We propose a new method to construct microchannels inside cell structures. Recently, three-dimensional cell structures have been actively developed such as cell sheets stacking or inkjet bio-printing method. However, those methods have some disadvantages such as stacking rate or non-biodegradable materials. In this paper, local melting of cell embedded hydrogel is employed to make microchannels inside cell structures. The fabricated microchannels can be used as vascular-like networks to supply nutrition and oxygen to cells. Temperature distribution inside the hydrogel was simulated using 1D unsteady heat conduction equation. A microchannel was experimentally fabricated using an electrode on a glass substrate. The results indicate that the proposed method can be used to making vascular-like networks inside cell structures to construct in vitro 3D cell systems.

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In this paper, we conducted the fabrication of cell embedded structures using biodegradable photocrosslinkable material gelatin methacrylate (GelMA). The mouse fibroblast NIH3T3 cells were mixed in uncured GelMA solution. The cell embedded microcstructures were fabricated by exposing ultra violet (UV) light under a microscope. The cell culture was conducted to check their growth inside the microstructures. The cell viability was checked using live/dead cell staining. The observation of cell structures under a confocal microscope was conducted to check the three dimensional shape of the structure. The experimental results validate that the cells can grow inside the GelMA structures and the fabricated structures can be used to construct in vitro 3D cell structures for tissue engineering applications.

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A microfluidic device that achieves manipulating a single cell in a simple harmonic motion up to 130 Hz is presented in this paper. Such a high-speed manipulation becomes possible because of an on-chip actuation transmitter. The transmitter plays the role of transmitting the actuation from a macro-scale actuator to a micro-scale driving force to manipulate single cells. The working principle of the transmitter is explained by a simplified mechanical model, and the experiments were conducted. Both the theoretical and experimental results show a clear enhanced dynamic response of cell manipulation with the proposed transmitter. Moreover, a pressure sensor is employed for measuring the change of fluid pressure during the manipulation for more detailed insights. The high-speed manipulation could benefit applications in the fields or biomedical diagnosis and bio-assembler.

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Tissue engineering is a study to construct fully functional tissues and organs using cell and scaffolds. Various tissue constructions have been attempted in vitro, such as skin, cartilage and cornea. In this study, we propose a method to construct an highly orientated muscle on chip. Furthermore, we have examined the difference of the differentiation procedure among different patterns by quantifying gene expression. PCR results show that microchannel patterning promotes myoD and myogenin expression. Combined with immunostaining results, we conclude that the optimum channel width for pattering muscle cells may be 100μm.

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In the field of life science, the manipulation and analysis of cells is important. However, manipulating micro objects by hand without the help of equipment is a difficult task. We developed a two-fingered micro-hand, which can help to operation of micro objects and increase operation efficiency. The cell's stiffness is an important mechanical property for the understanding the cell's condition. Kawakami et al. have developed a technique to measure cell hardness using a two-fingered micro-hand with needle-shaped end effectors. This paper proposes a method to measure the hardness of softer cells using plate-shaped end effectors. In this paper, we propose a model of a plate-shaped end effector and a hardness measurement method suitable for the new end effector, and compare the experimental results of our model and the needle-shaped model.

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Mechanical interaction between cell and scaffold has close relations with various function of the cell. By analyzing the force exerted by cell which adhering to scaffold, it's expected that some new mechanism of the cell is revealed. As a method for measurement of interaction between cell and scaffold, Traction Force Microscopy (TFM) is generally used. In this method, fluorescence beads as marker is randomly mixed in hydrogel scaffold, and it's able to calculate the cell traction force from deformation of the scaffold calculated from beads' displacement information. In conventional method, confocal microscopy is often used for the measurement, and measurement time is not taken into consideration. In this research, by arranging beads into two layer of lattice shape in hydrogel, we aim to improve measurement speed.

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This paper reports the two dimensional patterning method for micro object with arbitrary shape. We focused handling of micro objects utilizing temperature responsive gels and a micro heater. To assemble micro objects to arbitrary place on a glass substrate, micro heater array device which is possible to be heated regionally selectively is used. This device has been fabricated utilizing Micro Electro Mechanical Systems (MEMS) technology. As the result, assembly of micro beads to arbitrary place was successfully. And responsive gels which are used in this experiment are biocompatible materials. Therefore, if cells or spheroids as the micro objects are used, construction of cell tissue with arbitrary shape is also possible.

