLS-SEM).FindingsThe findings imply that SCI’s function in the information-sharing process is crucial as it fosters cooperation, coordination and connectivity throughout the DSC. Furthermore, the study’s conclusions offer helpful information on how businesses might enhance supply chain performance through information exchange. Businesses are constantly concentrating on the role that the DSC plays as a catalyst for sustainable growth and are improving supply chain performance through SCI and information exchange.Originality/valueThis study highlights the gaps and unexplored themes in the existing literature, catalogs the DSC published in the main logistics journals and helps people recognize and appreciate this kind of work. It also has the potential to contribute to future research on SSCP. Moreover, the novelty research is further reinforced by the coverage of the newfound mechanism, where SCI and IS mediate the relationship between DSC and SSCP, directly and positively enhancing SSCP

An overview of novel actuators for soft robotics

In this systematic survey, an overview of non-conventional actuators particularly used in soft-robotics is presented. The review is performed by using well-defined performance criteria with a direction to identify the exemplary and potential applications. In addition to this, initial guidelines to compare the performance and applicability of these novel actuators are provided. The meta-analysis is restricted to five main types of actuators: shape memory alloys (SMAs), fluidic elastomer actuators (FEAs), shape morphing polymers (SMPs), dielectric electro-activated polymers (DEAPs), and magnetic/electro-magnetic actuators (E/MAs). In exploring and comparing the capabilities of these actuators, the focus was on eight different aspects: compliance, topology-geometry, scalability-complexity, energy efficiency, operation range, modality, controllability, and technological readiness level (TRL). The overview presented here provides a state-of-the-art summary of the advancements and can help researchers to select the most convenient soft actuators using the comprehensive comparison of the suggested quantitative and qualitative criteria

Control system design for twisted and coiled polymer actuators

東京電機大学201

Thermomechanical Modeling of Polymerica Actuators

In this dissertation, the application of smart polymers as actuators was investigated, with focuses on shape memory polymers and twisted-then-coiled artificial muscles. Thermomechanical models have been developed for various polymeric actuators, so as to facilitate interpretation of the underlying mechanisms and to provide guidance for future design. The classical one-way shape memory effect in amorphous shape memory polymers was first reproduced. The amorphous shape memory polymer was treated as a frozen-phase matrix with active-phase inclusions embedded in it. A phase evolution law was proposed from the physics perspective and the Mori-Tanaka approach was used to predict the effective mechanical properties. Then, a phenomenological constitutive model was developed based on the multiple natural configurations framework for the semi-crystalline two-way shape memory effect. The model elucidated how the programming procedure affect the crystallization behavior and eventually determine the two-way shape memory effect via storage of internal stress. Artificial muscles with hierarchical chiral structure that can offer a hundredfold increase in power over natural muscles of equivalent lengths have recently been demonstrated experimentally. To investigate the physical origin behind the remarkable tensile actuation behavior and, therefore, the correlation between the actuation performance and the intrinsic material parameters, a multi-scale modeling framework from macro-scale helical spring structure top-down to the molecular chain interaction has been developed Then, based on the prediction results of the multi-scale model, a new type of hierarchical chiral structured artificial muscle was fabricated using two-way shape memory polymer fiber. The usual improvement in the axial actuation of the twisted-then-coiled muscles were demonstrated both experimentally and theoretically

Thermo-Mechanical Modeling and the Application of Coiled Polymer Actuators in Soft Robotics and Biomimetics

