This paper presents a manipulation strategy for producing a food bolus by using a robotic mastication simulator. Based on human mastication functions, a flexible surrounding mechanism comprised of two rigid teeth, four flexible belts, and two wringer rollers is introduced. For the mechanism, three motion modes are defined: biting mode, stirring mode, and compressing mode. In the biting mode, a food sample is fractured by closing two teeth and fragments are surrounded by belts. In the stirring mode, the surrounding area is reduced by closing two rollers. An important feature is that the fragments are stirred via an asymmetry shape of the area. In the compressing mode, a food bolus is formed by closing both teeth and rollers. Repeating the three modes, the mixing rate of the bolus increases. Using a prototype, the proposed method is experimentally validated.

The flexibility is an important factor for a robot system that cooperates with human. In order to realize both softness and high output force in a robotic gripper, we developed a prototype of the soft robotic gripper that is driven by a hydraulic pump. The gripper consists of two fingers made by a 3D printer, fabricating hard resin and rubber-like materials simultaneously. We aim to put high pressure on the finger using a hydraulic pump to hold heavy loads in industry areas. An experimental result demonstrated that the prototype currently could hold a 654 kg object.

As an effective way to grasp an object softly and robustly, many soft grippers have been developed and reported. However, it is still difficult to grasp objects that are easily damaged by local contact forces such as fruits. This paper proposes a soft gripper which grasps such easily damaged objects by wrapping around. This approach gives a wide area of contact and reduces local contact forces. Moreover, this gripper is composed of only soft materials and integrally molded. The opening-closing mechanism is realized by using snap-through-buckling. In this paper, we show the design concept and the performance of the first prototype of the gripper.

The McKibben artificial muscle is a pneumatic soft actuator that has a structure in which a rubber tube is covered with a sleeve formed by fibers. The artificial muscle contracts by applying air pressure.

In this study, we have developed a pneumatic smart artificial muscle with displacement sensor by including optical fibers into the fibers of the sleeve. The optical fiber has the characteristic that the amount of light propagating inside it decreases when it bends. The optical fibers braided into the artificial muscle functions as a displacement sensor because the amount of bending changes by the contraction of the artificial muscle. In this report, considering the dead zone of the optical fiber sensor, the artificial muscle is designed.

In recent years, industrial robots have been applied to food production because of its huge potential market. Although cooking large amount of foods are done by specially designed cooking machines, dishing up the cooked foods remains as a labor-intensive task. To solve this problem, we propose a new food handling robot hand composed by soft actuators and membranes which can handle easily damaged natural food and convey it at high speed. In this paper, we developed the soft robot hand with membranes (Mendako-hand) and evaluated the grasping and conveying performance with a food sample and some actual breads as targets.

The purpose of this paper is to realize omnidirectional movement by generating a traveling wave with a simple command that only applies pressure to a bending module made of a flexible material. Also, in order to realize moving operation only by pressurization without using a solenoid valve, it is necessary to develop a pneumatic self-excited valve. The leaf spring built into the developed pneumatic self-excited valve snap bucking, creating two states : shutoff and open in two flow paths

Dielectric elastomer actuator (DEA) has faster response speed than other polymer actuators. However, it is difficult to measure the mechanical impedance of a DEA due to friction or contact state of a measurement device. In this study, we propose a method to identify mechanical impedance of a DEA by suspending the DEA sample. We estimate the parameters of the mechanical impedance model of a DEA by applying a voltage to the DEA and measuring the displacement response.

We have already reported that nanoparticles and PO-type dispersion media are useful for suppressing the separation of magnetic materials in MR fluids. In particular, a structure design represented by the bond chain length and the number of amide groups in the PO type dispersion medium is important. Also, reducing the difference in specific gravity between the magnetic material and the dispersion medium effectively worked. In the test, a fluorine-based medium having a specific gravity of about twice that of a conventional hydrocarbon-based medium was used.

Encountered-type haptic interfaces using MR fluid have been developed for surgical simulators. This haptic interface can display high-frequency force and can be used with various surgical tools. In order to develop this haptic interface, the relationship between display force and magnetic flux density is required in the design process. However, it has not been studied. For understanding the relationship, MR fluid simulator has been developed. To evaluate this simulator, the flow was observed by a microscope when the fluid was cut by a plate. When the plate cut the chain clusters of ferromagnetic particles of MR fluid, the shape of the clusters was arch at the cutting edge of the plate. It was found that the higher the concentration of the fluid, the stronger the arch. It was also found that when the blade was removed after cutting, space remained in the cluster.

