This study is aimed for the construction of balance model of human body during standing on frontal plane. Generally, it is difficult to build the balance model because the sensory feedback system of human body is unknown. Therefore we suggest a stable balance model describing result from frequency response test. In the test, phase delay occurred in low frequency range less than 0.2 Hz. We hypothesized that this delay generated by velocity feedback of support surface through visual sensing. Based on this hypothesis, we built a model and estimated feedback parameters using least square method. Then a reasonable and stable model describing the peculiarity of frequency response diagram in low frequency range was obtained. To verify the validity of the identified parameters, we confirmed that the delay time almost accorded with the typical time.

It is important to quantitatively evaluate the usability of a product based on biomechanical load to a human. In general, force sensors and electromyography are used to evaluate mechanical load to the upper limb. However, this method requires embedding force sensor in the product. The purpose of this study was estimating physical load without the force sensor. First, the myoelectric potential and the joint angle were measured when gripping a fixed pipe and applying force. Then, the joint moment and muscle force were calculated based on a musculo-skeletal model. The mechanical relationship between measured hand force and smoothed electromyography was identified as a process of calibration. As an estimation process, reaction force on the hand was estimated from the calibration results.

We developed a new numerical model toward simulation of human-body movement in tsunamis. A combination of a multiphase fluid solution: CIP-CUP method and a method to represent a human body: link segment model enabled human-fluid coupled analyses. We evaluated the new model by comparing results with some flume experiments. Here, an isolated wave traveled in a large flume and generated a whirlpool behind blocks laid in the downstream sector. At the same time, a manikin was laid on the blocks and caught in the whirlpool. Our new model represented the body’s movement precisely there. Next, we applied some additional buoyancy to the human body model toward evaluation of performance of life jackets. Consequently, there was a threshold of life-jacket buoyancy which is required to keep a human body floating. Besides, we showed that computation of unsteady flow is necessary to evaluate performance of life jackets in tsunamis. Especially behind some structures like the experiment, the amount of buoyancy required to the life jackets can be evaluated by comparing it with center-seeking pressure of the whirlpool mainly applied to the legs.

In the work of removing soil and sand after sediment disaster, there are scenes that require heavy physical work rather than using machines. In general scooping work, lifting of earth and sand while bending over provides a load on the waist, and it is difficult to work for a long time. In this research, we decided to use only human power for situations where machinery cannot be utilized in sediment removal work, pay attention to work posture in order to reduce physical load, and furthermore focus on how to use the musculoskeletal system to make maximum use of human strength. We decided to reduce the load on the waist by maintaining the standing by the wearable tool. Using the combination of joint torque and joint reaction force with reference to traditional Japanese martial arts, the force is exerted and transmitted effectively. Additionally the force pushing in the vertical direction of the arm and the pedaling force are used with using self-weight. Then, we devised a novel tool applying such ideas to each work operation such as scooping, inserting, scooping, lifting and dumping. The tool corresponds to a height of 150-195 cm, the lift weight and sand weight was 5 kg or more, and the lift height fulfilled 600 mm. Some experiments indicated the potential that the operator maintained the standing position when the tool was used, and the force transmitted effectively due to the joint torque at the time of extension of the arm during gathering, scooping and lifting.

Walking is one of the most important physical activities in daily life. To prevent walking difficulty by muscle weakness, it is important to exercise to maintain muscular strength and balance ability. Authors found there were few tools which had two functions of exercising and assistant in walking and also which could be utilized in daily life. In this research authors focused on a stock walking’s feature that can achieve high exercise effect and load reduction, and devised an exercising tool combining stock with wire towing mechanism to support raising lower limb. The walking tool is composed of wire towing mechanism, walking cycle measuring device and pole on right and left side. Authors use floating gear, which automatically switches the engaging and releasing of gear by the tangential force generated to itself, and design a mechanism that switches winding and withdrawing of the left and right wires according to the rotation direction of a single motor. Authors also developed walking cycle measuring device to detect initial swing to medium swing and control the timing of assist. Finally, performance test indicated that auxiliary effect and property of timing raising the lower limb.

Ten of valley municipalities are managing the Tamagawa cycle path.The video camera was installed in the loading motorcycle in the Tamagawa cycle path and 640×480 Traffic was recorded with 30fps. The mileage was 457km on the total the 32nd the measurement days. Moreover, average per hour was 13.8 km/h. at 52.4km in the total length. It was assumed that the bicycle and the person were a left traffic rules in Kawasaki City, and other municipalities were also similar. On the other hand, the pedestrian died of the collision of the bicycle and the pedestrian who had got up in June, 2009 in Fuchu city. The width of the cycle path was expanded from 2.4m to 3 and 0m and the person changed to right traffic in Fuchu city as a result. It was 172. average of the pedestrian and the runner to the amount of traffic of one hour in total the traffic of 122 people on the average and bicycles Because it was width 2.4m or 1.8m of the cycle path, consideration of the investigation of actual conditions of bicycling and walking about the bicycle was done. Running with the deceleration belt by the bump of 10mm in height had the danger of Otoclma and the bicycle breakdown and it started decoupling the cyclist of about 15% in the dancing posture.

