In this study, a method to evaluate the effectiveness of adaptive driving beam (ADB) to enhance a driver's perception level for detecting pedestrians in a driving simulator is proposed. First, we investigated a driver's reaction time for applying brakes and the time taken to detect pedestrians stepping out from sidewalks. Next, we evaluated the effectiveness of ADB in terms of likelihood of collision mitigation using this reaction time based on the system reliability concept that we have proposed in previous studies. Using a driving simulator, we verified that it is almost possible to simulate the distribution of illuminance on the road surface by headlights and that it is useful to investigate the reaction time of drivers to detect obstacles such as pedestrians walking on a drive lane during the night.

View full abstract

We analyze pilot flight technique using the fixed base flight simulator of the Suzuki-Tsuchiya laboratory at The University of Tokyo. We look at pitch control style and input frequencies in particular, and identified differences between professional pilots and students without prior flight experience. Also students with a lot of experience playing the Microsoft Flight Simulator game show a typical control style. In addition we can distinguish control styles between instrument flight and visual flight. We provided simulator training to a number of students and followed them over a period of a few months. The analysis of their data shows that their control input frequency increases, and resembles the professional pilot's control style more and more. In addition, we found trainees develop a characteristic change in the pupil diameter just before landing comparable with professional pilots. We believe these findings are an important step towards the objective evaluation of trainee pilots.

View full abstract

The driving simulator (DS) is applied in many fields. In order to improve the realistic sensation on DS, we have developed a new system which is combined of turntable and the XY-stage, which center of rotation could be adjusted by the user. In this research, we have done the experiment on the DS with the XY-stage as a part, and analyzed the realistic sensation when the position of the driver seat is different.

View full abstract

The purpose of this study is to realize a vehicle dynamic analysis considering the influence of the compliance steer by using a simplified calculation method. In this method, the compliance steer was calculated by using stiffness matrices and the constraint forces acting on the suspension arms instead of considering the deformation of each rubber bush. The characteristics of the rubber bushes included in a suspension arm were merged in one stiffness matrix. In the multibody vehicle dynamic analysis, the obtained compliance steer of the wheel was considered in the tire force calculation. In order to confirm the validity of the proposed method, the dynamic analysis of the multibody vehicle model with rubber bushes defined as the force elements was conducted. The result of the vehicle dynamic analysis with rubber bushes defined as the force elements and the results of the vehicle dynamic analysis with the proposed method were compared.

View full abstract

Recently, driving assistance systems for the vehicle have been developed. For example, following support of preceding vehicle, collision avoidance support, and lane keep assist are implemented. Therefore, supported range is widening, but not enough for realization of driving with no traffic accident at all. Some of the causes of traffic accident are oversight in danger and lack of attention to sudden rushing out. In order to cope with these causes, it is required to drive with concurrent consideration for many noted point in large range. From this, the control using artificial potential function is contrived. With artificial potential function that is fuzzy control, however, creating course and speed freely is difficult. In this paper, a control system which applies the force depending on potential function to the vehicle to alter movement in case that there is no danger to avoiding one is proposed to solve this problem. This enable to control the vehicle without detailed information of the road but the target route.

View full abstract

When viscous damping of a steering system is too little, the steering system becomes vibrating in high speed. When the viscous damping is excessive, a response of a vehicle becomes slow. Therefore the optimal value of viscous damping must exist. To obtain insight of the influence of the viscous damping on dynamic behavior of vehicle and steering system, this paper formulates the natural frequencies and their damping ratios taken account of the viscus damping under force control. One of the formulas implies larger viscus damping of steering system reduces the fast response of vehicle. Finally, this paper studies optimal damping ratio of steering system from the angle of oscillationless behavior, over shoot and delay of vehicle response.

View full abstract

Yaw natural frequency is employed as an index of vehicle dynamic behavior. A yaw natural frequency taken in account of roll motion has been formulated. On the other hand, a mode of yaw natural frequency was studied in recent years. As a result of that, it was clarified a difference between the resonant mode and supposed condition for the formulating. Therefore this paper formulated yaw natural frequency based on the mode. As a result of that, it was clarified that the former formula of yaw natural frequency was taken in account of excessive roll motion and normal the load distribution affects yaw natural frequency.