To improve the pressure output of the EHD (Electric Hydro Dynamics) pump, we conducted the numerical simulations of the electric field in the EHD pump using OpenFOAM. In addition, the proposed EHD pump was designed based on numerical results, and the pressure output of the proposed EHD pump was measured. The better proposal from the numerical results was that the electric field in the EHD pump was directed to the flow direction. In addition, the numerical results were indicated that the pressure output of the proposed EHD pump was increased by multiple sets of the electrodes. Experimental results show that remarkable pressure can be generated by proposed EHD pump.

As a new soft actuator with flexibility and high power/mass ratio, a fishing line artificial muscle actuator had been proposed. This actuator expands and contracts in response to temperature change. Utilizing the flexibility, quietness and lightness, it has been applied to safe robot hands not to damage objects or environment. In this research, we estimate and control the contact force between an object and robotic arm. In this paper, we design the estimation system and verify the proposed method through experiments.

We aim to develop a flexible and lightweight adsorption device. By combining a hydrostatically coupled dielectric elastomer actuator (HCDEA) and a suction cup using silicone, a soft adsorption device is constructed. In this paper, the fabrication method of the adsorption device is explained and the performances of the device with different size of the device and with different hardness of silicon material are investigated.

A Twisted Polymeric Fiber Actuator (TPFA) has been attracting attention as a new actuator that is silent, inexpensive, and can directly extract a rotational motion. Until now, we have proposed a sensorless rotational angle controller using estimated temperature feedback in order to take advantage of the low cost of TPFA. In order to construct a sensorless torque control method as an expansion of the utility of the TPFA, the relationship between output torque and change in temperature is modeled and the sensorless torque controller is designed. The proposed method is eventually verified through experiments.

The purpose of the present study is developing a novel protective wear compatible with flexibility and impact absorption. In order to achieve the purpose, the soft epoxy foams, which shows extremely high strain rate dependency of compressive properties, was developed as a cushioning material of a protective wear. First, compression test revealed that the compressive stress at each strain can be expressed in a master carve with respected to strain-rate, temperature and compounding ratio of the matrix. Then, in order to evaluate the performance of the epoxy foam as a cushioning material of headwear, the falling impact test assuming a head impact in daily life was performed, measuring HIC. The impact tests suggested that the proposed epoxy foams are effective as a cushioning material of a headwear.

The field of Virtual Reality (VR) and its applications have been thoroughly researched during the past decades. However, improving the user’s immersion in a virtual world, while allowing complex interaction, is still a major challenge nowadays. SPIDAR-like cable haptic interfaces can display forces accurately and ensure a satisfying haptic rendering quality, though many cables can be required to provide feedback on both hands. Our purpose is to use a novel hybrid architecture integrating a linear actuator to the device, to optimize both the use of workspace and the number of cables. In this paper, we study the influence of the linear actuator on the quality of the haptic rendering and overall manipulability of the system.

There are many force feedback devices that focus on upper limbs. However, in the real world, not only the upper limbs get force feedback. Therefore, the authors attempt to develop a wearable lower limb force feedback device that enables users to move around in wide area. However, there is a limit to the size of a device worn by human, and it is difficult to present an acceleration equivalent to gravitational acceleration with a wearable type device. Therefore, the authors proposed a method of giving a descent acceleration smaller than the real world and evaluated the sensation of falling of humans.

In this study, we develop a driving assistance system for personal mobility with a haptic joystick to ensure the safety of the operator. By calculating scores of possible trajectories on the layered costmaps, such as an obstacle map and a semantic map, we generate reaction force to guide the wheelchair to a safer and preferable trajectory.

Robot therapy is a mental treatment method that uses a robot instead of an animal. However, conventional pet robots have a low degree of freedom, making it difficult to perform realistic movements. Therefore, we try to create a highly flexible virtual pet robot. we create a virtual simulation and couple it with a cable interface to display haptic rendering. Past research is have created haptic interfaces that display either power or texture. In this paper, we propose a control method to display both power and texture. Forces are displayed with a cable-driven haptic interface, and texture is displayed using piezo actuators.

