Dissertations / Theses on the topic 'Soft robots material and design'

This practice-led research examines how the emerging role of the ‘material designer’ can enrich the design process in Human Computer Interaction. It advocates embodiment as a design methodology by employing tacit knowledge; focusing on a subjective, affective and visceral engagement with computational materials. This theoretical premise is explored by drawing on the fields of soft robotics, as well as transitive and programmable materials. With the advancement and democratisation of physical computing and digital fabrication, it is now possible for designers to process, or even invent and composite new programmable materials, merging both their physical and digital capabilities. This study questions how the notion of soft can develop a distinct space for the design of novel user interfaces. This premise is applied through a phenomenological understanding of technology development—as opposed to generating data which is solely reliant on observable and measurable evidence. Bio-engineered technologies such as electroactive polymer, pneumatic and hydraulic actuator systems are deployed to explore a new type of responsive, sensual and organic materiality. Here, traditional medical diagnostic applications such as microfluidics are transferred into the experimental contexts of textiles and wearable technology. Therefore, by thinking through physical prototyping, a bodily engagement with materials and the interpretation of the elements of water, air and steam; a designer can create a fertile ground for a polyvalent imagination. Together, this methodology is used as a qualitative system for collecting and evaluating data on the significance of design-led thinking in soft robotic materials. This research concludes that there are insights to be gained from the creative practice and exploratory methods of material-led thinking in HCI that can contribute to the commercial research and development fields of wearable technology. Outputs include a prototype box of ‘Invention Tools’ for textile designers and the identification and creation of the role 04 of embodied making in relation to the imagination. Further, soft composite hybrids, incorporating elastomers, have potential applications in colour, texture and shape changing surfaces. Thus, this thesis argues that it is within the creative soft sciences that the next advancements in soft robotics may emerge.

Disaster support and recovery generally involve highly irregular and dangerous environments. Modular robots are a salient solution to support search and rescue efforts but are still limited to do their reliance on a rigid structure design. To enhance flexibility and resilience to damage, a soft-body interconnection mechanism for self-reconfigurable modular robotic systems has been developed. The soft-body interconnection mechanism utilizes elastomeric polymers instead of a rigid body. Hence, it is capable of deforming under extreme loads without damage. This thesis presents the work completed towards the realization of a soft-body interconnection mechanism. The functional requirements of the soft-body mechanism were broken down into two separate modules for extension and capture. An initial simulation demonstrated the inability of using a simulated model made of hypo-elastic materials as a basis for design. Hence, an iterative design process was used to develop an initial extension and capture soft-body mechanisms that conformed to the desired performance parameters. An empirical study which varied multiple structural parameters was then completed with the initial extension and capture soft-body mechanisms as a basis for the modified designs. The data from the study was correlated with measured performance data with resulted in diagrams useful for the optimal design of soft-body extension and capture mechanisms. The use of the diagrams for design was demonstrated in the design and development of a soft-body interconnection mechanism for an in-house designed small hard shell modular robot system.

Lorsque des changements inattendus de la surface du sol se produisent lors de la marche, le système nerveux central humain doit appliquer des mesures de contrôle appropriées pour assurer une stabilité dynamique. De nombreuses études dans le domaine de la commande moteur ont étudié les mécanismes d'un tel contrôle postural et ont largement décrit comment les trajectoires du centre de masse (COM), le placement des pas et l'activité musculaire s'adaptent pour éviter une perte d'équilibre. Les mesures que nous avons effectuées montrent qu'en arrivant sur un sol mou, les participants ont modulé de façon active les forces de réaction au sol (GRF) sous le pied de support afin d'exploiter les propriétés élastiques et déformables de la surface pour amortir l'impact et probablement dissiper l'énergie mécanique accumulée pendant la ‘chute’ sur la nouvelle surface déformable. Afin de contrôler plus efficacement l'interaction pieds-sol des robots humanoïdes pendant la marche, nous proposons d'ajouter des semelles extérieures souples (c'est-à-dire déformables) aux pieds. Elles absorbent les impacts et limitent les effets des irrégularités du sol pendant le mouvement sur des terrains accidentés. Cependant, ils introduisent des degrés de liberté passifs (déformations sous les pieds) qui complexifient les tâches d'estimation de l'état du robot et ainsi que sa stabilisation globale. Pour résoudre ce problème, nous avons conçu un nouveau générateur de modèle de marche (WPG) basé sur une minimisation de la consommation d'énergie qui génère les paramètres nécessaires pour utiliser conjointement un estimateur de déformation basé sur un modèle éléments finis (FEM) de la semelle souple pour prendre en compte sa déformation lors du mouvement. Un tel modèle FEM est coûteux en temps de calcul et empêche la réactivité en ligne. Par conséquent, nous avons développé une boucle de contrôle qui stabilise les robots humanoïdes lors de la marche avec des semelles souples sur terrain plat et irrégulier. Notre contrôleur en boucle fermée minimise les erreurs sur le centre de masse (COM) et le point de moment nul (ZMP) avec un contrôle en admittance des pieds basé sur un estimateur de déformation simplifié. Nous démontrons son efficacité expérimentalement en faisant marcher le robot humanoïde HRP-4 sur des graviers
When unexpected changes of the ground surface occur while walking, the human central nervous system needs to apply appropriate control actions to assure dynamic stability. Many studies in the motor control field have investigated the mechanisms of such a postural control and have widely described how center of mass (COM) trajectories, step patterns and muscle activity adapt to avoid loss of balance. Measurements we conducted show that when stepping over a soft ground, participants actively modulated the ground reaction forces (GRF) under the supporting foot in order to exploit the elastic and compliant properties of the surface to dampen the impact and to likely dissipate the mechanical energy accumulated during the ‘fall’ onto the new compliant surface.In order to control more efficiently the feet-ground interaction of humanoid robots during walking, we propose adding outer soft (i.e. compliant) soles to the feet. They absorb impacts and cast ground unevenness during locomotion on rough terrains. However, they introduce passive degrees of freedom (deformations under the feet) that complexify the tasks of state estimation and overall robot stabilization. To address this problem, we devised a new walking pattern generator (WPG) based on a minimization of the energy consumption that offers the necessary parameters to be used jointly with a sole deformation estimator based on finite element model (FEM) of the soft sole to take into account the sole deformation during the motion. Such FEM computation is time costly and inhibit online reactivity. Hence, we developed a control loop that stabilizes humanoid robots when walking with soft soles on flat and uneven terrain. Our closed-loop controller minimizes the errors on the center of mass (COM) and the zero-moment point (ZMP) with an admittance control of the feet based on a simple deformation estimator. We demonstrate its effectiveness in real experiments on the HRP-4 humanoid walking on gravels

