This paper deals with an automatic driving control scheme for tracked vehicles. Many control schemes have been developed in the presence of slippage of the tracks. Most of them were designed on the basis of kinematic models, under the assumption that the dynamics of a vehicle are completely compensated by velocity-controlled servo systems. Several of them were designed on the basis of dynamic models, under the assumption that the thrust forces of tracks are arbitrarily produced by torque-controlled or voltage-controlled servo systems. However, the motion of a tracked vehicle depends on the dynamic interaction between its tracks and a terrain, as well as on the dynamics of the vehicle itself. Moreover, it has been pointed out in the literature that the thrust forces of the tracks of a real tracked vehicle have wide dead-zones as well as saturations. In view of these situations, the authors have proposed a control scheme based on dynamic models whose thrust forces have dead-zones. In this paper, we propose its adaptive control version, under the condition that the numerical values of the physical parameters of the dead-zones (i.e., their widths and slopes) are unknown.

A traffic accident is one of the most important social problems. Many active or passive safety systems for vehicles have been developed to reduce damage of traffic accidents. It is serious to avoid collision with other objects, reduce external force applied to vehicles when a traffic accident occurs, and regulate vehicle locomotion after a traffic accident such as pileup. In this study, a novel passive model was proposed in order to regulate vehicle locomotion after impact. The proposed model has a free extra mass and two spring-mass systems placed at the forward and backward end on the vehicle, called damper mass and collision masses respectively. The damper mass repeatedly collides against collision masses during vehicle locomotion after impact. Whole kinetic energy is dissipated by inelastic collision and friction, which reduces the vehicle velocity. The effect of the proposed model on the vehicle locomotion when several physical parameters were changed was verified via numerical simulations.

With the accelerated development of automated driving technology, health hazards such as motion sickness are a concern. In this study, we used a driving simulator, Polymate II AP216 bio-measuring device and Emotiv+electroencephalography (EEG) system to analyze agitation-related diseases. As a result, an increase in the frequency of the center of gravity of the breath was observed. In addition, the LF/HF data showed a respiration-related component. The EEG showed a divergence of the left and right EEGs in the visual cortex, suggesting that they were affected by agitation sickness and VR sickness. Our future research goals are to improve ride quality in automated driving and to develop an analysis system that can detect motion sickness by analyzing EEG alone.

Recently, the technology of autonomous mobile robots has been actively researched and pratical use of it is expected in various mobility service fields. In a human living space, if a mobile robot move autonomously, it has to recognize the surrounding enviroments and plan a path from the start to the goal. In addition, it is also necessary to deal with obstacles. Especially, in case of a mobile robot with the ability to climb up/down steps, it is required to judge whether it can climb up/down steps and control the entering angle to steps. Our final goal is to propose a navigation system for autonomous mobile robots which can climb up/down steps. This paper reports necessary functions for a global path planning considering climbing up/down steps.

It is one of the most important tasks for a mobile robot to know its position. For example, in order to perform autonomous movement, it is necessary to estimate the self-position to recognize the surrounding environment. However, in most cases, it is premised on a flat terrain, and steps and slopes are often excluded. In this study, we estimate the position and posture in three-dimensional space for a leg-wheel robot, which can move on rough terrain, by using the odometry method. In addition, odometry accuracy was verified by comparing between estimated and true value of trajectory in simulation on rough terrain.

In flexible manufacturing systems, the importance of automated guided vehicles is increase as they can respond flexibly to changes in facilities and factory layouts. We propose an autonomous conveyance system for automated guided vehicles based on the operation of a taxi transportation system to solve indefinite and accidental problems. The system focuses on applying traffic engineering knowledge with regard to a flexible taxi transportation system. A taxi is a transport unit in a traffic system involving high flexibility in traveling routes and arrival/departure points. In this report, we suggest applying transport density, a measure of transport scale, to AGV transport systems to evaluate transport efficiency. As a result, a correlation is obtained between the task linear density ρ_T and the average matching time T_a, the transport efficiency can be improved by concentrating pick and drop stations, which are frequently transported, in a centralized location.

