The purpose of the study was to investigate the movements of the pelvis during pedaling motions. We, especially, analyzed a trajectory of the pelvis when cycling cadence or workload were changed. In this study, 7 non-cyclists were asked to pedal at 2 cadences of 60 and 90 rpm, and at 5 power outputs of 80, 90, 100, 110 and 120 W. We placed reflective markers on the anatomical characteristic points to define the body segments, and we measured a whole body movements during pedaling motion. As a result, from 0 to 60 degs during down stroke phase, the center of the pelvis moved posteriorly at both 60 and 90 rpm. Trajectories of the center of the pelvis at 60 rpm as low cadence shifted anteriorly, but 90 rpm as high cadence shifted posteriorly. The most posterior points of the trajectories tended to shift anteriorly at 60 rpm as workload increased, but the points at 90 rpm tended to shift posteriorly as workload decreased.

The ground reaction force generated by the interaction between the foot and the ground is one of the important parameters for gait analysis. However, force plates and instrumentation treadmills used for ground reaction force measurement are large and expensive, can be used only in a laboratory environment, and have the problem of being unsuitable for gait analysis in daily life. This paper presents a novel methodology for estimating the ground reaction force during walking based on inertial sensor and forward dynamics simulation. In this simulation, a human body was represented by the rigid links model, the walking pattern and ground reaction force synthesized by forward dynamics simulation was optimized so as to approach the walking pattern measured by the inertial sensors. The ground reaction force estimated by the proposed method should be improved to agree the actual ones.

A senior car is an electric wheelchair mainly used by elderly people. Senior cars are treated the same as pedestrians under the Road Traffic Act, so no license is required. As for the operation method of the senior car, the direction is decided by the steering wheel, the speed is set by the dial, and the vehicle can be driven by using the accelerator lever. However, senior cars currently on the market have low response performance to driving commands from drivers, and due to insufficient safety confirmation when crossing the road by senior cars, contact accidents with pedestrians, bicycles, and automobiles occur frequently. In this paper, using SIMULINK model of a senior car, we compared the conventional acceleration / deceleration method and the advanced S-shaped acceleration / deceleration method on the ride quality. Simulation results show that the advanced S-shaped acceleration / deceleration method is a well-balanced method.

In order to investigate vibration response characteristics for simple seismic isolation system set on a small structure, vibration test have been performed. From results of excitation experiment using sine waves as input, it was indicated that the system reduced seismic response in case of the smaller friction coefficient. And the larger acceleration amplitude on input wave, isolation effects of the system indicate good performance. These effects are confirmed in case of seismic wave as input. And from results of excitation experiment set a small structure on the system, it was found that the small structure generates the rocking vibration in case of the low reduction rate on the system and overturned at the time of transient state vibration.

It is important for seismic disaster prevention of exhibits in the museum to understand overturning behavior them by seismic ground motion. In this study, behavior of exhibits in the museum fixed by nylon guts have investigated simulated by excitation experiment for exhibit models with the same overturning limit acceleration and different masses. As a result, by increasing the friction coefficient at the bottom of the exhibit models, the sliding motion caused by overturning could be suppressed for all exhibit models, and the exhibit models could be prevented from overturning as long as the nylon guts did not break. Between the models with same overturning acceleration amplitude and different weight, effects of weight difference on overturning of the model are small.

We use many small electronic devices such as smart phones. When the disaster occurred and the power grid was damaged, we may not be able to charge up the battery of the electronic device. Therefore, it is necessary to build a generating electricity system by some kind of methods. This study focuses on a vibration energy harvester that one of the energy harvesting. The experimental device which got energy by a steel ball colliding with the piezoelectric elements was produced. Electric power generation of the vibration energy harvester is low. This study focuses on finding the conditions that lead to improve power generation efficiency. By vibration experiment, it is found that the generated voltage of vibration energy harvester is change by a steel ball being caught between the piezoelectric elements. Therefore, we attached a stopper to experimental devices. The generated voltage was improved by this improvement.

The main purpose of this study is to understand the characteristics of a nonlinear vibration system with a gutter subjected to irregular input. The third harmonic component of the main resonance was identified from the response displacement data by using the "trispectrum" method, which is one of the higher-order spectral analyses.

