This paper proposes a new type of absolute displacement and velocity sensor based on the principle of servomechanism. Because measuring range of the absolute displacement is over natural frequency, it is difficult to measure a low frequency vibration using conventional seismic type sensor. In order to expand measuring frequency range toward low frequency, the sensor with the low natural frequency is realized by using feedback control techniques. It is demonstrated that the developed sensor with feedback and phase lag compensations have 0.6Hz of natural frequency to measure from 1Hz to 100Hz and it is available to reduce the natural frequency for attempting more low frequency measuring range. This sensor is used for controlling structural vibration using active dynamic vibration absorber.

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This paper presents a new small tactile sensor that can detect the vertical force and the shear force. This proposed tactile sensor detects an applied force as a change in electrical resistance in strain gauges attached to the sensor's surface. This proposed tactile sensor has the structure of an upside-down plate supported by four legs, and its dimensions are 5mm in length, 5mm in width, and 1mm in thickness. This sensor's structure was evaluated by simulation and experiment from the viewpoints of strain gauge sensitivity, force sensitivity, conditional number, and rigidity. As a result, it was proven that the proposed tactile sensor could be miniaturized, and could measure tri-axial force.

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Surface acoustic wave (SAW) linear motor is a kind of ultrasonic motors. The advantages of the SAW linear motor are thin structure, high thrust force, high velocity and precise positioning. Relationship between applied voltage and output velocity, however, has non-linearity in a low-velocity area due to friction drive principle. Therefore the SAW linear motor cannot obtain stable driving without feedback control in the low-velocity area. Previously, to realize such low velocity, PWM control and flexible slider structure were employed. Flexible structure was installed to cancel vibration due to PWM carrier frequency. In this research, we change calculation algorithm for slider velocity measurement. As a result, SAW linear motor can be driven at a low velocity of 30mm/s. Additionally, driving characteristics is improved by using a feedforward controller.

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This paper deals with experimental study of active feedback control of leakage-flow-induced vibrations by bimorph PZT actuators. The self-excited leakage-flow-induced vibrations in an one degree of freedom system rigid body is suppressed by controlled fluid force. In order to stabilize leakage-flow-induced vibrations, we developed a control device by using bimorph PZT actuators and proposed a new active feedback control method. The active feedback control is conducted by moving baffle plate driven by bimorph PZT for changing inlet or outlet width of the tapered passage. By measuring RMS value of vibrations displacement and evaluating critical velocity ratio, we investigated control on vibrations performance. As a result, leakage-flow-induced vibrations can be stabilized by proposed the active feedback control technique. In the case of inlet flow control, leakage-flow-induced vibrations can be controlled by the phase progress between the motion of the baffle plate and the displacement of rigid body. Another outlet flow control can be controlled by the phase lag. In addition, inlet flow control is the higher stabilization effect than outlet flow control.

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Recently, research has concentrated on robots that can coexist with people and be of use to them. Such a robot needs to be both safe and flexible. Here, we use a pneumatic actuator as the driving source of a robot hand. We develop a pneumatic actuator driven by low pressure because we consider that the conventional pneumatic actuator is inadequate for the driving source of a robot hand. First, we examine the characteristics of our new pneumatic actuator. Next, we make a 2-link arm that has one degree of freedom using a pneumatic actuator. We construct a control system for the 2-link arm and verify its control performance.

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This paper deals with an experimental study on the self-excited flapping mechanism of flexible wings which mimicked a flight insect for a fluid in low-Reynolds number. This mechanism is based on biomimetics. To get the vibration (flapping motion) of the flexible wings with large amplitude, the driving with the natural frequency of the flexible wings is needed. However, the natural frequency changes with increasing the amplitude and changing of surroundings. So, this study uses the self-excited feedback control for flapping flexible wings. The self-excited driving system follows the natural frequency change of the flexible wings automatically, and the self-excited vibration with large amplitude occurs to the flexible wings. The propulsion force generated by the self-excited flapping wings is measured using a high-sensitive force sensor, and the performance of the propulsion force is clarified experimentally.

