Recently, the manned moon base project has been considered in Japan and some other countries as the next mission of the International Space Station. Space robotics technology has played an important role in space exploration due to its advantage of low cost, safety and high performance. Therefore, many robots will be expected to play an important role cooperating with astronauts for lunar exploration in this project. Especially, humanoid robot features could have many advantages, such as interacting with astronauts and the ability to perform human tasks. This research investigates the effect of gravity on bipedal robot motion, for example walking, running and jumping. Gravity is an important parameter in generating a bipedal locomotion trajectory. In this research, humanoid robot motion with low moving speed used in rooms of the moon base is investigated. This robot mainly does physical works with astronauts in the environment with air and a flat floor as opposed to Rover. Simulation results showed that optimal motion mode for a robot was walking considering small joint torques and energy conservation. On the other hand, jumping is suitable for an astronaut in a room, because jumping plays a role as the exercise so that muscular strength does not decline.

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Megaripples existing on the Martian regolith surface impede the travel of vehicles. In addition, periodic ripples and sand dunes exist in the deserts of Earth. Hence, for vehicles and robots to travel without getting stuck, the evaluation of traveling characteristics on periodic ripples is essential. However, on Mars and in Earth deserts, it is difficult to verify traveling characteristics by employing real-world testing methods. Although the application of numerical analysis based on terramechanics is indispensable, an appropriate off-road field model (terrain field model) is required to realize high-precision analysis. In this study, a field modeling method for terramechanics analysis is proposed for traveling analysis of vehicles in extreme environments. First, the simulation of wind ripple generation based on cellular automata was conducted, and a field model applicable to terramechanics analysis was created from the obtained three-dimensional data of the ground surface. A single-wheel travel simulation was subsequently performed using the field. Resistive force theory was employed to study the interaction between the wheel and the ground, which aids in the evaluation of traveling characteristics for arbitrary ground shapes and wheel shapes. Furthermore, traveling analysis was conducted for various wind ripple shapes and wheel specifications, and the corresponding effects on traveling performance were verified.

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This paper presents the current development status of the optional payload named Lunar Excursion Vehicle (LEV) for the Japanese future Lunar landing mission SLIM. The deployable exploration system LEV is released from the lander at the few meters above the Lunar surface after the lander’s terminal deceleration is finished. LEV consists of two probes that will move and observe around the landing site autonomously. They also help acquire the evidence of SLIM landing by taking pictures of the final status of the lander.

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Recent study revealed that slope traversability of a wheeled mobile robot in rough terrain can be improved by a wheel camber angle. However, a classical wheel-soil contact model may not accurately addresses an interaction of the wheel camber angle on sloped terrain. In addition, most of slope traversal controls in the past have exploited the wheel camber angle for straight-line traversal. Hence, this paper first analyzes the effect of camber angle for slope traversal. The experimental analysis uses a 3 m-long single wheel test bed in which the in-wheel camera is mounted with a certain camber angle. This analysis reveals that the wheel camber angle effects on the wheel sinkage and soil deformation. Based on the results, a camber angle control method is elaborated: a machine learning-based regression model is elaborated that provides an appropriate wheel camber angle for arbitral slope traversal motions.

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Loose soil called Regolith covering the surface on the Moon/Mars may impede construction machines that will be deployed for future manned mission. Track is widely utilized for the drive train of the machine because of its reliable traction performance on loose soil. However, to date, few researches have devoted to accurate estimation of traveling performance of track on loose soil. In order to investigate mechanical interaction between track and loose soil, this research develops an in-track sensor system as an experimental approach. In this system, a tiny 3-axis force sensor is installed on the surface of each track shoe which can measure normal and shear stress beneath the track while traveling. The measurement results show that the average of normal stress is much larger than that calculated by the conventional model, and the shear stress is divided in two directions. Reflecting these results in the theoretical model can lead to better estimation of the risks that have not been considered before, such as sudden rollover due to a large reaction force and lack of traction force due to negative shear stress.