Personal audio based on tangent line method (TLM) has been proposed by one of the authors. Since TLM works well at high frequencies rather than low frequencies, the robustness of the proposed method against low frequencies is verified in this study. Moreover, the loudspeaker array used in the proposed method is designed assuming that there is no case body of the loudspeaker array. In other words, free space is assumed in the design process. Hence, the robustness of the proposed method against a case body is also verified.

HEV and EV become popular in recent years. Road noise which used to be masked by the noise from the engine is relatively conspicuous and prevents the improvement of interior quietness.Improvement of the sound insulation performance can be achieved by increasing the mass or volume of the sound insulation, but this must be avoided in order to reduce the weight of the vehicle. Double-wall structure with an air layer between the walls is a method to improve the sound insulation performance without increasing the thickness or mass of the sound insulating material, but there is a problem of resonant transmission, in which sound penetrates at a certain frequency due to resonance in the intermediate air layer. In this study, we investigate the improvement of the sound insulation performance by suppressing the resonant transmission of the double-walled structure with acoustic metamaterials.

In the automobile market in recent years, there is an increasing demand for automobiles that have less impact on the environment due to concerns about the impact on the environment. In addition, with the stricter regulations on outside noise, it is becoming more necessary to take some measures against noise from automobiles. In this study, we focused on the acoustic performance of the DPF/GPF as a sound insulation material. The validity of the model and calculation method is verified by carrying out the calculation results by the homogenization method and comparing them with the measured values.

Fan motors used for cooling data servers are generally controlled by inverters to save energy and reduce noise.At this time, noise is generated due to the inverter.Even manufacturers have taken noise countermeasures, it is difficult to reduce the noise completely.In this research, we focus on the output current of the inverter to qualify the current characteristics that cause noise. Furthermore, the noise countermeasures which were taken by manufacturers were investigated ,and the connection between the current characteristics and sound quality of the fan motor. From these results, we aim to propose a sound quality improvement method by changing the inverter output.

In the previous studies, the stationary and transient response characteristics of linear systems subjected to non-Gaussian random excitation were investigated from the view point of the displacement response distribution and velocity response distribution. It was revealed that the probability distribution of the stationary response varies significantly depending upon the bandwidth of the excitation power spectrum. In this paper, we calculate the joint response distribution of the displacement and velocity by Monte Carlo simulation. The non-Gaussian excitation is prescribed by both a probability density function and a power spectrum with bandwidth parameter. In order to find the response characteristics that appear commonly for different non-Gaussian excitations, we consider two kinds of non-Gaussian distributions for the probability distribution of the excitation. Their shapes are much different from a Gaussian distribution and also distinct from each other. For such non-Gaussian random excitations, the joint response distribution is obtained, and the relationship between the response distribution and the bandwidth of the excitation power spectrum is examined in detail.

We consider a linear system under zero-mean stationary non-Gaussian excitation modeled by Cai and Lin’s model and analyze the effect of the non-Gaussianity of the excitation on the system response by the cross-bispectrum. Bispectrum is a kind of higher order spectra which are generalization of power spectrum. Just as the power spectrum is the distribution of the 2nd-order cumulant of the stationary stochastic process in the frequency domain, the bispectrum is the distribution of its 3rd-order cumulant in the frequency domain. Cross-bispectrum provides the input-output relations of the non-Gaussianity in the frequency domain. It is shown that when the bandwidth parameter of the excitation α is small, the non-Gaussianity of the excitation concentrated on the DC component is mostly transferred to the DC component of the response. Meanwhile, when α is large, the resonant frequency is obvious in the response power spectrum, but the resonant frequency does not transfer or amplify the non-Gaussianity of the excitation. These findings can only be obtained from the cross-bispectrum and cannot from the power spectrum.

This study conducted in-phase TMF loading on single crystal Ni-based superalloys to investigate the small crack propagation behavior of naturally generated cracks on the specimen surface. In addition, the effect of creep-fatigue interaction on small crack propagation was investigated by implementing the conditions of temperature and stress holding at the maximum temperature during in-phase TMF loading. The experimental results indicated that the elastic deformation was dominant in the cyclic deformation behavior, and the hysteresis loops contained almost plastic strain under all loading conditions. However, slight creep deformation occurred during the high-temperature tensile holding in each cycle. The naturally initiated small cracks propagated perpendicular to the loading direction macroscopically. However, the microscopic SEM analysis could not reveal the crystallographic crack propagation path due to the Al-rich-oxide (Al₂O₃) formed around the crack tip and surface. The crack growth rates under the in-phase TMF loading were significantly higher than those under the out-of-phase one at the same stress intensity factor range or the same fatigue J-integral range. In addition, the introduction of the high-temperature tensile holding in the in-phase TMF loading cycle accelerated the crack growth rates. The small-scale creep stress field at the crack tip might dominate the small crack propagation behavior under the in-phase TMF loading with high-temperature holding as the creep-fatigue interaction.