This study proposes a softness presentation method for when the finger slides on a hard touch panel. Herein, an electrostatic tactile display was made to present a friction stimulus, the frequency of which was changed by virtue of the normal force and speed of the finger. Such a stimulus imitates the stick-slip phenomenon that occurs between soft materials. In the experiment where four types of stimulus conditions were ranked, one of which was a control condition with no active friction stimulus, the new stimulus and previous method that presented a constant low-frequency friction were subsequently determined to be the softest among the four stimulus condition types

Human touch skills are expected to provide emotional responses. In this study, we develop a human-imitation hand and generate gentle stroke motions on the back of a human to consider that the stroke motion of the robot provides a human emotion responses. By comparing with a stroke motion of a human, we evaluate the stroke motion of the robot and the human with subjective (valence and arousal) and physiological (facial electromyography and skin conductance level) indices. From the results, we suggest that the subjective and physiological indices show the effect of speed commonly on the robot and the human. Furthermore, we suggest that the fast stroke motion (30cm/s) of the robot and human provides a subject with an emotion of valence.

Many systems employ a combination of vibrotactile information from transducers with acoustic information to produce immersive virtual sound field such as air vibration in a concert hall. Here, we propose a method to reproduce an immersive sound field on a user’s body by employing oscillating air-jet. In this paper, we report on and evaluate the reproducibility of the virtual sound field by the proposed method.

This paper investigated the difference on the effect of the knee Hanger-Reflex by simultaneously measuring the skin stretch and the pressure distribution. The measured data was analyzed by the weighted average, and two pressure peak positions were obtained. This result shows the same tendency observed at the other body parts. From the skin shear distribution measurement, the direction of the skin deformation is the same as the direction of the knee rotation. These results and measuring shape of the mounting site show that the clue for adjusting the mounting state and angle of the Hanger Reflex device is considering to be each person’s bone shape. In addition, to generate the Hanger-Reflex efficiently, the skin shear deformation near the compression point are important. The results and discussions contribute to the effective skin deformation techniques and devices like the Hanger-Reflex.

In this paper, we examined the timing of onomatopoeia and verbs when presenting vibrations in line with gaze movement. As a result of the experiment, it was confirmed that the presentation timing of the onomatopoeia depends on the number of characters and the verb depends on the number of characters.

The purpose of our research is to develop an electrostatic tactile graphics display for visually impaired to read figures. We have evaluated our tactile graphics system that displays a tactile sensation based on a user’s single finger movement. However, the result showed that it was difficult for the user to capture the shapes of figures correctly. In this paper, we proposed an electrostatic tactile graphics display with multi-finger and evaluated how accurately the user can recognize the figures. For our evaluation experiment, we printed four figures with silver nanoparticle ink. The result showed that the user can capture the outline of graphics more correctly with multiple fingers than with a single finger.

In this paper, we present a method to quickly guide a person’s motion in the context of sports coaching using vibrotactile stimuli. Users wear a ring-shaped device on the right ankle and the vibrotactile stimulus indicates where users should move. We use a tactile illusion called Phantom Tactile Sensation to produce localized vibrations at any point around the ankle in order to convey the direction to move. The desired distance to move is represented by different vibration patterns. We conducted experiments under two vibration patterns in order to evaluate their effectiveness in conveying distance. We found that distance and direction could be indicated simultaneously by using vibrotactile stimuli, but short stimuli might not be perceived while performing other tasks.

Pseudo-haptics, one of the cross-modal illusions between visual and haptics, can display various haptic sensation only by modifying visual stimuli. On the other hand, the decline of the illusion effect by long term experience of the illusion was found in size weight illusion, which is also a cross-modal illusion between visual and tactile senses. However, the possibility of declining pseudo-haptics effect made by habituation has not been concerned when designing virtual reality (VR) experiences with pseudo-haptics. Thus, in this paper, we constructed a experiment to verify the presence or absence of habituation, by presenting pseudo-haptics which manipulate weight perception over a long period of time. The result of study showed that the effect of pseudo-haptics, which made the object feel heavier than the actual one, decreased. From this fact we indicated that long term experience of pseudo-haptics which manipulate weight perception reduces its illusion effect.

This study aims to develop a tactile interface supporting the contracture palpation by physical therapists. It comprises a wearable skin vibration sensor that detects frictional vibrations relevant to the contracture during the palpation, a tactile headphone that gives vibrotactile feedback based on the sensor output to the therapist, and evaluation system of a laptop computer. They were wired to each other, which resulted in therapists having limited mobility and posture. Thus, this paper improved the system by wireless modules. A wireless system promotes natural palpation by therapists without giving any attention to wires. Furthermore, it can easily send the sensor output to additional tactile displays and other computers. This might be useful to the assessment by additional therapists and the training of the contracture palpation.