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 223-236).
The goal of this thesis is to explore how autonomous robotic systems can be created with soft elastomer bodies powered by fluids. In this thesis we innovate in the design, fabrication, control, and experimental validation of both single and multi-segment soft fluidic elastomer robots. First, this thesis describes an autonomous fluidic elastomer robot that is both self-contained and capable of rapid, continuum body motion. Specifically, the design, modeling, fabrication, and control of a soft fish is detailed, focusing on enabling the robot to perform rapid escape responses. The robot employs a compliant body with embedded actuators emulating the slender anatomical form of a fish. In addition, the robot has a novel fluidic actuation system that drives body motion and has all the subsystems of a traditional robot on-board: power, actuation, processing, and control. At the core of the fish's soft body is an array of Fluidic Elastomer Actuators (FEAs). The fish is designed to emulate escape responses in addition to forward swimming because such maneuvers require rapid body accelerations and continuum body motion. These maneuvers showcase the performance capabilities of this self-contained robot. The kinematics and controllability of the robot during simulated escape response maneuvers are analyzed and compared to studies on biological fish. During escape responses, the soft-bodied robot is shown to have similar input-output relationships to those observed in biological fish. The major implication of this portion of the thesis is that a soft fluidic elastomer robot is shown to be both self-contained and capable of rapid body motion. Next, this thesis provides an approach to planar manipulation using soft fluidic elastomer robots. That is, novel approaches to design, fabrication, kinematic modeling, power, control, and planning as well as extensive experimental evaluations with multiple manipulator prototypes are presented. More specifically, three viable manipulator morphologies composed entirely from soft silicone rubber are explored, and these morphologies are differentiated by their actuator structures, namely: ribbed, cylindrical, and pleated. Additionally, three distinct casting-based fabrication processes are explored: lamination-based casting, retractable-pin-based casting, and lost-wax- based casting. Furthermore, two ways of fabricating a multiple DOF manipulator are explored: casting the complete manipulator as a whole, and casting single DOF segments with subsequent concatenation. An approach to closed-loop configuration control is presented using a piecewise constant curvature kinematic model, real-time localization data, and novel fluidic drive cylinders which power actuation. Multi-segment forward and inverse kinematic algorithms are developed and combined with the configuration controller to provide reliable task-space position control. Building on these developments, a suite of task-space planners are presented to demonstrate new autonomous capabilities from these soft robots such as: (i) tracking a path in free-space, (ii) maneuvering in confined environments, and (iii) grasping and placing objects. Extensive evaluations of these capabilities with physical prototypes demonstrate that manipulation with soft fluidic elastomer robots is viable. Lastly, this thesis presents a robotic manipulation system capable of autonomously positioning a multi-segment soft fluidic elastomer robot in three dimensions while subject to the self-loading effects of gravity. Specifically, an extremely soft robotic manipulator morphology that is composed entirely from low durometer elastomer, powered by pressurized air, and designed to be both modular and durable is presented. To understand the deformation of a single arm segment, a static physics-based model is developed and experimentally validated. Then, to kinematically model the multi-segment manipulator, a piece-wise constant curvature assumption consistent with more traditional continuum manipulators is used. Additionally, a complete fabrication process for this new manipulator is defined and used to make multiple functional prototypes. In order to power the robot's spatial actuation, a high capacity fluidic drive cylinder array is implemented, providing continuously variable, closed-circuit gas delivery. Next, using real-time localization data, a processing and control algorithm is developed that generates realizable kinematic curvature trajectories and controls the manipulator's configuration along these trajectories. A dynamic model for this multi-body fluidic elastomer manipulator is also developed along with a strategy for independently identifying all unknown components of the system: the soft manipulator, its distributed fluidic elastomer actuators, as well as its drive cylinders. Next, using this model and trajectory optimization techniques locally-optimal, open-loop control policies are found. Lastly, new capabilities offered by this soft fluidic elastomer manipulation system are validated with extensive physical experiments. These are: (i) entering and advancing through confined three-dimensional environments, (ii) conforming to goal shape-configurations within a sagittal plane under closed-loop control, and (iii) performing dynamic maneuvers we call grabs.
by Andrew D. Marchese.
Ph. D.