In cycling motion, pedaling forces are important to evaluate pedaling performance. Especially, improvement of pedaling efficiency requires the three dimensional forces and the transition of the contact position on a pedal in detail. For this, we developed a novel pedaling sensor system. The crank is the detector of the sensor to measure three dimensional forces between the pedal and the cleat. Also, the sensor can obtain the contact position just on a pedal shaft using multiple strain gages. As a result of the calibration, the sensor had enough linearity for static loads. Moreover, a motion analysis for five subjects showed that the pedaling forces and the contact position changed along the crank rotation. Therefore, our sensor system can show mechanical pedaling condition in detail, and it should be useful for cycling motion analysis.

By Man-powered Robotics, a system controls motion intelligently using power served by a user. In previous works about man-machine cooperation, the user recognizes the environment and judges/decides motions of the machine, and the machine controls the motion based on local sensor-feedbacks. On the other hand, the system based on the man-powered robotics, is opposite. To execute simple tasks, such as locomotion, manipulation and so on, judges and decisions of the machine is better than the user, since computational hardware and algorithms has proceeded rapidly. The user only serves power: man-power. A smart-mobility, et. al., which are applied man-powered robotics, realizes not only intelligent motions, such as risk-avoidance, tracking a path, following an object and so on, but also safety according to the judgement of the user, who can stop supplying power of the system, health enhancement of the user and the protection of the environment. In this paper, focusing on the power supplying by pedaling motion of the user, an estimation method energy consumption of the user, based on a dynamical model, is proposed. In previous works, only energy consumption by the system was measured and discussed. By the proposed method, energy consumption on the human-structure is estimated. Experimental results show validity of the proposed method.

There are many studies for bicycles and pedaling; however, most of the pedaling studies are conducted based on experiments, such as inverse dynamics method. The purpose of this study is to develop a forward dynamics model of pedaling to generate pedaling motion on computer without experimental data. The proposed model was used proportional-derivative (PD) control for joint driving torque and the referred joint angles were optimized by genetic algorithms. Cost function of optimization was defined as minimum of the muscle load and differences between the objective crank angular velocity and that of the simulation. Joint torques and pedal forces was obtained from the simulation and was compared with the actual experimental data. Simulation results were tended to vibrate compared with the actual experimental data. In addition, magnitude of the cost function was investigated when changing saddle height as 0.700, 0.725, 0.750, 0.775 and 0.800 [m]. As a result, the cost function decreased as the saddle height became higher, and the cos function was minimum when the saddle height was 0.775[m].

In this study, pedaling motion was analyzed using a simulation model of a human-bicycle system. Pedaling motion was expressed by human body’s joint motion. In simulation, the joint motion was determined to satisfy geometric condition. And the pedaling motion was performed by PID control of the human body’s joints. First, with respect to the PID control, a target motion at the knee joint was changed to adjust knee joint power. As a result, it was confirmed that the simulator can reproduce results of a literature. From these results, it was considered that a difference in the way of pedaling can be expressed by changing the target joint motion, although there was a delay in the PID control. Next, another simulation considering the influence of a pelvis movement was conducted. It was assumed that the hip joint position draws an elliptical orbit in the sagittal plane. The rotation center of the pelvis was a middle point of the hip joints. The pelvis moved by PID control of the human body’s joints. As a result, it was suggested that pelvis movement and upper body movement were effective in reducing the knee joint power.

Generally, elderly people tend to be in slow motion and suffer from delayed reaction time; moreover, few are familiar with mechanical or electronic controls. Their behavioral symptoms are caused by physical deterioration at both cognitive and sensory levels. Therefore, when designing and developing a standing-up and sitting-down assist device for the elderly, an easy-to-learn and simple-to-use interface system capable of responding to complex and diverse environments is of particular importance. Next, the device is expected to employ in various kinds of public places. More than anything, protection of personal information is one of its fundamental requirements. For this purpose, our paper tackles a problem of designing a user interface between an elderly user and the assist device for standing and sitting behaviors. As an essential functionality, the paper introduce a novel distance-based interface scheme, allowing to recognize these 3-D behaviors and generate the device’s motions corresponding to the recognized behaviors without requiring any additional user inputs.

This paper introduces a new model composed of two computational functions describing standing-and-sitting behaviors toward the development of a standing/sitting assist robot. In this model, the one function estimates the locations of hip joints by employing relative distances. The other linearizes the behavioral trajectories estimated by the first function. Specifically, through the linearization, the standing and sitting behaviors are generalized as a well-known sigmoid function. As a result, the proposed model allows to obtain the geometrically linearized representation of the standing and sitting behaviors. This paper details the description of the proposed model. And, through extensive experiments, the effectiveness of the model is verified.