Recently, a modified CrMoV forging steel was developed with superior creep strength property by adding tungsten to conventional CrMoV forging steels. Generally, creep damage proceeds at stress concentration portion under multiaxial stress gradient. It is important to clarify creep rupture property and damage evolution process under the multiaxial stress states for the modified CrMoV forging steels. In this study, creep tests were conducted using plain and four kinds of circular notch specimens of the modified CrMoV forging steels. It was found that creep rupture times of the modified CrMoV forging steel are three times longer than those of the conventional one. Rupture times of the notch specimens of the modified one are longer as the tip radius decreases. The distribution tendency of creep void number density at the notch root sections corresponds to the distribution tendency of the maximum principal stress. The void growth simulation procedure was applied to predict creep damage. It was indicated that the initiation and growth of void under both uniaxial and multiaxial stress conditions quantitatively predicted by the void growth simulation.

The effect of primary Sn grain size on the deformation behavior of Sn-Bi-Sb alloy was examined. Sn-Bi-Sb alloys with various primary Sn grain sizes were used in this study. Tensile tests of Sn-40Bi-0.5Sb and Sn-40Bi-1Sb alloys were carried out at various temperature (30, 40, 50, 60, 70, and 80 ℃) and under strain rates of 5.25×10-4 /s. The Stress-Strain curves of Sn-40Bi-Sb alloys at low temperature are approximately the same. In the contrast, the Stress-Strain curves of Sn-40Bi-Sb alloys at high temperature are different from the breaking elongation. The variances are caused by differences in dominating factor of deformation in Sn-40Bi-Sb alloys.

Severe plastic deformation by cold rolling after multi-directional forging in commercially pure titanium is carried out. Mechanical properties are evaluated by hardness test and tensile test. Specimens cold-rolled after multi-directional forging can have a higher hardness than specimens that have only been multi-directional forged and cold-rolled. The tensile strength of specimens both only cold-rolled and cold-rolled after multi-directional forging increases with the increase in cumulative plastic strain. The elongation decreases with increase in the rolling reduction of cold rolling.

Inconel 718 is often used as mechanical parts for jet engines and rockets because of its excellent durability. On the other hand, it is a difficult-to-cut material because it has high-temperature strength and low thermal conductivity. In order to improve the accuracy and efficiency of machining difficult-to-cut materials, it is urgent to establish a system that accurately detects and automates the cutting state. The purpose of this study is to apply acoustic emission (AE) sensing to monitoring the cutting state of difficult-to-cut materials. AE sensing is a sensing technology that measures elastic stress waves that occur when a material is deformed and fractured, and can detect and evaluate changes with time in a material with high sensitivity. In this experiment, AE sensing was introduced at the actual machining site to measure the AE signals during Inconel 718 turning, and the relationship with the cutting state was investigated. As a result, it was found that the AE signals changed step by step as the tool wear progressed.

The purpose of this study is to clarify the relationship between the compressive deformation of urethane rubber and the temperature change. Repeated compression tests were conducted at seven stroke speeds from 45 mm /min to 10 mm/min. A theoretical formula of temperature change was considered two factor: one calculates the temperature from the increment of external work, and another calculates the temperature from the change of compressive stress as the thermoelastic effect. As a result, the faster stroke speed was, the stronger the influence of external work became. And the slower stroke speed was, the stronger the influence of thermoelastic effect became.