View full abstract

Ease of driving along lines which drivers assumed may be called "correctness of steering." The driving along lines causes meandering. To improve correctness of steering, this paper considers the natural frequency and amplitude of the meandering. First this paper introduces a driver model that employs driver's dead zoon of sense of visual and can describe this steady weaving. Secondly this dead zone is approximated to be a cubic function. Finally this paper formulates the weaving frequency and its amplitudes. The result shows the amplitude of lateral acceleration increases due to reduction of course tracking performance.

View full abstract

The purpose of this study is to investigate the behavior of CVT to consider the change of the transmitting efficiency during shifting. The apparatus consists of driving and driven pulleys whose groove width was adjustable, dry hybrid V-belt, a variable speed AC motor and an electric powder brake. The flange of the driven pulley was subjected to a constant thrust by an oil-pressured actuator. Pulley thrust, rotating speed and applied torque was measured in the test. The speed ratio (i) which was defined as the reduction ratio of number of revolutions of driven pulley to that of driving pulley was changed from 2.2 to 0.8 to execute shifting up motion of CVT. To change the width of pulley grove, applied thrust force (Qdn) to the driven pulley was linearly increased from 1000 to 1500N. Momentary transmitting efficiency which was defined as the momently variation of transmitting efficiency at shifting state was evaluated by measuring the change of torques and numbers of revolutions of the driven and driving shaft, respectively. Non-dimensional momentary transmitting efficiency (η) (normalized efficiency by that at certain condition) was improved during shifting with increase of shifting time (ti) in any conditions of shifting time. Non-dimensional momentary transmitting efficiency (η) was improved during shifting with increase of input number of revolutions (Nin) in any conditions of input number of revolutions. The radial displacement per one pulley revolution (λ_<rev>) was an index to evaluate the changes of non-dimensional momentary transmitting efficiency (η) and driving pulley thrust (Qdr) during shifting. The λrev is not only an index to evaluate the changes of non-dimensional momentary transmitting efficiency during shifting (η)) and driving pulley thrust (Qdr) but also an index to evaluate the changes of mean transmitting efficiency during shifting (η_<mean>) and mean driving pulley thrust during shifting (Qdr_<mean>).

View full abstract

The weight reduction of a vehicle is important for car development. However, the weight reduction leads to a stiffness drop. This stiffness drop affects the stability and the dynamic performance of the vehicle. But, these relationships are not clear. In this research, we build a multi-body dynamic vehicle model for a solar car. The part to change is the frame stiffness. We perform the evaluation by constant radius analysis and single lane change analysis. When frame stiffness is low, the elasticity transforms by the vehicle frame cornering force. It is understood that, the vehicle alignment changes, the vehicle stability and dynamic performance of the car decreases.

View full abstract

A lane tracking steering control algorithm with a preview point is investigated. In this system, the target yaw rate is calculated based on the lateral deviation at the preview point, and the vehicle generate the yaw rate. As a result, the vehicle can follow the target course. From the sensing point of view, it is generally required to use the preview point in the vicinity of the vehicle as much as possible. We proposed a new algorithm with two preview points and found that it is possible to make preview time shorter than one of previous algorithms. Moreover, it is possible to realize arbitrary dynamics of lane tracking performance with no steady state deviation during cornering theoretically that have not been done before. However, in our investigation, the delay of the system is not considered, such as calculation time of computer vision, so we conducted experiments with the driving simulator and verify the validity of this approximation with quantitative and subjective evaluation.

View full abstract

In order to control vehicle behavior, it is essential to estimate the tire force accurately. However, even today it is difficult to detect the tire performance degradation before the deterioration of vehicle dynamics in real time. This is because the tire force estimation is usually conducted by comparing the actual vehicle motion with the onboard reference vehicle model motion. Therefore, such conventional estimators do not perform well if there is significant difference between the actual vehicle and the model behavior. In this paper, a new tire state estimation method based on tire force characteristic is proposed. In addition, the estimator for tire-road surface friction coefficient ,u is proposed by using this geometric relationship.