Elderly people and persons with disabilities are likey to be obstructed activities in daily life by deteriorating of sit-to-stand ability. The population of elderly people are increasing rapidly in Japan, and the support of sit-to-stand is hard work for caregivers, who are likely suffering back pain. The purpose of this study is to develop a sit-to-stand assist chair, which assists sit-to-stand movement by lifting a seat. In this report, we focus on the trajectory of a buttock in sit-to-stand, and report results of experiments on three foot height conditions. The buttock's trajectories had a S shape on the high foot height, which was the hardest condition, and was changed to an arc shape on the low foot height, which was the easiest in this study. In the case that the buttock's trajectory gets close to the arc shape, the hardness of the standing motion might be reduced. The velocity of buttock movement varies with the person's height.

The current increase in health awareness has led to greater attention to exercise. However, the growing number of competitors in various sports has caused a concomitant increase in the number of injuries during matches. After an injury, an immediate return to competition is difficult. Thus, there is a need to develop rehabilitation devices that can provide an environment in which the amateur athletes can safely be rehabilitated while determining his or her own state of recovery even if no athletic trainer is available. Conventional rehabilitation devices have emphasized recovery of cardiopulmonary function or the function of specific joints, with little to no development of devices aiming for an early return to competition.

In the previous work, we aimed to develop a device which reproduces the motion of the leg during running by using a planar 6-link mechanism and reduces the load on the leg. Furthermore, we focused on the arm swinging effect during running, and tried to develop a device that can acquire linkage properties of the body by adding arm motion during running using a slider crank mechanism. As a result of experiments to measure motion, it was confirmed that the arm reproducibility of the arm swing is insufficient in the arm mechanism of the device.

In this research, we try to improve the usefulness by adding a new function that enables tracking of the locus of the arm. Further, in order to evaluate the utility as a rehabilitation device in a produced device, experiment of muscle action potential is conducted.

This paper deals with the estimation of gait velocity and distance by the velocity compensation using adaptive Kalman filter. This method compensates gait velocity by using the velocities calculated by forward time integration and backward time integration. We conducted the measurement experiment the 5m gait test and the 10m gait test. The motion capture was used to the experiment in the 5m gait test. The results for gait distance in the 5m gait test indicated the results by proposed method is corresponding to that by the motion capture. Furthermore, the proposed method indicated the effective results in the 10m gait test. This method can be used for the gait analysis using the wearable force plates.

In this study, we evaluated the running motion and the physical characteristics of body under the various floor condition. We measured, firstly, the running motion under three floor conditions, i.e., the rigid floor, one mat on the floor and two mats on the floor. From the measurement results, it was confirmed that the running motion did not change significantly due to the change of floor condition. Next, we simulated the running motion based on the multi-degree-of-freedom model whose parameters were identified such as to agree with the measured running motion. As the simulation results, it was shown that the rigidity of the hip joint became bigger in the case of running on one mat or two mats compared with the case of rigid floor.

Using multiple cameras such as motion capture systems with force platforms is a classical and popular method for gait analysis. Calculating a driving force of each joint by solving equation of motion on each body segment is common sense. The ground reaction force acting on the force platform is the requirement for this calculation. However, it is difficult to measure natural walking, because the subjects have to adjust the step length to place on the force platform. In addition, for the measuring of multiple steps, it requires large space. This study proposes two rigid body linked segment models to calculate the driving force of each joint and ground reaction force without force platform. For this solution, the authors solved the equation of the motion from the terminal segment toward the stance side of the foot. In order to validate the accuracy of the two different models, the authors compared their kinematic parameters, such as the joint reaction forces with those of classic model’s on the lower limbs. The results showed that two proposed models could be estimated the ground reaction force and the joint force with high accuracy. In addition, using the center of pressure from force platform could also estimate the joint torque with high accuracy. These results suggest that we can estimate the joint force, ground reaction force and joint torque with high accuracy, if provided by the center of pressure.

Recently, climbing has become more and more popular, while the accidents of falling down at descending a mountain remain a huge problem. The main reason of these accidents is considered muscle fatigue due to the load on the legs by stretching leg’s muscle and absorption of landing impact. This kind of muscle activity is called as eccentric contraction, which often causes muscle damage. As a support method of walking in descending a mountain without any power supply, authors devised the idea that reducing the knee flexion load by braking flexion and landing impact by making the time longer to flex. Based on this idea, we developed the novel device containing the brake mechanism with a hydraulic rotary damper suitable for continuous motion such as a walking and a floating gear having unidirectionality. After that, the result of performance test demonstrated that the device exerts braking force enough to brake the human knee joint torque.

The aim of the study was to investigate the effects of different shoulder bag conditions on swing motion of the bag, wobbling motion of human body, load of the shoulder carrying bag and muscle activity of the upper trapezius, lower trapezius and erector spinae during walking. Ten male graduate and undergraduate students walked on a treadmill for about 30 seconds at 4.2 km/h during six conditions; no bag, small size shoulder bag with contralateral shoulder strap, normal size shoulder bag with contralateral shoulder strap, tote bag with ipsilateral shoulder strap, carrying 1 strap shoulder bag ipsilaterally and contralaterally, each containing 10% body weight. The coefficient of variance of vertical motion of the bag and human body, average value of the load on the shoulder, maximum value of moment about the center of gravity of the upper body and %MVC of electromyography for each muscle were compared among bag conditions. Results showed that the effects of different shoulder bag conditions made swing motion of the bag reduced when the size is bigger and the bag is carried contralaterally. And there were no significant differences in wobbling motion of human body. Compared two bags, carrying contralaterally made the change of the distance. Compared three types, the sizes were smaller and smaller, the load was bigger and bigger. But the result couldn't show the types and how to carry effect the load. Compared all moments, the moment was the minimum on the sagittal plane despite the types. Compared all %EMG, the most active muscle is the upper trapezius despite the types.