In technological development of automobiles, a development process using Model Based Development (MBD) has been proposed to minimize process repetition. The purpose of this study is to reproduce the influence on the steering of an actual vehicle by applying the Model In the Loop Simulation (MILS) for MBD to the platooning of two heavy duty trucks. To apply MILS to the platooning of trucks, it is necessary to reproduce the vehicle interaction, and the truck model where the vehicle model and the sensor models are connected. In this study, truck model was created using a vehicle model in the highly accurate vehicle motion simulation software. MILS was constructed by integrating the truck model, the sensor models and the control model. The validity of the input/output characteristics of the MILS truck model was verified. The reproducibility of the influence on the steering control when switching the control method and the steering characteristics with a cant were also evaluated.

Although the final goal of this research is sharing control, which transitions between automatic driving and manual driving with the driver's intention, this time we focused on the steering feel of the SBW system during that transition.

We have verified the feasibility by the research that a steering reaction force generation control law that allows the user to intuitively understand the intention of the vehicle added information such as the vehicle states side and Road Information to the steering reaction force on the SBW system.

In the future, driver assistance technologies that will evolve that autonomous-driving vehicles will be familiar to the driver, will make the driver assistance vehicle or the autonomous vehicle a receptive mobility in a society where senior drivers are increasing.

We would perform a simulation to confirm the feasibility of Haptic adding the Road Information, therefore we would report these valuable results.

This study proposes the brake control method using the road surface friction coefficient. The traditional ABS (Anti-lock Braking System) usually controls the brake hydraulic pressure to have the slip ratio be 0.2, at which the road surface friction coefficient is supposed to be maximum. However, the slip ratio at which the road surface friction coefficient is the maximum varies depending on road surface conditions. Furthermore, it is difficult to measure the slip ratio accurately because the vehicle speed cannot be measured easily. The authors have already proposed a method to measure the road surface friction coefficient from strains induced on a tire side face. Thus, this study proposes the brake control method by using the road surface friction coefficient and the wheel acceleration instead of the slip ratio.

In this research, a method for autonomous control of a vehicle with limited actuator operation is proposed. Inexpensive DC motors are used for steering and driving actuators of this vehicle, and they can only be applied to On-Off control. Therefore, the vehicle cannot trace the desired route with high accuracy but has sufficient performance to reach the target point despite driving with unstable steering. An algorithm is proposed that realizes autonomous driving using only position information obtained from high-precision satellite positioning technology. The effectiveness of the proposed method is verified by driving experiments.

In the past two decades, simultaneous localization and mapping (SLAM) has been actively studied and realized reliable navigation especially in unknown but static environments. Since it usually assumes a static map as a model of the environment, moving objects may disturb the accuracy of the localization and map. To overcome this issue, it is common to extract observations possibly coming from moving objects by comparing them between multiple samplings. In this paper, we propose a SLAM for dynamic environment which naturally resolves this problem. Based on our previous study, a generalized dynamic model for the map is introduced and SLAM is solved through optimization problem. It is shown that the proposed method captures the motion of the object moving along its own edge. Numerical simulations in the environment comprising static and dynamic objects as well as only moving objects validate the effectiveness of the proposed method.

Micro-space-probes are ideal platforms for future deep space exploration missions because multiple micro-space-probes can piggyback together on most existing Earth launch vehicles. If the piggyback destination is GTO, the microsatellite can escape from the earth's gravity to go into deep space with only 700 m/s of additional acceleration. Low-concentration (60wt%) hydrogen peroxide has favorable storage characteristics as an oxidizer for in-space hybrid rocket propulsion but has unfavorable ignition and flame holding characteristics due to its high-water content. In this study, separate tests for ignition and flame holding were attempted using 60wt% hydrogen peroxide as an oxidizer and high-density polyethylene as fuel in a CAMUI-type configuration. A Pt catalyst, pressurized chamber, and low flow-rate oxidizer bypass line were used to promote ignition. The results of visualization experiments show that ignition was achieved, but flame holding was not achieved, probably due to an excessive oxidizer flow rate.

Combustion experiments were conducted to research the high-frequency combustion instability of the liquid-propellant rocket engine. Kanda conceived that off-design combustion would be cause of the high-frequency instability. The experimental model was designed to simulate the off-design combustion space created by the propellant jet and the injector wall surface. Propellant were 2-propanol and gaseous oxygen. In the experiment, there was a pressure increase of 1.5 to 3.3 times as high as the ambient pressure. Pressure increase time was located from 0.03 to 1.84 milliseconds The experimental results were similar to the pressure changes reported under the actual high-frequency combustion.