View full abstract

Recently, the electromagnetic damper, which is composed of an electric motor, a ball screw, and a nut, was proposed. The electromagnetic damper has high responsiveness, controllability, and energy saving performance, and it has been reported it improved ride comfort and drivability. The authors have proposed coupling methods of the two electromagnetic dampers. These methods enable the characteristics of bouncing and rolling or pitching motion of a vehicle to be tuned independently, and can realize a characteristic of roll stabilizer, and so on. In this study, the authors increase the number of coupling of electromagnetic dampers from two to four, and propose a method to couple the four electromagnetic dampers. The proposed method enables the characteristics of bouncing, rolling and pitching motion of a vehicle to be tuned independently. Numerical simulations of the tuning automobile is carried out, and the results indicate the proposed system is effective.

View full abstract

In recent years, traffic congestion and reduction carbon dioxide has become traffic problems. Narrow tilting vehicle has been anticipated as a potential solution to the various traffic problems. For further improvement of Narrow tilting vehicle, we propose a new steering method with a free front wheel that mechanically follows the vehicle body tilting. In this study, we have investigated the effects on the motion of the vehicle by the design of the front wheel caster angle and trail. We used the simulation by multi-body-dynamics as the research method to investigate the effect of the front wheel caster angle and trail. From the results of the study, it was found that (1) the design of the front wheel caster angle can give a significant change to the vehicle turning radius, and (2) the design of the front wheel caster angle and trail affect vehicle steering angle under disturbance on the front wheel.

View full abstract

A vibration suppressor is used to change the natural frequency of an elevator rope, and to prevent resonance. The elevator rope is modeled using a string. However, the vibration of the string that has a vibration suppressor has been studied for a few conditions because of its geometric nonlinearity. An exact solution of the free vibration of a string when the position of the vibration suppressor is 1/N (N is an even number) of the position of the string has been obtained. However, in the case where N is an odd number, no exact solution of the free vibration has yet been obtained. In this paper, an exact solution of the free vibration of this case is presented. Finite difference analysis of the string vibration with a vibration suppressor is performed. The calculated results obtained from the finite difference analysis are in good agreement with those of the exact solution.

View full abstract

Most elevators used in tall buildings include compensating ropes to satisfy the balanced rope tension between the car and the counter-weight. The compensating ropes receive tension by a compensating sheave, which is installed at the bottom space of the elevator shaft. The compensating sheave is only suspended by the compensating ropes, therefore, the sheave can move vertically. When the car can't stop at the highest floor in an abnormal situation, the counter-weight can reduce its downward speed by the buffer strike. During the buffer strike, the suspension ropes lose the tension and the car continues to move upward for a while against the gravity force. The upward motion of the car also induces the same upward motion against the compensating sheave. However the sheave can't move beyond a limited distance for safety reasons, and the restricted motion of the sheave induces higher tension to the compensating ropes. This paper shows the elevator dynamic model to calculate the compensating sheave motion during the buffer strike. Firstly, the transient behavior of the compensating ropes' tension and the compensating sheave's motion is validated by the multi-body dynamic model. Secondly, the equivalent 2-DOF vibration model is used to calculate the rope tension and the sheave motion. Finally, the relation between the permissible upward motion of the sheave and the rope tension is explained by the equivalent 2-DOF model. We can conclude that shorter permissible motion of the sheave causes higher rope tension to the compensating rope.

View full abstract

In this research, we performed curving simulation of one vehicle using versatile multibody dynamics analysis software SIMPACK to comprehend wheel loads, lateral forces and contact positions of a wheel and the rail and so on at the time of curve passage which we input into a rolling contact finite element analysis between wheel and rail in an estimation method for rail defect in consideration of a combination of a short crack growth and wear. By the simulation, we calculated vertical, running and lateral forces at the bearing considerable position of the axle and contact positions of a wheel and the rail and so on when a vehicle passed a curve as input at track condition (radius, cant etc.), rail profile, specification, wheel profile, running speed and so on. In this paper, we show an analysis of the tendency about an occurrence of creep force at the time of the curve in the simulation result.

