In this paper, we study the possibility that impact force, which is called "pulsating force", might suppress nonlinear vibrations arised on Duffing system. Our experimental equipment described by Duffing's equation is a buckled steel elastic cantilevered beam on a periodically moving support. This equipment has a hammer in order to add the pulsating force to the beam. The displacement of free end of the beam is measured by a laser displacement sensor. The paper show that the pulsating force suppresses the large-amplitude vibration arised on our experimental setup. We hope that the pulsating force will control nonlinear vibrations arised on flexible structures.

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Experimental results are presented on chaotic oscillations of a clamped shallow arch. The arch has a large curvature and initial axial displacement by heat expansion. Due to the large curvature of the arch and its axial displacement, the lowest vibration mode of the arch is asymmetric and 2nd mode is symmetric. The arch is shaken laterally by an electromagnetic exciter. Chaotic responses are examined by the Poincare projections, Fourier spectrum and the maximum Lyapunov exponents. Contributions of vibration modes on the chaotic oscillations are examined by the principal component analysis. Chaotic responses due to internal resonance and dynamic snap-through are obserbed in specific regions of the exciting frequency. The chaotic oscillation generated from internal resonance including super-harmonic resonance of second and third modes has relatively large contribution of higher vibration modes. Chaotic oscillations including dynamic snap-through generated from principal resonance of the lowest vibration mode have relatively large contributions of the asymmetric modes.

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The frequency of self-excited systems depends on the amplitude and under the large amplitude, the excited frequency deviates from the natural frequency. Therefore, to keep the excited frequency near the natural frequency, the response is required to have a small stable steady amplitude. In this paper, a self-excited cantilever beam of Van der Pol type is realized by using nonlinear feedback and the dependence of the response amplitude and frequency on the nonlinear feedback gain is theoretically examined.

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The vibration characteristics of translation-inclination coupled system, which is the model of train, vehicle, and so on, are studied. We consider the case that this system subject to the base periodic displacement, and investigate the dynamic characteristics by the numerical simulation. We observe the occurrence of the unstable region at the resonance point of translation motion when the difference of stiffness between springs increases, and clarify that this phenomenon occurs due to the bifurcation of the stable resonance curve by performing the nonlinear theoretical analysis.

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In this work, transient oscillations during passage through resonance of a three degrees of freedom vibration isolating system, taking into account of drive characteristics, with '2-1-1' internal resonance is studied.The equations of the system which considered the second order geometrical nonlinearities, angular velocity of rotor and an electric current in a circuit are derived.The mechanism of passage through resonance with and without internal resonance are examined. Furthermore, the effect of the increasing speed of the voltage on passage through resonance is inspected. A three degrees of freedom experimental equipment is set up, and the transient oscillations are investigated and compared with numerical simulation.

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The self-synchronized phenomena between two metronomes fixed on a horizontal plate are investigated by numerical analysis and by experiment. Reliability of analytical model and calculation methods in this study is corroborated by comparing the experimental results to calculated ones from the viewpoint of characteristics of self-synchronized vibration and quasi-periodic vibration. In addition, the adequacy of modeling of impulsive torque that acts on a metronome is judged from the computational results for the systems with different models of impulsive torque.

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Rotating machineries are the most widely used elements in mechanical systems. Many systems such as power plant and jet engine are multi-span rotor system, which is supported by multiple bearings. In this research, we consider a 2-DOF nonlinear rotary system in which the two nonlinear rotors are coupled by means of a weakly linear stiffness. We show nonlinear normal modes in this system using the method of multiple scales. Furthermore, we indicate the occurrence of mode localization in this system.

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A stand alone wearable power assisting suit consisting of shoulders, arms, a back, a waist and legs units was developed. The units of arms, waist and legs have direct drive pneumatic rotary actuators driven by portable Ni-Cd batteries. The muscle forces are sensed by a new muscle hardness sensor utilizing a load cell. The embedded microcomputer is used to calculate the necessary joint torque from static body mechanics using the joint angles, and the calculated torque is combined with the output signal of the muscle sensor to make control signal. The each unit of the suit transmitted assisting torque directly to each joint, and by wearing the suit to the body the weight could be lifted by half or less muscular power, i.e., muscular power became twice or more.

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In this research, the control technique of the robot hand, which used EMG signals measured on the skin surface, was proposed. The signals corresponding to motions were quantitatively generated from EMG signals using linear multiple regression models. A learning process is needed in this method, but it takes only a short time. By using the generated signals, discernment of hand motions and adjustment of grasping force were realized. In this paper, In order to prove the validity of this technique, the experiment, which used the robot hand, was conducted. And subjects was able to adjust grasping force with this method.