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Helicopters have the mobilities of vertical take-off and landing and hovering not possible with fixed-wing aircraft. And they have been used for disaster prevention extinguishing fire airborne photographing , rescue, pesticide spraying, news report and transportation. Unmanned small helicopters are more convenient than manned helicopters. But their flight is very difficult and usually limited to flight visible to the operator. So training take long time. Which is why autonomous flight control is indispensable to practical unmanned helicopter use. Now height control use governor which conserve revolution. And this appliance is switched by the hand. So revolution control behoove for autonomous flight. This thesis carry on research which is revolution control. We use system identification approach for revolution data and derived engine model. And we analytically derived resistance torque based on aerodynamics. So we combined them and derived control model. We designed controller based on derived model using Plcontrol theory and actualize revolution control.

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When the horizontal rotation is given to the toy called rattleback to have the shape of the boat put on the desk, it rotates only to one direction. When the rotation of the opposite direction is given to the toy, the pitching vibration begins stopping rotating like disliking the direction, and it shifts to the rotation in the opposite direction gradually with the given direction. A dynamic feature of the toy is that the inertial roll axis is a little twisted around the vertical axis, i.e. it is not included in the vertical plane that a lower ridge line forms. Putting this shape feature on the mind, this paper tries to give an intuitive explanation about following two items: reason where direction that rotates easily and direction not rotated easily exist, and cause of pitching vibration generation and reverse-rotating torque generation.

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In this paper, we design a control system of an electric power steering for vehicles applying the gain-scheduled control according to the vehicle velocity and the sensor torque of the steering axis. The self aligning torque generated from the vehicle model was considered as a disturbance to the steering system. We formulated a generalized plant including the weighting functions of scheduling-parameters depending on the vehicle velocity and the sensor torque to design the gain-scheduled controller. By carrying out simulation using driver's second-order prediction model, it is verified that the controller designed is effective to improve stability of the steering system and to obtain a desired hysteresis curves on steering torque-steering angle characteristics.

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It is well known that a good method for improving fuel economy is to engage the lock-up clutch of the torque-converter. In the lock-up clutch, it is necessary to control the slip speed from lower speed region in order to improve fuel consumption performance. However, the plant parameters are changed by a turbine speed, and the control is difficult. In this paper, we apply the gain-scheduled H_∞ control method to the slip speed control system of the lock-up clutch. Since the plant parameters can be scheduled by the turbine speed, the gain-scheduled control will be an effective way to improve the control performance. The effectiveness of the proposed method is shown by the simulation comparing with μ synthesis and H_∞ control method.

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This paper deals with robust stabilization of running self-sustaining two-wheeled vehicle with varying running speed and mass variations. Recently, some researches about stabilization of two-wheeled vehicle have been reported. These researches have achieved the stable running only by the steering control. However, an actual two-wheeled vehicle is stabilized by not only the steering control but the control of a vehicle's center of gravity. We have proposed the stabilization control method of two-wheeled vehicle in the state of stillness, and have shown the effectiveness. In this research, we construct the control system for the running stabilization of two-wheeled vehicle. H_∞ mixed sensitivity problem is used to design the robust controller to achieve running stability even if the running speed changes and the mass of two-wheeled vehicle changes. The experimental results show the effectiveness of our proposed approach.

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In recent years, semi-active suspensions have been widely used in order to improve ride comfort of automobiles taking advantage of less energy and cost. This study aims at achieving simultaneous realization of ride comfort and steering stability in the controller design for semi-active suspension considering the most sensitive frequency range of human body and vehicle behavior for steering. In this study, an algorithm which can improve both the ride comfort and the steering stability is proposed by separating the control range in terms of frequency domain. In consideration of the above concepts, the frequency weightings and the criterion function are designed in frequency domain. Furthermore, the controller is scheduled in time domain in order to realize the positive pitch angle mode at the slalom. In this study, the dynamics of road disturbance is supposed and is accommodated into that controller to make the control performance more effective. In order to investigate the effectiveness of the proposed control system, simulations are carried out by using a full vehicle model which has variable stiffness and damping semi-active suspension system. As a result, it is demonstrated that the proposed method can realize improving the ride comfort, reducing the vehicle attitude change, and synchronizing the roll and pitch angle caused by steering.