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This paper reports on assembling method for 3D cellular structure. The precise and automated system for the 3D tissue construction is important for regenerative medicine. Large size functional 3D tissue needs blood vessel-like structure for supplying oxygen and nutrients. For constructing complicated structure like these, micro-heater and thermoresponsive gel is focused. Using this device and thermoresponsive gel, 2D arbitary structure can be constructed. And assembling the 2D structures, 3D structure having 2D arbitary structures is possible to be constructed. In order to put this in practice, at first, change of gelation ragne by heating time and electricity is confirmed. As the result, optimal condition for grasp is obtained. Furthermore, grasping and releasing two micro objects by heating and gelation two points is successed.

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This paper reports the releasing method for micro manipulation utilizing manipulator. In micro-scale, since surface forces such as adsorption force is greater than body forces such as gravitational force, adhesion force between the end-effector and the object is strong. Therefore in the case of micromanipulation utilizing manipulator, to set the object to an arbitrary place, manipulation techniques without adhesion are required. In this time, to decrease adhesion force, manipulators with nanostructured surface were fabricated. And cell manipulation experiments using mouse fibroblast cells were conducted. When a manipulator with nanostructured surface was used, releasing without adhesion was successful 85.0% of the time. On the other hand, when a manipulator without nanostructured surface was used, releasing without adhesion was successful 6.3% of the time. As the results, high accuracy cell manipulation without adhesion was performed successfully.

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In this paper local swirl stream around a glass needle is analyzed. The local stream is generated by circular vibration of the glass needle, which is actuated by one piezoelectric actuator. At first we observed the motion of the glass needle in water when swirl stream is generated around the glass needle. From this experiment we confirmed that the glass needle's motion is circular. Then we analyzed the stream around the glass needle in 3 dimension using micro beads. We confirmed two facts: the bigger the radius is, the smaller the angular velocity and the velocity toward the root of the needle are, and the bigger the amplitude and the frequency are, the bigger the angular velocity and the velocity toward the root of the needle are. This phenomenon and analysis can be used for non-contact manipulation of micro objects.

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In this paper, to improve the spatiotemporal resolution and to reduce the invasiveness, we genetically introduce Optically-Manipulated molecular switch, channelrhodopsin (ChR), into sarcoplasmic reticulum (SR) of C2C12 myoblast, mouse muscle cell lines. A myotube inserted with SR-targeted ChR can respond rapidlier than a myotube inserted with non-targeted ChR for 10-20 ms. A myotube inserted with SR-targeted ChR can contraction only by intracellular ion transportation. We can control intracellular Ca^<2+> ion of the myotube. This technique could facilitate the studies on the myogenesis, the stem cell therapy for muscular disorder, and the bioengineering using the muscle-powered actuator.

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We constructed three dimensional (3D) microchannel networks inside gelatin-based hydrogel towards 3D in vitro cell structures. The 3D assembly of cells in vitro is one of the important techniques to reveal cell growth, differentiation and hystogenesis for applications in tissue engineering, drug screening, and cell characterization. To achieve functional 3D cell structures, vascular networks are important to supply oxygen and nutrients to cells, and remove waste product from cells. An alginate hydrogel fibers were employed to construct the microchannel networks like blood vessels. The patterned hydrogel fiber can be melted using standard saline citrate (SSC) buffer and the melted area can be used as vascular networks. The flow inside the melted alginate hydrogel fibers were visualized using fluorescent microbeads. The results validate that the proposed method can be used to make arbitrary patterns of vascular networks inside cell structures and contribute to achieve in vitro 3D cell structures.

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We present design of V-beam type on-chip probe of which displacement is enlarged in a microfluidic chip for cell mechanical property measurement. In order to actuate on-chip probe with high-accuracy, we deformed the microfluidic chip by piezoelectric actuators. The displacement of the piezoelectric actuators is enlarged by the V beam structure in the chip. Firstly, we designed V-beam and fabricated microfluidic chip having V-beam. Secondly, position accuracy of the fabricated V-beam type on-chip probe was measured. The probe was actuated from 0 μm to 93.3 μm with high linearity. Finally, we measured reaction force of oocyte and calculated the young's modulus of zona pellucida by using Hertz contact theory. We applied reaction force of oocyte up to 9 μN, and Young's modulus of zona pellucida was measured 1.09 kPa.

