It is important to model friction forces between tire and load, and friction coefficients of brake materials when designing brake control systems, because there are uncertainties of the model which result from nonlinear characteristics of oil hydraulic or brake fluid pressure. This study presents the state equation to design a new estimation system using modern control theory. The authors performed simulations for the proposed discrete-time observer. The simulation results proved the effectiveness of the proposed observer under nonlinear characteristics of brake dynamics.

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In this paper, transverse vibration control and transport velocity control of a moving web in a rewinding section of a roll to roll system are investigated. The moving web is modeled as an axially moving beam. Two independent adaptive control schemes are proposed. The first control scheme using a control force exerted from a hydraulic actuator is to suppress transverse vibrations of the moving web of unknown mass per unit length under a spatially varying tension and a time-varying transport velocity. The second control scheme using a control torque applied to the rewind roller is to maintain the transport velocity levels of the moving web in spite of disturbances such as the variations of rotating elements and unknown bearing friction. From the decentralized control viewpoint, the uniformly exponential stability for suppressing the transverse vibrations and the uniformly asymptotic stability for maintaining the transport velocity are achieved. However, as a whole, the uniformly asymptotic stability is concluded. Simulations for demonstrating the effectiveness of the proposed control schemes are presented.

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Focusing on uncertain aerodynamic coefficients which characterize the thrust and torques, an adaptive controller for a four-rotor mini helicopter is designed based on Immersion and Invariance (I&I) approach. In order to deal with the complex multivariable parameter adaptation, a relatively simple model parameterized with respect to a few unknown coefficients is developed. It is shown that the adaptive controller is capable of estimating not only the unknown parameters but also external torque disturbances and rejecting them. Numerical simulation illustrates the robustness of the controller against the parametric uncertainties and external torque disturbances.

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In this research a bladed disk model is equipped with a pair of collocated piezoelectric actuators on each of the eight blades. Thereby, one is used for engine order excitation and one is used for piezoelectric shunt damping. In a case study the effects of a tuned inductance resistance network are compared to piezoelectric switching techniques. In the latter case the Harmonic Balance Method is used to derive a frequency dependent complex stiffness and calculate the linearized Frequency Response Function. Therefore, one bladed disk sector with cylic symmetry constraints is modeled with the Finite Element Method and reduced with a modal reduction technique. In parameter studies different shunt damping techniques are compared with respect to their effectiveness. Thereby, the passive tuned inductance resistance network shows a good damping effect in a frequency range around the resonance frequency of the network. In case of the adaptive switching techniques the frequency range of the damping effect is limited by the resonance frequency of the network only.

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Piezoelectric switching networks for vibration damping offer advantages compared to classical inductance-resistance circuits. However, the strong nonlinearity of these networks must be accounted for in the modeling. Especially for the calculation of frequency response functions a linear replacement system can drastically reduce the computational effort. In this paper the synchronized switch damping on inductor (SSDI)-circuit is substituted by an equivalent linear circuit, which can be used to obtain the frequency response. Measurements on a clamped beam with attached piezoceramics are conducted to validate the results.

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In this study, a semi-active vibration suppression system comprising piezoelectric elements is developed for flexible structures. The vibration suppression system comprises a cantilevered beam with bimorph piezoelectric ceramic tiles shunted by an RL electrical circuit with a switch. A general design method for vibration suppression of the beam is theoretically analyzed using mode analysis, wherein it is assumed that the piezoelectric elements are sufficiently thin and do not change the mode shape of the beam. With this assumption, the vibration suppression system for the beam is designed by tuning the optimal resistance and inductance parameters of the shunted RL network. In this paper, we propose a semi-active vibration control law to improve the damping effect while maintaining the stability of the passive control system. The proposed control law is similar to a sliding-mode control that accelerates the convergence of the system by using switching functions. As an example, numerical simulations have been performed for a cantilevered beam. This study shows that the resonant circuit functions as a type of a dynamic damper for mechanical systems and that sliding-mode control is very effective in damping the multi-mode responses. The results of the numerical simulations show that the semi-active vibration control system is practically more effective in damping vibrations than the passive control system.

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When implementing an active wave control system with the feedforward control technique, a wave filtering method is necessary for establishing an adaptive scheme. However, most of the control methods are proposed for one-dimensional structure such as a flexible beam, and there are few reports on a two-dimensional structure case. Therefore, this paper presents the wave filtering method for a rectangular panel using smart mode sensors, and clarifies its validity in the control system. Firstly, a transfer matrix method for a rectangular panel is introduced to describe the wave dynamics of the structure. This is followed by the derivation of a shaping function of the smart sensors. It is found that the shaping function of the smart sensor is a complex function. In this case, an imaginary unit is realized by the phase shifter of 90 degrees. This signal processing is realized by a Hilbert transformer. Next, from a viewpoint of numerical analysis, the accuracy of the wave filter and the performance of the control system are clarified. Finally, an experiment of the active wave feedforward control system is carried out, demonstrating the validity of the proposed method.