Compliant mechanisms are flexible structures that utilize elastic deformation to achieve their desired motions. Using this unique mode of actuation, the compliant mechanisms have two distinct advantages over traditional rigid machines: (1) They can create highly repeatable motions that are critical for many high precision applications. (2) Their high degrees-of-freedom motions have the potential to achieve mechanical functionalities that are beyond traditional machines, making them especially appealing for miniature robots that are currently limited to only having simple rigid-body-motions and gripping functionalities. Unfortunately, despite the potential of compliant mechanisms, there are still several key challenges that restrict them from realizing their full potential. To facilitate this discussion, we first divide the compliant mechanisms into two categories: (1) the stiffer flexural mechanisms that are ideal for high precision applications, and (2) the more compliant miniature soft robots that can reshape their geometries to achieve highly complex mechanical functionalities. The key limitation for existing flexural mechanisms is that their stiffness and dynamic properties cannot be optimized when they have multi-degrees-of-freedom. This limitation has severely crippled the performance of flexural mechanisms because their stiffness and dynamic properties dictate their workspace, transient responses and capabilities to reject disturbances. On the other hand, miniature soft robots that have overall dimensions smaller than 1 cm, are unable to achieve their full potential because existing works do not have a systematic approach to determine the required design and control signals for the robots to generate their desired time-varying shapes.

Soft robotic systems have recently been considered as a new approach that is in principle better suited for tasks where safety and adaptability are important. That is because soft materials are inherently compliant and resilient in the event of collisions. They are also lightweight and can be low-cost; in general, soft robots have the potential to achieve many tasks that were not previously possible with traditional robotic systems. In this paper, we propose a new manufacturing process for creating multi-chambered pneumatic actuators and robots. We focus on using fabric as the primary structural material, but plastic films can be used instead of textiles as well. We introduce two different methods to create layered bellows actuators, which can be made with a heat press machine or in an oven. We also describe origami-like actuators with possible corner structures. Moreover, the fabrication process permits the creation of soft and soft/rigid hybrid robotic systems, and enables the easy integration of sensors into these robots. We analyze various textiles that are possibly used with this method, and model bellows actuators including operating force, restoring force, and estimated geometry with multiple bellows. We then demonstrate the process by showing a bellows actuator with an embedded sensor and other fabricated structures and robots. We next present a new design of a multi-DOF soft/rigid hybrid robotic manipulator. It contains a revolute actuator and several roll-pitch actuators which are arranged in series. To control the manipulator, we use a new variant of the piece-wise constant curvature (PCC) model. The robot can be controlled using forward and inverse kinematics with embedded inertial measurement units (IMUs). A bellows actuator, which is a subcomponent of the manipulator, is modeled with a variable-stiffness spring, and we use the model to predict the behavior of the actuator. With the model, the roll-pitch actuator stiffnesses are measured in all directions through applying forces and torques. The stiffness is used to predict the behavior of the end effector. The robotic system introduced achieved errors of less than 5% when compared to the models, and positioning accuracies of better than 1cm.
Doctor of Philosophy

Research within the field of human motion assistive device development, with the purpose of reducing the metabolic cost of daily activities, is seeing the benefits of the exclusive use of passive actuators to store and release energy during the gait cycle. Designs of novel exoskeletons at the University of Ottawa implement the Pneumatic Artificial Muscle (PAM) as the primary method of nonlinear, passive actuation. The PAM is proven as a superior actuator for these devices when compared to the linear mechanical springs used by other researchers. There are, however, challenges regarding PAM pressure loss and the limitation of PAM elongation that have been identified. This thesis aims to develop a hyperelastic tubular soft composite that replicates the distinctive mechanical behaviour of the PAM without the need for internal pressurization. The final soft composite solution was achieved by impregnating a prefabricated polyethylene terephthalate braided sleeve, held at a high initial fibre angle, with a silicone prepolymer. A comprehensive experimental evaluation was performed on numerous prototypes for a variety of customizable design parameters including: initial fibre angle, silicone stiffness, and braided sleeve style. Moreover, two separate analytical models were formulated based on incompressible finite elasticity theory using either a structural model of Holzapfel’s type, or a phenomenological model of Fung’s type. Both models were in good agreement with the experimental data that were collected through a modified extension-inflation test. This research has successfully developed, tested, and validated an innovative soft composite that can achieve specific mechanical properties, such as contraction distance and nonlinear stiffness, for optimal use in human motion assistive devices.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第10287号
農博第1359号
新制||農||870(附属図書館)
学位論文||H15||N3808(農学部図書室)
UT51-2003-H708
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 梅田 幹雄, 教授 笈田 昭, 助教授 大須賀 公一
学位規則第4条第1項該当