The purpose of this study is to investigate the mechanical and tribological properties of carbon fiber (CF) and carbon nanotube (CNT) reinforced bismaleimide-based polyimide (PI) composites to develop the tribomaterials based on fiber reinforced PI composites. Thermosetting type commercially bismaleimide-based PI was used as a matrix polymer for composite materials. CF and CNT were used as a reinforcement fiber. CF/PI and CF/CNT/PI composites were manufactured by defibration of fiber, pre-forming, dry mixing, hot press molding (compression-molded) and heat treatment. Mechanical properties were measured by three-point bending test and tribological properties were evaluated by the ring-on-plate type sliding wear test under dry condition at 23 oC and 100 oC. It was found that bending strength and modulus of CF/PI composites decrease when filled with CNT. On the other hand, the influence of addition of CNT on the tribological properties, namely frictional coefficient and specific wear rate, of CF/PI composites differed for each tribological property. In particular, specific wear rate improved when filled with CNT. This may be attributed to change in the wear mechanism of CF/PI composites according to CNT fills or not. On the other hand, the frictional coefficient of CF/PI and CF/CNT/PI composites at 100 oC is lower than that of 23 oC. However, the specific wear rate of these composites at 100 oC is higher than that of 23 oC.

For the purpose of developing the new engineering materials such as structural materials and tribomaterials based on all plants-derived materials, we investigated the effect of addition of maleic anhydride grafted polypropylene (PP-g-MA) on the tribological properties of biomass polymer blends of plant-derived polyamide 1010 (PA1010) and polylactic acid (PLA). Both PA1010 and PLA were plant-derived biomass polymer. PA1010 was made from sebacic acid and decamethylenediamine, which are obtained from plant-derived castor oil. PLA was also obtained from renewable resources such as corn or sugar cane. The PA1010/PLA biomass blends having various blend ratio (100/0, 80/20, 50/50, 20/80 and 0/100) were extruded using a twin-screw extruder and injection molded. PP-g-MA (2 wt.%) was used as a compatibilizer. The mechanical properties such as tensile test and tribological properties were evaluated by the ring-on-plate type sliding wear test. The effect of addition of PP-g-MA on the tensile and tribological properties of PA1010/PLA biomass polymer blends differed for each property. Although the tensile strength and modulus decreased when filled with PP-g-MA, the frictional coefficient and specific wear rate increased when filled with one. This may be attributed to the changes in the mode of friction and wear mechanisms according to PP-g-MA uses or not.

Piezoelectric materials can be used as actuators and sensors by poling that applies an electric field while heating from the outside. However, there is a risk of dielectric breakdown due to poling piezoelectric materials. The closer to the Curie temperature, the closer the coercive field is to zero, and the voltage required for polarization is reducing. Therefore, we measured the hysteresis loop of the piezoelectric material and poling while lowering the temperature from around the Curie temperature by the manufactured temperature controllable device (Cooling poling treatment). Then compared with results of poling while lowering the temperature from below the Curie temperature and the results of poling at a constant temperature below the Curie temperature, which is a normal poling treatment. As a result, higher piezoelectric performance was obtained at a voltage of 10% by performing the cooling poling while lowering the temperature from around the Curie temperature with the manufactured temperature controllable device. Furthermore, it was found that the piezoelectric performance was improved after the cooling poling from above Curie temperature.

Different bonding of carbon fiber reinforced plastic (CFRP) and metal attracts tremendous interest due to the increasing use of CFRP in the aerospace and automobile industries. In this study, in the direct laser bonding of the thermosetting CFRP and titanium plate, laser ablation was applied to the titanium plate as a pretreatment to improve the joint strength. In the laser ablation, the scanning speed and scanning direction were changed, and the effect of each on the joint strength was investigated. When laser ablation was performed under the condition of scanning speed of 100 mm/s in the direction perpendicular to the tensile direction during the tensile shear test, the joint strength was more than twice that of the untreated condition. However, when the scanning direction was laser ablated in the direction parallel to the tensile direction during the tensile shear test, the joint strength was about the same as the untreated condition.

In recent years, robots are expected to be utilized in places where rescue activities are difficult, such as disaster-stricken areas and former nuclear power plant sites.in disaster area, Rescue activities are often necessary to move over rubble and debris. Humans can easily step over rubble by bipedal walking. In realizing a fully autonomous bipedal robot there is a problem of posture control in the case of the robot falling over when it makes a large posture change. In this paper, the inverted pendulum, which is the simplest model for posture control of bipedal walking, is considered. The effectiveness of a linear controller is verified by using Scilab/Scicos. when it is applied to an inverted pendulum with a large posture change that is a highly nonlinear model. Simulation results show that an inverted pendulum with large posture change is stable, when close loop poles are located near origin,

This paper presented a fabrication of a hand rehabilitation support device driven by pneumatic soft actuators. When damaging a finger, it’s difficult to take back usual movement. The rehabilitation added to the symptom is needed. We propose the new support device with which rehabilitation of a hand is supported. A support device for move winding and extension motions.