Two-dimensional numerical simulations based on Eulerian-Lagrangian method are conducted to model a gaseous detonation laden with the polydisperse water spray in a two-dimensional straight channel. The premixed mixture is a stoichiometric hydrogen oxygen slightly diluted with nitrogen at low pressure. The behavior of the polydisperse water spray behind the leading shock front are analyzed by categorizing water spray based on whether the water droplet experienced the transverse wave or the jet. The jet and transverse waves, which play a dominant role in inducing the breakup and polydispersity, have different effect on polydisperse spray depending on the initial droplet diameter. For the water droplets with smaller initial droplet diameter, the breakup process tends to be completed shortly before the droplets experience the jet, and the transverse waves contribute to breakup more than the jet. In contrast, the time of breakup process is lengthened with larger initial droplets, and the contribution of the jet overcomes that of the transverse waves as the droplets experience the jet before the end of breakup process. Indeed, the jet can induce higher relative velocities, which leads to a more intense breakup relative to that induced by transverse waves.

Pulse detonation engine (PDE) performances were calculated. Simple relationships were derived for detonation, exhausting and ventilation to calculate the engine performances. Calculated Isp were about 20 km/s in subsonic flight and 5 km/s in supersonic flight, respectively. A spaceship with PDE and a rocket engine was conceptually designed, and its transportation performance was estimated with use of the extended Tsiolkovskii method. When the mass at take-off was 3,000 kg, 2,230 kg was carried to the altitude of 101 km.

Axial-injection end-burning hybrid rocket (EBHR) is excellent in fuel regression rate and throttling characteristics than conventional hybrid rockets. However, in the firing tests of throttling operation using multiple port fuel, a very long response time was observed. In this research, the authors postulated that the fuel regression shape of each port might be affected by chamber pressure to explain the reason for long response time and verified this hypothesis by using numerical simulation. The calculation result showed the long response time, and the response time coincides with the shape-changing time, which indicates that the shape-changing causes a long response time. Moreover, the history of characteristic exhaust velocity suggests that the fuel-rich condition may make response time short.

When designing axial- injection end-burning hybrid rocket (EBHR), it is essential to obtain the boundary between stabilized combustion mode and flame spreading mode. Oxidizer friction velocity has been used as an indicator of them. The threshold value has obtained in the case with PMMA fuel and O₂ as a constant value and used when designing EBHR. Recently, however, N₂O is said to be useful for oxidizer, so we have to research if we can use N₂O for EBHR. In this study, we aim to obtain the threshold value of friction velocity with PMMA fuel and N₂O as the oxidizer. We conducted some combustion experiments and explored the relationship between friction velocity, chamber pressure, and flame behavior. As a result, we observed pressure dependencies of the threshold value of friction velocity, which is different from the result of the O₂ experiment. There are two possibilities why such a result arose, 1) difference of oxidizer chemical species, 2) development of boundary layer.

Authors are developing a small scale hybrid rocket. It is essential to release a parachute around the apogee point of the flying hybrid rocket, and to obtain the experimental data from the sensors on the rocket for confirmation after the experiment. In this study, authors examined an attitude estimation method of the rocket as a preparatory study for activing attitude control by estimating the attitude of the rocket based on the acquired data. In this study, we made a water rocket with a small computer and sensors and launched it for experiments. The roll, pitch and yaw angles were calculated using the values of acceleration and angular velocity, and Euler angles were obtained from the data acquired during the rocket's ballistic flight. The attitude estimation of the rocket is verified by representing the rocket attitude in 3D graphics.

The purpose of this research is to develop a rated thrust 50kgf class small hybrid rocket engine with paraffin wax filled in radial-hole type fuel. A shortcoming of hybrid rockets is its low thrust. In this study, a new fuel configuration, radial-hole type fuel, has been designed to improve the low thrust of hybrid rockets. Radial-hole type fuel has holes drilled on the outer surface of the fuel in a spiral pattern in the circumferential direction, and paraffin wax is cast into the holes. A single-port fuel which is a conventional fuel configuration is also prepared for comparison. As a result, the following conclusions were obtained; (1) The target thrust of 490N (50kgf) was achieved using the radial-hole type fuel. (2) Thrust increased with the radial-hall type fuel compared to the single-port fuel.