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This article described on implementation of self-tuning impedance control with adaptive element from environment identification to provide compliant body balance for hydraulic-actuated hexapod robot. With force-based walking control, this impedance control is applied to provide stable final stepping during walking phases by adapted the environment stiffness and force applied. Proposed self-tuning impedance control is designed with variable stiffness tuning method using time division method and exponential time reduction. The case of study is focused on walking on the soft terrain which is crucial part for this robot. The propose controller is verified with walking experiments on several layers of square rubber plate to represent soft terrain such as wet ground.

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This paper analyzes the lifting mechanism of one forging manipulator. The lifting mechanism is a hybrid serial-parallel mechanism, composed of a parallel 4R mechanism and a parallel mechanism. At first, mobility properties of the lifting mechanism are analyzed based on screw theory. Then, position analysis of the lifting mechanism is carried out. Because the motions of lifting, pitching and back-and-forward translation are independent of the motions of left-and-right translation and yawing, the lifting mechanism can be divided into two independent mechanisms, i.e., position analysis of these two mechanisms can be carried out separately.

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In this paper, a novel 6-PUS/UPU parallel mechanism is presented. The mechanism exhibit advantageous characteristics such as higher rigidity, better positioning accuracy and can be used in the fields of vision measure, force control and redundant research. At first, kinematics analysis of the parallel mechanism is carried out; constrained wrench of the moving platform imposed by the middle limb UPU is obtained. Then, singularity analysis is performed.

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Robotic surgery is rapidly being adopted as one of the most important new techniques especially in laparoscopic surgery. Yet the only currently commercially available surgery robot, although very successful, has several evident drawbacks, most prominently its large size. A completely different approach for teleoperated minimally invasive surgery is proposed here, based on a parallel structure as external positionner and an internal micro-manipulator inserted into the body through a single port as known from mini-invasive surgery. The main features of the entirely novel external positioning mechanism will be presented in this contribution.

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A high performance digging algorithm for hydraulic excavator has not established, because a relationship digging parameters and digging performance is complex. Therefore, we have investigated how digging performance may be affected by the digging trajectory. The ultimate goal of this study is to learn the digging performance by the simulation for the automatic digging process. Authors define the soil volume per the applied energy as digging efficiency in this paper. A miniature test device was developed to simulate the digging by the pre-programmed bucket tip trace. In addition, a digging simulation model by two dimensional distinct element methods (2D-DEM) was developed. The simulation is validated by comparing with the digging test results of the miniature. Finally, using the developed simulation, we tried to clarify quantitatively that the digging efficiency with respect to the tip trace. We simulated digging efficiency to modulate digging trajectory and speed. In this simulation, it is quantitatively clarified that the digging efficiency due to the tip trace and the digging speed

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A prototype of dual-wheel inverted-pendulum vehicle (DIPY) was developed. DIPV have become popular in crowded area because of their compact size and maneuverability. However, no technical report has been published on the control of such a vehicle with its rider on, in spite of the fact that rider's inertia and maneuver skill has strong effect on the vehicle performance. This study tried to simulate the DIPV-rider system movement using a simple dynamical model. The actual DIPV and rider movements were measured using LabView and motion capture system. From the time domain analyses, the effects of rider's maneuvering skill and experience, the control gains were observed.

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A conventional two-wheeled inverted pendulum vehicle consists of a step for a driver and motors for driving the wheels. In this study, a two-wheeled inverted pendulum vehicle pedaled by a driver was investigated as a personal mobility vehicle. The vehicle uses stabilization control for an inverted pendulum and pedaling torque provided by the driver. We made a prototype vehicle and carried out driving experiments to confirm successful operation. Stabilization control was realized when the driver pedaled. From the results of the input voltages of the pedaling and stabilization control, we found the vehicle moved according to the driver's pedaling. In addition, the vehicle moved forward even with a negative pitch angle.

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An on ground stereo vision system is used for autonomous hovering of a quad-rotor Micro Aerial Vehicle (MAV). A stereo vision system has advantage compared to a single camera that it can measure 3D position of an object from camera without any information about the target in advance. Therefore, the distance measurement can be conducted accurately. A weighted histogram CAMSHIFT is used for object tracking purpose. This algorithm uses color information as the feature of the object. A sliding mode controller is used for autonomous hovering of the quad-rotor. The sliding mode controller design is based on zero point of the system. Experiment on autonomous hovering using weighted histogram CAMSHIFT and sliding mode controller was conducted. The accuracy of the system achieved in autonomous hovering shows a good result which is about 0.4 m in the horizontal movement and 1 m in the vertical movement.