Robot grippers with elastic fingers have been recently developed to resolve challenging issues for gripping irregular objects adaptively. The finger of these grippers is flexible and jointless. The gripping motion is performed utilizing large elastic deformation of the fingers. The flexibility of the fingers enables the grippers to adapt to various objects. However, the fingers are also elastically deformed by the object’s weight loaded on the fingers. This deformation significantly reduces the gripping force at the moment of picking up the object. This paper analyzes the large deflection of an elastic finger gripper to estimate the reduction in gripping force at the moment of picking up an object. The elastic finger is modeled as a series of rigid links connected with torsional springs. The finger deflection is analyzed based on the principle of stationary potential energy. The estimation of the reduction in gripping force of the elastic finger gripper in picking-up operation is shown in a numerical example of picking up a rigid rectangular object with a pinching motion.

This paper presents a Haptic Master Device with Non-Contact Position Measurement for Surgical Robots. This system operates the surgical robot using data tracked by the motion capture of the haptic master device, and control of the band-type soft actuator and the vibration motor for force sensation. Soft actuator is designed band-type because the grip operation is used to manipulate the surgical robots, and made of a combination of the stretchable silicon and the nonstretchable silicon because present strong pressing force with little pressure. From experiment, soft actuator has pressing force of 3.7 N for middle finger and 5.1 N for big finger at an internal pressure of 60 kPa, and there is a monotonically increasing and decreasing relationship between pressure and pressing force. This research can solve the problems of conventional surgical robots without, such as re-registration of positions required due to narrow range of motion, and reduced operability due to near singularities, the weight, inertia, and viscosity of the arm, without losing the haptics.

Recently, soft growing robot have attracted interest. They can extent from its tip and make various shape with many bends. Hence, they are expected to be used in clutter environments and narrow spaces. However, geometric modeling of their bending shape is very difficult due to their highly complex deformation. In this paper, we introduce the finite element analysis model of an inflatable tube bent by heat welding. The bending angle is simulated by changing welding shape, and the relationship between them is investigated. The result of analysis is compared with actual measured bending angle, and it shows that the analytical model is good agree with an actual bending inflatable tube. Moreover, we confirm that the bending angle increases as the height of welding shape increases, but it is not affected by the width of the welding shape. This analytical model enables us to obtain the bending angle by simulation and assists in determining the parameters of welding.

The herbicide-free weeding method used in this study is to stir the paddy field by dragging the chain attached to the rear of the weeding robot, float the seeds of weeds, and make the paddy field turbid to prevent the growth of weeds. Then, in order to automate the weeding work, we built an automatic driving system. The automatic driving system is a position control system that follows a predetermined work path based on data from GNSS sensors. The driving unit of the robot attaches propellers to the propulsive and steering motors, and outputs thrust by rotating the propellers. However, during the automatic driving, it may not follow the work path due to wind and disturbance in the experimental environment. In this study, we introduce a disturbance observer to a feedback control system. The validity of the disturbance observer is verified by simulations with considering disturbance.

This paper proposes a velocity tracking control strategy based on the backstepping method for a Wheeled Inverted Pendulum Robot (WIPR). However, it is difficult to apply the high-gain feedback control to WIPR because of an unstable zero. Proposed strategy comes up with following solutions. First, a linearized model is created using the coordinate transformation to separate the unstable zero property from the WIPR model. Next, a velocity tracking controller based on the backstepping method is applied to the linearized model to follow the reference velocity trajectory while stabilizing the attitude. In addition, the proposed controller can design pre-specified transient characteristics to stabilize the upright position. On the other hand, the solution to the tracking error caused for non-minimum phase systems is to design a pre-compensator that compensates for effects of unstable zeros. To verify the effectiveness of proposed control strategy, simulations for WIPR were performed using two types of reference velocity trajectories: sigmoid-step and sine wave. As a result, the effectiveness of the proposed strategy was confirmed.

In this paper, we describe the fabrication of an in-pipe traveling robot that can move through pipes and measure the load using on-board sensors. Direct inspection of pipes is an effective way to check for damage and health conditions in pipes. In recent years, a method using a small robot has been studied for pipe inspection. However, inspection by a robot requires a load to be applied to the pipe to obtain propulsion. Therefore, we constructed a system that can check the load transition by installing sensors on the pipe contact area of the robot, and examined the load applied in the pipe. The robot consists of three rubber bellows, two frictional brake mechanisms, and a sensor to check the load. The braking force by the brake mechanism was calculated.