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DESTINY+ is a flyby space mission for the asteroid named Phaethon and will be launched in 2022. Camera system in Flyby space mission has been conventionally controlled by a PD controller. However, PD controller cannot generally consider constraints. A flyby mission requires a robust control for constraints in traversing at high-speed. This paper proposes a control scheme based on Model predictive Control for a flyby mission with robustness for constraints of input and angular velocity. The simulation study shows that Model predictive Control is effective for robustness in a flyby mission.

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This paper proposes a Terrain Relative Navigation (TRN) method for high-precision position estimation at the Moon’s shadowed regions by fusing the camera image and Synthetic Aperture Radar (SAR) data. TRN, which estimates the position of the lander by comparing the preliminary maintained terrain information in a database with the observed terrain, is an effective method to correct the drift errors of IMUs. Optical cameras are mainly used for TRN sensors to observe the terrain, but shadow images do not have enough characteristic points to match with the database. SAR is a form of radar that can generate high-resolution photo-like images regardless of light conditions. In this study, we proposed the use of SAR as navigation sensors and showed its effectiveness.

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In this study, we conducted the numerical analysis of excavation the wheel loader. In particular, we focused on bucket excavating behavior for a sloped gravel mountain and its collapse phenomenon after the excavation. The resistive force theory (RFT) was adopted for evaluating of excavation force, while a cellular automaton method was applied to the collapse behavior of gravel mountain.

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In order to realize the robust docking and capturing system, the efficient development methods based mainly on the high-fidelity numerical simulations were proposed and investigated. Efficiency on the probabilistic design analysis to cover the various uncertainties, and reduction of the required number of the model validation and system certification tests are key issues. Contact force models for the spacecrafts under the microgravity environment are currently investigated in this study. It was found that the dynamic structural finite element method (FEM) analysis and the reduced-order model are the promising approach to understand key physics mechanism and to predict the contact force characteristics accurately under the wide range conditions. It was found that the reduction in the initial contact kinetic energy due to the irreversible plastic deformation is the root cause of reduction in coefficient of restitution. Numerical results were generally in good agreement with the proposed ball drop test results without changing constitutive law model parameters. Contact force characteristics predicted by the reduced-order model employed in ADAMS© with optimized model parameters were agree well with the FEM results.

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The world's smallest moon lander (OMOTENASHI) will be launched by NASA's space launch system. The lander impacts to the moon at 100km/h. The landing impact is absorbed by crushable materials and an airbag consisted of an external cover and an air chamber made by polyimide films. However, the coexistence of tough glued strength and lightweight will not be expected. Meanwhile, welding technique for polyimide films has been proposed which can be fabricated stronger and lighter than the glued films. In this paper, the development of the air chamber fabricated by using the welding technique for polyimide films is shown.

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Understanding the interaction between granular materials on surface of a small body and a spacecraft is the key issue to design equipments of the spacecraft utilized in a future planetary exploration. Aiming to realize a safe long-term stay on the small body, this paper presents the experimental results that acquired the basic data about the interaction through the drop tower test.

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Hayabusa2 is a Japanese asteroid explorer which aims to get some fragments from the C-type asteroid “Ryugu” and bring them back to the Earth. It was launched in December 2014 and arrived at the target asteroid at the end of June 2018 after 3.5 years’interplanetary cruise. The authors developed two tiny twin rovers for Hayabusa2 spacecraft. The rovers had a fully autonomous capability to move over the microgravity environment of asteroid surface by hopping. The rovers were deployed onto the Northern hemisphere of the target asteroid on 21 September 2018 at the altitude of approximately 50 meters above the surface. Both rovers made autonomous surface explorations by hopping as planned. This paper summarises the mobile system of MlNERVA-ll rovers as well as the actual hopping behaviors of the rovers on the asteroid surface.

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The surface of Mars and the moon is a rocky area with rocks and a rough ground, where soft sand exists. A future rover is required to have high driving performance for exploration of the crater interior etc. In soft ground travel, the reaction force generated by the deformation of the travel surface is small, and the surface may be excavated due to the rotation of the wheels, making it impossible to travel. In this paper, we focus on the travel of the exploration rover on soft ground, and experimentally verify the effective travel system for soft ground travel.