Ethylene Vinyl Acetate (EVA) foam with low fabrication cost and good formability has been widely applied to shoe midsole. Considering the fatigue reduction of runner, it is necessary to reduce the shoe weight and the midsole is the most important target. On the other hand, shoe weight reduction can lead the sustainability in shoe industry. In this study, as a way to weight reduction of foam material while maintaining mechanical functions for shoe midsole, fiber compounding to foam material was investigated. It was clarified that fiber composite foam has higher plateau stress and strain energy compared with conventional foam material at any density range. The reason for increasing plateau stress seems to be shared compressive load by composited fiber. Furthermore, it was concluded that aramid fiber was more suitable than carbon fiber for fiber composite foam as shoe midsole. The fiber length observation was indicated that carbon fiber broke during compounding process.

Running is one of the popular sports in Japan. But it is sometimes difficult for a lot of runners to continue it due to running-induced injuries. To prevent such injuries, running shoes have two different functions such as shock absorption and foot stabilization in the midsole, which contradict each other unfortunately. Then the effects of midsole’s structure and material on these functions have been investigated intensively. But with respect to gel materials recently used in the midsole, their functional effects have yet to be studied sufficiently. Then we studied how gel stiffness and arrangement in the midsole affect the afore-mentioned functions, by means of a motion analysis and a sensory test. Shock absorption and foot stabilization were evaluated in terms of midsole deformation as well as plantar pressure and the eversion computed from the relative orientation between the shoes and the thigh, respectively. Experiments using five subjects, all long-distance runners belonging to a track and field club, demonstrated that shock absorption could be improved by locating a low- stiffness gel in the lateral midsole, while stability could be improved by locating a low-stiffness gel and a high-stiffness gel in the lateral and medial midsole, respectively. Sensory test revealed that softness was affected by the elasticity of gel material located in lateral midsole as well as the deformation of the lateral midsole. All these findings suggested that the two functions of the midsole could be controlled objectively by the stiffness and midsole arrangement of gel material.

In ball game sports, quickness is one of the most important abilities for players. Various methods to improve quickness are proposed in training scenes, and several studies which focused on athletes’ posture with taking one step motion supposed to quickness have been reported. The purpose of this study is to get basic knowledge to design shoe structure producing quickness required in ball game sports. Two females and one male participated in this study and a target motion is a sprint movement in the front direction from the standing position under five different foot conditions (Normal, Plate Toe, Plate Heel, Tow down and Toe up). Ground reaction force and passing times on 3m and 5m were measured, and influences of the conditions on the quickness performance were investigated from viewpoints of GRF and COP trajectories. The results are as follows: (1) moving distance of COP and kicking time have negative correlation and (2) propulsion impulse in kicking time and transit time on 3m and 5m have negative correlation.

In long distance running, increase of injury risk has been reported due to change of running form associated with muscle fatigue. In the designing process of running shoes, it is necessary to clarify the required functions considered these changes. The purpose of this study is to design functional running shoes to adapt long distance running based on the motion analyses. Ground reaction force and 3 dimensional motion data during long distance running were measured by using a force plate and a motion capture system, respectively. In comparison of fresh and fatigued conditions, higher loading rate (LR) and larger heel eversion angle (β)were confirmed under fatigued condition. This result implies that injury risk becomes higher in fatigued condition. In other words, importance of cushioning and stability are getting higher with increase of running distance. Based on the obtained results, new prototyped shoes with adaptive devices were practically manufactured and the validities were checked.

There is a growing need for a gait analysis system that can be used for personal use at low cost and for a long time. Also, even in sports, there is a great need for a system that can be used by the player at all times during practice of daily running and that can perform motion analysis without a force plate. Accordingly, we aim to develop a sensing system to estimate the floor reaction force from the acceleration of the body without using a force plate. Firstly, we measured the accelerations of 15 parts of the body during walking with a motion capture system, and confirmed whether the floor reaction force can be estimated from inertial and gravity force. Next, we tried to decrease the number of sensing point by camera and examined the accuracy of the estimated ground reaction force, and confirmed there is no big difference between the acceleration measured by the camera and by the inertial sensor. Finally, frequency response analysis for the measured acceleration during walking was carried out and the relationship between the motion of the trunk and other parts were clarified.