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This paper presents the result of preliminary study toward applying Simultaneous Localization and Mapping (SLAM) to the hydraulic-driven 6-legged robot, COMET-IV. However the SLAM concept to be applied is a different approach compared to the method applied by other researchers. We are proposing a method that is utilizing the good points of Occupancy Grid Mapping method (OGM) and Extended Kalman Filter (EKF) method, which could optimize data processing time and produce precise localization of the robot in outdoor environment. The OGM is used to generate a shortest and safe travel path from starting point to the targeted goal, at the beginning of the journey and the EKF is used to simultaneously updating the robot's location while moving toward the targeted goal. All the data used to determine the coordinates of the robot and the obstacles are based on 3D points cloud data produced by rotating laser range finder (LRF) together with gyro data and the robot's center of body (COB) data. The experiment shows promising result.

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This paper reports on the development and control of a compact, high dynamic camera orientation system with three degrees-of-freedom (DoF). The system orients a small camera around its pan, tilt, and roll axes, using a parallel kinematics driven by ultrasonic piezo-actuators. To fit its application as part of a gaze-driven head-mounted camera system (EyeSeeCam) or as an artificial eye for humanoid robots, the camera orientation device was designed to be small in weight and size as well as to replicate the high dynamic movements of the human eye. The mechanical setup is described and the closed loop control architecture, including a dead zone compensation for the actuators, is introduced. Control experiments conducted with the prototype demonstrated that the system performance is comparable to and even exceeds that of the human oculomotor system.

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This paper presents our work on realizing the manipulation of nut and bolt for assembly work using dual arm manipulator. The robot architecture consists of multiple active sensors and control procedures that are structured to work for real time operations. It is specifically designed to be similar to human arm which has seven joints for each arm to perform complicated assembly tasks on small parts using both hands that usually requires high cost human labour. Sensors are optimally used to provide data of the environment and the target object in variable conditions, shapes and sizes. Data between eye-in-hand and eye-to-hand cameras are fused and handled together with force sensors and encoders to calculate the required robot dynamics of the seven link arms for object manipulation. The first experiment that has been used as the basic platform in preparing our robot for assembly task consists of autonomous picking and placing an M8 sized bolt and hexagonal nuts of minimum 2 mm radius. Besides, based on the proposed vision processing, the robot hand could self adjust its wrist angle to avoid collision between the fingers and objects during grasping. Moreover, we showed application of vision to align M10 bolt and nut for complicated screwing operation. Experiment results are laid out to show the robot performance for above operations thus producing a dexterous dual arm robot for assembly work purposes.

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This paper describes an object tracking system using an autonomous Micro Air Vehicle (MAV) and demonstrate its potential use for civilian purposes. The vision-based control system relies on color and feature based vision algorithm for target detection and tracking, Kalman filters for relative pose estimation, and a nonlinear controller for MAV stabilization and guidance. The color based vision algorithm uses simple and fast technique object color detection using integral images, while optical flow is utilized for feature tracking. Each vision algorithm has its own weakness depending on the environment when vision-based tracking is done. The color based object tracking very much depends on suitable light condition, and the tracked object and its background color. The feature based object tracking works well with object with strong features but risks loss of detection when there is noise in the streaming image while tracking. An algorithm that combines the two approaches is presented to compensate each single vision algorithm weakness. The vision algorithm relies on information from a single on-board camera. An arbitrary target can be selected in real-time from the ground control station, thereby outperforming template and learning-based approaches. Experimental results obtained from outdoor (light tests, showed that the vision-control system enabled the MAV to track and hover above the target as long as the battery is available. We also propose this object tracking system to track a moving object on the ground as well in leader-following system setup.

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A vision system which is mounted on an unmanned mobile robot has been developed. The vision stabilization system consists of a wireless camera, 3 BLDC motors and drivers, AHRS (attitude and heading reference system), a Bluetooth communication module, a DSP controller, vibration isolation rubber mounts, a monitoring system and a joystick. To develop this system, 3D CAD geometric modeler, Pro-Engineer has been utilized for mechanism design. For required motor torque analysis, inverse dynamic analysis has been carried out using ADAMS multibody dynamics code. A stabilization algorithm has been developed based on kinematic constraint conditions of the camera coordinates. In order to stabilize vision camera, PID controller algorithm has been implemented into the DSP controller. To verify the performance and design of the vision stabilization system, the system has been tested using a motion platform which generates motion that represents an unmanned mobile robot motion. Stable camera images have been obtained.

