竹原 昭一郎

Tethers (strings and wires) are used in various mechanical systems because they are lightweight and have excellent storability. Examples of such systems include elevators and cranes. In recent years, the use of tethers in special environments, such as outer space, is expected, and various systems have been proposed. In this study, we propose a mobility system using a tether that moves a human by winding a tether attached to a wall. However, the method has a problem whereby the attitude of the human can lack stability during the winding of the tether. We developed the attitude control method of the Tether Space Mobility Device during tether winding while focusing on fluctuations in the rotational kinetic energy of systems. The effectiveness of the control method was shown using numerical simulation. In this paper, the proposed control system is installed in the experimental device for validating the numerical simulation model. Then, we verified the effectiveness of the proposed control method through experiments using an actual system. The experimental results confirm that the angular velocity of the Tether Space Mobility Device converges to 0 deg/s when control is applied. In addition, it was shown that the proposed control method is effective for automatically winding the tether.

Advances in space technology have opened up opportunities for human beings to work in outer space. It is expected that the upsizing of manned space facilities, such as the International Space Station, will further this trend. A unique means of transportation is necessary to ensure that human beings can move about effectively in microgravity environments. Here, we propose a tether-based mobility system that moves the user by winding a tether attached to a structure at the destination. To overcome the attitude instability of the user during tether winding, the Tether Space Mobility Device (TSMD) attitude control method for winding a tether is applied and examined through numerical analysis. The proposed analytical model for motion analysis consists of one flexible body and three rigid bodies. The contact force between the tether and the TSMD inlet is determined. Using the numerical analysis model, we investigated the effect of slit shape during tether extension and winding.

In this study, as part of efforts to assist beginners in sports such as tennis and badminton in selecting the most suitable equipment, an index for objectively evaluating such equipment is proposed. To accomplish this, standard swing trajectory variations are used to create an index from the viewpoint of human motion control. We begin by noting that human body data gained via motion capture are large in number because of the wide variety of equipment types used and due to the significant diversity of human body characteristics. Hence, even though motion capture devices are often used to capture swing motions, the most suitable human body segments for use in equipment evaluations have not yet been clarified. To facilitate this, it is necessary to reduce the overall number of body segments under consideration. In this paper, the method of deriving the feature points in sports motion was examined. More specifically, in order to obtain fundamental findings, tennis stroke and badminton smash motions are used as representative movements, and experiments using a motion capture device are performed. In the motion analysis that follows, we then investigate which markers can most clearly express the relationship between the racket and the human body in order to capture stroke motion characteristics. Then, an index of contribution is adapted to tennis swing and badminton smash motions, the motion feature points in the stroke and smash motion are derived, and the significant markers for motion analysis are identified and discussed.

Recently, environmental consideration, energy-saving performance and low fuel consumption become important, therefore personal mobility is actively developed. When vehicle become small, it is expected that human body behavior has a big influence on running performance. The influence is related to stability of vehicle and safety of its driver. Simulation is used as a method to investigate the interaction between vehicle and its driver, and the body behavior can be reproduced in advance. However, since it is necessary to consider the validity for the use of simulation, experiments to capture body behavior are indispensable. This research is aimed to obtain knowledge about dynamics of driver riding inside the vehicle. Therefore, subjects are placed on a simple truck simulating a vehicle. The truck is applied lateral acceleration and acceleration in the direction of travel, and the motion of subjects was recorded with the motion capture camera. From the measured data, human characteristics are examined by comparing the body behavior of subjects for each condition.

The mass of very small vehicles is often comparable to that of their drivers, and thus there is a greater degree of coupling between the vehicle and the driver, compared with a case for traditional vehicles. When developing small vehicles, it is necessary to give ample consideration to the dynamics of the person who ride them. Here, a model of a human body riding a small personal vehicle was constructed to investigate the dynamics of the person inside such a vehicle. Moreover, an experiment on posture maintenance by acceleration of direction of travel was conducted and the parameters for posture control were identified using a genetic algorithm. Results shows that body behavior could be successfully simulated using the proposed model, and the control parameters were effective in determining the posture maintenance characteristics of the vehicle occupant.