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When the lander carries a large amount of fuel, the landing on a celestial body becomes difficult and dangerous due to sloshing of fuel. Sloshing of fuel causes turbulence of attitude and overturning of the lander. In order to design a landing gear and attitude control system, landing simulation with a sloshing will be required. The mechanical sloshing model that takes the place of experiment and computational fluid dynamics is required for the landing simulator. This paper describes the modelling of mechanical concentrated-constant sloshing models for a landing simulator and the result of numerical simulations of landing on a small body celestial bodies.

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Electromagnetic transducers (ETs) has been getting attention to harvest energy from low-frequency vibration of structures. To improve the ET, the tuned inertial mass electromagnetic transducer (TIMET) has been proposed by the authors. The TIMET consists of a ball screw mechanism, rotational mass, turning spring, and permanent magnet synchronous motor (PMSM) and its energy absorption capability can be increased by taking advantage of the resonance effect of the rotational mass due to the tuning spring. However, the TIMET cannot give the high performance under vibration with unexpected frequencies because of the mechanism. To address this issue, this paper proposes the electromagnetic transducer with a variable tuned inerter which can adapt to the frequency change of external disturbances. This paper introduces the variable inerter system and presents the energy harvesting performance obtained from the sine sweep wave testing.

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We are conducting research with the goal of realizing an anomaly detection system that operates without the need for batteries by generating electricity from vibration generated by impact and using it as a power source. Since the magnetostrictive type is excellent in durability, it is suitable for power generation using impact. In this study, a guard pipe was used as a structure to attach the device. By measuring the superior frequency of the guard pipe and calculating its vibration mode, we searched for the mounting position of the device. In addition, the device was attached to a guard pipe and shocked to generate power, and the operation of wireless transmission using it as a power source was confirmed. As a result, 0.55 mJ was generated with a single impact, and radio transmission was possible with a single impact on the guard pipe. In the future, we will design a device to use the secondary mode frequency of 378.8 Hz to increase the power generation.

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We are conducting research for the practical application of vibration power generation using magnetostrictive material (Fe-Ga). The power generation device, consisting of magnetostrictive material, U-shaped frame, coil, and permanent magnet, has simple and high output characteristics. However, the practical use of vibration power generation has a problem that it is difficult to put it to practical use because there are environmental vibrations having a plurality of vibration frequencies. In general, the power generation device can obtain a large amount of power generation when the frequency of the vibration source matches the resonance frequency of the device. For this reason, when there are a plurality of vibration frequencies, it is impossible to determine which frequency band the resonance frequency is adjusted to generate a large amount of power. Therefore, in this paper, optimization parameters are used to derive the primary and secondary resonant frequencies that maximize the amount of power generation and the parameters related to the devices for achieving these resonances. This time, as the first step, we report the vibration that can set the evaluation function necessary for the optimization calculation.

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In the practical application of IoT in recent years, button batteries are typically used for communication modules and sensors. However, since these have a finite lifetime, there is a drawback in that it requires time and effort for replacement. On the other hand, we are conducting research on vibration power generation to replace batteries. Therefore, in this research, the relationship between the generated voltage of the device and the velocity of the device installation location is considered, and the velocity is detected from the generated voltage based on it. We also propose a self-sensing system that can operate the communication module with the same power, transmit the generated voltage, and calculate the velocity.

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We investigate magnetostrictive vibration power generator using iron gallium alloy for battery-free wireless module. This generator harvest energy efficiently, but there is problem that huge energy loss occurs in power inverter circuit. This energy loss is especially large in the case of micro power generator. In this paper, we optimized power inverter circuit and reduced this energy loss. Then, we made battery-free wireless module for practical use with optimized power inverter circuit. Finally, we succeeded to transmit temperature signal in every 72 seconds from vibration of 1.5 G and 657 Hz, in every 9 seconds from vibration of 5 G and 657 Hz.