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In this study group, we are developing a micro air vehicle (MAV), which is equipped with an automatic flight control system and a camera, for the purpose of performing rescue/relief tasks in natural disasters, security surveillance and observation tasks. MAV, however, has a limited performance due to its low payload or short duration of flight. On the other hand, unmanned ground vehicle (UGV) research and development is being pursued actively in Japan and overseas. Unlike MAV, UGV has a long continuous run time and a relatively bigger payload. It can carry many kind of equipment and play an important role in rescue. Therefore, we proposed a UGV that can assist the MAV, to make effective usage of our MAV in scenes. The UGV needs WayPoint and Mapping system. This paper shows Mapping using SLAM and WayPoint of UGV.

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This study aims at proposing a control method for an Adaptive Cruise Control (ACC) to improve not only following capability to a leading vehicle but also suppression of fuel consumption. It is said that a low acceleration drive contributes suppression of fuel consumption, but an excessive low acceleration drive causes worsening following capability. They should be considered all together because there is trade-off between them. A control law for an ACC to balance the following capability and the suppression of fuel consumption using Linear Quadratic Integral control is designed. To verify the control law, two ways of simulations are carried out. One is the simulation of two vehicles consisting of a leading vehicle and an ACC vehicle. The other is the simulations of a platoon of ten vehicles. It is demonstrated that the control law is effective for suppression of fuel consumption by comparison to the existing Two Degree Freedom (TDF) Control.

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This paper presents control system design for occupant lower extremity protection in vehicle frontal collision. In order to protect the occupant's lower extremities in vehicle collision, a protective control system consisting of an active knee bolster and an active lap belt is designed to reduce the maximum load to the femurs and the maximum lap belt force. The lap belt force and the contact force between the knees and the instrument panel are controlled. The lap belt force acts on the pelvis. The contact force between the knees and the instrument panel acts on the lower limb after the knee collision. The control problem is formulated as reducing the load to lower extremities while restraining the occupant forward motion. The lap belt force and the contact force are calculated so that the load to the femurs is reduced while the lap belt force is not increased compared to passive lap belt. In this paper, we assume that the protective control system can vary the initial distance between the occupant's knees and the active knee bolster. Simulation results clarify the effects of the initial distance between the knees and the knee bolster on occupant protection.

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Safety systems in intelligent cars have been developed to enhance driving convenience and safety of drivers. Adaptive Cruise Control(ACC) system, Pre-Crash Safety(PCS) system and Collision Avoidance(CA) system have been already developed by many automobile companies. But direct implementation of aforementioned approaches can't reduce the damage caused by mismatch of bumper heights between two cars when rear-end collision occurs. The proposed control system is designed to reduce the crash damage, when unavoidable rear-end collisions occur, by controlling active suspension of the subject vehicle to match bumper heights. The proposed algorithm is a modified control scheme using the finite horizon LQ control and the receding horizon LQ control. In real situation, estimated time to collision may be varying at each sampling time by unpredicted driving conditions of object car and subject car. The modified optimal control scheme is called by varying horizon LQ control. Conventional onventional optimal control schemes are special case of the varying horizon LQ control. The tracking performance of the finite horizon LQ control and varying horizon LQ control is verified by numerical simulations.

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The investigation for the seat back and headrest according to rear-end collisions has been actively studied. However, most of these studied are mainly performed for the seat back and headrest related with human body. Whiplash was recognized as a major injury in rear-end collisions. In this paper, it was considered the connection mechanism how to reduce the contact time and backset was proposed from the mathematical modeling for link structure between seat back and headrest for design parameters assuming the virtual link, pivot point, guide bracket were selected. As results, from the design for link connection, kinematic and dynamic simulation was performed. And also validity for link connection was conformed. Conclusively the contact time and backset were effectively reduced real dynamic conditions

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For an autonomous vehicle that travels off roads, its driving speed should be adjusted by considering road roughness and slope. To maintain stability, the driving system should compromise road conditions such as obstacles. Thus, the road roughness and obstacle are the most important disturbance factors for autonomous maneuvering. This paper presents an algorithm to determine the vehicle maneuvering speed running over off roads. To determine the maneuvering speed maintaining stability, the speed detecting algorithm must be predicted in real time through vehicle dynamic analysis. To achieve this goal, the equation of motion of the vehicle is derived in terms of the chassis local coordinates and the velocity transformation technique is combined with symbolic computation to achieve real time analysis. And the operating stable velocity is determined from the database, where the maximum speed is stored depending on road conditions.

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This paper presents a sliding mode controller of rudder angle servo mechanism in electronic controlled steering system of pleasure boats. The sliding mode control theory is applied to the proposed controller so as to have high robustness against the normal pressure of the rudder, which is regarded as an unknown disturbance. With the twisting algorithm and the describing function method, a new switching input of the sliding mode controller is designed in order to lead the switching function to a limit cycle. As a result, the chattering could be improved by the relatively smooth control input.