Soft robotic systems are becoming increasingly popular as they are generally safer, lighter, and easier to manufacture than their more rigid, traditional counterparts. These advantages allow an increased sense of freedom in both the design and operation of these platforms. In this work, we seek methods of leveraging this freedom to both design and plan motions for two different serial-chain, pneumatically actuated manipulators developed by Pneubotics, a small startup company based in San Francisco. In doing so, we focus primarily on two related endeavors: (1) the optimal kinematic design of these and other similar robots (i.e., choosing link lengths, base positioning, etc.), and (2) the planning of smooth paths in joint space that enable these robots to perform useful tasks. Our method of design optimization employs a genetic algorithm in combination with maximin multi-objective optimization techniques to efficiently generate a diverse set of Pareto optimal designs. This set represents the optimal region of the design space and highlights inherent tradeoffs that designers must make when choosing a particular set of design parameters for manufacture. In our work, we have chosen to optimize inflatable robots to be both dexterous, and to be able to support loads near the ground with limited deflection. We have also applied our framework to optimize a plastic manipulator to perform painting motions. In our approach to motion planning we simultaneously optimize the base position and joint motions of a robot in order to enable its end effector to follow a smooth desired trajectory. While this method of path planning generalizes to any kind of robot, we envision it to be especially applicable to soft robots and other mobile robots that can be quickly and easily repositioned to perform tasks in varying environments. Our method of path planning works by moving a set of virtual robot arms (each representing a single configuration in a sequence) branching from a common base, to a number of assigned target poses associated with a task. Additional goals and hard constraints (including joint limits) are naturally incorporated. The optimization problem at the core of this method is a quadratic program, allowing constrained high-dimensional problems to be solved in very little time. We demonstrate our method by planning and performing painting motion on two different systems. We also demonstrate in simulation how our planner could be used to perform several common tasks including those involving, pick-and-place, wiping and wrapping motions.

In this study, a soft assisted mobilizer called MOSAR from (Mobilizador Suave de Asistencia y Rehabilitación) for upper limb rehabilitation was developed for a 11 years old child with right paretic side. The mobilizer provides a new therapeutic approach to augment his upper limb active use and rehabilitation, by means of exerting elbow (flexion-extension), forearm (pronation-supination) and (flexion-extension along with ulnar-radial deviations) at the wrist. Preliminarily, the design concept of the soft mobilizer was developed through Reverse Engineering of his upper limb: first casting model, silicone model, and later computational model were obtained by 3D scan, which was the parameterized reference for MOSAR development. Then, the manufacture of fabric inflatable soft actuators for driving the MOSAR system were carried out. Lastly, a law close loop control for the inflation-deflation process was implemented to validate FISAs performance. The results demonstrated the feasibility and effectiveness of the FISAs for being a functional tool for upper limb rehabilitation protocols by achieving those previous target motions similar to the range of motion (ROM) of a healthy person or being used in other applications.

This work places itself in the field of textile design, weaving and interactive objects. It explores how the combination of solid and soft materials in a woven structure affect its flexibility and pliability. By integrating solid materials as a weaving material the work aims to propose an alternative context for woven structures, not necessarily becoming fabrics but rather objects that can be interacted with. The design process consisted of series of workshops where woven samples were made on a hand loom, weaving frame and by hand. The result are three woven structures each of which show of different flexibilities attained through the combination of solid and soft materials. The pieces are meant to be interacted with and can be shaped in various ways by folding, stacking or connecting parts of the structure. Combining solid and soft materials with the weaving technique shows the potential of interactive structures and objects which propose multiple functions, and can be developed further into products for interior design or play.

This paper aims to understand whether there is a difference in how socially interactive robots are perceived based on the material they are constructed out of. Two studies to that end were performed; a pilot in a live setting and a main one online. Participants were asked to rate three versions of the same robot design, one built out of wood, one out of plastic, and one covered in fur. This was then used in two studies to ascertain the participants perception of competence, warmth, and discomfort and the differences between the three materials. Statistically significant differences were found between the materials regarding the perception of warmth and discomfort
Denna uppsats undersöker huruvida det finns en skillnad i hur socialt interaktiva robotar uppfattas baserat på vilket material de är tillverkade i. Två studier gjordes för att ta reda på detta: En pilotstudie som skedde fysiskt, och huvudstudien skedde online. Deltagarna ombads att skatta tre versioner av samma robotdesign, där en var byggd i trä, en i plast och en täckt i päls. Dessa användes sedan i två studier för att bedöma deltagarnas uppfattning av robotarnas kompetens, värme och obehag, samt skillnaderna i dessa mellan de tre materialen. Statistiskt signifikanta skillnader hittades i uppfattningen av värme och obehag.

The design and fabrication of a novel soft landing instrument Soft Landing Ion Mobility (SLIM) is described here. Topics covered include history of soft landing, gas phase mobility theory, the design and fabrication of SLIM, as well as applications pertaining to soft landing. Principle applications devised for this instrument involved the gas phase separation and selection of an ionized component from a multicomponent gas phase mixture as combing technique to optimize coatings, catalyst, and a variety of alternative application in the sciences.