In order to assess living space for assisting stable walks by elderly people, this paper proposed an evaluation index for single support object which is calculated from four fundamental measures expressing capability of balance recovery corresponding to the support object, derived from the directionality of generative force by human’s upper extremity and the directionality of reaction force corresponding to the surface shapes of objects. Experiments were carried out to (1) obtain the parameters necessary to calculate the fundamental measures and (2) carry out organoleptic evaluation of the support objects. Compared to the results obtained in these experiments (1) and (2), effects of the indices were discussed, and an effective index among the four for evaluating the effect of the support objects was clarified and proposed. Assessment of sample support object using the proposed index was shown as a demonstration.

The purpose of this study is to investigate the relationship between runners' characteristics and their foot behaviors during stance phase in running. We collected foot motion data from 450 recreational runners by using a newly developed 3-D motion analysis system based on AR technology, and analyzed the data from standpoints of gender, running experience, and bilateral differences of foot behaviors. Therefore it was clarified that 25%, 32%, and 42% of runners were categorized into underpronators, neutral pronators and overpronators, respectively. There was no significant difference in pronation types between male and female runners but experienced runners tended to have shorter contact time with small contact angle of foot planter flexion, resulting in lesser overpronation ratio. About 20% of the participants showed bilateral difference in their pronation types. Judging from an extra experiment, it was found that ankle supporter was effective to curb foot overpronation and decrease bilateral difference.

It is known that a phenomenon in which a cardiac rhythm synchronizes with a locomotor rhythm occurs during running. At this synchronization, the cardiac rhythm rate increases in proportion to the locomotor rhythm intensity, and when it approaches the limit locomotor rhythm intensity, an unstable phenomenon of the cardiac rhythm increases becomes sometimes observed. This instability of the cardiac rhythm causes lower exercise efficiency, so it is necessary to keep the stable cardiac rhythm up to the faster locomotor rhythm as far as possible. Therefore, we obtain a frequency domain model with a locomotor rhythm added to the Van der Pol equation that expresses the cardiac rhythm, and propose a reset controller to suppress the instability of the cardiac rhythm by using the descriptive function method for this model.

We control our posture by using in-shoe insole. However, The effect of different heights of arch support in-shoe insole on foot and lower extremity is unclear. The aim of this study is to examine the relationship between heights of arch support in-shoe insole and foot posture and muscle activity of lower extremity. 10 middle foot arch type males were recruited for this study. Foot kinematic variables, plantar force and muscle activity of lower extremity (Gastrocnemius medialis (GM), Tibialis anterior (TA) and Flexor hallucis longus (FHL)) were collected during static standing, walking and running on a treadmill inserting 3 types of foot arch support insole (low, mid, high) or not inserting insole, respectively. The results show that there were no significant effect on planar force, ankle supi-pronation angle range of motion and muscle activity of lower extremity. In conclusion, there was no large effect of different heights of arch support in-shoe insole on plantar force, foot kinematics and muscle activity of lower extremity.

In this study, we developed a novel sensing system for the planta while walking on any surface and in any condition. A plantar image is reflected at the reflecting surface and photographed by a camera attached to a shoe. The obtained visual information of plantar can provide the detailed information on the plantar surface unlike pressure and IMU data obtained from conventional sensors. We investigated the relationship between the activity in the toe area and stumbling experiences. The results indicate that high toe activity is associated with the group which did not have stumbling experiences and low toe activity is associated with the group which have stumbling experiences.

This paper proposes the evaluation method for stabilometer installing center of gravity feedback system using the wearable force plates. This method estimated PD control parameters and offset value using the ankle joint angle and the forward-backward component of force. The ankle joint torque is calculated by inverse dynamics using ground reaction force, moment and acceleration. We conducted the measurement experiment using the stabilometer and the wearable force plates, and we estimated the PD feedback control parameter and offset parameter. The results indicated the change of parameters between first test and last test. The method can be used to depiction the effect by using the stabilometer.

This paper proposes the measurement system of foot pressure distribution for the stabilometer installing cencer of gravity feedback system. The evaluation method for stabilometer installing center of gravity feedback system. This system consists of the conducting material, the flexible basal plate and control system, and this feature size of system can be changed by changing the flexible basal plate. We conducted the measurement experiment this system and the stabilometer. The mode of stabilometer was set In-phase mode. The results indicate the characteristics of foot pressure distribution by using the In-phase mode in the stabilometer. This system can be used to measurement of various pressure distribution.

In motion measurement, a measurement method using 9 axis sensor is attracting attention in that they are less expensive, convenient and less restrictive in measurement area than optical motion capture. We focused on the motion information in the relative coordinate system and proposed and verified the Kalman filter algorithm that estimates the 3D body posture with high accuracy by correcting the drift error of the gyrosensor using the acceleration. In this study, we attached each 9 axis sensors to the femoral and shank segments in order to measure the knee joint angle and verified the accuracy of the algorithm to estimate the 3D posture in the relative coordinate system by measuring simultaneously with optical motion capture. As a result, it was found that alignment between sensor and body segment is important. Therefore, we proposed and verified the algorithm of alignment adjustment method. We could find the possibility to correct axis alignment by using the proposed algorithm.