Flows in the rocket engine nozzles are numerically analyzed to assess the performance of Thrust Vector Control (TVC) system of fluidic type by using Direct Simulation Monte Carlo (DSMC) method. In the calculation, rigid sphere model is adopted to simulate molecules, and perfectly elastic collisions are assumed. Secondary jet is injected into the flow field through a small port at one side of two-dimensional dual throat nozzle wall. Performance of thrust vector inclination is evaluated and the possibility of hysteresis occurrence is researched.

This study is developed a 5 kN thrust level hybrid rocket motor for reaching an altitude to 30 km high. In the combustion experiments, low-melting-point thermoplastic (LT) fuel was used as the solid fuel, nitrous oxide was used as the oxidizer, and the performance of the motor was evaluated with and without a baffle plate in the combustion chamber. Combustion experiments confirmed the increase of fuel regression rate near the baffle plate, and the characteristic exhaust velocity C* was higher with and without the baffle plate, from 1094.7 m/s to 1119.9 m/s. This suggests that the baffle plate contributes to the improved performance of the LT fuel motor.

We are developing the HSU-SAT1, which is our first micro satellite. The size is 1U and the orbital altitude is about 400 km from ISS. It is scheduled to launch at the end of 2020. The satellite missions are on-orbit demonstration of self-made bus equipment, three axis control experiment of 1U satellite and Uplink communication by IR remote controller. We report on the development status of this satellite.

HSU-SAT1 is a nano satellite under development at Happy Science University, and is scheduled to launch in 2021. It is an Earth pointing satellite for experiments of optical wireless communications. To keep required attitude, we will utilize aerodynamic torque and magnetic torquers as control actuators. This paper explains the outline of Attitude Control System of HSU-SAT1, on-board equipment and planned experiments. Additionally, we show the method of degaussing magnetic torquers. It is expected to contribute to satellite’s attitude stabilization.

HSU-SAT1 is a 1U Cubesat for the education of space engineering technology. Communication system is one of the satellite bus systems aimed at establishing communication between satellite stations and ground stations. We designed circuits, designed and developed communication systems including radios and antennas, and built an environment for controlling and operating satellites at ground stations.

Optical communication is capable of transmitting a large amount of data at high speed, and the confidentiality of the data is maintained. Therefore, the optical communication is currently being used for satellite communication. Such optical communication requires sophisticated technology and expensive equipment. Against this background, as a simple optical communication, the purpose of this research is to develop a new satellite operation system by sending a simple command to the satellite by a command uplink with the same signal and receiver as the remote controller. It is considered that this device can be used as an emergency line. Remote control signals by near infrared light are used on the ground side, and the pointing software to the satellite is based on an equatorial mount. Satellite position information is only TLE data, and there is no feedback from the satellite side, we are considering scanning high power light on the ground side to cover the coordinate error of 2 km due to TLE.

Hybrid rockets are suitable candidate propulsion systems for space exploration missions because they can produce similar levels of thrust to solid and liquid bi-propellant rockets without the fire/explosion safety hazard. Space probes equipped with a hybrid rocket thrust can more readily be integrated in piggy-back launches without the need for lengthy and expensive risk mitigation activities. This study reports the results of four static firing tests of an engineering model hybrid rocket thruster using high-density polyethylene as fuel and liquid nitrous oxide as oxidizer for space-probe propulsion. Measurements of thrust, chamber pressure and propellant mass flow rates reveal that performance in atmospheric conditions was nominal: I_sp ≦ 220s; C_F ≦ 1.4.

HSU-SAT1 is a nano satellite currently under development at Happy Science University. This satellite will be equipped with a magnetic sensor and a gyro sensor. In this paper, the method of calibrating these sensor data on the magnetic sensor and gyro sensor required for the attitude determination of this satellite was examined. For the magnetic sensor, the sensor error was corrected and the origin was calibrated. The gyro sensor obtained the offset value from the sensor and made a correction. As a result, it was possible to make a correction that satisfies the required accuracy for the attitude stability of the satellite.