Recently, advancements in space technology have opened up more opportunities for human beings to work in outer space. It is expected that upsizing of manned space facilities, such as the International Space Station, will further this trend. Therefore, a unique means of transportation is necessary to ensure that human beings can move about effectively in microgravity environments. In the present study, we propose a tether-based mobility system, which moves the user by winding a tether attached to a structure at the destination. However, there is a problem in that the attitude of the user becomes unstable during winding of the tether. Therefore, a Tether Space Mobility Device (TSMD) attitude control method for winding a tether is examined through numerical analysis. The proposed analytical model consists of one flexible body and three rigid bodies. The contact force between the tether and the inlet is considered. We verified the validity of the proposed model through experiments. Furthermore, we proposed a TSMD attitude control method during tether winding while focusing on changes in the system's rotational kinetic energy. Using the proposed analytical model, the angular velocity of a rigid body system is confirmed to converge to 0 deg/s when control is applied.

Recently, as space developments have progressed, the opportunities for human beings to become active in outer space have increased. It is now expected that upsizing of manned space facilities, such as the International Space Station, will further this trend. Therefore, a means of individual transportation is necessary to ensure that human beings can move about effectively in microgravity environments. In this study, we propose a tether-based mobility system named the Tether Space Mobility Device (TSMD), which moves the user by extending and winding a tether attached to destination point within the structure. Additionally, a TSMD attitude control method is examined via numerical analysis. This model consists of one flexible and three rigid bodies. In microgravity environments, it is expected that tether motions will involve large deformations. Therefore, tether placements are formulated using the absolute nodal coordinate formulation suggested by Shabana, and coupled motions between tethers and rigid bodies are based on an augmented formulation. Furthermore, the contact force between the tether and arm is formulated by spring and damper elements. In this paper, the TSMD posture is confirmed during extension and winding operations. In our experiments, we examined the TSMD attitude control method during tether winding while focusing on changes in the system's rotational kinetic energy. The numerical results of our analysis confirm that the attitude of the system is stabilized by our proposed controller.

<p>This study aims to create a system that can be used to evaluate vehicle characteristics while simultaneously controlling human body behavior through numerical simulations. The proposed system consists of a vehicle model, a human body dynamics model, and a musculoskeletal model. In the present paper, a human body dynamics model using multibody dynamics is proposed. However, attempting to implement a whole-body model would necessitate dealing with multiple degrees of freedom and give rise to problematic phenomena. Furthermore, the influences of human motion are uncertain and difficult to parameterize. Accordingly, in the present research, the human model is limited to the head and trunk of a human body riding inside a vehicle. This human body dynamics model is composed of an internal model and an external model. The internal model incorporates a motion control model. The internal model, which is composed of an inverse model and a forward model, generates commands to control body motion, while the external model simulates the actual body motion. Then, in order to identify the parameters of the motion control model, the motion of maintaining posture is measured using a simple experimental device that can simulate horizontal acceleration applied to a subject. In order to demonstrate the effectiveness of the proposed human body dynamics model, a simple human dummy model (which simulates the experimental model used for experiments such as automobile collisions) that consists of only a spring and a damper was created. Comparing this dummy model with the human body dynamics model reveals that the human body dynamics model can simulate details of human motion that the simple dummy model cannot.</p>

<p>In this paper, we discuss the motion of a tethered system during winding a tether in microgravity. When the tether is being wound, it comes into strong contact with the feeding section of the system. Accordingly, both are expected to undergo complex motion as they interact with each other. We have therefore carried out both a numerical and an experimental study to clarify the motion of such a system using a mobility device using the tether named TSMD proposed by us as an example. We first developed a numerical model composed of three rigid bodies and a flexible body that serves as the tether. To take into account the large deformation and displacement of the tether, the flexible body was modeled using the absolute nodal coordinate formulation. It is important for the tethered system to consider the motion of winding the tether. In this model, the flexible body which is pulled into the rigid bodies contacting with its feeding section is formulated. This numerical model allows the interaction between the rigid and flexible bodies to be investigated as the tether is being wound. To verify the numerical results obtained using the proposed model, experiments were performed for a tethered system in a microgravity environment, where the tether was being wound. Good agreement was found between the numerical and experimental results. The tension in the tether was shown to influence the motion of the rigid bodies when the tether was under strain, and the rigid bodies were moved by an inertial force when the tether had a deflection. It was also found that the tension in the tether could be controlled by the winding speed, so allowing rotation of the rigid bodies to be suppressed.</p>