This paper proposes the estimation method of seating face geometry using belt-shaped inertial sensors system. This method uses the sensor fusion for posture estimation and the forward kinematics for position calculation. The sensor fusion estimates the Roll and Pitch angles using gyro sensor and acceleration sensor outputs, and the effect of drift error is reduced. The estimated geometry information is validated using the calibration device designed by CAD, the results indicated the effective accuracy. Furthermore, we conducted the measurement experiment using three sensor systems in dynamic condition. The results indicated the face geometry in settling and floating conditions. This system can be used to represent the face geometry in static and dynamic conditions.

A motion capture is also a technique to record the movement of a real person and object digitally. We analyzed the behavior of Kendo using motion capture system and force plate. As a content, it is about the motion of each body part in the Men-strike. As a result, I was able to analyze the characteristics of the position of the wrist and how to carry the foot. It was possible to visualize the behavior of each subject, it is considered to be effective in the scene of guidance. They will be able to understand their own characteristics and lead to higher levels. Also, it was possible to summarize the muscle-tendon complex when delving in the motion of the Men-strike. It was confirmed that the vastus lateral muscle and the semimembranosus functioned greatly in any subject. In this way, we plan to establish a new method of guidance.

There are many studies about swimming by kinematic and partial kinetic analysis. In order to obtain muscle activity during swimming, the experiments using the electromyogram were conducted as well. However, measurable muscles are limited in this experiment. And there are few musculoskeletal analysis of swimming, since it is difficult to compute the fluid force acting on the whole body of a swimmer. The objectives of this study were to construct the method of musculoskeletal simulation from swimming motion capture data, and analyze muscle activity. First, swimming motion capture data was transformed into body geometry data and swimming motion (absolute angles of segments) of SWUM using Blender. In SWUM, fluid forces of each segments were calculated. Then, swimming motion of SWUM was transformed into joints angles of AnyBody Modeling System using MATLAB. Finally, muscle activity of the whole body was calculated using AnyBody inputting the swimming motion and fluid forces. From the example of breaststroke, it was found that all transformations except for 2 DOF joints were conducted successfully.

A motion capture system with force platforms is a popular method for gait analysis. However, one of our authors, Maeda suggested a force platform free gait analysis (Maeda 2016, Maeda 2017). He proposed that if the center of pressure on the ground was provided, his proposed method can estimate both the joint force/torque and the ground reaction force with high accuracy In this study, the center of pressure was obtained by a large scale pressure sensor carpet (“JUTAN^TM”, Nissha Printing Co.,Ltd.) during walking. The purpose of this study was to examine our force platform free gait analysis using the optical motion capture system with the large scale pressure sensor. The result showed that joint torque can be estimated with satisfactory. Therefore, our force platform free gait analysis can be adopted at any place, such as stairs, rough terrain, etc.

This study investigated relation between the initial release conditions of a JaveBall in the javelic ball throw and flight distance. In 160 trials by 17 participants, the flight distance of the JaveBall was measured and its initial release conditions were calculated and analyzed. As a result, it was found that initial velocity had the strongest effect on flight distance. Release angle, angle of attack, and horizontal angle of attack at release also affected flight distance, but it was not greatly affected by large increases in these values. Also, increased initial velocity decreased the actual flight distance relative to the theoretical flight distance (neglecting the effects of air). Flight distance was large when the rotational speed at release was somewhat large or very low, suggesting that the effects on flight distance were different in each case.

The purpose of this study was to quantify dynamic contributions of joint torques to the generation of launched ball parameters (i.e. ball velocity and angular velocity) in baseball pitching. Two types of analytical models, first one is 22-segment model with finger segments taken into consideration and second one is 16-segment model without consideration of finger segments, were proposed to derive the equation of motion for the whole-body system with ball. Dynamics contributions of joint torque, gravity, motion-dependent term(MDT), and modeling error term to the generation of ball state variables such as ball speed and ball angular velocity were quantified using the equation of the target system. Furthermore, the generating factor of the MDT was considered using a recurrent formula derived from the equation. The results in this study indicate that 1) joint torques, especially finger joint torques, are the major contributor to the ball speed when using 22-segment model because finger exerted force directly to the ball, 2) the MDT become the major contributor when using the 16-segment model, and 3) with consideration of the generating factor of the MDT, the horizontal adduction joint torque of the shoulder joint and the extension joint torque of the elbow joint play roles in the generation of ball speed just before ball release.

The purpose of this study is to develop the system analyzing pitching data using baseball-type sensor and to examine the accuracy of the developed system using Doppler radar system (Trackman baseball, Trackman) and high speed camera. The developed baseball-type sensor in this study, which consists of accelerometer, gyroscope, and Magneto-Impedance sensor, measured 6-axis acceleration, 3-axis angular velocity, and 3-axis magnetic field. The weight, moment of inertia, and material in baseball-type sensor was the same as a normal baseball. The spin rate of pitched ball was calculated from data of 3-axis magnetic field using zero crossing method. The spin axis of pitched ball was calculated from data of 12-axis sensor using the sensor fusion by extended Kalman Filter. The measurement experiment was conducted to indicate the accuracy of the developed system. The spin rate calculated by the proposed method was corresponded with the spin rate obtained by the Doppler radar system (r = 0.99, R² = 0.99). Also, it was indicated that the developed system could measure the low spin rate (less than 8.3 rps) which Doppler radar system could not measure. In overthrow data, it was indicated that the spin axis calculated by the proposed method was corresponded with the spin axis obtained by the Doppler radar system. From these result, the developed system can be used to evaluate baseball pitching skill with high accuracy.