Coiled polymer actuators (CPA) are a recently discovered smart material. Due to their large tensile stoke and power densities they are often used as actuators or artificial muscles. CPA’s are fabricated from a polymer fiber, typically nylon, mechanically twisted into a coil or coiled around a mandrel and annealed. When heated over the glass transition temperature they can contract, expand or exhibit torsional actuation, depending on the fabrication method and end conditions. The fabrication and application of CPA is well documented and has made many innovations in the fields of smart materials, soft robotics and the likes. However, there is a lack of knowledge in the modeling of CPA, this is partly due to the novelty of the actuator. To address this problem, a theoretical and experimental investigation of thermo-mechanical response is proposed. An energy and variational methods and continuum mechanics approach is utilized with numerical methods to describe the actuation response. To verify the model, the numerical simulation displacement response is compared to CPA samples that are fabricated and experimentally tested in lab using a dynamic machine analyzer (DMA). The results indicate the proposed model accurately predict the actuation response of the CPA under thermal loading. The numerical simulation and experimental comparison is in good agreement and helps to further understand the underlining cause of the actuation behavior of the coiled polymer actuator. Furthermore, the model can be used in application purposes where the results of the model can be used in designing and optimizing soft robotics using CPA as an artificial muscle. In addition to the numerical and experimental investigation of the CPA’s thermomechanical response, an application in biomimetics is being studied. Biomimetics is an interdisciplinary field in engineering and sciences used to overcoming complex human challenges by designing and fabricating materials and systems modeled after nature. Applications of biomimicry can be seen in many technological advancements such as catheters, hearing devices, and artificial appendages such as arms, legs and fingers. The inspiration for this study is the hydrofoil like structured pectoral fin of the Harbor Porpoise whale. Studies will be focused on understanding the fluid forces acting on the pectoral fin. First and foremost, a highly accurate pectoral fin is fabricated from CT scans of a Harbor Porpoise whale fin. 3D models are obtained using Simpleware ScanIP and post-processed in Autodesk for 3D printing components, which were used to assemble to artificial whale fin. An array of thermally driven Coiled Polymer Actuators (CPA) fabricated from Nylon and heated with Nichrome are used as artificial muscles for actuating the pectoral fin. CPA’s were used for their similarity to biological muscles and are of great interest due to its high specific power and large actuation stroke. A simple control circuit for supplying power to the Nichrome heating wires is developed using an Arduino and motor drivers. The displacement over time of the fin is tested and captured using a laser distant sensor. The fin shows a great displacement response, largely deflecting in both direction relative to its size. The artificial fin was then be further utilized in our studies. The fluid forces imposed on the fin while in motion was measured in a laboratorycontrolled setting. A low-velocity belt driven tow tank was used to displace the artificial fin through water. The tow velocity was varied, and the drag force measurements were taken with and without fin actuation using a cantilever beam load cell. A theoretical derived drag force was compared to the experimental drag data and showed good comparison for the non-actuated fin. Increased drag was exhibited with actuation in both directions when towed through water. This demonstrates the ability of the fin to manipulate is geometry to change the drag force on itself serving as a controllable hydrofoil. We hope to elaborate on this ability and apply it to mechanical designs such as under and above water vehicles

Soft actuator and agile soft robot

Robots play an important part in many aspects of our society by doing repetitive, dangerous, or precision tasks. Most existing robots are made of rigid components, which lack passive compliance and pose a challenge in adapting to the environment and safe human-robot interaction. Rigid robots may be equipped with sensors and programmed with proprioceptive feedback control to achieve active compliance, but this may fail in the event of unforeseen situations or sensor failure. In contrast, animals have evolved flexible or soft body parts to help them adapt to changing environments. Soft robotics is an emerging field in robotics, drawing inspiration from nature by integrating soft material into the actuator and mechanical design. With the inclusion of soft material, soft actuators and robots can deform actively/passively, making it possible to sense, absorb impact, and adapt to its environment with deformation. However, while soft actuators/robots have superior properties to rigid ones, they are often challenging to manufacture and control precisely. In addition, they may suffer from slow speed and material degradation. Thus, in this thesis, we aim to address the issues in developing high-performance soft actuators and soft robots. The thesis is divided into two parts. In the first part, we focus on improving the manufacturability and performance of a self-contained soft actuator originated in the Creative Machines Lab. The soft actuator is composed of a cured silicone-ethanol mixture embedded with heating coils. When the coils are electrically actuated, ethanol trapped inside undergoes liquid-vapor transitions, and thus the actuator undergoes extreme volume change. While this actuator exhibits high strain and high stress, it is very slow to actuate, has limited life cycles, and requires molds to manufacture. The first part of the thesis will address these issues. Specifically, in chapter 2, we discuss using multi-material 3D printing to automate the manufacturing of silicone-ethanol composite. In chapter 3, we discuss using laser-cut flexible Kirigami patterns to improve the manufacturability of its heating element. Chapter 4 characterizes its actuation profile and addresses improvements to the thermal conductivity by infusing thermally conductive fillers. Soft actuation is an actively researched area; however, many high-performance soft actuators are challenging to manufacture and thus are less accessible to the general robotics community. Conventional actuators such as electric motors are widely available but lack flexibility. Therefore, the second part of the thesis aims at combining rigid motors with soft materials to design and control high-performance hybrid soft robots. Simulation is a good way to evaluate and optimize robot design and control. However, existing simulators that support motor-driven soft robots have limited features. Chapter 5 discusses this issue and presents a physically based real-time soft robot simulator capable of simulating motor-driven soft robots. In addition, chapter 5 presents the design and control of a 3D printed hybrid soft quadruped robot. Chapter 6 presents the design and control of a 3D printed hybrid soft humanoid robot. The two parts of the thesis aim to improve aspects in soft actuators and soft robots. In conclusion, we summarize the lessons learned in developing soft actuators/robots and new possibilities and challenges for advancing soft robotics research