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There is a demand to introduce a battery-free wireless sensor for the forecast maintenance of machine tools and production machines. At this time, the power generation device which generates the practical electric power more than that of coin cells by the vibration of high frequency of these machines is required. In this paper, a micro magnetostrictive vibrational power generator is introduced. This is about 20 mm in length and 1 g in mass, using 2 × 0.25 × 8 mm³ Fe-Ga alloy plate. By experiment, it was confirmed that effective power of 234 μW was generated at vibration of 522 Hz and 1 G. The device could be easily fixed to the machines by magnets, and that the resonance frequency could be adjusted in the width of 39 % and 7 %, respectively, by affixing of additional weight and adjusting magnetic force.

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In the authors’ previous report, a new wind energy harvesting method using flexible piezoelectric films bonded on the surface of a flexible cylinder, termed as Piezoelectric Cylindrical Shell-type Wind Energy Harvesting Flag (PCSWEHF) was proposed. In order to overcome the low power generation of the piezoelectric wind energy harvesting method at small wind speeds, vortex-induced vibrations (VIVs) of the flexible cylinder excited by the Karman vortex generated downstream of PCSWEHFs was used and it was shown in the preliminary experiment that more than ten times larger power was generated by PCSWEHFs compared with the conventional planar-type piezoelectric energy harvesting flags. However, the mechanisms and the conditions needed to cause the synchronization phenomena were still not clear. In this study, natural frequencies of the PCSWEHF and vortex shedding frequencies were derived from theoretical analyses and fundamental fluid dynamics theories, and by comparing these results, the method to construct superior PCSWEHFs which could generate large power at low wind speed was investigated.

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In this research, in order to reproduce the probabilistic resonance phenomenon of the bistable nonlinear vibration system in the random wave environment in nature, using the vibration characteristic measurement device of the offshore structure, it is excited by the periodic signal and the random signal, respectively. Vibration wave forms are measured, and the generation conditions and characteristics of stochastic vibration of a bistable nonlinear system are examined. Then, in order to study the effectiveness of the vibration power generation system that makes use of the superiority of bistable vibration, a vibration power generation device using a piezoelectric element is developed, and measurement experiments of vibration power generation are conducted.

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This paper presents a new method for identifying a non-proportionally damped system with consideration of the model structure to assure the consistency of the results with the generalized modal model, which is represented by a symmetric modal damping matrix and real normal modes instead of complex normal modes. We applied the proposed method to the ground vibration test of JAXA Jet Flying Test Bed ”Hisho“, where the aircraft was excited by two shakers attached to the main wings and the vibration responses were measured using accelerometers distributed over the structure, and extracted undamped natural frequencies, a non-proportional modal damping matrix, and real normal modes from the vibration data.

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Semiconductor manufacturing equipment is so expensive that its operation rate influences profit directly. Vibration is one of the causes of their non-operation or malfunction, so vibration control is very important technology for semiconductor manufacturing. To suppress amplification of vibration, semiconductor manufacturing equipment is installed on a pedestal, which is high rigidity table. However, there are cases when further measures against vibration become necessary after installation due to deterioration of vibration level. There is a problem that it takes time to retrofit a conventional vibration control device. As mentioned above, non-operation time equals to damage. The purpose of this study is to develop a vibration control device that is easy to retrofit. We proposed a vibration control device with piezoelectric actuator that can be attached to the side of a pedestal. In this paper, we have demonstrated effectiveness of a proposed device by vibration control experiments of 1-degree-of-freedom.

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A sharp noise generated during low speed braking of automobile disk brakes called “brake squeal” is required to be reduced. In-plane squeal which the disk vibrates in-plane direction and occurs squeal has become a problem. However, the essence of in-plane squeal is not clear. And since the deformation, such as expansion and contraction in the in-plane direction of the disk is not transmitted vibration in the air. Therefore, the clarification of the mechanism of in-plane squeal is required. In previous studies, the disk vibrates greatly in the in-plane direction and has natural vibration that simultaneously vibrates in the out-of-plane direction. In this research, we create the disk which construction is investigated, and conduct squeal test to confirm whether the disk generate in-plane squeal.