<p>The purpose of the present study is to propose an analytical model for tires and to examine the mechanism of polygonal wear based on numerical results obtained using this model. Polygonal wear is an abnormal phenomenon that occurs in time-delay systems. A number of studies on polygonal wear of tires have been conducted. However, investigation of the growth process of polygonal wear is not sufficient because the surface shape of the tire changes constantly with wear. Therefore, a numerical simulation model that can examine transient behavior is necessary. In the present paper, we propose a tire model composed of mass points. The wheel is simulated as a rigid body, and the tire tread as a number of masses positioned around the circumference of the wheel. The tire masses are connected to points around the circumference of the wheel by rotational and translational Voigt elements, and the tire masses are connected by rotational and translational Voigt elements. The contact between the tire and the road surface is assumed to be elastic. Numerical simulations are carried out under several conditions using the proposed model. The distributions of the stress and the slip ratio are obtained, and the wear shapes of tires are examined using the proposed model. We show that polygonal wear occurs under certain conditions. Finally, a tire model that expresses these basic characteristics is proposed and its usefulness is demonstrated.</p>

<p>Accurate modeling of a flexible body must take into account motion with large deformation, rotation and time-varying length. Numerical analysis, employing a variable-domain finite element model and the absolute nodal coordinate formulation, has been used to model such motion. Unfortunately, the calculation cost of this approach is very high due to the use of nonlinear finite elements with time-varying length. In order to the reduce calculation cost without sacrificing accuracy, we apply the multiple timescale method to the equation of motion. We define three timescales for the multiple timescale method, and refer to them as Cases 1, 2, and 3. Case 1 is based on longitudinal vibration, Case 2 is based on lateral vibration, and Case 3 is based on motion of the rigid pendulum. We compare these three sets of timescales and evaluate the analysis range for each of the sets. The numerical results show that Case 1 delivers the best accuracy when the velocity of the time-varying length is high, whereas Case 2 delivers the quickest calculation time.</p>

Wire rope and pulley devices are used in various machines. To use these machines more safely, it is necessary to analyze the behavior of the contact between them. In this study, we represent a wire rope by a numerical model of a flexible body. This flexible body is expressed in the absolute nodal coordinate formulation (ANCF), and the model includes the normal contact force and the frictional force between the wire rope and the pulley. The normal contact force is expressed by spring-damper elements, and the frictional force is expressed by the Quinn method. The advantage of the Quinn method is that it reduces the numerical problems associated with the discontinuities in Coulomb friction at zero velocity. By using the numerical model, simulations are performed, and the validity of this model is shown by comparing its results with those of an experiment. Through numerical simulations, we confirm the proposed model for the contact between the wire rope and the pulley. We confirmed that the behavior of the wire rope changes when both the bending elastic modulus of the wire rope and the mass added to each end of the wire rope are changed.

Recently, the demand for improvement of passenger comfort in automobiles has increased. An automobile does not have a large amount of volume to physical space, and space planning of the seat arrangement greatly influences passenger comfort. The seat arrangement changes the visual environment of the passenger. Previously, the authors proposed a technique to evaluate comfort through the seat arrangement by using the passenger's space and vision. In this evaluation technique, vision is recognized as volume. A useful seat arrangement with a rotated seat utilizes the effect of vision for improving passenger comfort. In this paper, a sensory evaluation and a biomedical measurement are performed. Therefore, the effectiveness of a seat arrangement with rotated seats is shown to improve passenger comfort.