De nouvelles solutions basées sur la technologie de l'intégration hydraulique ont été introduites dans la mise en œuvre d'un système robotique humanoïde à actionnement hydraulique compact et léger. Pour ce faire, les chercheurs ont appliqué des méthodes et des technologies récentes basées sur des techniques d'usinage avancées et sur la fabrication additive de métaux. Malgré cela, ces méthodologies ont montré des limites liées non seulement au temps de réalisation, ce qui induit des coûts élevés, mais également au poids total du mécanisme obtenu. Ainsi, il important de développer des travaux de recherche sur de nouvelles méthodologies pour réaliser des mécanismes robotiques hydrauliques intégrés, compacts, légers et à faible coût économiques.C’est l’objet de travail développé dans cette thèse qui a pour objectif de proposer de nouvelles méthodologies pour la fabrication de composants mécaniques de robots humanoïdes à commande hydraulique. Cela concerne, en premier lieu, la fabrication additive de matériaux composites qui sera développée pour la réalisation des pièces structurelles classiques. En second lieu, deux nouvelles méthodologies sont proposées pour l’obtention de composants hydrauliques intégrés légers, avec une résistance élevée et un temps de réalisation et un coût réduits. La première méthodologie consiste à combiner la fabrication additive de polymères thermoplastiques et la simple formation de composites aléatoires en carbone. Tandis que la deuxième propose l'utilisation de tuyaux en silicone à la place des thermoplastiques imprimés tout en gardant le même matériau de renfort. Les deux méthodologies sont détaillées étape par étape et appliquées au bras du robot HYDROïD. Des gains importants sur le poids total du bras sont donnés. Par ailleurs, un nouvel vérin hydraulique composite léger est développé pour remplacer les vérins métalliques dont le poids est fatalement très élevé. Une procédure développée à partir du modèle de contraintes, passant par un processus d'optimisation et se terminant par la conception mécatronique est présentée. L’actionneur hydraulique est mis en œuvre et testé pour l'articulation du genou du robot HYDROïD et une proposition de généralisation à toutes les articulations est également avancée. Enfin, des perspectives à court et à moyen termes pour des développement ultérieur de nouvelles générations de systèmes robotiques à actionnement hydraulique intégré concluent cette thèse
Modern researches have been inducted in the implementation of a compact and lightweight hydraulically actuated humanoid robotic systems, using the technology of hydraulic integration. In the a eld, researchers have applied recent technologies starting from advanced machining methodologies and ending with additive manufacturing of me-tals. Despite, these methodologies have shown inconvenient points related to cost, time and weight of the obtained mechanism. This motivates the research of new methodologies toward developing compact, cost effective and light-weight hydraulic integrated robotics mechanisms, which are discussed in this thesis.This thesis represents new methodologies toward fabricating mechanical components of the hydraulic actuated humanoid robots. This starts with the classical structural parts which will be fabricated using additive manufacturing of composite materials. Then, the hard task comes. Two new methodologies are proposed to obtain hydraulic integra-ted components with lightweight, high strength and with low time and cost. The rst methodology is by combining the additive manufacturing of thermoplastics polymers and the simple forming of random carbon ber composites. While, the second methodology proposes the usage of silicone pipes instead of the printed thermoplastics, keeping the same reinforcement material. The two methodologies are explained step by step and applied to the arm of HYDRO•D robot. Lately, a new lightweight composite hydraulic actuator is developed to replace the heavy weight metallic one. This is using a developed procedure starting from stress model, passing by an optimization process and ending with the mechatronic design. Then, this hydraulic actuator is implemented and tested. This is applied to the knee joint of the robot and generalized to all the robot joints. By the end of this thesis, an important conclusion will be drawn and the perspective of the research will be settled for further development

The commercial exoskeletons are often heavy and bulky, thus reducing the weight and simplifying the form factor becomes a critical task. This thesis details the process of designing and making a low-profile, cable-driven arm exoskeleton. Many advanced methods are explored: 3D scanning, generative design, soft material, compliant joint, additive manufacturing, and 3D latticing. The experiments on TPU kerf cut found that the stress-strain curve of the sample can be modified by changing the cut pattern, it is even possible to control the linear region. The TPU TPMS test showed that given the same volume, changing the lattice parameters can result in different bending stress-strain curves. This thesis also provides many prototypes, test data, and samples for future reference.
Master of Science
Wearing an exoskeleton should be easy and stress-free, but many of the available models are not ergonomic nor user-friendly. To make an exoskeleton that is inviting and comfortable to wear, various nontraditional methods are used. The arm exoskeleton prototype has a lightweight and ergonomic frame, the joints are soft and compact, the cable-driven system is safe and low-profile. This design also brings aesthetics to the exoskeleton which closes the gap between engineering and design.

As the major electricity consumer, electrical machines play a key role for global energy savings. Machine manufacturers put considerable efforts into the development of more efficient electrical machines for loss reduction and higher power density achievements. A consolidated knowledge of the occurring losses in electrical machines is a basic requirement for efficiency improvements. This thesis deals with iron losses in electrical machines. The major focus is on the influences of the stator core magnetic material due to the machine manufacturing process, temperature influences, and the impact of inverter operation. The first part of the thesis gives an overview of typical losses in electrical machines, with focus put on iron losses. Typical models for predicting iron losses in magnetic materials are presented in a comprehensive literature study. A broad comparison of magnetic materials and the introduction of a new material selection tool conclude this part. Next to the typically used silicon-iron lamination alloys for electrical machines, this thesis investigates also cobalt-iron and nickel-iron lamination sheets. These materials have superior magnetic properties in terms of saturation magnetization and hysteresis losses compared to silicon-iron alloys. The second and major part of the thesis introduces the developed measurement system of this project and presents experimental iron loss investigations. Influences due to machine manufacturing changes are studied, including punching, stacking and welding effects. Furthermore, the effect of pulse-width modulation schemes on the iron losses and machine performance is examined experimentally and with finite-element method simulations. For nickel-iron lamination sheets, a special focus is put on the temperature dependency, since the magnetic characteristics and iron losses change considerably with increasing temperature. Furthermore, thermal stress-relief processes (annealing) are examined for cobalt-iron and nickel-iron alloys by magnetic measurements and microscopic analysis. A thermal method for local iron loss measurements is presented in the last part of the thesis, together with experimental validation on an outer-rotor permanent magnet synchronous machine.