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This paper describes support-equipment of operating a personal computer for users who have an obstacle on the regions of upper limb. The user wears a head set device with an angle sensor, and holds a plastic pipe connected to a pressure sensor in his or her mouth. Tilting his or her head and breathing are used for a mouse cursor operation and characters input. The voluntary tilt angle range and breath strength are memorized to the controller beforehand, so that operations can be performed without fatigue considering user's body situations.

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The research purpose is the ride comfort improvement of an electric wheelchair. The questionnaire was performed to the users of an electric wheelchair. The answers show that many of them are not satisfied with ride quality. The comparison examination was carried out on a road surface where many people felt disagreeable because of vibration and on a road less disagreeable. The result is to be used to investigate the vibration characteristic, the number of heart rate, and ride comfort evaluation.

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This paper deals with the support of sit-to-stand motion for supporting independence of the people with muscle weakness. Contrivance of rising motion which reduces physical work load is mentioned kinematically. Kinematic conditions for rising are clarified by the experimental observation of sit-to-stand motion. Then the effectiveness of self-assistance in rising and care of rising is verified.

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At this laboratory we have been studying and producing comfort-chair-type power assisted chairs using a pneumatic system. The power assisted chairs were evaluated by the questionnaires of the subjects before. In order to get quantitative design guideline, this study aims to evaluate assist-effect by dynamic parameter. In particular the forces exerting human body under stand-up and sit-down motions were measured by load sensors, and the joint angles were measured by motion capture techniques using digital video camera. The torques which works at knee joint and hip joint were calculated based on a human body assuming a 3-link model.

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This paper proposes the wearable mechanism composed of the tube type actuators designed from the aspect of the clothing comfort. At first, we tried to improve Tail-arm, which we had already proposed, to be able to assist the lower limb exercise. But it can't generate enough torque. So we propose new driving mechanism. This mechanism uses Z-tube Actuator, which can generate directly torque. The developed mechanism showed us it had enough torque to assist the lower limb exercise and had the desirable structure with the excellent clothing comfort.

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In this study, we aim at developing a wearable foot joint walk support equipment for the purpose of fall prevention of elderly peaple. This support equipment works to enlarge an angle between the sole of foot and ground sarface in swing term. In order to give sufficient torque for a foot joint, we introduced commercial products of Ankle Foot Orthosis and equipped with pneumatic rubber artificial muscle. Walking of human is analyzed to determine the support timing during a walking. Validity of the proposed equipment as foot joint walk support equipment is confirmed through some experiments.

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The support function to the movement functional fall of the leg has many easy things. When requiring advanced support, there is a tendency to give up walking and to sit it on a wheelchair immediately. Therefore, the research on the advanced support for the walk of the leg is important. Since examination fundamental about the structure whose use controls drive power and braking power for walk support, and is enabled in a wide area, and its system was performed, it reports. So The will at the time of a supported operating, and few support of sense of incongruity is aimed at as much as possible

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The main functions in support of the leg functional fall for a walk would be mostly subject to the handle part of the walk support device used in the movement. This part simultaneously supports leg and gravity-center movement in the walk function. Therefore, the walk support device suited as to support the walk operation needs to be consisted of a movement controller which can fit walk operation between a user and a machine without sense of incongruity. Here, relating to the topic, the fundamental knowledge on how various kinds of handle systems and its form would have influenced to walk operations is discussed.

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Changing diapers hurts prides of the patient, so that a panty type toilet that can be worn to the patient is of importance., in which feces and urine are washed automatically. One of the panty type toilets has been reported. In the report, however, the principle of the toilet was only discussed, and so it cannot be used in practice, because of lack of production process. In addition, since the clamp up pressure to the body was not controlled, it often gives pains to patients. The present article gives a method of producing the panty type toilet, and a new rotary type electromagnetic valve, and a method of pressure control is presented. To have cheaper toilet, this article also provides a device of detecting faces and urine by using a humidity sensor. Some demonstrations are performed for the toilet made in this experiment.

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The development of the excretion support device used temperature gradient. As a result, the actuator has understood a reversible movement to the temperature and a quick-return motion mechanism, and movement of about 8mm is possible between the room temperature and the temperature of humanbody. In addition, it has been understood the model of the made excretion support device is to be able to reciprocate once every ten seconds.

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In this research, the auto-priming device of Adacolumn was developed, and the utility was verified by the experiment. This device aims to actually use it on the medical treatment site. Adacolumn was vibrated with this device because of various vibrations, the state of the priming was confirmed and the noise at this time was measured. As a result, when Adacolumn was vibrated mixing a compound vibration and a simple vibration, it was confirmed that priming being able to do best. And, it succeeded in shortening the priming time greatly.

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