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Measurement of natural vibration of acoustic space is effective for noise reduction in the cabin room of vehicle (e.g. auto-mobile, railroad car and so on). In general, multi-point excitation is useful to measure natural vibration of threedimensional acoustic space with high damping on boundary surface. However, multi-point excitation needs adjustment of amplitude and phase for each actuator. Thus, multi-point excitation is difficult to implement. In this study, the measurement technique of natural vibrations of acoustic space by multi-point excitation using decentralized control with local feedback control is used. Local feedback control generates force in the direction of motion, which had been presented by authors. In this paper, excitation was performed using an acoustic excitation device placed face to face.

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Balance modeling during standing is an important issue in the medical field and the vehicle development. There have been a number of reports based on impulse response and frequency response. However, very little studies have been achieved to identify personal parameters. It is very difficult to reproduce the experimental results and to identify a stable system. This study focused on the balance modeling on sagittal plane from a frequency response diagram with support surface sway. To identify personal control parameters from the response of the center of mass (COM), we assumed a mechanical model and an internal feedback system composed of the state feedback control with time delay and a target posture control according to the velocity of the support surface. In addition, we proposed a COM estimation method from measurement of a force plate. We found that the present method identified personal parameters which were almost same as the parameters from the motion capture measurement.

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One of the substitute voices of laryngectomy patients is the fluty-type artificial larynx. This is a device that uses your breath. This device has the problems of blocking both hands and making the sound monotonous. The purpose of this study is to solve this problem by using a blower instead of human breath. For acoustic analysis of the artificial larynx, we modeled the air inside it as concentrated masses connected by linear springs and dampers. The validity of the proposed method is confirmed by the results of numerical simulation and experimental. We confirmed that the effects of periodic and chaotic sounds on naturalness. Also, we confirmed the difference in naturalness when sound sources were instead from the lip side and glottis side.

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Measuring human movement is important in various fields such as ergonomics, rehabilitation, and sports. An optical system is generally used for motion measurement. However, this method is expensive and has limited measurement space. Therefore, in this study, we measure the motion using inertial sensors. Research has already been conducted on the lower limbs, but there have been few studies on the upper body with many complex joints. Therefore, in this study, we determine the joint positions of the upper body and connect them with vectors to construct upper body motion measurement model. We also propose a system for estimating the human spine curve.

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Measurement and analysis of human movements in a real environment are important in various fields such as ergonomics, nursing care and medical care. In particular, considering the interaction between human work and the environment, it is necessary to analyze detailed finger movements. Therefore, we proposed a model construction method using inertial sensors to accurately obtain complex finger shapes and verified their accuracy. As a result, the finger movements with various grip shapes were measured, and it was confirmed that there was no unnatural intersection. From this, it was shown that finger movement measurement using inertial sensor system and link model construction method has sufficient position accuracy.

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In recent years, Personal Mobility Vehicles have been attracting attention as a new means of transportation. They are environmentally friendly without exhausting harmful gases. These vehicle bodies are relatively smaller than cars, so they have a high affinity for pedestrian space. However, depending on the specifications of the vehicle, driver’s behaviors have great effect on the vehicle movement because the weight of the vehicle is comparatively low. In this study, we developed measurement system of the forces exerted by the driver for stand-up type Personal Mobility Vehicle, and carried out the braking test.

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Palpation is widely performed in today's medical field, and it is easy to grasp the bioflexibility. However, it depends on the experience and skill of the doctor and is not objective. In this study, we propose a method to identify Young's modulus from changes in the resonance frequency of the vibrator by pushing it into the soft tissue. This is based on the assumption that it can be applied to actual living bodies. As a result of experiments on silicone with the proposed method, Young's modulus was identified with high accuracy in soft silicone. However, it was found that the identification accuracy of the hard silicone is poor and the proposed analysis method needs to be reexamined.