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Single cell analysis has attracted much attention for revealing detailed and localized biological information. A local environmental control technique is desired when analyzing the detailed and localized properties of single cells. In this paper, we propose a local environmental stimulation system with micro dual-pipettes to stimulate the local reagent concentration dynamically, freely and automatically. When the local environment is controlled with chemical stimuli, the chemical solution is diffused and affects other objects. The local environment stimulation system with micro dual-pipettes can solve this problem by using spout pipette and suction pipette. For the evaluation of developed system, we used fluorescent substance and confirm controllability of local concentration quantitatively. Furthermore, we confirmed usefulness of this system by measuring and controlling the rotational speed of flagellar motor, and by peeling off certain area of adhered cells, as an application of the system.

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Cell tissue construction is one of the important issues for tissue engineering, which is a key-technology in regenerative medicine. Recently, several studies have reported, the in vitro fabrication of simple cell tissues. However, organs are made of some kinds of cells and they are complex tissues. Therefore, a technology to reproduce the complex structure and biological function of the organ is needed. In this paper, we propose an automated system for the construction of a cell tissue in vitro, based on hydrogel fiber. We designed a gel fiber discharge nozzle using laminar flow, and fabricated the lattice structure using laminar flow fiber. Through the experiments of the lattice shape structure construction, we observed the cell growth in the constructed lattice form, which proves the functionality of the structure.

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This paper describes the wrapping-advancing Interlocking winding mechanism to realize tubular tissues with certainty. In this study, the idea of the mechanism with circular cross-section to realize the tubular tissues is proposed. Based on this proposed mechanism, the prototype model with perfectly circular cross-section has been designed and developed. The basic performance and effect of this proposed mechanism was confirmed through the basic experiments with the developed prototype model.

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We developed a valved hybrid fractal stent to treat the cerebral aneurysm what is one of a cerebrovascular disease. Stenting and coil embolization can be used together by the stent. The stent has a valve part to coil insertion hole. The valves have fractal structures. So, the blood flowing into cerebral aneurysm is prevented. We have designed a fractal pattern that takes into account the flexural rigidity of the stent on the loading into catheter and deployment during detention. On the basis of these designs is to create a 5-fold stent model and observed the behavior of their contraction and expansion.

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We present a novel cell manipulation method based on vibration-induced flow in open-chip environment. By applying circular vibration to a chip having micropillars, local flow is induced around the micropillars. Therefore, by patterning micropillar array on the chip and applying the circular vibration, we can achieve cell transportation along the array in the open chip environment. We theoretically analyzed this phenomenon with a single micropillar, and experimentally evaluated behaviors of manipulated microbeads with two micropillars. We confirmed there are different manipulation modes according to the pitch of micropillars. We designed the micropillar array for transportation of mouse oocytes based on these evaluations. We succeeded in transportation of oocytes with up to 35.6 μm/s and confirmed that the transportation velocity can be changed by changing the frequency and amplitude of the applied vibration.

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We evaluated a survival rate of micro-injection into Caenorhabditis elegans, (C. elegans) after 24 hours with a fluorescent micro-gel bead. The fluorescent micro-gel beads were fabricated by a salting-out method. One of the micro-gel bead was picked up at the micropipette injection tool by suction forces. The microbead was injected into C. elegans by a microinjector using a piezo actuator based on micromanipulation. After microinjection of the fluorescent microbead, the microbead was confirmed in the C. elegans using a fluorescent and a confocal microscopes. From experimental results, the viabilities were achieved in 71 % (12/17) and 62% (8/13) at 10 μm and 20 μm different injection depths.

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This paper presents the aqueous observation of three-dimensional information using scanning electron microscope- computed tomography (SEM-CT) inside an environmental-SEM (E-SEM). It is required to control the sample temperature for an aqueous condition inside the E-SEM. In this paper, a cooling system was installed into the SEM-CT system. The aqueous observation was confirmed by the E-SEM and SEM-CT observations.