The aim of this study was to clarify the characteristics of softball pitching by measuring and analyzing the trajectory of softball pitched in the game. In two games of softball league, the trajectories of pitched balls were recorded by using two video cameras. And they were analyzed from the video data by a three-dimensional direct liner transformation method. As a result, most of the pitchers threw balls of different kinds with different the ball velocity and the variation of trajectories, which were similar to baseball pitching techniques. In addition, although pitchers who did not clearly change the ball trajectory were seen, the pitching balls of many pitchers changed vertically downward. It is thought that the ability to respond to the vertical variation of pitched ball is required for the batter because the vertical variation of trajectories during pitching of each pitcher showed characteristics, in the softball.

Softball is different from baseball in that the pitcher throws a ball with an underhand motion. Almost all softball pitchers throw a ball with a windmill pitching method (the arm one revolution as well as a windmill rotation). The windmill pitching method is different from the baseball pitcher throwing, so batters have a difficult time hitting the ball. For this reason, a softball pitching machine which can perform repetitive exercises for batting is required. However, currently, there are few machines capable of throwing with the windmill method on the market. In this study, we focused attention on the arm type and aimed to create a prototype pitching machine realizing a real pitcher’s windmill pitching method. We will add a ball gripping mechanism to the pitching arm of a commercially available arm type pitching machine. Based on the experiment results, the prototype machine had a maximum ball speed of 77 km/h. Also, the throwing position (pitching accuracy) of this machine was 460 mm in the vertical direction and 50 mm in the horizontal direction, so the tolerance in the vertical direction became large. The prototype machine is able to pitch fastballs and curveballs. It was found that the prototype machine can be controlled the spin rate by changing the length of the hand. In addition, there is a possibility that the eccentricity of the spin axis reduce from the simulation results. The prototype machine had the necessary throwing performance for junior high school student level softball practice. Key Words : Softball, Pitching machine, Windmill-type, Arm type, Curveball, Spin rate

In football and volleyball, players control behaviors of the ball by hitting with their own body. At this time, unlike the tool (tennis racket, baseball bat, golf club and so on), it is difficult to find the center of percussion. In the present study, at the first, we used a simple mechanical model to clarify the center of percussion on underhand pass. At the Next, we discussed the existence of the center of percussion on the instep kick. Furthermore, shock reduction technique was also mentioned. Finally, we also proposed how to utilize the knowledge of the present study for coaching.

The top players of field hokey experientially know that high restitution area of their hokey stick exists not near the head but on the position slightly shifted to grip end. They would have to swing the stick horizontally with low posture to hit the ball near the area when strong and high speed balls were needed in the game. Therefore, we have been developing a new hockey stick that has high restitution area near the head. In this study some FEM analysis has been carried out to examine relations of shape of field hockey sticks and the position of the high restitution.

Baseball batting demands batters to respond instantaneously to balls with high speed flying from the front while they accelerate the bat head to high speed within a brief time by utilizing the motion-dependent term (MDT) effectively. During this period, time constraint occurs in the operation. However, the bat head speed generating mechanism of the baseball batting motion under such time constraint condition, assuming the game, has not been reported. Therefore, the purpose of this research was to clarify the generating mechanism of bat head speed under time constraint condition. Ten collegiate baseball players participated in this experiment being done under two types of ball conditions such as teed ball batting and thrown ball batting. Dynamic contribution analysis was carries out using a total of 16 segments of rigid body link model consisting of body with 15 segments and bat with one segment. The results obtained in this study shows (1) most of the bat head speeds at the ball impact were generated by the contribution of the MDT under the thrown ball batting condition similar to the teed ball batting condition, and (2) the timing of the contribution to the bat head speed at the ball impact was different and the SD was very large. These results indicate that the batters mainly adjusted the bat-head speed before 60% of the normalization time when the influence of the MDT became large.

The purpose of this study was to analyze how the bat moves in correspondence with the pitching course in the batting of baseball from the viewpoint of differential geometry. Three subjects made swings corresponding to the three courses of center, in and out, with the aim of the tee stand set to the waist height. In order to obtain three-dimensional coordinates of the reflective marker affixed to the bat tip and the grip end, the marker was tracked using a VICON system. After interpolating and smoothing the obtained three-dimensional coordinate values, the tangent vector, the principal normal vector, and the binormal vector were calculated, and then the curvature, the radius of curvature, the center of curvature, and the torsion were calculated. From the trajectory of the bat tip and the grip end, it was possible to observe the difference of the swing corresponding to the course, but in order to clarify local bat movements near the impact, the tangent vector was useful. In addition, the curvature, the radius of curvature and the torsion were also useful for analyzing the movement of bat from start to impact. The trajectory of the center of curvature, that is, the evolute showed the difference of the swing corresponding to the course, but further investigation in the future was necessary by increasing sample since the shape of the curve is complicated and its characteristics are difficult to clarify.