View full abstract

In recent years, condition monitoring technology using various sensors have been studied with the development of the ITC technologies. In the railway field, condition monitoring system using an acceleration sensor mounted on the vehicle body or bogie have been studied. In our research group has studied the sign detection system of the flange-climb derailment using an angular rate sensor attached to the bogie frame. In previous research, a basic detection algorithm was developed using 1/10-scale vehicle experiments. Following the development of a sign detection algorithm from the scaled model, verification of the sign detection algorithm was then completed using real-scale bogie experiments and Multibody dynamics simulation. This time the running test using an actual vehicle has been done and focuses on the result of the bogie behavior while passing the rail joint, which is not reproduced in the simulation. In this paper, vibration characteristics of the bogie behavior was analyzed while passing the rail joint.

View full abstract

The aim of this study was to develop a specific additional device to in-situ evaluate the changes of resistance forces of belt conveyor at the locations of carrier idlers supporting at the string part, in order to estimate the wear damage of the conveyor belt during driven state the at the site. Some practical carrier idlers were modified to attach the strain gages at the center position of the shaft. The changes of driving resistance and carrying load acting on the carrier idler shaft were simultaneously observed by measuring the difference of bending strains directly. The penetrative displacement of the carrier idler into the belt was measured to evaluate the deformation of conveyor belt due to the compressive force in thickness direction. The bending stiffness of the belt was measured by three point bending test to examine the effect of the difference of the bending stiffness by wear damage on the driving resistance. Test results showed that the data of measured resistance forces by the proposed device in this study were almost reasonable compared with those of known results by other conventional methods. It was said that proposed method was effective to explain the behaviors of resistance forces of the belt conveyor around the carrier idler.

View full abstract

The authors have proposed a kind of lane keeping system using roadside markers and onboard sensors to achieve safer and smoother road traffic in adverse weather conditions. The system acquires the relative positions of roadside passive markers by laser sensor, and their absolute positions by communication with roadside active markers. Using these data, the system estimates the vehicle's relative position in the lane, and assists the driver to keep the lane. In this paper, the developed system and the implemented logics are verified. Moreover, various kinds of Human Machine Interfaces are listed and a Head-Up Display projected to windshield with Augmented Reality is introduced.

View full abstract

This paper deals with measurement of road surface condition by Quasi Electrostatic Field (QEF) sensing technology. The QEF is distributed over a dielectric of a human body, the vehicle body and a substance like electrostatic charge. The QEF sensing measures an electric change in a tire and a road surface with a sensing on the vehicle body by using this property without installing a sensor in the tire. A road surface sensing by wireless and electricity supply-less is possible. Because a tire will be a sensor, so-called tire sensing. An experiment was conducted in a dry surface road, a wet surface road, a snow surface road and a frozen surface road. It was indicated by the amplitude and a frequency analysis about the identifiability of the dry, the wet and the snow. The influence an environmental factor brings was indicated by a frozen surface road as a problem.

View full abstract

Japan has a lot of volcanically active mountains. Recently, intense volcanic activities have been observed in a few volcanoes. A large-scale volcano eruption causes serious damage. Especially, volcanic ash is the most serious in volcanic hazards, because it has long term effects over large area. This affects economy, industry, traffic and the others seriously. Even in the hazard, vehicles need to run for rescue and transportation. In this case, we examined the effects of volcanic ash on vehicle running motion. We used an equipment to measure the interaction, such as friction coefficient and rolling resistance, between a tire and volcanic ash on paved road. We also examined the characteristics of multipass, the sinkage of tire and compared with silica sand. As a result, we confidently concluded that it is difficult for vehicles to run on ash-covered road. When ash falls less than 10 mm, vehicle run depends on a status of the tire tread wear. Over 10 mm, the friction coefficient and the rolling resistance increase with the depth of ash. Over 40 mm, the friction coefficient is nearly as low as one on the road covered with snow. In this case, driving vehicle has to be avoided. When ash falls more than 100 mm, a vehicle cannot run.