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In recent years, the importance of intracellular material introduction technology is increasing. Our large scale cell membrane perforation method is a new cell modification technique. The feature of this perforation method is efficient in order to make the perforation to the group of cells, with high cell survival ratio. The problem on the current technique is, only limited part of the sequential process is automated. The target of this research is to automate sequences of operations associated with the cell modification. As the result, we could successfully construct the system for the automation and shorten the whole process time from 3-4 hours to 45min.

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The mechanical properties are indispensable parameter for evaluate the tissue structures. In this report, we developed a micro vacuum chuck which could fix the three-dimensional multilayered tissue to tensile test system without breakage of sample. The three-dimensional multilayered tissues were fabricated with technique of layer-by-layer (LbL) nanofilm coatings. By using the micro vacuum chuck, we succeeded to measure tensile force of the three-dimensional multilayered tissues. In the result, the maximum tensile force was about 626 μN (strain: 1.9). When maximum force occurred, the sample detached from the chuck. The profile of force-strain curve was similar to that of tendon or the ligament. This result indicates that the three-dimensional multilayered tissue has mechanical properties which are same to living tissues.

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Piezoelectric inkjet printer has been applied into the bio-field to deposit proteins and living cells due to its high speed printing capability and high resolution patterning of small bio-ink droplets. Recently, it is also utilized to deposit single cells on arbitrary pattern in order to isolate single cells for further analysis or for high resolution biofabrication application. Better spatial control of cell patterning possibly allowed fabrication of a more delicate structure. In this research, shutter system was developed and combined with an automatic single cell printer based on piezoelectric inkjet printer to deposit single cells on collagen substrate for biofabrication application.

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Cyanobacterium has ion channels on its cell membrane, and they work to protect the cell from osmotic stress. Since functions of some ion channels relate to intracellular pressure changes, we aim to develop the mechanical characteristics measurement system of Synechocystis sp. PCC 6803, which is one of the most commonly investigated unicellular cyanobacteria. There are two important concerns in constructing the system: one is how to transport the target cell to the measurement point, and how to deform it because the cyanobacteria is a floating cell whose diameter is a few micrometer. In this paper, we propose the system utilizing the robot integrated microfluidic chip with optical tweezers for transportation of the target cell. The chip has an on-chip probe actuated by a micromanipulator, and a force sensor. We present the concept of the total system, and perform mechanical characteristics measurement of a single cyanobacterium.

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This study reports on the time-lapse observation of sarcomere assembly under optically-induced calcium transients. C2C12 muscle cells were genetically modified with optically-sensitive channelrhodopsin to induce calcium transients, and alpha-actinin sarcomeric proteins fused with red fluorescent protein for live imaging. Myotubes (muscle cells) were stimulated using blue light at varying frequencies, and time-lapse fluorescence imaging was done on live cells over 4 hours to observe sarcomere assembly. Fast Fourier Transform was employed to qualitatively analyze the degree of sarcomere formation. Based on our experimental results, myotubes under optical stimulation showed earlier sarcomere formation compared to myotubes that were not stimulated.

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Recently, we found that a stress-fiber-like contractile network of microtubule formed by mixing a genetically engineered kinesin and microtubule in a self-organaization manner. In micro-chamber having pillar structures, the contractile network formed a bridge between the two pillars and became a muscle-like fiber about 1 mm long.

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Motor proteins, biomolecular machines, have been successively integrated into microdevices such as MEMS and lab-on-a-chips. For successful integrations, guiding of cytoskeletal filaments is one of key issues. The guidings can be achieved with microfabricated substrates or by imposing external force to the microtubules. Here, we present a computer simulation which reproduces the guidings of microtubules propelled by kinesin motors.

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This paper points out that the human auditory sensitivity is enhanced by the resonance of the organ of Corti and the leverage of stereocilia. We supposed a simple common vibration model for both the organ of Corti and the stereocilia, where they are represented by 2 parallel linked levers. The model suggests the longitude of stereocilium reinforces vibration detection with elasticity leverage. We also manufactured a device article obedient to the model, and, through 4 experiments, measured the system transfer function with static/dynamic and concentrated/distributed loads. The device response had a resonance peak in both concentrated and distributed excitation condition. We presume this resonance enhances the frequency resonance and vibration amplification on human cochlea.