Our research group is studying the method that use Braille blocks as a graphical map and as landmarks when driving for the purpose of Autonomous running of a robot in an underground passage at Shinjuku Station. In this paper, we present a method for detecting Braille blocks using deep learning, and a method for calculating data about nodes and edges from the detection results. In addition, we evaluated whether the angle of the robot to the guiding blocks could be calculated. The evaluation was conducted by setting up a cart equipped with an RGB camera against the induction block and determining whether the angle between the induction block and the cart could be calculated. As a result, when the induction block and the cart were not parallel, the error in the calculated angle was small. The reason for the large error when the rows of induction blocks and the cart are parallel may be that the method of correcting the coordinates is wrong.

In recent years, research on walking of biped robots has been conducted in various places. Among them, a control system using a central pattern generator (CPG) has attracted much attention. However, most of the studies on walking control using CPGs are limited to two-dimensional space. In this study, we propose a walking control system for a biped robot in three-dimensional space that can immediately respond to changes in the environment. In this paper, as a preliminary step, we propose a control system based on a new CPG for a biped robot and verify whether periodic walking is possible. Two robot models, one based on the conventional CPG control system and the other based on the proposed control system, are created, and their robustness is compared and evaluated by simulation.

In recent years, the development of quadruped robots with both high-speed running and agility has been actively pursued. In the previous study, this kind of motion was achieved by improving the performance of the actuator. However, the leg mechanism itself has a simple structure in which a single motor drives a single joint, and the performance of a single motor has a great impact on the movement performance of the robot. In this paper, we propose a leg mechanism with parallel link mechanism by vertically mounted linear actuators to further improve the mobility of the robot. A set of the design parameters, which can satisfy the kinematic model of the robot running in a steady state, are investigated by mechanical analysis, and the characteristics of the leg mechanism are discussed.

To achieve the high output performance and light weight required for the joints of a walking robot, we proposed a two-input/two-output differential mechanism with driving links. As in the parallel link mechanism, the differential mechanism requires a ball joint with a wide range of motion and parts with complex shapes for the passive joints of the links, which makes the mechanism design difficult. Therefore, we introduced a slider and a knuckle joint instead of a ball joint to realize an equivalent 3-DOF passive joint and simplify the mechanism design. Then, as an application of the proposed differential mechanism, we designed a 2-DOF joint mechanism for the body mechanism of a walking robot using this mechanism and conducted motion tests using an experimental model. We confirmed that the designed mechanism can rotate 90 degrees around the pitch axis and 82 degrees around the yaw axis.

We have been developing a novel hexapod walking robot, ASURA II, inspired by the physical features of a harvestman’s behavior. ASURA II has a special mobile form with one compact body and much longer legs than conventional hexapod walking robots. To achieve this mobile form, we introduced the multiple coupled drive systems using wire-pulley mechanism, which powerfully and widely drive the leg joints. In this paper, we discuss the development of wire holder to fix the wire terminals. The wire holder must be able to adjust the initial tension of the wire and be strong enough to withstand high wire tension. The effect of the wire holder is verified by a motion test using one leg model.

Ultra-compact electric vehicles (EVs) have been become the popular tools of new transportation recently. However, there is interior noise problem such as road and wind noise from outside during driving in these vehicles. Our research group has proposed an active noise control (ANC) system for mounting an ultra-compact EV. The proposed ANC system includes giant magnetostrictive actuator which is one of the small actuator. We have been studied on noise reduction effect for control signal generated wall vibration by giant magnetostrictive actuator installed plate shaped part of ultra-compact EV. In this report, we conducted a basic study of noise reduction performance using an adaptive filter based on the LMS algorithm by simulation, and considered the noise reduction effect by comparison the settling time.

Texture has a great influence on the deliciousness of food. Its evaluation has been carried out by the measurement of physical properties of food using testing machines such as texturometer and rheometer, or by the mastication test by subjects. The former is simple and highly reproducible, but it differs from the actual mastication in many points, and the latter has a problem of large data variation due to individual differences among subjects. In addition, aroma components released from food in the oral cavity have a great influence on the deliciousness as well as texture. However, there was no appropriate equipment which could evaluate aroma by simulating the cavity condition. In order to solve these problems, we have developed a food mastication device with the following functions:

Simulating the mastication movement of human oral cavity,

Controlling system of temperature condition of human oral cavity,

Inflowing system of artificial saliva, and

Collecting system of released aroma components.