View full abstract

Recently, in order to decrease the number of traffic accident, various automotive safety technologies have been studied. As one of those technologies, the authors have proposed the autonomous frontal obstacle avoidance system, which recognizes a frontal obstacle such as a pedestrian, predicts the location of collision based on the obstacle motion and avoids it by autonomous evasive steering. However, the proposed system calculated avoidance trajectory based on the predicted obstacle position by first-order prediction. Since pedestrians' motion in the real world is not always constant, change of motion of the obstacle must be considered. Therefore, in this paper, the authors solves this problem by consecutive prediction of obstacle position and revision of avoidance trajectory during avoidance action. In addition to, we also proposes the method to judge whether or not it is necessary to update the avoidance trajectory and a method to choose the appropriate avoidance trajectory in response to the change of the motion of the obstacle. Then, the newly proposed system is verified by numerical simulations. The results show that the newly proposed system is effective.

View full abstract

In order to promote researches aiming at reducing the number of traffic accidents, the near-miss incident database has been developed by summarizing near-miss incidents recorded by drive recorders mounted on taxis in Japan. The database is equipped with the distance measurement tool, by which researchers can obtain distance from the camera to an object in video images recorded by the drive recorders. However, it is a heavy task for researchers to obtain the distance data for a large number of incidents. Therefore, in this study, the authors proposes a method to obtain distance data to a target object automatically by using image processing. The algorithm performs tracking of the preceding vehicle by TLD, estimates the mounting position of the camera from the position of the fender mirrors and the bonnet, and calculate the vehicular gap using a perspective projection model. From the comparison with the vehicular gap obtained manually, it is indicated that the vehicular gap obtained by the proposed algorithm has satisfactory accuracy as the manual annotation process.

View full abstract

The experiment that assumed a derailment and transgressing the crash occurring by earthquake accident disaster such as railway vehicle and tunnel and ground structure crash, by using two types precision models railway experimental device. In this paper, we measure and analyze the shock of vehicles and ground structure by HIC(Head Injury Criterion). And also, we report the method of crash behavior and the inspection of accident, using the model railway.

View full abstract

When an air spring of railway vehicle goes flat, wheel load is decreased by track irregularity. In order to examine a running safety for railway vehicle under the air spring deflation, the running tests were carried out, and various data such as wheel load, lateral force, force acting on the air spring, amount of climbing of wheel were measured. Furthermore, we constructed a numerical simulation model of railway vehicle in consideration of an air spring deflation, and its validity was confirmed through the comparison with the test results.

View full abstract

In this study, we evaluated the contact stiffness between the wheel and the concrete track member after derailment to be used in the MBD analysis. Firstly, we conducted the static experiments using contact shoe to simulate the wheel flange shape to confirm fundamental characteristic of the contact stiffness. Secondly, we investigated the wheel marks that a derailed train made on slab track during an earthquake. Finally, we evaluated the effect of the contact stiffness on the wheel behaviors in the MBD analysis.

View full abstract

So far, dynamic motions and running safety of railway vehicles against an earthquake have been analyzed using Vehicle Dynamic Simulator (VDS) developed by RTRI. The analysis has been executed under the uniform oscillating condition for all the wheelsets. In a practical sense, however, railway viaducts do not vibrate uniformly, thus angular rotations and misalignments could occur at the railway track on the viaducts. In this paper, we analyzed the dynamics of railway vehicle under different oscillating conditions such as angular rotations of the track for the respective wheelsets. The results show that the effect of angular rotations of the track on running safety during an earthquake is not remarkable, but derailments tend to occur near the angular rotation.

View full abstract

This paper describes the effect of vehicle motion when the passenger, clipped between the car-body and the platform, is rescued by the number of passengers. Filed test was carried with the collaboration of railway operator first. Numerical simulation with a half vehicle model was performed to study the effect of vehicle motion in rescuing. Results showed that the cyclic load applied at the car-body by the small number of passengers caused the dangerous situation instead.

View full abstract

In recent years, the traffic accident shows gradual decreasing in the number of fatalities, whereas slowly decreasing the total number of accidents and injuries. In order to decrease the total number of accident, it is necessary to investigate what kind of accident has happened. So the feature of accident and near-crash incident involving pedestrian was analyzed from near-miss incident database. For further details, vehicle speed and position involving pedestrians. And the positional relationship was investigated from picked up typical near-crash incidents.