Magnetic Compound Fluid (MCF) rubber is a new smart sensor obtained by mixing rubber with MCF. It has practicality of being a wide variety of new elements such as haptic sensor, capacitor and solar cell. We have planned to load MCF rubber sensor on a disaster corresponding robot, decommissioning robot, or robot for internal investigation in the nuclear building. However, common rubber has serious problem such as degradation in case of used for instrument in nuclear facility. Additionally, the behavior of MCF rubber on radiation environment is not investigated in detail. In this study, we investigated the fundamental study of sensing technique using MCF rubber under radiation environment. As first step, we clarified change of induced-voltage of MCF rubber, and mechanical property of the MCF rubber after irradiation.

This study developed a measurement system of floor cleaning task using the marker-based optical motion capture (MoCap) and inertial measurement unit (IMU). In this system, full-body motion of the cleaner and motion of the sheet-type mop were measured, both of which were used for estimating the swept area on the floor. The floor cleaning experiment was conducted with 16 healthy participants. The participants were classified into five groups based on the mop motion during the task. The cleaning complete time, swept area, and motion of the mop were analyzed and compared among participant groups. Our results indicated the possibility of evaluating the effectiveness and efficiency of the floor cleaning task based on the cleaning complete time and the movements of the mop, respectively.

This paper describes a new face detection method based on facial feature colors. In this study, we constructed a facial feature point system using a PC camera. First, we focused on skin color as a facial feature and constructed an automatic detection system. In order to extract the face of a person from the obtained image, the feature of the skin color information in RGB color space under different brightness environment was investigated. As a result, regardless of the brightness, the R component was stronger in the skin, nostrils and lips than in other regions, and the difference between the R and B components was very large.

Electrocardiogram(ECG) is often used for affective evaluation using biosignals. However, adhesive-based sensors are difficult to use on daily basis and may affect participants’ emotion. In this study, we measured blood pressure pulse (BVP) using wearable sensor, and compared physiological indexes between calculated from ECG and BVP during floor cleaning task. As the results, we found the tendency of physiological indexes calculated from BVP. For example, BVP-based RRI had large dispersion. Approximately 20% of data showed a strong correlation between indexes calculated from ECG and BVP. Our results suggested that BVP measurement would be useful if the effects of body movement were removed.

This paper presents a novel method to measure subjective palatability using facial expression via video analysis. We recorded facial expression using 30fps video camera to classify them to each subjective palatability using 512 facial landmarks. Self-Organizing Maps (SOM) is applied to them as classification algorithm. In this paper, we verify the usefulness of this method to use for subjective palatability sensing. This result has a tendency such as symmetrical facial expressions if a subject feels good taste, and unsymmetrical facial expression if a subject feels bad taste. This indicates the potential to measure subjective palatability using this facial expression pattern. From these results, our proposed method is useful for subjective palatability sensing.

Since recent years, society has been described as more and more stressful, and necessarily stress has an impact on people. In this context, stress is said to have a negative effect on human performance. In order to tackle this problem, previous researches have measured stress in real time and proposed assist methods. However, it is difficult to provide feedback on stress, and a physical load caused by wearing many sensors has been an pointed out. Therefore, the purpose of this research is to create an individual model of stress from machine learning, and to examine a method of feedback which doesn’t differ depending on each individual.

Japan faces a super-aging society. In order to support stable walking of elderly people with walking dysfunction, wearable walking support devices have been developed. However, no index for evaluating the effect has been shown. The purpose of this study is to construct an index to evaluate the walking stability with a wearable walking device. And, this new index aims to reflect the margin of stability based on Lyapunov exponent. In addition, using small and light Inertial Measurement Unit (IMU) acceleration data, it is expected that it will be possible to measure the effects of ancillary equipment anytime, anywhere. By clarifying the effect using this index, it is expected that the promotion of the spread of walking assist devices will be supported.

Electromyogram (EMG) and mechanomyogram (MMG) have been used to quantify muscle activities. In this study, we analyzed muscle activity using both EMG and MMG, and compared their spectral responses. We considered with this comparison what kind of muscle is dominant in each frequency range. These results indicate that the activity of slow muscle appears more clearly in MMG than in EMG. In addition, it is confirmed that muscle fatigue increases muscle sound when moderate load is added to the muscle for minutes.