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The paper presents a method to improve "maneuverability" which is the characteristics of the rotational motion from the rudder, as well as "steering feeling" which implies the characteristics from the steering wheel to the rudder for pleasure boats. To achieve this aim, the maneuverability of pleasure boats is evaluated and a simplified simulator including a steering system with simulation software is equipped. Then it is considered a method to give a virtual reaction torque on the helm in order to improve steering feeling on the maneuverability. The results show that it may be able to navigate stably and reduce the meanders by feeding the appropriate reaction torque on the steering wheel.

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Mobility Research Center (ITS Center), Institute of Industrial Science, The University of Tokyo has approached to improvement of realistic sensation on "Universal Driving Simulator for Human, Vehicle and Traffic Research"(DS). The DS has a 6-DOF motion platform with the turntable mechanism. The turntable mechanism is effective to suppress a motion sickness and to improve driving feeling. Especially, it is particularly effective in the situation that a driver steers to the right or the left at the corner. However, lack of lateral acceleration caused uncomfortable driving feeling of the DS. To investigate the relation between driving feeling and a yaw motion, the subject experiments were performed using the DS when some values of the scale factor were determined. In this paper, subjects' evaluations based on largeness of a yaw motion of the DS are described through experimental results.

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Although active suspensions have better control performances, they consume energy to operate actuators. Then in previous researches, to reduce this consumption, active control systems using regenerated energy were proposed. These researches focused on the methods of control or how to design active controllers, however, it is needed to consider more basic issue, that is, the number of actuators and their arrangements suitable for the active control. This contributes to cost-cutting as well as saving energy. Then, the optimal number of the actuators and the arrangements are examined through numerical simulations. The results indicate actuators installed in the rear suspension can suppress vibration with less energy, while reducing the number of actuators tends to increase the power consumption. These remarks may depend on the specifications of the automobiles, however, it is found the number of the actuators and their arrangements are worth considering for an efficient active suspension.

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While global warming is concerned, eco-driving is proposed for reduction of vehicle CO_2 discharges. Eco-driving is a driving mode through driver behaviors mainly about accelerator work such as smoothing acceleration at start, preservation of the steady speed and active use of engine brake. However, few studies clarified muscle fatigue of driver to analyze driver behaviors during eco-driving. In this study, in virtue of a universal driving simulator (DS), driving experiments by subjects were conducted in the modes of normal driving, eco-driving, and eco-driving with eco-indicator. In the experiments, surface electromyography (sEMG) of leg muscles of driver was measured to clarify muscle fatigues in different driving modes, and further driver behaviors were also analyzed. Through comparing analysis results, it is validated that eco-driving with eco-indicator is effective as an eco-assistant-system.

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An electric Vehicle uses the system to a power source whether it limp a high efficiency, without environmental pollution. It coincide the best at the 21th century environmental regulation and energy frugality. The design and making of a self manufacture and AC Servo Motor control system for a speed control are carried out in this study. The Frame of a Self Manufacture Electric Vehicle is manufacturing, the system construct and speed control simulation using a variable resistor of Motor control system complete.

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High performance of the catenary and pantograph dynamic interaction is required in the operation of high speed railway vehicles. Due to the constraint of field test, simulation and lab experiment procedures are performable to verify the interaction. Such simulation needs accurate modeling of the response of the pantograph for the consistency in prediction and control. A simple system identification of the pantograph is executed based on the lab experimental data using commercial software and regression method. The validation of the procedure is performed through comparison between extended experimental data and numerical simulations of the pantograph system. Further analysis is by applying active pantograph control on the system by simulation. The results show availability of the design for active pantograph system.

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In this paper, a method for three-dimensional dynamic simulation analysis of rotary snow removing machines is constructed to contribute to optimum design and control of the machines. The simulation analysis method is based on the Distinct Element Method, which is suitable for simulation of the dynamic behavior of discontinuous objects like snow. The key part in the simulation analysis is contact judgment between snow and rotary equipment and described in detail. As a first step to evaluate the validity of the constructed method, motion characteristics of snow thrown from a shooter into the air were analyzed and compared with experimental results. The simulation results showed a similar tendency to the experimental ones. Moreover, as snow removal characteristics, we analyzed and discuss not only the motion characteristics of the snow in the process of snow removal but also the resistance torque on the equipment such as auger from the snow. These results demonstrate the practical usefulness of the constructed method.

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This research introduces a method to estimate vertical track irregularity from accelerations of the bogie using ICA (Independent Component Analysis) and examines the performance through the experiment using test track and an actual bogie. The authors propose to apply ICA to monitor the railway system. It is a method to identify the signal sources from the multi data sets of the mixed signals. The vertical accelerations of bogie frame at several points are measured, and the velocities and the displacements at those points are calculated by integrating and double integrating the measured accelerations, respectively. They are treated as parts of the observed data sets as well as the accelerations. By using ICA, the vibration of front and rear wheels are separated. From this result it is expected to separate some disturbance mixed to the track irregularity such as bias of wheels.