View full abstract

This study examines the driver assistance system which informs the passage possibility at a signalized intersection ahead. The assistance system informs a driver visually of the distance which the vehicle can forward by maintaining the present velocity until the red signal. If the indicated distance is shorter than the distance to the intersection from the vehicle, the system also indicates the stopping distance by assuming the ordinary deceleration. By examining the driver simulator experiments, the assistance system realizes the earlier deceleration before the amber signal and prevents the emergency braking behavior. In addition, the margin to pass through or stop at the intersection is examined by the evaluation indices concerning the intersection. The assistance system improves the safety margin at the intersection.

View full abstract

This study proposes the driver assistance system informing the necessity of deceleration at a signalized intersection ahead during the red signal. The assistance system indicates the distance which the vehicle can forward by maintaining the present velocity until turning to the green signal using the signal information. If the indicated distance is longer than the distance to intersection from the vehicle, the system encourages driver the deceleration by blinking the indicated distance. The driving simulator experiments are conducted to evaluate the proposed assistance system. The assistance system could reduce the unnecessary deceleration and re-acceleration. These effects make it possible to reduce the fuel consumption.

View full abstract

This study proposes a collision avoidance tactics for micro vehicles (MV) at medium or small-sized intersections which are not controlled with traffic signals. An empty space would be found in this tactics based on the geometric shape at the intersection and it moves MV into the space to avoid a crossing vehicle. The avoidable speed of the MV will be calculated based on the estimation of the existence of crossing vehicles before the crossing vehicle is not detected.

View full abstract

In the current railway vehicle, the railway station attendant to prepare the plate when the wheelchair passengers are getting on and off, thereby performing the assistance of getting on and off. It has become possible to getting on and off in the ride time, departure delays are also up as a problem. In this study, it is an object of the present invention wheelchair development equipped with a new mechanism that can be getting on and off without using pass plate at the time of railway vehicle getting on and off. Many wheelchair users are elderly, physically it is under stress at the time of many traveling even number of users of the self-propelled manual wheelchair. In the self-propelled wheelchair equipped with a new mechanism, even with a small force made it possible to overcome the stepped-gap. In this presentation, we report the evaluation results in the prototype wheelchair.

View full abstract

When railway vehicles pass through a sharp curve, yaw moment is generated at the bogie. This moment affects the lateral force of the outside wheel of the front axle of the leading bogie, which is important factor for assessing the running safety of railway vehicles. A Lateral-force/Wheel-load estimation equation has been developed as a method to calculate the lateral force and the wheel load during the curve passage of railway vehicles taking into account the yaw moment of the bogie. This equation is useful to estimate the risk of flange-climb derailment. The authors have newly suggested a more versatile Lateral-force/Wheel-load estimation equation with a focus on the improvement of the estimation of yaw moment of the bogie. Running tests using test track which has sharp curves were carried out to measure the generated forces of several components of the bogie, which are the sources of the yaw moment of the bogie. New equations were produced based on the test results, and compared with the measured lateral forces and wheel loads.

View full abstract

Recently, AACN (Advanced Automatic Collision Notification) that presupposed cooperation with emergency life-saving organizations is expected. Therefore, emergency life-saving organizations must recognize injury speciation of patients, as quickly as possible. So, the author tried the traffic accident analyzing method by statistical data analysis from combing analysis items analysis items for main site of injury and analysis items for injury contents (indicated in the traffic accident statistics vote by Japanese National Police Agency). And furthermore it is necessary to improve the safety of vehicles not only for same class collisions but also for collisions between vehicles of different types (e.g., between SUVs and sedans). In this study, the author applied the method of analysis as described above for frontal collision between SUVs and middle sedans, and analyzed using statistical data stored in ITARDA (Institute for Traffic Accident Research and Data Analysis). In the case of fatal or severe injuries, it is shown that the component rate of chest fracture of middle sedan drivers is higher than that of SUVs. It is supposed that the difference in these rates is caused by the vertical offset configuration between the frames of the two different types of vehicles when they crash into each other.