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In a manufacturing plant, the various parts are transported or assembled by industrial robots. Because these robot has a special robotic hand for a part, there are the problems of exchange time of hand and cost of development and storage of hand. These problems are solved by universal hand which can grip the parts with various shape, size and weight. We previously proposed the vacuum gripper imitating octopus sucker. This gripper can absorb the flat, curvature, and uneven surface. The purpose of this study is the fabrication of the gripper with micro protrusions imitating denticles on an octopus sucker, which has the effect of enhancement of absorption force. The diameter and height of denticle were 2 μm and 1 μm, respectively. The adsorption force was improved, since the denticles are arranged on the gripper.

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This paper explains a snake-like robot with a thin body and a large wheel and its simulation. This study aims to improve the energy efficiency of the snake-like robot. In order to evaluate the algorithm of the snake-motion, new snake-like robot has been developed. This snake-like robot can make a three-dimensional movement with powerful servo motors and has a thin body. The mechanical design of the thin body snake robot and the optimization of the motion of the simulated snake robot, which is equipped with a large wheel in each section, through Genetic Algorithm are explained. An acquired optimal motion is the cycle between a propulsion phase with serpentine locomotion and sliding in straight.

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The objective of this study was to investigate propulsive performance of the breaststroke by the swimming humanoid robot. The developed swimming humanoid robot had 24 servo motors for the whole body and could perform basic human swimming motion. For the breaststroke, however, the propulsive performance was not fully investigated in the previous report since the buoyancy balance was not sufficient. In this report, the buoyance balance was adjusted and a free swimming experiment was conducted again. As a result, it was found that the robot could swim at the swimming speed of 0.12m/s for the stroke cycle of 2.3 s.

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The objective of this study was to improve the stability of crawl swimming for the swimming humanoid robot. The swimming humanoid robot had 24 servo motors for the whole body and could perform basic human swimming motion. This robot can swim freely by the crawl stroke. However, this robot sometimes changed the propulsive direction while free swimming. The change in the propulsive direction was caused by instability of body rolling. Therefore, swimming motion that can change propulsive direction and roll angle amplitude were designed by simulation. Effectiveness of the proposed swimming motion was confirmed by a free-swimming experiment.

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We proposed a gripper imitating the octopus sucker for universal gripper which can grip the various parts in production site. This paper described the gripper imitating a funnel structure of octopus in order to improvement of shape followability. The imitated structures were necking, radial trench and slope of sucker. We evaluated the pressing force for absorption, which the shape followability is high when the pressing force is low. The necking structure has an effect of decrease of the pressing force, since the sucker with neck was flexible. The radial trench has effect of increase of maximum absorption force of gripper, since the absorption area is increased.

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This paper describes an effect of particle size in vacuum gripper imitating octopus sucker on adsorption performance. The particle in thin elastomer sack has Jamming transfer effect. It has advantage that the absorption area is fixed, since the sack behaves the solid substance under the vacuuming in sack. The relationship between particle size and gripper size is influenced the formation of adsorption area. When the particle size was larger than the distance between suckers, the adsorption success rate is decrease because the sucker was compressed by particles. Because of the friction between particle, the pressing force was large when the particle was too small. The suitable particle size to this gripper was around 0.8 mm.

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This paper newly develops a novel robotic joint mechanism by means of twisting a small-diameter round-belt, which enables slow movements of the joint rotation unlike direct-drive actuator mechanisms. The actuator mechanism proposed in this manuscript is composed of a couple of small-diameter round-belts located at near the joint with opposite configuration. The two round-belts are twisted by DC motors placed on a motor stage, which can be activated by a step motor. This novel mechanism realizes that the robotic joint is able to move around its axis due to contraction forces generated by twisting the both round-belts. That is, these round-belts act as agonist and antagonist actuators for the robotic joint, which give a human-like compliance in the joint revolution. Experimental results using the one-link robot proposed show that extremely high position resolution on the joint control can be achieved by the increase/decrease of twists of the round-belts. In addition, we clearly indicate a relationship between the amount of twist and the joint angle of the robot. Finally, experimental results can clearly explain that one DC motor acting for the joint motion activates adaptively in accordance with the slow movement of the other DC motor moving to the desired angle.