In order to evaluate the driver's fatigue during long-time driving, we examined an amount of muscle activity on the back of the driver. In this research, we evaluated long-term sitting fatigue by an evaluation method using a myoelectric potential measurement device. A driving experiment was performed using a driving simulator. before and after experiment we confirmed in muscle activity in the seated state and in the state of back muscle exertion. And evaluated the driver's fatigue by both biological information and subjective evaluation. As a result, It was found that driving fatigue can be evaluated by Increased amount of muscle activity in the state of back muscle exertion.

In this study, we constructed a system that generates a Kinesthetic Illusion by using muscle contraction caused by electrical stimulation and visual stimulation in which fingers move. And we investigated the temporal consistency between the electrical stimulation and the visual stimulation. The results showed that the presentation of the electrical stimulation tended to enhance the sense of ownership and the Kinesthetic Illusion compared to the case of only visual stimulation. In addition, when the electrical stimulation was presented in synchronism with the visual stimulation, the sense of ownership and the Kinesthetic Illusion tended to increase.

In recent years, the number of road traffic law violations associated with road rage has increased rapidly. In this study, in order to examine the analysis method for its occurrence process, driving experiment with environments to induce road rage behavior were conducted, and the state of stress using heartbeat interval was investigated.

Generally, an autonomous mobile robot is equipped with various sensors such as a web camera and a laser range finder (LRF). However, it is difficult to read necessary information from a lot of obtained information and process it appropriately. On the other hand, humans can grasp the situation appropriately from surrounding information even in the environment where they have visited. Focusing on this, we investigated the human environment recognition method using a gaze measurement device. As a result, it became clear that humans specified he location from the whole landscape and characteristic objects. In this study, based on this, we propose a point recognition method that combines global scene detection with CNN and local features. As a result, it was found that the landscape recognition using CNN can reduce errors caused by angles and positions, and is more robust than GIST features and superior in scene recognition.

Grip strength have an essential role in daily life. However, it has been confirmed that the average grip strength decreases with age. In order to prevent the decreasing of ADL (Activities in Daily Living) for elderly women, it is necessary to support the reduced grip strength. In this study, to construct the support system at the opening the package situation with the necessity for the hand posture optimization, the pressure measurement between the finger and the plastic bottle cap have been conducted. In this report, the methodology of the pressure sensor arrangement where have effective for measuring the gripping force has been proposed. And its validity have been examined through the experiment.

Compared to 30 years ago, Japanese children’s motor skills are decreased. Decreases in children’s motor skills not only increase the risk of injuries in their life, but also reduce the joy of enhancing their own motor skills and the opportunity to form a human harmony through sports. It is very important for improvement of motor skills to have exercise habits since childhood. Because we believe that improving motor skills can lead to enjoyment of exercise, we will develop a system to assist motor skills improvement. In the first step, we pay attention to a lower limb motion which is the basis for motor function and then have been developing a real-time monitoring system for instruction of a lower limb motion.

This study proposes a wearable magnetic sensing device for measuring whole body coordinated motion of children with developmental coordination disorder. Each sensing device attached to the limbs consists of three magnetic sensors and a inertial moment sensor. The magnetic sensors measure the magnetic field around a electromagnet attached to the waist. By using the proposed method, the system allows the user to need no complicated calibration and to move around.

This paper extracted features that do not depend on posture from body shape, and worked on personal authentication using the extracted features. Heat Kernel Signature is a method of extracting features that do not depend on posture from the body shape. Using the shape descriptor that is resistant to non-rigid deformation, the same part between humans was searched, and the part was identified as a feature. The proposed method achieved 96.9% accuracy when narrowing down from 20 to 3 people. We also verified this method for actual walking. By transforming the previously acquired skin model so that it fits the three-dimensional joint position acquired by Video Motion Capture, the body shape can be reconstructed from the footage image. As a result, the accuracy of identifying one person out of four was 88.75%

For performing complex and precise micromanipulations, double-arm optical tweezers are a powerful tool. Furthermore, for cooperative manipulation tasks using two arms, real-time measurement of the contact forces is crucial. We present an interactive interface to the double-arm optical tweezers, based on a combination of a commercial haptic device and image processing techniques. Our system allows the users to perceive real contact forces exerted during cooperative manipulation of objects by two trapped beads which are end-effectors for indirect optical tweezing tasks.