View full abstract

This paper describes preventive measures against deropement incidents in ropeways and chairlifts. In ropeways and chairlifts, it has been pointed out that accidents and incidents similar to those that happened in the past have recently occurred more frequently than before and it is necessary to take appropriate measures as soon as possible to prevent such accidents from recurring. We reported the statistical analysis results of ropeway and chairlift incidents in the past eight years. This statistical analysis includes cause analysis of the incidents and analysis of conditions in which similar incidents occurred. The results of similar incidents analysis showed the highest frequency of occurrence was in deropement incidents. Deropements in ropeways and chairlifts could cause serious accidents such as carrier falls and carrier collisions. This paper provides corrective actions to prevent deropement incidents based on the above analysis results.

View full abstract

Particulate matter (PM) emitted from diesel engines has harmful influences on human body and the regulations on the emission have become increasingly stringent. It is difficult for conventional electrostatic precipitators to treat the highly conductive PM in diesel exhaust gas. This study aims to achieve the electrostatic collection of PM with the electrode configuration that enables both the control of PM re-entrainment and the incineration of the collected PM with nonthermal plasma. The result of a basic PM collection test with DC corona discharge showed a collection efficiency of 76%.

View full abstract

Drivers who are driving vehicles, rely on visual sense as approximately 90% of necessary information, for example transforming of road environment or behavior of pedestrians etc. Therefore, good or bad of visibility performance cause a big effect for comfort or convenience concerned about driving vehicles. In this paper, authors introduce previous studies concerned with improving visual sense of heavy duty vehicles, the relationship between driving view area of heavy duty bus and driving comfort or the indirect visibility system (Periscope system) that improving visual sense of surrounding area of heavy duty trucks, etc.

View full abstract

This paper describes influence of support condition against bending eigenvalue. For comparison, rigid simple support and soft airspring support conditions were employed. As a result, results under simple support condition were affected by ground rigidity at test site, and rigid ground state is required to acuire good accuracy. But under airspring support condition accuracy is enough high even at soft ground condition. From the results we obtained, soft airspring support is suitable for measurement and evaluation of bending eigenvalue.

View full abstract

In our past studies, a ride quality index: "complex ride quality index (CRQI)" that predicts the change of ride comfort due to complex vibration was proposed, and a unified data-indication system (UDIS) as the application of the CRQI were presented. The system's users are able to watch the change of the CRQI and the existing ride quality indices together, and to grasp the shape of the acceleration-waves, the kind of the structures, and the track alignment, which exist around the spots where the CRQI becomes worse. This paper introduces the newly improved points of the UDIS for practical use and reports an analysis example using this system.

View full abstract

In the subway, half or more of the railway are curve shapes, and the driver cannot look around the front. Therefore railway vehicle is controlled by the protective device and operated to perform acceleration and deceleration frequently. As a result, the passengers receive an inertial force by the acceleration of the railway vehicle, and they cannot keep the balance of the body, and riding comfort turns worse. In this study, we examined the experiments of riding comfort evaluation by the simulator that can reproduce the floor acceleration of the railway vehicle. And we analyzed to focus on the floor acceleration, the floor jerk, the center of gravity of the subjects and the momentary riding comfort evaluation by the switch. As a result, we clarified the relationship between the floor acceleration of the railway vehicle and the displacement of center of gravity of the subjects. As for the direction of movement of railway vehicle, we showed the relationship between the floor acceleration and the floor jerk that influence the riding comfort of railway vehicle.

View full abstract

Ventilating equipment for keeping constant ventilation volume of the passenger cabin is mounted on Shinkansen vehicle. Since fresh air that ventilating equipment inhale are mixed with dust. The equipment has a nonwoven fabric filter at fresh air inlet. Clogging of filter due to dust causes to lower ventilation volume, and we need periodical maintenance. In order to prevent ventilation volume decline and to reduce maintenance, we are developing cyclone dust collector that is substitute from the inlet filter. In this development, we confirmed basic performance of cyclone dust collector by using iron powder, aluminum powder and silica sand. For practical use in commercial vehicles, there is a need to further improve.