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Women experience specific anatomical and physiological changes during pregnancy. These changes cause postural and movement instability and impose excessive strain on body muscles contributing to low back pain (LBP). Thus, motion teaching of some motion might be effective for management of LBP during pregnancy. Although conducting motion analysis related to LBP is needed for motion teaching, motion analysis performed several times is not suitable for pregnant women. It can be said that standing posture is related to motion and posture assessment has less burden on the pregnant women. Therefore, the purpose of this study was to investigate the relationship between standing posture and motion for pregnant women. Analysis of standing posture and motion of lumber spinal column of pregnant women was conducted by using a force plate and inertial measurement units (IMUs) connecting seat attached at the back of along the spinal column for seven pregnant women. Then, the relationship between standing position and motion evaluation indexes were investigated by statistical analysis.

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The joint strategy is one of the primary representations for the balance analysis of standing. Although the ankle joint strategy and the hip joint strategy are generally defined from the viewpoint of the neurological field, it is hard to estimate the contribution of the joint strategies from a test result. To solve the problem, this study defined the joint strategy from kinematics and proposed to evaluate the contribution of the strategies from the acceleration of COM of lower and upper bodies. The method can be applied by using the motion capture system, however, there is a practical difficulty in clinical tests. For easy measurement, this study demonstrated the estimation method of modes of joint strategy from the measurement of a force plate and an inertia measurement unit (IMU). The validity of the estimation method was verified by standing tests in comparison with motion capture measurement.

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In this study, we focus on a four-wheel stand-up type vehicle because of its static stability, its compact size and its easiness to ride. We aim to enhance the safety of personal mobility vehicles (PMVs) by using driving support systems, for example, automatic braking and self-driving. However, a driver has a possibility to fall down due to driver’s behavior during acceleration or deceleration because the mass of a driver is comparatively larger than that of a PMV. Moreover, a driver’s behavior with driving assistance system is different from a driver’s behavior without driving assistance system. In this study, we carried out the numerical simulation to confirm the relation between deceleration and the behavior of the driver with intention and that without intention. As a result, it was found that, 1: COGP of the driver with intention is half of that without intention, 2: preliminary behavior for braking cannot suppress his COGP movement if the deceleration is too large.

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In order to reduce the risk of injuring an infant in a traffic accident, we have proposed the in-car crib with joint application of regular and inverted pendulum mechanisms. This paper is reporting performances on a two degrees of freedom control system for the mechanisms by the numerical simulation. First, the state equation is set and a sliding mode control technique is applied to the mechanisms. However, the resulting movement of Arm2 is not realistic, although the horizontal deceleration of the crib decreases to the reference approximately. Then, the trajectory of Arm2 is set, and the optimal control system is developed. The simulation result shows that the horizontal deceleration of the crib increases gradually and remains around the reference. In addition, the robustness for the disturbance in the optimal control law or the state equation is examined and confirmed.

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This research proposes the high efficiency method of vibration propulsion mechanism by decentralized control using local feedback control. Recently, the various multi-articulated propulsion robot that is used when disasters happened, such as snake-like robot, worm-like robot, and so on, have been developed. Robustness for the variation of external environment is required to these robots. The driving method at resonance point by multi-point excitation by the decentralized control using local feedback control is proposed as robustness driving method. When the vibration propulsion mechanism is driven by decentralized control, the frequency and phase of driving signal of actuators are adjusted to natural vibration automatically. In this paper, the effect of wave shape and the amplitude ratio for driving efficient is investigated by simulation of the multi-point vibration system driven by driving signals which shape is rectangular waves and sinusoidal waves.

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This paper shows experimental results of a newly designed Tailless Quad Tilt Rotor of which capability is VTOL and carrying 1kg payload. Previous paper discussed the design concept of tailless wing based on aerodynamic performance, such as the drag, the lift and the dynamical stability. For the practical use of proposed VTOL system, it is necessary to achieve a long distance level flight and a certain amount of payload. In order to carry 1kg payload and hover for 15 minutes, motors and propellers are selected and combined into the Quad Tilt Rotor with tailless wing. Experimental results in real field are shown by flight logs obtained from the control unit.