In this study, FEM numerical simulation was made to estimate surface pressure of string beds. This model is able to calculate all axis direction displacement of all nodes by setting an arbitrary load. Two tests were conducted to measure the relationship between a load and a displacement of nodes. One was compressing test of square string beds in static. The other test was tennis balls was collided against string beds. Square string beds of three string pattern was produced in FEM. The reasonableness of this FEM numerical simulation was verified by comparing the result of simulation and the result of the experiment. As a result, this FEM model is able to evaluate stiffness of string bed properly in static behavior. On the other hand, in collision test, velocity of ball and displacement of string bed were measured. Kinetic energy loss of before and after the collision was calculated. Stiffness of string bed calculated in FEM and displacement of string bed measured in collision test were used to get the potential energy of string bed. The relationship between kinetic energy loss of tennis ball and the potential energy of string bed was considered.

This paper examined the KANSEI evaluation of racket during tennis strokes. To analyze it, questionnaires of SD method on rackets were taken to 12 subjects after actual tennis strokes, and psychological estimations were gotten. Using them, analyses of radar chart, cluster analyses, and principal component analyses were taken. At the same time, the motions of tennis strokes were measured and digitized using the 12 motion capture devices and were compared with psychological estimations. At first, personal preferences were charted. Secondly, subjects were classified into the three groups of experienced persons and the one group of novices from result of cluster analysis. Thirdly, experienced persons emphasized different evaluation factors from those of novices from result of principal component analysis. Finally, it was confirmed that the sum of the standard deviations of the locus during tennis strokes was related to the racket's comfort in experienced persons. Therefore, the results clarified the relationship between psychological estimations on tennis rackets and motion of human bodies during tennis strokes.

The structure of the current tennis ball is covered with a uniform felt fabric on the outer surface made of hard rubber. The inside of the ball is filled with air about 1.8 atm. The seam is filled with adhesive or resin. The seams are filled with glue or resin. The ball in tennis is always struck with rotation. Rotational speed of the serve ball is about 5,500 rpm maximum. It is up to about 4,700 rpm for the stroke. As the ball continues to hit, the surface felt wears. Also, air leaks out through the structure inside. These factors cause a difference in the aerodynamic characteristics of new and used balls.

In general it is a new ball to use in the game, but the one used in practice is a used ball. Worn out changes the hydrodynamic properties of the ball, and the trajectory of the ball also changes. Therefore, the performance difference between the new tennis ball and the used tennis ball should be confirmed by measuring the fluid force.

In this research, the aerodynamic characteristics of the old and new tennis balls rotating were investigated and the PIV results of the flow around the ball due to the wear of the felt producing these characteristics. For the four types of tennis balls tested, used balls showed higher in drag coefficient than new balls, and new balls tended to be higher than used ball in lift coefficient. It is believed that deformation due to deterioration of ball rubber brings about a change in drag coefficient, which causes a change in lift coefficient due to wear of the surface felt. In the new ball, feltfluff stands, which indicates that the wake flow is large and inclined diagonally backward compared to the used ball, and the air around the ball is found to be caught by the felt fluff.

The drag and lift of footballs have been measured mainly by wind tunnel tests, which have provided the basis for many studies on ball flight trajectories. However, the dynamics of the fluid flow around the ball, particularly in relation to the vortex structure’s influence on drag and lift, are not clearly understood. In recent years, Computational Fluid Dynamics (CFD) has been developed as a tool for the visualization and analysis of flow dynamics and vortex structures. Further, advancements in computational resources and computational methods have made it possible to realize a highly accurate visualization and analysis of fluid dynamics. As a result, in this study, using the Lattice Boltzmann method, we have visualized the wake of spinning and non-spinning soccer balls and demonstrated the dynamics of their vortex structures. Consequently, the dominant vortex structure of the wakes from spinning and non-spinning footballs was determined to be a large-scale counter rotating vortex pair. Further, the variation in the large-scale counter rotating vortex pair for a spinning ball was estimated to be smaller and more stable than that of a non-spinning ball. Although the presence of an unstable, large-scale counter rotating vortex pair in the wake of a non-spinning ball has been observed in past wind tunnel tests, according to this study, the dominant vortex structure of a spinning ball can be considered to be a stable, large-scale counter rotating vortex pair.

It is thought that the jet flow between the three dimensional twin vortices that can be generated in the ball downstream flow greatly influences the cause of the knuckle shot. In this study, by synchronizing the Stereo 3D-PIV and the three component load cell, the fluctuated fluid force of the ball and the jet flow which can be made in the soccer ball wake in the speed range of the knuckle ball speed was measured and the phenomenon of the knuckle shot was ellucidated dynamically and visual analytically. As a result, the high correlation was confirmed between the fluctuations in the fluid force and the wake fluctuation acting on the ball.