QC 20140516

L'alternateur à griffes est l'alternateur le plus utilisé dans l'industrie automobile. Afin d'augmenter sa puissance volumique, une solution classique consiste à utiliser des aimants NdFeB entre les griffes. Ces dernières années, le prix des aimants NdFeB a beaucoup augmenté remettant en question leur utilisation. Ce contexte implique de trouver de nouvelles solutions techniques permettant de conserver la même puissance volumique sans utiliser d'aimant NdFeB. Dans le cadre de ces travaux de thèse la solution proposée consiste a utiliser des matériaux magnétiques doux nobles tels que les FeCo (AFK18, AFK1 et AFK502). De part leur coût élevé, nous avons limité leur utilisation au noyau de l'alternateur même si leur utilisation au rotor est également évaluée. Ces travaux s'appuient sur une démarche de dimensionnement multi-niveaux (modèle reluctant et modèle éléments finis) ce qui apporte un bon compromis temps de calcul/précision. Une série d'études a été réalisée avec dans un premier temps, l'identification d'une géométrie de noyau favorable à l'utilisation de noyau en FeCo. Dans un second temps, une étude compare les courants batteries en fonction du FeCo utilisé au noyau avec une optimisation du rotor. Ensuite une étude présente le dimensionnement complet de l'alternateur (optimisation du rotor et du stator avec une étude sur le nombre optimal de paires de pôles) avec un noyau en AFK502 ce qui d'identifier le gain maximal en courant batterie apporté par l'utilisation d'un noyau en FeCo. Pour finir, une dernière étude compare les courants batteries en fonction du FeCo utilisé au rotor avec une optimisation du rotor et du stator.

The growing demand in the industry towards sustainability and the globalization of manufacturing lead to an industrial climate of constant development and improvements, and automotive interior design is not excluded. In 2017 the European Union declared that the material used to generate the bright chrome surfaces of car interiors (CR VI) is toxic and carcinogenic. This implies that Volvo will ban the use of Chrome VI for decorative parts from September 2024.  Finding a more eco-friendly alternative to replace CR VI not only functionally but also in terms of perceived quality and user experience will be an urgent and decisive action.  In this project, the parameters of gloss, haze, color temperature, and metallic depth are investigated in order to figure out which elements ensure the perceived quality of chrome surfaces.  For this purpose, a user study based on different sensory tests and soft metrology was carried out with 48 people, as well as seven samples, five of them more eco-friendly alternatives. This project aims to introduce a set of tools to assess and guarantee the perception of quality by supporting the development of "chrome-look" surfaces in the automotive interior with new sustainable materials. Through this study, correlating soft and hard metrology, it is observed what makes a surface perceived as "high-quality" and which of the more eco-friendly alternatives could be the most optimal to replace Chrome VI in Volvo's car interiors.

Cette thèse intervient dans le cadre du projet ANR ARMS. L'objectif est de concevoir un système robotisé multi-bras pour la découpe anatomique de muscles. Ce travail vise à développer les modèles mécaniques nécessaires à la mise en place de la stratégie de commande. Il expose le cycle de développement d'un modèle mécanique faisant intervenir la construction de modèles géométriques à partir d'images IRM, l'identification expérimentale des paramètres rhéologiques des matériaux modélisés en passant par les étapes de maillage, de paramétrage, d'implémentation et de validation de tels modèles. Il présente une nouvelle méthode de modélisation dynamique de structures intitulée modèle masse-ressort non-linéaire isotrope transverse, une méthode qui témoigne d'un comportement mécanique alliant réalisme et interactivité. Il intervient aussi dans l'identification dynamique des trajectoires de coupe robotisée en proposant de nouvelles approches de modélisation de la découpe de corps mous et en développant un nouvel algorithme basé sur le calcul de courbures. Cette thèse aborde, aussi, le problème de variabilité des muscles bovins et propose une méthode de recalage dimensionnel du modèle géométrique générique par le biais de transformations géométriques définies par optimisation multicritère d'une fonction objectif. Enfin, en vue de synchroniser le flux d'informations entre les différents modules de commande de la cellule robotisée, une combinaison de la méthode des éléments finis avec la technique de condensation statique de Guyan a permis de développer un modèle mécanique quasi-statique réduit permettant de prédire rapidement l'évolution de la trajectoire de coupe robotisée.

Robot assisted therapy is becoming increasingly popular. Research has proven it can be of benefit to persons dealing with a variety of disorders, such as Autism Spectrum Disorder (ASD), Attention Deficit Hyperactivity Disorder (ADHD), and it can also provide a source of emotional support e.g. to persons living in seniors’ residences. The advancement in technology and a decrease in cost of products related to consumer electronics, computing and communication has enabled the development of more advanced social robots at a lower cost. This brings us closer to developing such tools at a price that makes them affordable to lower income individuals and families. Currently, in several cases, intensive treatment for patients with certain disorders (to the level of becoming effective) is practically not possible through the public health system due to resource limitations and a large existing backlog. Pursuing treatment through the private sector is expensive and unattainable for those with a lower income, placing them at a disadvantage. Design and effective integration of technology, such as using social robots in treatment, reduces the cost considerably, potentially making it financially accessible to lower income individuals and families in need. The Objective of the research reported in this manuscript is to design and implement a social robot that meets the low-cost criteria, while also containing the required functions to support children with ASD. The design considered contains knowledge acquired in the past through research involving the use of various types of technology for the treatment of mental and/or emotional disabilities.

Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia
Atualmente, os robôs operam em diversos tipos de indústria, serviços médicos e até mesmo em aplicações de lazer. Os robôs têm melhorado as suas características ao nível da velocidade, precisão e capacidade de repetição de tarefas. Contudo, os mecanismos robóticos tradicionais são normalmente constituídos por materiais rígidos, apresentando dificuldades de deformação e adaptação, principalmente no manuseamento de objetos frágeis e/ou complexos, assim como em aplicações onde o ambiente não é perfeitamente conhecido. Estas aplicações requerem um comportamento robótico complacente, tanto ao nível de software como de hardware. Assim, surge uma nova subárea da robótica, chamada soft robotics. Baseando-se em estruturas biológicas, esta assenta no desenvolvimento de componentes robóticos com materiais elásticos, flexíveis e de baixa rigidez (materiais suaves). Esta subárea comprovou apresentar potencial significativo na fabricação de grippers e manipuladores. A possibilidade de fabricar estruturas de materiais suaves, permite criar formas realísticas, diminuir o peso, lidar com um vasto número de objetos e aumentar a segurança dos equipamentos. Neste âmbito, esta dissertação apresenta o design e o processo de fabricação de um protótipo de uma mão robótica, atuada pneumaticamente, concebida com materiais suaves, parcialmente fabricados pelo processo de impressão 3D. Este conceito permite o desenvolvimento de uma mão robótica a um custo relativamente reduzido, com forma anatómica e reduzida complexidade de controlo. O estudo do comportamento dos materiais elásticos é também estudado nesta dissertação. É proposto um modelo numérico, utilizado na Análise de Elementos Finitos (FEA) para simular o comportamento da mão quando esta está atuada. Os resultados das simulações são comparados com testes experimentais, comprovando assim parcialmente a viabilidade do modelo numérico.
Nowadays, robots are used in a wide range of applications such as industrial manufacturing, medical services and even in leisure applications. Robots have substantially increased their capabilities in terms of speed, precision and task execution abilities. However, they are commonly made of rigid materials, presenting limitations in terms of deformation and adaptation when handling fragile and/or complex objects, especially when the environment is not entirely known. These applications require a complacent robot behaviour both at software and hardware level. In order to deal with such a requirement, a new robotics subarea, called soft robotics, arises. This new subarea is based on biological structures and allows a designer to create robot components, with elastic, flexible and low rigidity materials (soft materials). Soft robotics has proven its potential in the manufacture of grippers and manipulators. Soft materials provide the ability to create realistic shapes, reduced weight and increase the safety of the equipment. In this context, this dissertation presents the design and manufacture of a pneumatic robotic hand prototype made of soft materials, and partially fabricated by 3D printing. This concept allows the design and fabrication of an anthropomorphic hand at a low cost, with anatomical shape, desired compliance and reduced control complexity (since the number of actuated degrees-of-freedom is lower than the number of degrees-of-freedom of the robotic hand). There is no systematic procedure or methodology to simulate the behaviour of elastic materials. A numerical model implemented in Finite Element Analysis (FEA) is proposed to simulate the hand behaviour when it is actuated. Simulations results proved the model effectiveness when compared with experimental tests.

By using flexible and stretchable materials in place of fixed components, soft robots can materially adapt or change to their environment, providing built-in safeties for robotic operation around humans or fragile, delicate objects. And yet, building a robot out of only soft and flexible materials can be a significant challenge depending on the tasks that the robot needs to perform, for example if the robot were to need to exert higher forces (even temporarily) or self-report its current state (as it deforms unexpectedly around external objects). Thus, the appeal of multifunctional materials for soft robots, wherein the materials used to build the body of the robot also provide actuation, sensing, or even simply electrical connections, all while maintaining the original vision of environmental adaptability or safe interactions. Multifunctional material systems are explored throughout the body of this dissertation in three ways: (1) Sensor integration into high strain actuators for state estimation and closed-loop control. (2) Simplified control of multifunctional material systems by enabling multiple functions through a single input stimulus (i.e., only requiring one source of input power). (3) Presenting a solution for the open challenge of controlling both well established and newly developed thermally-responsive soft robotic materials through an on-body, high strain, uniform, Joule-heating energy source. Notably, these explorations are not isolated from each other as, for example, work towards creating a new material for thermal control also facilitated embedded sensory feedback. The work presented in this dissertation paves a way forward for multifunctional material integration, towards the end-goal of full-functioning soft robots, as well as (more broadly) design methodologies for other safety-forward or adaptability-forward technologies.