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This paper presents a vibration control method for multiple high-rise buildings against large earthquake motion. In recent years, the connected control method (CCM) has attracted attention as a new control method for vibration of high-rise buildings. This method utilized the interaction forces among buildings as control forces. Larger control force compared with TMD is available in this method. However, CCM requires huge control force to suppress large earthquake excitations. Therefore, semi-active control is more preferable for practical CCM systems. MR dampers are used as actuators of semi-active control. By introducing semi-active control, it is able to control vibrations of super tall buildings against the strong wind and large earthquake. The effectiveness of CCM in one-dimensional vibration has already been established using two building structures arranged in parallel. To confirm the effectiveness of CCM in two-dimensional vibration, we introduced four building structures arranged in square as a control object so that two-dimensional (x-y) vibration control experiment can be performed. In this paper, LQ control theory is used to design control system. Based on the LQ controller, semi-active controller is obtained by applying so-called "clipping" . Using this method it is confirmed that the semi-active control has a vibration control performance as well as active control.

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Existing wooden buildings are vulnerable to earthquake damage. In Japan, where earthquakes occur frequently, it is important to know the condition of wooden buildings. Therefore, tools for evaluating seismic capacity are essential. However, as wooden buildings are built in various ways no perfect tool is available. Especially, the conventional tool is inadequate to evaluate the aging deterioration and the changes that occur before and after earthquakes. In addition, it is costly and time-consuming. The evaluation that can find the aging deterioration of wooden buildings easily and economically is thus needed. In this paper, we focus on a complexity index from inspiration that there is a similarity between human and wooden buildings. The aim is to evaluate the aging deterioration of wooden buildings in a simple manner. The paper discusses the possibility of using Approximate Entropy as a performance index of seismic capacity for wooden buildings.

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Various system identification methods and damage detection methods have been proposed. Thus, Structural Health Monitoring (SHM) systems have been improved. As a result, the number of real structures with SHM systems is increasing. However, the system which monitors many buildings by SHM technologies is not popular, yet. In our laboratory, smart sensor unit (data acquisition and data management), data analysis method (system identification and damage detection), and user interface (Web-site and MATLAB Web server) for SHM have been studied and developed. This SHM system surveils the soundness of structures dotted over wide areas using SHM technology and networks, and publishes the result of diagnosis to the public. In this study, a new SHM system which uses database is proposed. It is indicated that the database (PostgreSQL) and Hypertext Preprocessor (PHP) enable extraction of data required from a large quantity of data.

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Authors promote development of a sensor aim for wireless sensing of a city infrastructure. Till now, significance of the sensing which WISP which was one of the wireless acceleration sensors having function to work and collect data was used for by a rudimentary vibration experiment, but improvement of WISP was started because improvement of plasticity of the measurement was expected. As a result, WISP was able to get the performance that was able to measure no problem about a simple oscillation. Therefore design and implementation of an application assuming using WISP for structure health monitoring (SHM) was examined experimentally as the next stage by this scheme and one end of system in SHM to place with an arrival aim was suggested.

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The various sensors development to quantify the deterioration of brittle structures for structural health monitoring is on the rise now. In this paper, strain measurement using the piezoelectric of the PVDF film is paid attention. An experimental confirmation of PVDF film's sensing performance is done by the comparison with traditional strain gauge sensor. To use this PVDF film as a crack detection sensor, first the crack progress on aluminum specimen were monitored and measured. Then the PVDF film sensors were used to monitor the generation and propagation on cracks due to progressive application of loads on RC beams in the laboratory. These film sensors were able to identify the appearance and propagation of cracks better than those of traditional strain gauge sensors.