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The high energy-saving new public transportation system called the "Eco-Ride" has been developed to solve various traffic issues. Eco-Ride vehicle does not have on-board driving devices. The vehicle runs using potential energy with the principle of the roller coaster. The test track and the prototype vehicle were made to examine the basic performance. It was confirmed that running velocity could be estimated based on rolling resistance and track geometry by comparing the results of calculation and actual measurement with the test track and the prototype vehicle. This suggests that rolling resistance and track geometry are important to optimize velocity control. Also, the vibration acceleration of the prototype vehicle was measured and analyzed for the ride comfort of Eco-Ride prototype vehicle based on measurement results by the method widely used in conventional railways.

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Japan is a seismic country and it is worried that a big earthquake will hit the urban area in the near future. Medical treatment is indispensable so it is very important to keep the healthiness of medical equipments to maintain the function of the hospital after earthquake. Many types of medical equipments, especially heavy equipments, have casters for their easy treatment or movement. These equipments were damaged in the past big earthquakes. If casters are free, large movement is happened and causes a disconnection of the connecting point or collision to the other equipments. On the contrary, if casters are locked, displacement of the equipment becomes small but large response acceleration causes turnover or falling of the installed equipments. In this paper, seismic response mitigation strategies of the wagon with casters were investigated. Soft braking technique and brake force control by ER brake were proposed and the effectiveness of these methods was confirmed by simulation studies and experiments using small shaking table. Soft braking, which means the constant force braking by smaller force than normal locking, could reduce the response acceleration compared to the case of normal locking, and also could reduce the response displacement compared to the case of no braking. This method needs no sensor and analytical model of the equipment, so it can be realized easily and cheaply. Brake force control needs sensing of the equipment responses and analytical model to use the modern control theory. So first, the simple analytical model of the wagon with caster was investigated and good agreement with the simulation results using proposed model and experimental results was confirmed. Then controller using instantaneous optimal control algorithm was designed to reduce the seismic response and the effectiveness of the system was confirmed by simulation and experiments.

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The number of amputees has increased by industrial or traffic accidents, although safety control and accident prevention are emphasized in modern society. Since more amputees use a prosthetic limb, its needs have increased year after year. Contact relation and position relation between a prosthetic limb and the human body must be detected to fulfill a function of a prosthetic limb. In this case, force and moment applied to a prosthetic limb are important indices. Especially, it would appear that greater applied moment is generated to a prosthetic limb when amputees with a prosthetic limb are walking on the uneven ground. Lately, Since clinical studies of gait analysis has been advanced, functional evaluation has been performed to the people who have a disability in the walking motion by current motion analysis systems; However, more practical exercise condition cannot be measured outside of specially-cleaned environment. Therefore, the system that can measure long continuous walking motion of amputees under wide environmental conditions has not been put to practical use. For these reasons, in this paper we developed a six-axis force/moment sensor that can be attached to a prosthetic limb and improved performance of this sensor by structural optimization. The developed sensor in the present study can be easily fixed between the artificial knee joint and the prosthetic foot to detect the load condition during walking. Measurement principle of this sensor is to measure force and moment from a change in electrical resistance of strain gauges on the sensor elastic body. We used finite element analysis, response surface method, desirability function and mathematical programming as proposed techniques for structural optimization and calculate response surfaces by central composite design. As results in the present study, we optimized the structure of this sensor and validate the effectiveness of optimum design variables and the proposed techniques.

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In the field of vibration control, accelerometers have been widely used. The velocity and displacement sensors are convenient for vibration control in stead of this kind of sensors, because the former can simultaneously detect the velocity and acceleration signals. For the latter, the displacement, velocity, and acceleration signals are simultaneously detectable. We previously proposed both sensors characterized by using calibration coil as a back electromotive force detector. However, servo parameters for both sensors were tuned by trial and error. Namely, there are no adjusting criterions in their frequency shaping. In this paper, we propose a design method based on the state feedback. It is firstly shown that the velocity sensor can be realized by the type-1 servo system and that a special weight setting is required for the frequency shaping. Next, the type-1 servo system is constructed by using an equivalent transformation of pseudo-differentiator for the subject of the displacement sensor. Through the weight matrix tuning for optimal control, it becomes clear that specialized weight is also required.