With the increasing use of the International Space Station, humans have more opportunities to work in space. In space, a mobility device that operates efficiently is needed. But, some problems must be solved. First, the human body is suspended without the force of gravity. Second, the air cannot be polluted in the closed space of the Space Station. Thus, an air-polluting mobility device, such as a device with a gas jet using a thruster is objectionable. In this research, a mobility system called the "Tether Space Mobility Device" (TSMD) is proposed. In general, the tether is a cable or a wire rope. The tethers are expected to shift the orbit of another object without using a thruster and to move robots in space. TSMD has a mechanism that enables the tether to move an object. In this study, the TSMD model is composed of two rigid bodies and one flexible body that can express motion with large deformation and large displacement. Several modeling of TSMD is performed. An influence on motion and control of TSMD is discussed. Copyright (c) 2010 by JSME.

Recently, increasing numbers of very small-sized automobiles like a personal vehicle have been developed. As the mass of such small-sized vehicles is often comparable to that of their drivers, the coupling motions between them is increasing in comparison with traditional vehicle types. Therefore, when developing small-sized vehicles, it is necessary to give ample consideration to the dynamics of the human body riding inside them. In this research, a model of a human body inside a small-sized personal vehicle is proposed. However, attempting to implement a whole body model would necessitate dealing with multiple degrees of freedom and give rise to distracting phenomena. Furthermore, the influences of human motion are uncertain and difficult to set into parameters. Accordingly, in this research, the human model is limited to the head and trunk of a human body riding inside a vehicle, and numerical simulations were used to investigate conditions that exist when lateral acceleration is applied. Additionally, the influence of human behavior parameters is considered.

With the increasing use of the International Space Station, humans have more opportunities to work in space. In space, a mobility device that operates efficiently is needed. In this research, a mobility system called the "Tether Space Mobility Device" (hereinafter called TSMD) is proposed. In general, the tether is a cable or a wire rope. The proposed system has a mechanism that uses the tether for enabling a human to move to a target point. However, this system has the problem that the center of mass of the human and that of the TSMD are different from the direct line to the target point. Then, the human is rotated by the tension of the tether. Thus, to use this device safely, rotation of the human body must be controlled. For this reason, a numerical simulation model is proposed. The numerical model is composed of three rigid bodies and one flexible body that can express motion with large deformation and large displacement. In this model, winding motion of the tether can be expressed. An experiment of the TSMD was designed to move under two-dimensional micro-gravity. The experiment confirmed the validity of the numerical simulation model. The possibility of the mobility device using the tether and the influence of the control system are discussed.

In this study, we construct an evaluation system for the muscular activity of the lower limbs when a human pedals an electric power-assisted bicycle. The evaluation system is composed of an electric power-assisted bicycle, a numerical simulator and a motion capture system. The electric power-assisted bicycle in this study has a pedal with an attached force sensor. The numerical simulator for pedaling motion is a musculoskeletal model of a human. The motion capture system measures the joint angles of the lower limb. We examine the influence of the electric power-assisted force on each muscle of the human trunk and legs. First, an experiment of pedaling motion is performed. Then, the musculoskeletal model is calculated by using the experimental data. We discuss the influence on each muscle by electric power-assist. It is found that the muscular activity is decreased by the electric power-assist bicycle, and the reduction of the muscular force required for pedaling motion was quantitatively shown for every muscle.

In this research, the dynamic characteristics of bicycles are investigated focusing on small wheels. Multibody dynamics is used for the formulation of the bicycle model. The effects of the parameters of tire diameter and head angle are examined by focusing on a small wheel bicycle. The straight-ahead stability and upstanding stability are evaluated at each parameter. The results show the tendency of stability at each parameter and the influential parameter to the small wheel bicycle is found. The driving experiment using the small wheel bicycles with variable head angle is evaluated by the subjects. It is confirmed that varying head angle increases the stability of the small wheel bicycle. The results are corresponding with the simulation results and it is shown that the simulation captures the tendency of the stability and expresses the characteristic of the small wheel bicycle. Furthermore, the simulation using the effective parameters for small wheel bicycle was shown at the end. It showed the possibility of increase of the stability of a small wheel bicycle.