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This paper is verified movements of a new experimental system using an omnidirectional treadmill mechanism. We have developed a robot for small insects such as Camponotus. The robot is named as ANTAM (ANT Activates Machine), and configured to perform as cockpit for insects. However, this robot has a problem which is strong vibration of the mechanism during movements. The vibration is serious problem for small terrestrial insects which is meaning of predator stimulus. The robot is able to adapt to various small insects by reducing these vibrations. We achieved the improvement of motion compensation device. In addition, we have succeeded a measuring of the ants (Camponotus) walking trajectory. We consider that this mechanism drives ethology strongly.

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This paper describes an insect-inspired walking and jumping miniature robot. The walking and jumping motion enables the robot to avoid large obstacles and extends the moving area remarkably. A cricket-inspired robot that can walk and jump stably was developed. Shape memory alloy actuators were used for walking and jumping to reduce the size and weight of the robot. The motion of the robot was analyzed using a high speed video camera. The leg for walking moved by drawing a triangular trajectory. The robot also jumped stably with a small amount of body axis change. The jumping distance and height were 75.2 mm and 24.2 mm, respectively.

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This paper describes a flapping-wing robot inspired by a dragonfly. Dragonflies are able to perform sophisticated aerodynamic feats including hovering and sharp turn. These feats are performed by flapping and feathering motions of the wings. A flapping-wing robot with a passive feathering mechanism that generates asymmetrical rotation of the wing has been developed. The wing motion was analyzed using a high speed video camera, and thrust and lift forces were measured using a three-axis load cell. The results showed that a feathering angle approximate to the designed value was obtained. Time-averaged thrust and lift forces were 11.1 mN and 12.5 mN, respectively.

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We proposed repairing method for the self-repairable joint of robot body. We adopted the copper-electroplating from three proposed methods (plating, self-assembled monolayers, and electro polymerization). We conducted two tests; evaluation test and abrasion test. In evaluation test, we established 3 criteria (adhesion, smoothing the surface, and decrease of friction force) to evaluate repair performance of the plating. In abrasion test, we made a system that supposed the joint, and tested abrasion and plating simultaneously. As a result of evaluation test, we confirmed that plating can repair the worn down surface. As a result of abrasion test, we confirmed that plating can repair the surface in the sliding portion.

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The oar of Japanese traditional boat resembles the fin of fish, compared the oar of the European boat to the crawl of the swimming. A human power promotion method of a Japanese traditional boat has high efficiency in comparison with other human power promotion methods. The reason why the human power promotion method of a Japanese traditional boat has high efficiency is to use lifting force as propulsive force. In this study, we manufactured a small model of the Japanese traditional boat for experiment to examine the specification of the boat. Propulsive force and propulsive speed of the model have been measured. In addition, by using PIV measurement and CFD analysis of water flow around oar, we investigated about four oar types.

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Bacteria exhibit collective motion when the freely-swimming cells are cultivated and become tightly packed. This collective motion has some spatio-temporal patterns that are not found for the freely-swimming cells. In this study, we conducted the observation and numerical simulation to find some characteristics in the collective motion. In the microscopic observation, the overall flow velocity of the bacterial swarming is analyzed by the particle image velocimetry. The correlation between two velocity vectors is calculated. With the increase in the number density of cells, the correlation length becomes larger, up to 10 micrometers. In the numerical simulation, the effect of alignment of cells due to their interaction is considered, where the close cells have only repulsion like a collision of the rigid rodlike bodies. With increase in number density of the model cells, the correlation length of the velocity correlation becomes larger, which agrees with the observed result.

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Proboscis of a mosquito for sucking blood consists of complicated seven parts. For example, labrum has hollow structure, and maxilla has micrometer-sized toothlike projections on its tip part. In this study, microneedls imitating one labium and two maxillae were fabricated using precision three-dimensional laser lithography system "Nanoscribe" Maximum length of the fabricated microneedle is 1.5 mm, which is minimal to reach to capillary blood vessel underneath human epidermis.