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Boarding-type personal mobility is required to achieve a mutual walkway with a smooth pedestrian without Boarding-type personal mobility's deviating from a narrow sidewalk. In this study, it is designed a path planning for the boarding type movement personal mobility based on the model who imitated pedestrian's walk. BPM pass planning design and simulation results are shown.

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This study proposes a method to compensate for backlash of vehicle drivetrains under the condition where the control period is made longer. A vibration control must be developed to compensate for the backlash of gears because this nonlinearity degrades the vibration amplitude. Additionally, an engine used as an actuator have a constraint in which control cycles are made longer due to roughly updated cycles of torques. We apply a sampled-data controller, which can explicitly evaluate responses between sampling points thanks to its design process without discrete approximations, to the extended control cycle. To cope with backlash effects, a simple control mode switching algorithm is presented. In the algorithm, unscented Kalman filter estimates the plant states to identify the contacts in backlash. Simulations verify the effectiveness of the proposed control system.

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Crawler vehicles are often used in dangerous sites such as forestry land and sediment disaster sites because of their high traveling performance on bad roads. In various situations where crawler vehicles are used, slope traveling is considered one of the most dangerous situations. In a steep slope, the vehicle must follow precisely the safe target trajectory so as not to slip down. Thus, the operator needs to skillfully adjust the rotational speed of the crawler according to the changing situation around the vehicle. Consequently, the automatic driving technology that automates traveling a steep slope is necessary for the operator's safety. For a case study in a controller design, a traveling simulation model with low calculation cost is necessary. In this study, the slope traveling simulation model based on the theory of Terramechanics was constructed. As a result, the model has overwhelmingly low calculation cost than a model using DEM. In addition, in order to verify the usefulness of this model in traveling controller design, a case study of a target path following simulation with PID controller was carried out. As the results, it’s indicated that our proposed model can be applied for a travel controller development.

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Labor shortage at the site of nursing care is a serious problem in Japan. Autonomous driving technique of wheelchair as a solution of this problem has been studied. However, the cost of that wheel chair will be expensive due to use high performance sensors and stereo camera. Under these circumstances, a control strategy of wheelchairs platooning has been studied in this research to solve the labor shortage problem. To realize the automated platooning of wheelchairs, estimation and control technique of the wheelchair position and angle are required. And that, expensive sensor devices such as stereo camera were not used in this automated platooning wheelchair due to suppress the increase in cost. Modeling and driving simulation of the robot equipped with two independent driving wheels considered as a wheelchair is described in this paper.

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The two types of three-wheeled tilting vehicle are modeled. One has two front frame which are linked to vehicle body by the arm and rotating respectively around the joint. The other one has a front frame that has two tyres connected by the link. We derived equation of motion by referring to Sharp’s 4 DOF two-wheeled vehicle model, and carried out the eigenvalue analysis.

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We constructed the model of three-wheeled PMV (Personal Mobility Vehicle) with two front-wheel and one rear-caster. By changing the vehicle velocity or road gradient, we considered the safety position of driver and luggage. We found that the vehicle can run safely when the position of the center of gravity (COG) of the model is set from 200~300 [mm] behind from the front wheel. When COG is behind from this area, tire idling may be occurred during traveling on the uphill road. Likewise, when COG is ahead from this area, turnover may be occurred during traveling on the uphill road. Also, we found that the speed of the velocity should be reduced to at least 2 [km/h] when the vehicle is turning on more than 5 degrees gradient road.