A spaceflight validation of bare electrodynamic tape tether technology was conducted. A S520-25 sounding rocket was launched successfully at 05:00am on 31 August 2010 and successfully deployed 132.6m of tape tether over 120 seconds in a ballistic flight. The electrodynamic performance of the bare tape tether employed as an atmospheric probe was measured. Flight results are introduced through the present progressive report of the demonstration and the results of flight experiment are examined as the premier report of the international cooperation between Japan, Europe, USA and Australia. Future plans for maturing space tether technology, which will play an important role for future space activities, are also discussed. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

This paper deals with the motion of a submerged tethered system subject to large deformations and displacements. A tethered system usually employs a cable or wire rope to tether an attached piece of equipment to the ground or to a vehicle, e.g., a remotely operated vehicle (ROV) in the sea. The motion of a tether was modeled using the Absolute Nodal Coordinate Formulation in which absolute slope of elements are defined as nodal coordinates. Herein, this formulation is adapted to account for hydrodynamic drag, buoyancy and added mass. By using the slope coordinates, the hydrodynamic drag acting on the curved shape of the deformed elements can be accurately calculated. Three kinds of experiment were conducted into the fundamental motion of the submerged tether when subject to large deformations and displacements. The numerical results from the proposed model agreed well with the experimental results.

In this study, the vertical jump is examined as a basic study of jump. And we examine the influence of each muscle of the human body in vertical jump. The human body is modeled as four rigid bodies and analyzed in detail by using the model that includes muscles of the leg. In this research, the mechanism of jump is discussed by using numerical model to which the concept of multibody dynamics and biomechanics is adapted. We performed the experiment of jump and observe the feature behavior of vertical jump. Experimental results show that the angle of each body becomes vertical for ground and the change of the foot angle is small. Then we perform the numerical simulation referring to this experimental data. In order to reduce the amount of calculation, we calculate muscular activity level by correlating it with fewer parameters. We discuss which muscles are necessary for vertical jump. It is found that vasti exerts the biggest power and gluteus maximus has the highest state of normalized muscle activity.

One of the applications of tether system is in the field of satellite technology, where the mother ship and satellite equipment are connected with a cable. In order to grasp the motion of this kind of tether system in detail, the tether can be effectively modeled as flexible body and dealt by multibody dynamic analysis. In the analysis and modeling of flexible body of tether, large deformation and large displacement must be considered. Multibody dynamic analysis such as Absolute Nodal Coordinate Formulation with an introduction of the effect of damping force formulation can be used to describe the motion behavior of a flexible body. In this study, a parameter identification technique via an experimental approach is proposed in order to verify the modeling method. An example of swing-up control using the genetic algorithm control approach is performed through simulation and experiment. The validity of the model and availability of motion control based on multibody dynamics analysis are shown by comparison between numerical simulation and experiment. © 2010, Versita. All rights reserved.

Sensory evaluation of ride on a railway vehicle is performed based on international standards such as ISO2631. However, it is expected that this evaluation would be insufficient because of the development of technologies of a railway vehicle. The evaluation for view and sound from the viewpoint of ergonomic and psychological perspectives might be needed as well as traditional evaluations in the future. Authors focused on the relation between view and motion of the railway vehicle. The experiment in sensory evaluation of ride on a railway vehicle using a motion simulator was performed. In this paper, the way and results of the experiment and the environmental psychological analysis are described.

Research on multibody dynamics in engineering and science is developing at a high pace in Japan and in the world. These activities provide efficient and powerful solution tools for solving complicated dynamic problems with control via theoretical or high performance in-house and/or general purpose computer programs in academic and industrial fields. Thus, advancement of research is an important index for measuring competitiveness in education and industry in terms of &ldquo;dynamics and control&rdquo;. The aim of this paper is to present an overview of the various research activities of multibody dynamics in Japan.