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In this paper, a newly designed wireless sensing network platform for structural monitoring applications is presented and the results of a validation test performed in the authors' laboratory are reported. The main features offered by the proposed wireless platform are the capability of real-time and multi-channel data transmission, a high compatibility to different types of sensors, a highly efficient power-supply, and low-cost. Instead of adopting the most commonly used commercial wireless modems, the wireless communication is pursued by implementing an optimized and customized solution based on a recent System on Chip wireless transceiver. The Frequency Division Multiplexing method is exploited to ensure the real-time feature of the multi-channel data transmission. A simple and practical point-to-point topology is pursued. The usage of switching regulators which feature low quiescent current, highly efficient power conversion, the adjustable output voltage, and the high output power make this platform suitable for both low-power and non low-power structural monitoring applications involving different types of sensors. In order to validate the prototyped platform, a laboratory test is performed. The measurements of the acceleration response of a simple 3-storey structure mounted on a shaking table are acquired from both a wired DAQ system and the developed wireless platform. The data comparison enables to validate the efficacy of the real-time, multi-channel wireless transmission.

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In order to overcome the disadvantages of parallel structure six-axis force sensor with traditional sphere pair, four kinds of pre-stressed parallel structure six-axis force sensor using modified spherical pairs are proposed. The structure feature of the sensors are analyzed in comparison with the traditional Stewart platform-based sensor. The experimental study of static calibration of a sensor prototype is carried out, and the experiment results prove the superiority of the structure and the correctness of the theoretical analysis.

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GPS (Global Positioning System) has been proved to be one kind of effective non contact displacement sensor for measuring structural deformation, but it has shortcomings in dense urban areas and inside the building. This suggests the study of LPS (Local Positioning System). In this paper, the principles of several distance measurement procedures, which include the measurement methods based on signal propagation time, are investigated, and their precisions is discussed. Then, the ways used to reflect signal propagation time precisely, such as UWB (Ultra Wide Band), CSS (Chirp Spread Spectrum) and FMCW (Frequency Modulation Continuous Wave), Code-Phase measurement, Carrier-Phase measurement are reviewed. The available solutions are investigated mainly in terms of measurement precision, covering range, complexity of equipment. The satisfaction of the requirements for structural mechanics applications is pursued.

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Micro scale products such as a MEMS gyroscope usually have relatively large manufacturing uncertainty compared to normal macro scale products. The material and geometric uncertainties caused by a micro manufacturing process inevitably lead to the uncertainty of the product performance. Therefore to achieve a reliable design of a product, the performance uncertainty of the product needs to be estimated. In this paper, the equations of motion of a MEMS gyroscope model are derived to analyze performance indices such as sensitivity and bandwidth. The statistics of some critical design variables are determined from the performance requirements. Finally a statistical procedure based on sample statistics is proposed to estimate the confidence interval of the performance statistics.

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This paper deals with a theoretical analysis and experiments of a non-contact active feedback control, which is based on flow and aero-dynamical control, to suppress a leakage-flow-induced vibration of translational 1DOF system. In the proposed active feedback control method, the leakage-flow-induced vibration is suppressed by using a movable plate, as an actuator, set at inlet and outlet of the passage to control fluid force acting on the controlled target and fluid flow in the passage actively. The strategy of this active control method is based on active flow and aero-dynamical control which cancels the exciting fluid force acting on the rigid body. The root locus and critical flow velocity with and without control are calculated with changing the controller gain and phase-shift to evaluate the control performance, and experiments are conducted to verify the theoretical calculations. As a result, it is indicated that the leakage-flow-induced vibration is effectively suppressed by the proposed non-contact active control method and the suppression effect is very sensitive to the phase-shift and actuator position. For the inlet flow control, the vibration is effectively suppressed when the phase-shift is positive, and for the outlet flow control, the vibration is suppressed when the phase-shift is negative. The suppression effect of the inlet flow control is greater than that of outlet flow control.

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This paper deals with an active feedback control to suppress a flow-induced web flutter using pressure wave. Non-contact suppression of the web flutter by the active feedback control is demonstrated experimentally. In the experiments, a flexible web, as a controlled object, is supported at both ends and subjected to fluid flow in the passage, and a tensile force is applied to the web. The flutter occurs to the web due to the fluid flow with a self-excited feedback mechanism resulting from fluid-structure interaction. The web flutter is suppressed by the active feedback control using the pressure wave from a loudspeaker. The loudspeaker is set at downstream of the passage, and is driven by a control signal with changing the controller gain and phase-shift between the web displacement and control pressure. The ratio of the flutter displacement with control against that without control is examined for various controller gain and phase shift. As a result, it is indicated that the web flutter is effectively suppressed by the proposed active control technique without contact, and the critical flow velocity increases by about 20%.