Artificial life is a research field that uses artificial systems such as computer simulations to reproduce life phenomena and expand our understanding of life. Artificial life research is mainly concerned with emergent behavior using multi-agent systems, which is a part of artificial intelligence research. Pheromone communication in ants is a study that focuses on the organized behavior of ants that use pheromones to communicate with their fellow ants and efficiently transport food during foraging behavior. Ants have low individual abilities and behave according to simple behavioral principles. In this research, we focused on the efficient activities of ants and applied the foraging behavior of ants to establish an algorithm that mimics it for application to a multi-agent system using their organized behavior. In this paper, we aim to model the foraging behavior of ants, and confirm that our model creates a pheromone trail and that foraging behavior is emergent.

In recent years, the aging of agricultural workers and the reduction in work force is progressing. Especially in farm work, the management of levee is very burdensome for workers. Conventionally, a brush cutter has been used for levee management, but this task is very dangerous for workers. Therefore, various robots have been developed for levee management. In the development of robots, it is important to suppress sideslip to improve working efficiency. In addition, the Ministry of Agriculture, Forestry and Fisheries is promoting technological innovation to autonomously drive robots. In this research, we propose a slip estimation method using a drone and develop a system that linearly controls the slope. As a result, it was confirmed that the proposed method can stably estimate sideslipping and is sufficiently applicable to straight-line automation control.

We tried to make the miniature prototype of the flying car combination between upper car and lower drone. The Ryze Tech Tello with the length of 180mm was adopted as a base drone. Flow simulation around the flying car was done in order to make a design for the reduction of fluid drag. By the shared battery between car and drone, the weight ratio of flight, common and running parts became 24:60:16, respectively. This weight ratio is approximately equal to the advanced development flying car. Finally, our miniature prototype of a drone based flying car succeeded in a stable flight. The utilization image of a drone based flying car is the transportation to remote islands and the disaster site with the cutoff road.

We are aiming to sweep the high place such as buddha and the restricted area such as solar panels using down airflow induced by a drone. Our target of this study is to sweep the dust on the cardboard robot with the height of 1.3m. JIS standard dust was used and distributed on the cardboard robot in the sweeping experiment. In the case of the shear sweep method with the bamboo leaves or silky duster, the drone positioning was difficult and the sweeping rate was bad. In order to improve the sweeping rate, the 45-degree inclined flow control plate was set under the drone. As the result, the dust on the cardboard robot was swept away at the rate of 100%. The drone with the 45-degree inclined flow control plate was swept away using not only down airflow but also side airflow.

In this study, the aerodynamic characteristics of a lift-type small unmanned VTOL aircraft were performed by using a low speed wind tunnel. A low speed wind tunnel was used to investigate aerodynamic characteristics. The wind tunnel is a total length of 11500 mm, a height of 2000 mm from the ground to the center of the exit, a square cross-section outlet of 1500 mm x 1500 mm, an open test section, and a contraction ratio of 4. In this study, the nozzle part of this wind tunnel was disassembled and the experiment was performed with the flow from the harmonic combo 3000 mm × 3000 mm. The six components balance system was setup in the test section. And the lift type VTOL as the test model. The weight of the aircraft is 12 kg, the wingspan 250 mm, the fuselage length 1440 mm, and the maximum flight speed 27 m / s. As a result, the influence of the arm that installs the lift type rotor in front of the main wing showed a small impact, and the trend of the aerodynamic characteristic was similar to that of the general fixed wing aircraft within the present experiment.

This paper describes fabrication of a cylinder type gas-liquid phase change actuator. Pneumatic actuator is used for endoscopic surgery support robot. However pneumatic actuator have some faults. Its peripheral equipment is large and makes oscillation and electromagnetic noise. These adversely affect medical equipments. We think that new actuator which does not have those faults is necessary. We suggest a gas-liquid phase change actuator. It is an actuator which big power is got from in the small size. And it can work only with DC power supply such as dry cells. Its device is small and has a small influence to give medical equipments. In this study, we aim to improve the cooling characteristics of the actuator by comparing and examining several working fluids in the actuator. We created a cylinder-type actuator that can move a piston using a gas-liquid phase change. Actuators and a DC power supply were used to apply voltages to six different working fluids and check their displacement response. As a result, it was determined that the best fluid at present is liquid II.