We present the microgripper having soft-rigid hybrid structures without complex feedback systems. Soft materials have sensors and feedback systems in oneself because soft materials can change and fit the shape against stimulations from external world. The proposed microgripper is made of thermoresponsive gel as soft actuators and SU-8 as rigid structures. Then, we mix thermoresponsive gel with graphene as a light absorber to actuate this soft structure by near infrared laser irradiation. The proposed microgripper can be switched release and grip by laser irradiation. In this paper, we succeeded in fabrication of the microgripper with sacrificial layer process. Additionally, we confirmed that the micro gripper can be driven by switching laser irradiation and grip single cell.

Single cell manipulation techniques are needed to realize a single cell analysis. On-chip actuator is a potential candidate for manipulation tool to realize various cell manipulations in a microfluidic chip. Among on-chip actuators, on-chip gel actuator is attracting large attention because it can realize low-invasive cell manipulations. We proposed drive method of on-chip gel actuators by using light irradiation. The gel actuator is made of temperature responsive hydrogel and fabricated on microfluidic chip with light absorbing pattern. Thus, the actuator can be driven by irradiating light. Furthermore, multiple actuators can be integrated at short distance. In this study, we show cell manipulation in microfluidic device by using multiple gel actuators. To realize driving arbitrary actuators, we irradiate patterned light by using DMD. Furthermore, we succeeded in transporting cell through flow path made by gel actuators. In this result, we show the proof of concept of cell manipulations in microfluidic device by using integrated gel actuator.

This Paper describes biological nanopore probes that biological nanopores are reconstituted into the lipid bilayer formed at the tip of micro and nano electrodes. Stochastic nanopore sensing is a powerful technique for single molecular detection with high sensitivity. In addition, bio-inspired scanning ion conductance microscopy (bio-SICM) that can image topological and chemical information by using the biological nanopore probe has been reported and attract attention as a live cell imaging technique. However, it is still challenging to form stable lipid bilayers at the tip of the probe. Here, we describe formation methods of lipid bilayers using micro and nano electrodes to prepare stable lipid bilayers by supported on the electrodes. Furthermore, we demonstrate spatially resolved chemical sensing in a microfluidic channel and high throughput nanopore sensing by using a 3D printed micro chambers. From these results, we believe that our nanopore probe technology can potentially be applied as a probe of bio-SICM and a high throughput nanopore sensing platform.

In this research, we develop a micromanipulation system using an inverted microscope that can acquire both high-resolution and large field-of-view images with free viewpoint selection. Image acquisition and simultaneous displaying algorithm of high-resolution and large field-of-view images is implemented the proposed system for efficient microinjection without changing objective lens and light intensity. Finally, we demonstrate the proposed system though microinjection experiments using swine embryos.

The micro/nanostructures (micro-hairs), which exist on the surface of the water strider’s legs, can maintain the air layer between the water surface and the insect’s legs. In this study, we proposed a physical model of water strider by using Laplace pressure, and then we introduced the directly measured leg-rowing force of water strider. First, we considered relationship between the water pressure around the micro-hairs and the intersection of the surface of micro-hairs and the water surface by using the proposed model. As a result, it found that when the water surface touched on the micro-hairs and the air layer was maintained, maximum Laplace pressure P_max reaches 35.2 kPa. This means that if the pressure generated by rowing motion of legs is required to exceed 35.2 kPa to impregnate water into the space between the micro-hairs by water pressure which is caused by the rowing motion of legs. In contrast to this, we calculated maximum water pressure P_L, which was loaded around the surface of the water strider's leg by rowing of the insect’s leg. P_L was 546 Pa, and this value is sufficiently smaller than P_max. It is thus shown that the water cannot impregnate into the space between the micro-hairs by the rowing motion and water strider can maintain its water repellency when water strider rowing its legs.

Cell cryopreservation stops the biological activities in the freezing state and can maintain cells without subculture which sometimes causes contamination and genetic drift. However, the freezing process for cryopreservation injures or damages the cells due to cytotoxicity of cryoprotectant agents or dehydration by osmotic pressure difference. We previously reported a cryoprotectant agent-free cryopreservation method based on inkjet technology. In the study, the vitrified cells in droplets were thawed by soaking manually into prewarmed medium by tweezers. During the process, the cells had to pass through the atmosphere at room temperature, which caused devitrification by temperature rise and often lowered the cell viability. In this study, we developed an automatic thawing apparatus to carry the vitrified cells rapidly into prewarmed medium. Furthermore, the apparatus was evaluated by high-speed camera and thermal flow simulation.