View full abstract

We have devised a steering system in which the magnetic elastomer is used for the elastic members such as a rubber bush of the axle box suspension. The magnetic elastomer is composed of magnetic particles and the elastomer such as synthetic rubber. This material is characterized by its hardness variation depending on the magnetic field. This axle box suspension is capable of varying the longitudinal stiffness. In straight sections, the application of this axle box suspension ensures running stability by increasing the longitudinal stiffness by means of applying a magnetic field. On the other hand, in curve sections, it improves curving performance by decreasing the longitudinal stiffness by means of turning off the magnetic field. We made test pieces towards the development of the magnetic elastomer for the steering truck. In a characteristic test, we confirmed that the Young's modulus of the magnetic elastomer changed in the range of about five times depending on the presence or absence of the magnetic field. In addition, we simulated the vehicle running model by applying the longitudinal stiffness change of the magnetic elastomer to the axle box. We confirmed that this axle box was capable of reducing the average of the outer wheel lateral force in the circular curve section compared to that of the normal axle box.

View full abstract

However, the conventional pedestrian models using these systems are intended to predict the behaviour of the pedestrian as a single mass. In addition, the pedestrian speeds in the system have been assumed almost constant during the crossing. Therefore, we have analysed the pedestrian image of the live camera that is installed in Shibuya scramble intersection in this study, especially to analyse walking speed change. Furthermore, in order to examine the change of leg joints on the condition, we have conducted experiments in the 10-meter-long road, which is divided into four conditions. We have constructed the prediction model by the Kalman filter using the participant behaviour. As a result, the prediction model is substantially equal to the observed value; the error was 0.74% and 0.62%, 0.66%, 0.75%. It seems to be possible to estimate the change of state of the pedestrian from this approach.

View full abstract

Advanced Driver Assistance Systems (ADAS) is receiving increased attention throughout the world for avoiding traffic accident. The authors' research focuses on "Mutual Assistance" paradigm which drivers will mutually assist each other for safer automobile society. The authors' previous research examined the effectiveness of the mutual assistance system from both the recipient and the assister side with a driving simulator. However, in condition of experiment, examinee did recipient-side and assister-side separately. Therefore, examinee have to do recipient and assister simultaneously to obtain data in a more realistic situation. This paper reveals effectiveness of mutual assistance system for system user in realistic situation. As evaluation items, success rate of warning, mental workload, attitude change rating and collision rate were used in analysis. These experimental results indicate that fully automatic system(it is written automatic level IV in the text) kept high success rate of warning and decrease mental workload. On the other hand, semi-automatic system(these are written automatic level II or III in the text) induce positive attitude changes, and guided feature semi-automatic system(it is written automatic level III in the text) is most effective for assister's collision rate decreasing. These experimental results indicate that guided feature semi-automatic system is the most proper automatic level for mutual assistance system and has potential of restrain risk compensation behavior.

View full abstract

This study investigated the effect of green phase countdown timer (CDT) on the reduction of drivers dilemma at signalized intersection. The proposed system provides the remaining green time to the drivers in real-time to support the stop/pass decision making. Driving simulator experiment equipped with the CDT indication system showed that the proposed system significantly increased the probability of selecting stop. Also, logistic regression analysis (LRA) revealed that the system reduced the probability of facing the dilemma and encouraged the drivers to decelerate earlier and stop before entering the intersection. Especially, it contributed to decreasing the approaching speed for the drivers who travels at high speed.

View full abstract

In recent year, the study of the automatic vehicle is popular. My laboratory started a public road experiment in first Suzu-shi, Ishikawa at the university in Japan in February, 2015.We suggest the detective technique of the moving object in the urban intersection for automatic driving using the Omni-directional millimeter wave radar in this study. Therefore I attach a millimeter wave radar to an experiment vehicle and try the detection of the moving object on a crossroad and the opposite lane. I use IMM (Interacting Multiple Model) unifying the estimated state of the Karman filter using the different model. In addition, I use GNN (Global Nearest Neighbor) as solving method of assignment problem. When I use Omni-directional millimeter wave radars, the number of observation becomes enormous. The real time processing becomes difficult due to this reason. Therefore I perform the detective experiment of the moving object on a crossroad and the opposite lane each. As a result, I succeeded in detecting the moving object of the distant place quickly. I want to work on speedup of the processing and reduction of the false detection in future.

View full abstract