The purpose of this report is introducing examples of making things in KAIT Solar Car Project. And also is considering on the Project Oriented Engineering Education in KAIT Solar Car Project. In our university, these days we have been increasing active learnings as integrated units of classroom lecture and practical work or projects. In our team, fairing and chassis of the racing solar car have been developed from DIY level to high amateur level in 20 years. At first, we built chassis from ICE racing kart. Next, we tried to build space frame chassis, nowadays we use carbon honeycomb monocoque chassis utilizing dry-carbon sandwich panels. To make fairing, we used to utilize hard foaming material at the beginning, later we acquired carbon-fiber reinforced plastics (CFRP) on the foaming materials. Vacuum forming of the CFRP and dry-carbon technics, we have been learned from the engineer-passionate high school teachers and helpful working people.

Compared to the automation of package transportation such as large-scale logistics, there are still many manual operations for small and irregular package transportation. Since autonomous transport vehicles are effective for transporting small and medium-sized home deliveries at our university, we used a parallel link mechanism so that we can drive on flat roads inside the building and on non-flat roads outdoors based on differential drive wheeled vehicle with a small turn. In order to introduce a parallel link mechanism to the drive wheel and the front driven wheel, we examined, designed and manufactured the optimization of the link lever ratio and wheel diameter. Furthermore, the effectiveness was confirmed by running on campus and operating on indoor and outdoor non-flat roads.

We report a science class based on active learning for elementary school students cooperated by the board of education of Matsubushi town. This class aims to promote science and engineering education for the 5th-grade elementary school students by collaborating between the universities and the town. The class introduces a scientific viewpoint to the students through active learning. The class consists of an introductory lecture about contemporary science, a discussion about science among students with specific subjects, and a simple hand-made experiment by students themselves. We have concluded that biomimicking technology is an excellent theme for students to promote primary science and engineering education in the last five years.

In recent years, the demand for satellite structures with high dimensional stability is becoming severer as space mission becomes more advanced. For example, the telescope is one of the structures that require the highest dimensional stability. To prevent deterioration of observation performance caused by thermal deformation, low thermal expansion materials such as CFRP, glass, and low thermal expansion metals are applied. Especially for the interface parts of such structures, low thermal expansion metals are applied for their strength and machinability. However, there is a problem that these metals such as Invar alloys have high specific gravity. In addition, these interface parts often require thermal insulation as well. Therefore, in this study, we design and develop an interface plate made of Invar, which is light, and has both low thermal expansion and low thermal conductivity. To achieve this goal, we focused on the lattice structure, which can be manufactured by making use of metal additive manufacturing technology. We manufactured 4 types of lattice specimens with Invar, and examined their weight, thermal conductivity, and compression stiffness. It was confirmed that the lattice structure reduced the weight by 70 % or more, and the thermal conductivity by 90 % or more compared to solid member. However, it was identified that there is room for more improvement in experimental technique and analytic technique.

In this study, a robust topology optimization method for a structure with damage due to a crack is proposed. A crack is assumed when the topology optimization is carried out. Then, the mean compliances for various assumed crack lengths are used to define the proposed objective function for the robust topology optimization. Then, the objective function is minimized. In the present paper, the proposed method is briefly discussed and an example problem is presented.

Plastic gears have many advantages including their low weight, low cost, negligible lubrication requirements, vibration absorption and quiet transmission relative to their metal counterparts. Polyacetal (POM) is used for approximately 80% of all injection-molded plastic gears used in Japan. However, mechanical properties of polymer are temperature-dependent, and the strength and fatigue life of plastic gears are affected by the frictional heat during operation. Therefore, polymer gears are often improved by adding some reinforcing materials that will improve their resistance to heat and wear. In recent years, cellulosenanofibril (CNF) have been attracting attention as reinforcing filler for engineering plastics. The purpose of this study is to evaluate the effect of adding CNF on fatigue life of polymer composite gear. The test gears are fabricated from the composite materials of POM combined with CNF. The endurance tests are conducted without lubricant. The test gears were operated at a constant transmitting torque and a rotational speed until broken. The bulk temperature and meshing noise are measured during operation. The results showed that the adding CNF increased the fatigue life, and the least amount of tooth wear. These results suggest that CNF can be useful as a reinforcing material for POM.