Recently, the personal mobility vehicle (PMV), a vehicle suitable for personal use, has been developed. It moves at low speed and is sufficiently small that it can be ridden in pedestrian space. This vehicle is expected to be a new method of transportation that is practical and environmentally friendly. As one form of PMV, the authors propose a twowheel vehicle with two modes: a two-wheel steering and two-wheel driving bicycle mode and a parallel two-wheel mode. This vehicle has four electric motors, two for driving and two for steering, and one generator connected to the pedals. In the bicycle mode, the rider rotates the pedals to generate electric power, and the motors in the wheels produce torque using the generated energy. The front and rear wheels are steered by the electric motor according to the angle of the handle. Therefore, this bicycle is controlled by a steer-by-wire and a drive-by-wire system. In the parallel two-wheel mode, the vehicle is stabilized according to the theory of the inverted pendulum. In this paper, we focus on the bicycle mode and analyze its stability. Stabilizing the bicycle is not easy since the proposed vehicle has tires with small diameters and the traveling speed is assumed to be low. It is known that the stability of bicycles is tuned by adjusting the bicycle parameters and changing the rear steer angle. However, since we aim to use the vehicle in a narrow walking space at low speed, such conventional methods are not always suitable. The authors propose the stabilization of the bicycle using driving forces and design a controller using linear-quadratic control theory. The results of the numerical simulations show the proposed method is effective in stabilizing the bicycle.

本研究は，ドライバ操舵行動に着目し，個々のドライバ特性を把握するための基礎検討として，技能差に着目し，クランク走行やハンドリング路の走行などから，ドライバの操舵行動特性に関して，車両特性や走行環境に対する適用力を考慮した分類を行うための評価法の考案を行う．

In this paper, we discuss the difference of driver's characteristics. Nowadays, driver assist systems are developed. It is very important to develop an effective driver assist system. We focus our attention on steering maneuver. We performed the experiment using the actual car. In the experiment, we measured not only a vehicle state but also the force acting on steering wheel and the motion of driver's arm. The six-degree-force transducer on steering wheel is newly developed. The motion capture system using supersonic wave is adapted. We found three kinds of characteristic maneuvers. First, it is the difference of steer angle. A beginner driver steers with high frequency. On the other hand, an expert driver steers without high frequency. Next, we investigated the location of grabs on steering wheel of each subjects. The beginner grabs particular place of steering wheel. They don't cross their arms during cornering. Finally, we found the difference of characteristic about pushing and pulling force on steering wheel.

This paper is concerned with a quantitative classification based on driver characteristics of steering maneuvers. The evaluation indexes that can be used for quantifying differences of driver groups such as experimental driver or beginner driver are proposed. The experiment using actual car is performed in order to classify the driver's steering maneuvers. The crank course test and handling course test are performed in order to classify the driver's steering maneuvers. Experimental results show the difference of driver characteristics of steering maneuvers on various courses.

This paper is concerned with a quantitative classification based on driver characteristics of steering maneuvers. The evaluation indexes that can be used for quantifying differences of driver groups such as experimental driver or beginner driver are proposed. The slalom test and the crank course test are performed in order to classify the driver's steering maneuvers using the driving simulator that has 6 degrees of freedom motion base and turntable. It is demonstrated in this investigation that the method can be effectively used for classify an important characteristics of driver's steering maneuvers. The proposed evaluation indexes are verified by experimental test with 24 subjects.

In the present paper, the motion of a tethered system with large deformation and large displacement is discussed. In general, a tether is a cable or a wire rope, and a tethered system consists of a tether and the equipment attached to the tether. A tethered subsatellite in space is an example of a tethered system. In the present study, a tethered system consisting of a very flexible body (the tether) and a rigid body at one end is considered as the analytical model. A flexible body in planer motion is described using the Absolute Nodal Coordinate Formulation. Using this formulation, the motion of a flexible body with large deformation, rotation and translation can be expressed with the accuracy of rigid body motion. The combination of the flexible body motion and the rigid body motion is performed, and their interaction is discussed.<br>Experiments are performed to investigate the fundamental motion of the tethered system and to evaluate the validity of the numerical formulation. Experiments were conducted using a steel tether and a rubber tether in gravity space. In addition, an experiment of the motion of the tethered system with a rigid body in microgravity space was conducted.

This study is focused on dynamic behavior of a small size tire. A small size tire is used for personal mobility, for example, a bicycle, a wheelchair and so on. We made experiments device for vertical behavior on bump for small size tire. We performed experiments to investigate the vertical behavior on bump for small size tire. We measured the force, the acceleration acting on tire and the vertical displacement of tire.