The HSU-SAT1 is a 1U Cubesat, which is scheduled to be launched in 2021 with the mission of orbital demonstration of self-made satellite bus devices, three-axis attitude control by magnetic torquer, and satellite uplink by infrared remote control. The Electric Power Subsystem of the HSU-SAT1, which is designed to stably supply power to each device in the satellite without damage under space environment, consists of solar cell panels, batteries, a charging circuit, a power control circuit, and an inhibit circuit. The five solar panels used in our satellite consist of four panels made of single crystal silicon cells and one panel made of three-junction solar cells. The main battery is a lithium ion battery. According to the electrical interface requirements of the J-SSOD, the satellite must be inactive when the three deployment switches are pressed prior to satellite deployment, and the transmitter in the satellite must not emit radio waves within 30 minutes after satellite deployment. The inhibit circuit is designed to meet these requirements.

The first HSU-SAT is a 1U size Cubesat. In this paper, we designed and developed a satellite structure using Autodesk Inventor to develop the thermal structure of HSU-SAT1. In addition, structural analysis and thermal analysis of the satellite were performed using Excel and Autodesk Nastran in cad. We verified whether the satellite can withstand the launch environment and whether the onboard equipment is within the allowable temperature range.

We evaluated the internal resistance of commercial cylindrical lithium-ion batteries (LIB) as a power source for micro/nanosatellites including cubesats by two kinds of measurements, electrochemical impedance spectroscopy (EIS) and current-rest-method (CRM) to understand and predict the battery condition on orbit. Comparing the EIS and CRM response, the observed internal resistance of CRM was larger than that of EIS, presumably reflecting the difference in chemical situation inside the battery: the increse in the CRM resistance might be due to the overvoltage relaxation coming from continuous charging/discharging. The two measurements also revealed that the internal resistance of LIBs at low temperature, where the power supply of the CubeSats experiences, were more than double compared to those in a mild environment for larger satellites. Moreover, incredibly high resistance at a higher state of charge (SOC) was observed, especially in low-temperature EIS measurement. Such resistive behaviors strongly affect the battery performance on orbit, and probably lead to the risks in the satellite operation.

The probable performance distribution in an orbit environment of a power supply of micro/nanosatellites was evaluated by electrochemical measurements using hundreds of commercial cylindrical lithium-ion batteries (LIBs). According to the distribution map of the initial characteristics, there were 3% distribution in the discharge capacity and 11% in the internal resistance. Despite careful selection of LIB cells having same initial characteristics from the above-mentioned distribution map, the large differences in discharge capacity were found at relatively high current density with low temperature of 0°C, where the batteries installed in the CubeSats experiences. Although the difference in low-temperature performance of LIB cells fairly depended on their internal resistance, causeless factors affecting the exothermic behavior in the cooled batteries at its early stage of discharging, which leads higher or lower discharge capability, were observed. Such characteristic behavior may cause deterioration of the performance of the power supply module, overcharge/over-discharge failures, and cause safety hazard of the satellites, especially CubeSats.

Formation Flying enables us to get high-resolution data which we have not got before. Owing to the advantages of Formation Flying, new missions such as long focus telescope, high-resolution radio interferometry, and InSAR are proposed. From the viewpoint of cost, small satellites including nanosatellites are necessary for these missions. As satellites get smaller, more efficiency in Power or fuel consumption is required. Conventional studies considered the periodic condition under CW equation and Kepler problem without any disturbance. Although, in the case of little orbital control capability as small satellites, Orbit disturbances should be considered into the periodic condition. The previous study derived the periodic condition under J2 force. In Low Earth Orbit (LEO), not only J2 force but also aero drag strongly affects the satellites’ orbit. This research considers periodic condition under aero drag and shows that Formation control makes more effectively with the proposed condition. As the characteristic of aero drag is different from J2 force, this research cannot adopt the previous approach, and focuses on energy reduction. To evaluate the proposed condition, numerical simulation with the air density model close to the real atmosphere is conducted. It shows that the proposed condition reduces the drift from periodic to 32 %.

Angular momentum management in small spacecraft is important to maintain power, heat balance and communication environment. As a practical method, thruster is difficult to install because the smaller the spacecraft, the greater the influence of deviation from the torque axis during fuel injection. In this paper, we propose a method of angular momentum management using magnetic torque caused by an interplanetary magnetic field (IMF). Since the IMF fluctuates stochastically, it is unknown whether it can be used for angular momentum management. To indicate this, this report focuses on the frequency characteristics of the IMF and analyzes the noise component at first. Next, this report investigates the amount of angular momentum change caused by white and brownian noises then shows the possibility of angular momentum management. Numerical simulation shows angular momentum management using 1-axis MTQ and RWs considering IMF distribution.