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Making a diameter of needle small is effective for reducing the pain of patients. However, thinning a needle leads to easy buckling in the puncturing process, because the aspect ratio of needle becomes high. When thin needle, it is effective to reduce the patient's pain. From acupuncture and mosquito needle behavior tips, we propose a mechanism to puncture the needle little by little. Furthermore, by enveloping the cylinder needle from directly above the skin, we propose a mechanism for preventing buckling. Therefore, by using a mechanical pencil system, and performs various studies and found a method capable without buckling puncture the thin needle

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A precise 3D CAD model of mosquito central labrum and side maxillae, i.e., totally three needles, was constructed. Mosquito inserts these needles inside the human skin with vibration. To confirm the effect of vibration, explicit FEM analysis was conducted using the model. LS-DYNA was adopted as the software. In this report, only the central needle was preliminarily considered among the three, and this needle was inserted into the skin in the simulation. It is proven that the resistance force was reduced by 6.5 % at the maximum with applying vibration. Next, Stress applied to a skin was visualized using an artificial skin with grid pattern. The visualizing test result also indicated that stress applied to skin by inserting needle is reduced by applying vibration. The simulation and image analysis results indicates the effect of vibration on easy needle insertion without buckling.

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We noticed the difference of the propulsion direction between polychaete worm and nematodes, and developed the omni-directional aquatic multi-link propulsion mechanism modeled on polychaete worm. However, fins of the mechanism corresponding to parapodia of polychaete worm were simplified and fixed to the bottom of the body of the mechanism. We conducted the motion analysis of parapodia of polychaete worm for the development of improved omni-directional mobility. In this study, we developed new omni-directional aquatic multi-link mechanism with active fins regarding the results of the motion analysis of parapodia of polychaete worm.

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In this paper, a method for analysis of motion of flapping butterfly is proposed. Time series of angles of 4 joints of wing and abdomen, and position and attitude of thorax are obtained by movies of a free flying butterfly in a wind tunnel with high speed cameras. By applying singular value decomposition, it is divided into 2 principal modes. Contribution of the first mode is about 81%, and of the second is about 17%. By comparing these modes between climbing flight and steady flight about each category, this research shows that difference of control between the two flight states.

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To clarify how butterflies stabilize the flapping flight, this study discusses an effect of structural flexibility of butterfly abdomen and wings. The effect of flexibility is evaluated on butterfly free flight based on numerical simulation with a panel method. A butterfly is modeled by rigid body with 4 links. In an abdomen flexible model, the whole abdomen flexibility is expressed by a joint with a spring and damper. Also in a wing flexible model, flexibility along feathering axis is expressed by a joint with a spring and damper. The stability of flapping flight is measured by the time of flight within which the butterflies continuously fly without falling down. Compared with a non-flexile model, an abdomen flexible model and a wing flexible model can fly longer, but the characteristics of these flexible models are different.

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Recently, robots are expected to work alongside humans in our daily environment. To realize a safe physical interaction between the robot and its surroundings, the robot must be able to control the flexibility at the end effector to external forces. In this research, a 2-link robotic arm with a biarticular muscle mechanism using an air cylinder was developed. Thanks to the mechanism, the robot can adjust the response characteristics at the end effector by changing the restriction condition of two joints. We conducted an experiment that the robot with and without the biarticular muscle mechanism rotated a roller by its end effector. The performances of the robot for the task in each restriction condition were compared. The results suggested that the robot can modify its response to external forces by changing the restriction condition depending of the assigned task.

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In this study, we propose a smooth propulsion method for cord robot to move underground. Inspired by the motion of spotted garden eel from the family of congridae, we focused on the propulsion method to generate propulsion force in whole body by actively undulate the body, carry out the research of the basic movement principle. We made an observation of moving eels in granular medium and analyzed the motion of the eels. As a result, the tip undulated at high frequencies, while the body moved through the same trajectory. Joint driving device was made to make an experiment in the granular medium. We proposed a hybrid undulate motion inspired by the eel which can move faster under the granular than the snake's motion. This motion is a combination of snake's sinusoidal motion and high frequency motion of the tip.

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This research describes the development of a mobile robot to achieve adhesive locomotion on walls and ceilings. To achieve the objective, we focus on adhesive locomotion of a snail and study basic principles of the locomotion. Although it is known that snails ejecting mucus while moving, the precise mechanism was unclear. Therefore, to examine the movement and characteristic of snail, basic experiments were performed using Euhadra peliomphala. Next, we examine the principle of snail type adsorption. As a result, the snail mucus unique rheology characteristic had been shown. Using these experimental results and findings, we developed a snail-type mobile robot and the possibility of snail type adhesive locomotion robot had been implemented.

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