abstract: Deformable heat exchangers could provide a multitude of previously untapped advantages ranging from adaptable performance via macroscale, dynamic shape change (akin to dilation/constriction seen in blood vessels) to enhanced heat transfer at thermal interfaces through microscale, surface deformations. So far, making deformable, ‘soft heat exchangers’ (SHXs) has been limited by the low thermal conductivity of materials with suitable mechanical properties. The recent introduction of liquid-metal embedded elastomers by Bartlett et al1 has addressed this need. Specifically, by remaining soft and stretchable despite the addition of filler, these thermally conductive composites provide an ideal material for the new class of “soft thermal systems”, which is introduced in this work. Understanding such thermal systems will be a key element in enabling technology that require high levels of stretchability, such as thermoregulatory garments, soft electronics, wearable electronics, and high-powered robotics. Shape change inherent to SHX operation has the potential to violate many conventional assumptions used in HX design and thus requires the development of new theoretical approaches to predict performance. To create a basis for understanding these devices, this work highlights two sequential studies. First, the effects of transitioning to a surface deformable, SHX under steady state static conditions in the setting of a liquid cooling device for thermoregulation, electronics and robotics applications was explored. In this study, a thermomechanical model was built and validated to predict the thermal performance and a system wide analysis to optimize such devices was carried out. Second, from a more fundamental perspective, the effects of SHXs undergoing transient shape deformation during operation was explored. A phase shift phenomenon in cooling performance dependent on stretch rate, stretch extent and thermal diffusivity was discovered and explained. With the use of a time scale analysis, the extent of quasi-static assumption viability in modeling such systems was quantified and multiple shape modulation regime limits were defined. Finally, nuance considerations and future work of using liquid metal-silicone composites in SHXs were discussed.
Dissertation/Thesis
Doctoral Dissertation Engineering 2020

碩士
國立臺南大學
綠色能源科技學系碩士班
101
In this paper, an optimal design of a high-speed switched reluctance motor (SRM) with higher efficiency using the Taguchi method for household appliances has been presented. To enhance the efficiency and reduce the manufacture processes of the proposed double-salient SRM, soft magnetic composite (SMC) material is adopted. Moreover, to decrease noise and vibration of the double-salient SRM, torque ripple must be reduced; thus, the best SRM geometry should be found. To find the best geometric parameters, the Taguchi method and the finite element method (FEM) has been utilized and presented in this paper. The proposed high-speed SRM will be applied to household electric power blenders and food processors. The results have shown that the proposed SRM can achieve the design goal for higher efficiency applying to household appliances.

碩士
高苑科技大學
電機工程研究所
105
Spindle motor is one of the importance core parts in many industrial machines. The performance requirements of a spindle motor are sufficient torque at high-speed operation, high power density, more wide speed range, robustness and reliability. Because of the soft composite material has fewer eddy current loss during high-frequency operation, the flux-switching permanent-magnet motor (FSPM) with the iron core of soft composite material (SMC) has the potential to become the high-speed spindle motor. Hence, the novel geometrical structure of the proposed FSPM motor with C-type SMC core (SMC-based FSPM) has been proposed in this paper. The results show the proposed SMC-based FSPM motor has potentials as a high-speed spindle motor in high-effectiveness and robustness.

Metamaterials are artificially structured materials which attain their unconventional macroscopic properties from their cellular configuration rather than their constituent chemical composition. The judicious design of this cellular structure opens the possibility to program and control the optical, mechanical, acoustic, or thermal responses of metamaterials. This Ph.D. dissertation focuses on scalable design and manufacturing strategies for optical and mechanical metamaterials.

The fabrication of optical metamaterials still relies heavily on low-throughput process such as electron beam lithography, which is a serial technique. Thus, there is a growing need for the development of high-throughput, parallel processes to make the fabrication of optical metamaterials more accessible and cost-effective. The first part of this dissertation presents a scalable manufacturing method, termed “roll-to-roll laser induced superplasticity” (R2RLIS), for the production of flexible optical metamaterials, specifically metallic near-perfect absorbers. R2RLIS enables the rapid and inexpensive fabrication of ultra-smooth metallic nanostructures over large areas using conventional CO₂ engravers or inexpensive diode lasers. Using low-cost metal/epoxy nanomolds, the minimum feature size obtained by R2RLIS was <40 nm, facilitating the rapid fabrication of flexible near-perfect absorbers at visible frequencies with the capability to wrap around non-planar surfaces.

The existing approaches for designing mechanical metamaterials are mostly ad hoc, and rely heavily on intuition and trial-and-error. A rational and systematic approach to create functional and programmable mechanical metamaterials is therefore desirable to unlock the vast design space of mechanical properties. The second part of this dissertation introduces a systematic, algorithmic design strategy based on Voronoi tessellation to create architected soft machines (ASMs) and twisting mechanical metamaterials (TMMs) with programmable motion and properties. ASMs are a new class of soft machines that benefit from their 3D-architected structure to expand the range of mechanical properties and behaviors achievable by 3D printed soft robots. On tendon-based actuation, ASMs deform according to the topologically encoded buckling of their structure to produce a wide range of motions such as contraction, twisting, bending, and cyclic motion. TMMs are a new class of chiral mechanical metamaterials which exhibit compression-twist coupling, a property absent in isotropic materials. This property manifests macroscopically and is independent of the flexible material chosen to fabricate the TMM. The nature of this compression-twist coupling can be programmed by simply tuning two design parameters, giving access to distinct twisting regimes and tunable onset of auxetic (negative Poisson’s ratio) behavior. Taking a metamaterial approach toward the design of soft machines substantially increases their number of degrees of freedom in deformation, thus blurring the boundary between materials and machines.