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In this paper, the sensing behavior of the pulse-prepump Brillouin Optical Time Domain Analysis (PPP-BOTDA) based distributed sensing technique with a 0.1m-order spatial resolution is experimentally studied, and the sensing features of different types of fiber optic sensors (FOSs) are compared. Based on experimental results, we found that slippage occurred between bare fibers and coating materials, and that a different FOS type has a different degree of slippage. Despite possessing 10cm-order spatial resolution, if the gauge length of FOS is shorter than the critical effective sensing length (CESL), the measurement accuracy is significantly affected by the slippage. In order to enhance the sensing performance of FOS, a packaging design for the practical adaptation of no-slip FOS for structural health monitoring applications is proposed. Finally, the performances of packaged optic fibers isare experimentally verified.

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Hybrid magnetic bearing is recognized as an efficient one even with wide airgap and is suitable for such application. Previously sub-pole type IPM hybrid magnetic bearing has been proposed. However the sub-pole produces bias flux and cannot produce control force. To overcome this problem, two new types of hybrid magnetic bearings are proposed which have permanent magnet within the stator core. This paper introduces structure and principle of the proposed magnetic bearings. The geometric parameters of these new type mechanisms are optimized by FEM analysis. The experimental setups are made based on these analytical results. The fundamental characteristics are measured and compared with the estimate bearing performances. The results show stable levitation and good rotated levitation.

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This paper describes the axial force and rotating torque characteristics of the axial self-bearing motor using as a generator. The axial self-bearing motor is a combination of an axial magnetic bearing and a disc motor, and performs position control of the axial position of the rotor and generating of rotating torque. Since a single rotating magnetic field controls axial position and generates rotating torque, it has simple structure and control system. The axial self-bearing motor has the same structure as the usual AC motor, then it can be used also as a generator. It aims at controlling a rotor position by the electric power generated with the axial self-bearing generator. Furthermore, it is examined whether it is possible to generate the electric power for driving other radial bearings and external apparatus. In this paper, the voltage-current relationship of an axial self-bearing motor/generator is derived, and the characteristics axial force and rotating torque is examined when 3-phase equilibrium load is connected. The result of analysis is confirmed by simple experiment.

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This paper discribes a new type of noncontact positioning mechanism. This mechanism consists of electromagnets, superconductor, and actuators. The principle of the proposed system is same as an inchworm positioning mechanisim. Electromagnets are used for chucking mechnism which is hold by pinning flux of superconductor. In the prior research, positioning mechanism which uses superconductor, permanent magnet and piezoelectric actuator. In this paper, permanent magnets are replaced with electromagnets. The principle of the mechanism is explained. The experimental setup is introduced and some basic experiments are carried out. These results support the feasibility of the proposed noncontact positoning mechnism. used in place of permanent magnetsthe.

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Electromagnetic cantilevered actuators are simple for fabrication and operation, while its mobility region is strictly limited due to pull-in instability. To extend the mobility region, we have proposed a novel open loop oscillatory control method which does not need additional sensors. In our previous reports, a sufficient condition for electromagnetically driven cantilevered actuators that cause pull-in instability is introduced, and the synthesis and robustness of the the open loop oscillatory control for the electromagnetically driven cantilevered actuators are discussed, while we showed that the oscillatory controlled system can prevent pull-in instability without feedback at the cost of the applied current and persistent oscillation. In this study, several types of moving part geometry are numerically examined to reduce the current and persistent oscillation.

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In this paper an active knee bolster to actively control shock to the occupant legs is designed for a one-dimensional model of the lower extremity and is verified for the three-dimensional model on an crash simulation software. The one-dimensional model using the passive type of the knee bolster was validated for the three-dimensional model including the motion of the upper-body and the head. The feedback control system to follow a reference signal of the contact force between the knee and the instrument panel was implemented with the three-dimensional model. It was verified that the feedback control system designed is effective to suppress the femur load of the model near actual movement of the human body on the software.