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Rotor systems possessing a number of rotor blades are characterized by a set of linear differential equations with periodically time-varying parameters. For such rotor systems, the multi-blade coordinate (MBC) transformation can be applied to transform all coordinates of the individual rotor blades into the multi-blade coordinates, which describe overall motion of the rotor blade group in the inertial reference frame. Especially, in the case where all the rotor blades are identical both structurally and aerodynamically, periodically time-varying parameters in the equation-of-motion are eliminated in the process of the coordinate transformation and it allows the ordinary eigen-value analysis for linear time-invariant systems to be applied. In the field of wind turbines, therefore, the MBC transformation technique has been commonly adopted to obtain eigen-solutions of a wind turbine system, under the assumption that all the rotor blades are identical both structurally and aerodynamically. The MBC transformation, however, often leads to erroneous eigen-solutions, unless the degree of asymmetry on the row of rotor blades is negligibly small. In the present paper, a coordinate transformation approach that employs the Hill's method of infinite order determinants is proposed to carry out the stability analysis for the periodically time-varying linear system, regardless of the group symmetry condition of the rotor blades. A numerical example is treated to demonstrate the effectiveness of the proposed approach in yielding precise eigen-solutions against the conventional MBC transformation technique.

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Fundamental aerodynamic characteristics are studied for the ornithopter in this paper. Three types of movement of wing are examined including 1) flapping motion to move the wing into the vertical direction, 2) feathering motion to change the angle of attack in the flapping motion, and 3) lead-lag motion to move the wing into the horizontal direction. A wing model in two dimensional motion in vertical plane is analyzed numerically in the flapping, feathering, and lead-lag motion. The aerodynamic characteristics are examined for the resulting vertical forces and horizontal forces obtained by the wing due to these three types of motion. These numerical results show the importance of the method of combination between the flapping, feathering, and lead-lag motion. A small size model for experimental demonstration is also cited as to enable these three movements, employed with an ornithopter model The flapping mechanism is implemented in a small size model.

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Flow-induced vibration may occur in the structures such as elastic beams subjected to annular flow in the narrow passage. Once the flow-induced vibration occurs, vibration amplitude becomes larger, consequently it causes a lot of troubles such as fatigue or failure in mechanical structures. In this paper, for the purpose to avoid these troubles, the active control of vibration of an axisymmetric elastic beam subjected to annular flow is investigated. An air-pressured actuator is attached on the surface of the circular cylinder for the vibrational control. As the shape of the actuator changes by control, the gap width in narrow passage changes locally, which causes the change of the fluid pressure. Therefore, the vibration of the fluid-structure coupled system can be suppressed. The fluid-structure coupled equation based on the Euler-Bernoulli type of partial differential equation and the Navier-Stokes equations is analytically derived including control terms. By applying the optimal control law to the coupled system, the unstable behavior is stabilized. The stability of the coupled system with optimal control is investigated by eigenvalue analyses of controlled coupled equations. Numerical simulations are performed to investigate the efficiency of the proposed control method.

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The aim of this paper is to grasp the occurrence condition and the vibration behavior of combustion oscillation as the fundamental study of control of combustion oscillation. Here, combustion oscillation is treated as one-dimensional phenomenon, and pressure and flow velocity fluctuations are analyzed. Combustion chamber is divided into three regions, that is, the region of non-reacted gases, the region of reacted gases, and the reacting zone. In these regions, basic equations are derived from the law of conservation of mass, law of conservation of momentum, law of conservation of energy considering heat quantity, equation of state of ideal gas. In this paper, the response time delay between the response and the generation of heat is introduced considering the structure of the flame. As a result, the relation between the equivalent ratio and the time delay is derived. Analyzing the complex eigenvalues, damping and frequency of the vibration are investigated. Simulation studies are performed to investigate the stability area, taking the length of combustion chamber, the position of reacting zone, the equivalent ratio, the preheat temperature and so on as parameters. To investigate the stability area, the experiments are also performed by making the simple experimental apparatus. The predominant frequencies and the vibrational modes are investigated experimentally, varying the length of combustion chamber, the position of reacting zone, the equivalent ratio, the flow volume of gas and air. It is seen that the analytical and experimental results coincide qualitatively.

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Electro Dynamic Tether (EDT) system is one of the non-chemical propulsion systems on low earth orbit (LEO) in the future. The tether technologies rocket experiment (T-REx) mission was proposed, which is the first attempt in the world to employ a bare tape tether. The sounding rocket S520-25th is provided for the T-REx mission. In this mission, the tape tether is stored in a storage box in a foldaway manner, which is a new concept of tether deployment schemes. To expand EDT system feasibility, a small satellite mission of EDT system, following T-REx mission, is planned, in which a bare tape tether of 3km stored in the folding manner will be deployed. However, shape of the foldaway tape tether storage is concerned to affect the design of the spacecraft in case that the tether length becomes longer, and simple expansion of scale will not be able to cope with this problem. In this paper, in order to improve store efficiency, we expand foldaway manner to the two dimensions, called "cross-shift foldaway storage." To evaluate deployment performance, the tape tether is described as a discriminate model with springs and dampers.

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