It is now possible to use aluminum alloy structural materials, which are inexpensive and highly recyclable, for drone bodies that are expected to grow in size in the future. The three-dimensional truss structure makes it easier to use aluminum alloy space frames as structural materials for large drones. As a result of structural analysis during hover flight by CAE, it was confirmed that it has a minimum safety factor of 2.7 and a higher safety factor of 1.5 than that of general aircraft. In the test with the actual aircraft, the flight was stable and there was no deformation, confirming the simulation results.

In recent years, plans to land on Mars have been made using parachutes and shock absorbers. One of the challenges of this project is that the attitude of the lender at the time of landing should be consistent with its own velocity vector. Therefore, we modeled a parachute and a lander as a multibody system and analyzed their behavior during landing. In addition, we propose a control system to make the attitude of the lander follow the velocity vector. A nonlinear model predictive control is applied as a control law, and the control is based on the predictions of velocity vectors. Furthermore, a thruster is used as the actuator, and the analysis is performed with input constraints explicitly taken into account.

The Vortex Generator ("VG") is well known as an aerodynamic device that improves the velocity distribution inside the boundary layer. In this study, the effect of VGs inside the boundary layer on a flat plate was investigated by using the hot wire anemometer. In the experiments, the wake of VG was measured using a robotic arm. The measurement interval was 5 mm, and an X-type probe was used for the hot wire experiment. The uniform velocity of the wind tunnel is set at 20 m/s. The boundary layer thickness in the measurement plane is 60 mm. The velocity distribution in vertical V_z and spanwise V_y components are visualized.

In this study, the CFD was performed to investigate aerodynamic characteristics of the supercritical airfoil (SC-0414) attached with Gurney Flap. The ANSYS FLUENT was used to simulate transonic airfoil flows. And the results were compared with the previous experimental results that was obtained by PDI (Point Diffraction Interferometer) flow visualization technique. The Mach number is M = 0.8, the Reynolds number is Re = 1.5×10⁵, respectively. The height of flaps are 1% (GF1%) and 3% (GF3%) chord length. As the results, the negative pressure of GF3% is larger than GF1% and clean condition. The characteristic showed the same trend with the previous experimental data.

Flexible deployment structure system are used for various spacecraft from the viewpoint of cost reduction of transportation by rocket. In this paper, the stress due to thermal strain was evaluated for the deployable cubic structure proposed in this study. First, we investigated the on-orbit temperature of the deployable cubic structure in the sun-synchronous LEO, and found that the temperature ranged from -90℃ to 98℃. Secondly, based on this thermal analysis result, the tensile test of the pillar member at -80℃ to 80℃ was performed, and the Young's modulus was changed by about 25%. Thirdly, thermal structure analysis was performed using on-orbit temperature analysis and tensile test results. The stress due to thermal strain was the largest at the eyelet part of the hinge joint. Although the stress of any member does not exceed the proof stress, it was found that there is little margin for eyelets.

The Hyogoken Nanbu earthquake (Kobe earthquake) that occurred on January 17. 1995, caused extensive and severe damages to a large number of buildings in Kobe city area. After the earthquake many steel structures were constructed using frame welded joint of welded construction and welded base. However, the capacity of these weld joints to absorb energy during earthquakes is small. In this paper the use of piezoelectric limit sensors to evaluate the resistance and displacement characteristics of welded construction for means of simple measurements is presented.

Effects of anchor head shapes on loading anchors on debris structures were investigated through numerical simulations. Johnson-cook model was used in the numerical simulations and the penetration behaviors during harpooning the anchors to flat or tilted targets were analyzed. Three types of anchor head shapes, cone, double bladed and sphere, were employed and their penetration behaviors were compared. It was observed from the results that the minimum penetration velocity of double-bladed head was lower than those of the other head shapes and it indicates that the required kinematic energy for capturing can decrease. However, a small piece was generated during the penetration using the double-bladed head anchor and it can be a new space debris.