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In this paper an active knee bolster is proposed for the purpose of injury protection of passengers on his/her lower extremity in vehicle collision. Control objectives are not only to reduce the load to femur less than the passive knee bolster but also to suppress the pelvis movement and the pelvis deceleration to the same level as the passive one. The feedback control system is applied to follow a reference signal of the contact force between the knee and the instrument panel. The appropriate reference signal is decided to the step reference signal lowered like the ramp at the latter time of the duration to suppress the pelvis deceleration. It is demonstrated that the proposed active knee bolster can improve the performance of the passive one by carrying out simulations and experiments.

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In a car crash, if deformation of occupant thorax is held to the allowable value, no aftereffect will remain. In order to realize this condition, a seat belt tension must be adjusted instantaneously by a feedback control system considering the thorax deformation. Therefore, the seat belt tension control system on the basis of the semi-active shock control has been proposed. An advantage of this system is requiring no large power actuator because the seat belt tension can be controlled by a brake mechanism. And the effectiveness has been confirmed by an experiment using the scale model of about 1/10. Though the deformation of the thorax model was made to settle at the desired value, the overshoot of about 20% was occurred for the narrow control range of the actuator. In this study, the control law and the actuator which controls the tension using the friction are improved in order to suppress the overshoot of the deformation, and the effectiveness is confirmed by the control experiment. As the result, the overshoot of the deformation can be suppressed to 10%, the deformation after the overshoot is made to settle near the target.

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For the purpose of improving productivity, auto conveyance machines like fork lift are introduced as a part of production system and enlarged ones are required to shorten its task time. In this case, the input not considering the dynamics of the machine excites the vibration of the fork and the vibration affects fast positioning. Moreover, in lifting motion, fork lift has time-varying characteristics due to the existence of load mass on the fork. To solve this problem, a methodology on the basis of nonstationary robust control theory is proposed in this paper. The uncertainties of controlled object and load mass are included in the generalized plant and time-varying frequency weightings are designed to consider the change of natural frequency. By use of this proposed method and a two-degree-of-freedom control method as a comparative approach, the effectiveness of the proposed method is verified through the experiment.

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This paper presents a method of nonstationary optimal control considering collision for lifting and reducing vibration of positioning by a conveyance machine with flexible fork. For large-scale conveyance machine vibration is caused by its motion and the impact at the lifting motion. The vibration affects the next motion, so that the settling time is extended. Requirements for motion control of lifting are as follows; first, to control motion and vibration simultaneously; second, to suppress the impact; third, to control the vibration for either case that there is a load mass on the fork or not. Nonstationary control method is able to consider time-varying systems. Time-varying weightings could be designed considering several control demands changing with time. The usefulness of the proposed method is verified through the experimental examinations; consequently, the settling time of motion and vibration control is considerably reduced in the comparison with the result of the conventional method.

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In recent years, construction sites arising from the impact of the lifting operation by the strong winds cause big problem, the process greatly influenced by the weather effect. Therefore it is necessary to curb the rocking lifting object. This research refer to the object in the programs which installed on the upper part of dynamic vibration absorber. Based on the light of quality dynamic vibration absorber and short stroke Inhibit the object of the rocking. In this research feedback control and nonlinear input control be used. Simulation results proved that the effectiveness of proposed practices has inhibited the shock..

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This paper shows that the active hammer can reduce the deformation of the icebreaker by applying Active Control of Shock to the icebreaking process in the icebreaker. Although a usual icebreaker pushes the ice which has elastoplastic deformation characteristic to break ices by the breaker's hull, the icebreaker in this paper has the active hammer provided at the bow. The motion of active hammer is controlled by using two types of the triangular pulse, an acceleration pulse and a velocity pulse. For various peak positions and durations, the optimal command is searched to reduce deformation of the ice breaker by the numerical simulation. This paper shows not only the effective pulse shape of the active hammer, but also the difference of performance between steel and ice as the object to be plastically deformed.