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In this paper, we propose control method of Active Mass Damper (AMD) considering physical constrains. AMD is highly effective against after shaking, but conventional controller can suppress shaking of building only by small or medium earthquake or wind due to range of motion. So, we propose method that uses idea of model prediction control for Gain scheduled control to fit AMD in range of motion in various scale earthquake. It can suppress shaking of building in range of AMD motion by predicting response and selecting optional performance controller. Firstly, we explain proposed method, Gain scheduled predictive control. To verify effectiveness of proposed method, we simulate vibration control in medium and big earthquakes. It results in reduction to 1/10 in after shaking time

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Antiseismic devices, which control the damage of an apparatus and the device from earthquake vibration, play an important role for maintenance and continuation of social activities. Though three-dimensional antiseismic devices have a function to reduce the vibration component of each the horizontal and vertical directions, in the vertical direction, the correspondence structure is complicated from the need to find rigidity to support target mass in particular. Therefore, for reasons of vertical seismic isolation effect is restrictive or needs the energy such as air sources, it needs the further improvement. This paper proposes new mechanism using constant load spring and movable pully to support the load in the vertical direction, pull a target apparatus above and cancel the dead weight. In this way, it can reduce vertical support rigidity as the mass, and plan becoming it easily in the long natural period and we can expect improvement of isolation effect by simple constitution. Horizontal seismic isolation mechanism is used of cross linear bearing, reconstruction spring and damper. To clarify the dynamic behavior of an apparatus under a simulated earthquake vibration ( maximum input acceleration, vertical: 704gal, horizontal: 1710gal ) , experiments using an air conditioner ( total mass of approximately 360kg ) were conducted, and the performance of the proposed antiseismic device was investigated. From experiments with using the antiseismic device, the response acceleration of vertical direction was as low as 14% compared with the case without the device. The numerical value like one of a horizontal direction was 10%.

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We have developed a control law of AMD (Active Mass Damper) which reduces vertical vibrations of floors, etc., using reinforcement learning, which is a kind of AI (Artificial Intelligence). The simulation and the experiment applied to the actual system using the learned control law confirmed that the vibration control effect exceeded the control law by the conventional optimal regulator theory under certain conditions.

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This paper proposes a novel structure of a slotless single-drive bearingless motor, which is driven by only one three-phase inverter with one active suspension control in the axial direction. The motor consists of three-phase six square-shaped coreless coils as a stator for high speed applications, and a 4-pole surface-mounted permanent magnet (SPM) rotor. The rotor PMs are partly twisted by 90 degrees. The d-axis current, which is commonly used for magnetic field weakening or strengthening, generates the axial suspension force due to the Lorentz force on the end-windings of the coreless coils. The driving torque is generated with q-axis current. Hence, the proposed bearingless motor can generate axial suspension force and torque by only one three-phase inverter. The proposed structure, principle of suspension force and torque production, and calculation results are shown in this paper.

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We have developed a magnetic levitation system with an intelligent function. In the system, sinusoidal current is intentionally superposed to electromagnets and the levitating rotor is vibrated. By measuring the phase difference between the displacement of the rotor and current in the electromagnets, the change of the bearing gap and viscosity of working fluid can be detected. The proposed function is applied to the detection of thrombus in a magnetically levitated artificial heart. The experimental results with the porcine blood showed the phase difference increased to two degrees when the thrombus was generated in the pump. Then, the function was further developed for preventing the pump thrombus. By intentionally levitating the impeller with the frequency of 300 Hz and the amplitudes of 2.5 μm, the pump thrombus generated on the impeller was decreased compared with the thrombus without vibration.

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Recent clinical results show that implantable centrifugal blood pumps (CBP) utilizing magnetic or hydrodynamic bearings are superior to those using contact bearings in terms of durability, thrombus formation and hemolysis. Magnetic bearing technology is also expected to be used in extracorporeal disposable CBPs. However, the use of NdFeB magnets in the rotor of the disposable part is expensive, and this needs to be addressed. Our research group has developed a switched reluctance type bearingless motor (SRBELM) that doesn’t use NdFeB magnet in the disposable part. However, the generated torque of the SR-BELM has not been sufficient for the pump. To improve the rotation controller, a torque simulator of our SR-BELM system is designed. The simulator considering self-inductance and torque coefficient that change with the rotational angle can reproduce the previous experimental results.

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