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A 3-D Full Scale Earthquake Testing Facility (E-Defense) was built in Miki Hyogo in January 2005 by National Research Institute for Earth Science and Disaster Prevent (NIED). The E-Defense makes it possible to do full-scale 6 DOF shaking tests. The E-Defense reproduces the earthquake wave which was actually observed. The test body for the E-Defense is assumed about 1200tons while the shaking table mass is about 750tons. The mass ratio becomes substantially large, and greatly influences shaking performance. Therefore simulation tools are needed which allow us to understand shaking performance in advance. In this research, we identify the component of E-Defense, and we make simulation tools. And it aims at the development of simulation tools that can verify the performance.

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The shaking table tests using real scale structure have been carried out in recent years. It is difficult that the dynamic response displacement of such test model by using existing displacement transducer, specially, it is severe problem to measure the fracturing or collapse process of real scale model using contact type displacement transducer with good accuracy. This study has developed the measurement method of three dimensional displacement using image processing system. This paper describes the measurement result of collapse process of real scale wooden house model in E-Defense.

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In this paper, our experimental investigations show that the resonance vibration occured on Duffing system is effectively suppressed by the pulsating force. In recent years, many researchers have been reported about methods to suppress the flexible structure's vibration. Many flexible structures is difficult to control, because they have nonlinear characteristics. Our experimental setup is a Duffing system constructed of a thin SUS430 stainless steel sheet which is a simple model of flexible arm. The pulsating force is produced by the collisions between a stainless steel sheet and a steel stick. As a result of our experiments, we clarify that the reduction of the major harmonic resonance and the super harmonic resonance in the Duffing system is accomplished by adding the pulsating force. Therefore, we consider the pulsating force make effecive use of the reduction of the flexible sturcture's vibration.

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This paper presents a disturbance-force compensator for an electrodynamic shaker. The characteristic of a shaking system is considered to be nonlinear and variable because of the influence of the test piece. In order to compensate for this problem, the influence of the disturbance force needs to be suppressed. It is assumed that the disturbance force is measured in the form of a controlled variable, and the controller is designed using μ-synthesis by considering the uncertainty of the shaker. Finally, the experiment using the electrodynamic shaker is executed. A good performance is achieved for the variation in the characteristic of the controlled plant.

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The development of clean and the fuel economy engine is one of the important issue for the global environment protection. It is thought that the EGR control of the engine with turbo charger becomes important as one of the solutions. However there is mutual interference between the boost pressure and EGR rate. And also the system has nonlinear characteristics caused by the turbo lag. These problems make it difficult to control the EGR rate accurately. To overcome the above problems, we applied the Sliding Mode Controller with MIMO. And furthermore, we adapted the model structure that does not require the observer. Then we could get the good performance.

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This paper proposes two types of high-speed electromagnetic linear actuator for engine valve drive. One is previous model, and the other is HD model. The proposed actuator uses permanent magnet (PM) in addition to the electromagnet. The PM produces bias flux to hold the armature on the surface of the stator pole. Hence this actuator can reduce the driving power drastically than the conventional solenoid type one. Firstly, the concept of two types of electromagnetic valve actuator is explained. Secondly, the previous model is designed considering the installation on the real engine. The experimental setup of previous model is fabricated and tested. Thirdly, the HD model is proposed to improve the driving speed. The experimental setup of HD model is fabricated and tested, but the performance is not enough. Finally, the previous model is redesigned to improve it's driving speed. The analytical results show better performance and possibility for driving speed improvement.

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This study proposes new high responce engine torque control system. To satisfy high responce, we construct a feedforward controler consisting of a inverse engine model. That controler achieves high responce but amplifys turbulence. So modified controler to reducte the influence of turbulence is proposed.Finally,the practicable high responce engine torque controler is shown.

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