A hybrid experimental method, in which an actuator-excited vibration experiment and a response analysis using a computer are combined on-line and conducted simultaneously, is being developed as a new seismic experimental method for investigating structural systems.In this report, a mehtod using a shaking table as the actuator is proposed so that the hybrid experimental method can be applied to a secondary structural system attached to a primary structural system.A response analysis algorithm is proposed for this experimental method and its stability and calculation error are investigated by using a rigid mass as a secondary system.In addition, the feasibility of this seismic experiment was demonstrated by using an experimental system consisting of a small shaking table and a digital signal processor.

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Dynamic behaviors are analyzed for an automatic ball balancer with double races, which is a device to reduce unbalanced mass of rotors.The nonlinear equations of motion are derived by using Lagrange's equations with the polar coordinate system.It is shown that the polar coordinate system provides complete stability analysis while the rectangular coordinate system used in other previous studies has limitations on the stability analysis.For the stability analysis, the equilibrium positions and the linearized perturbation equations are obtained by the perturbation method.Based on the linearized equations, the stability of the system is analyzed around the equilibrium positions;furthermore, to confirm the stability, the time responses for the nonlinear equations of motion are computed by using a time integration method.

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The nonlinear vibration of the coupled textile / rotor system is investigated by using the finite difference method.Both the partial differential equation for the textile transverse vibration and the ordinary differential equation for the rotor whirling vibration are derived by Hamilton's principle.When the textile is wound either on or off the rotor, the physical modes is non-conservative because the mass, inertia and unbalance magnitude of the rotor change with time, and also the length of the textile is time-dependent.A special technique of the finite difference method is developed for such a time-dependent length of the textile.The approach used here is with fixed-size grid and changing the grid number as the length varying.Finally, numerical examples are presented to demonstrate the effects of the rotating angular speed, roating angular acceleration and nonlinear terms on the transient amplitudes of the coupled system.

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The Authors have developed a four wheel steering controller which can handle nonlinear tire forces.A new technique, Intelligent Sliding Surface Control, has been used to prevent control system instability induced by saturated functions.In this paper, unknown tire-road contact conditions are discussed.The roubust performance of two types of controllers, a siliding mode controller and an adaptive sliding mode controller, is compared using simulation.

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This paper proposes a control method of a rigid body motion system which includes unknown nonlinearity by using motion learning.Defining the motion learning as achievement of objective motion control by obtaining the model of motion system, the proposed control structure consists of feedback controllers to stabilize the unstable motion system, a motion learning system to obtain nonlinear model and to linearize the motion system by using the obtained nonlinear model, and an inverse motion system to generate inputs to be applied to the linearized motion system.The obtained model is described as series of weighted basis functions, and the explicit learning rules of weights are derived by using Popov's hyperstable theory.The tuning rules of feedback gains are determined by using the obtained nonlinear models.Futher, this paper shows the high performance of the proposed method by demonstrating an experiment of the tracking desired trajectory in the electromagnetic levitation and positioning system.

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This paper discusses the modal decomposition of the Operating Deflection Shapes (ODSs).The ODSs offer an important contribution in the understanding of the dynamic behavior of a system under operation.The modal decomposition can express each ODS as a linear combination of modes, and have been usually done in a least squares sense.However, there are scarcely modal vectors which cross at right angles, and consequently the result obtained from the ordinary method give obscure interpretation.Therefore we propose that the modal decomposition based on the General Definition of Projectors (GDOP) is most suitable for the detailed description of the modal decomposition.Moreover, we present a new model correlation technique based on the GDOP to verify the modal vectors, because the accuracy of the modal vectors is important in the modal decomposition.These approaches are demostrated using numerically simulated FRFs and modal vectors.As a result, it was shown that these approaches give good clearer results compared to the ordinary modal decomposition method.

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An integrated control system of active rear wheel steering and yaw moment control using braking forces is presented in this paper.Due to the tire nonlinearity that is mainly due to the saturation of cornering forces, the improvement of vehicle handling and stability is limited to a certain extent when using only rear wheel steering control.Yaw moment control using braking forces is effective not only in linear but also nonlinear ranges of the tire friction circle.Considering the tire friction circle, the control system is designed using model matching control theory to make the vehicle performance follow a desired dynamic model even during large decelerations or lateral accelerations.Various computer simulations in severe driving conditions were carried out and verified that vehicle handling and stability are much improved by the integrated control system.

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We have proposed a new optimal trajectory planning method for a system with nonholonomic constraints due to passive joints based on a function approximation method.The trajrctory is approximated by a linear combination of Hermite functions and Fourier series.The combination variables are solved by a nonlinear programming method that considers the constraints in the same function space as that of the trajectory.We have examined the validity and features of this method by applying it to the optimal trajectory planning of a steady giant swing motion.We found that this method has efficient convergence characteristics in iteration calculations and can provide accurate solutions depending on the order number of the approximating functions.Optimal giant swings with no input torque can be obtained for various motion periods.

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It is necessary to measure the flying height of a slider on an actual magnetic disk when designing magnetic disk drives.However in typical methods for measuring spacing, the magnetic disk is usually replaced with a glass disk.To measure this real spacing, we developed a flying-height sensor based on frustrated total relfection.However, to measure the real flying height optically, the phase shift on reflection at a magnetic disk is an important problem.We developed a theoretical treatment of this problem and introduced the modified effective-refractive-index method.We measured the effective-refractive-index of an actual magnetic disk.Flying height on the magnetic disk was also measured by using the obtained effective-refractive-index.This result was compared with the flying heights measured by using the traditional interference method.Both measurements agreed well with an error of less than 2 nm.

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In quantized control systems, the control can take only discrete (e.g.integer)values.Optimization of such systems has been conventionally performed by the mathematical programming mehtod such as dynamic programming or integer programming.In a quantized, linear, time-invariant, discrete system with rational coefficients, a minimal-time control problem is formulated by using the transition between two points in the state space.Considering the properties of the system expressed by the state equation employed in the present investigation and the relation-ship between a discrete-time control problem and a mathematical programming problem, a solving method of this optimal quantized linear discrete control problem is demonstrated with two numerical examples.

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In this paper, the static characteristics of the four-nozzle pintle type servovalve are studies theoretically, under constant supply pressure and constant supply flow conditions.The study is on an eye to the effect of the valve improper configuration, the required pintle driving torque, and the effect of using unsymmetrical loads on the static characteristics.Errors in valve control gaps resulting from inaccurate initial adjustment, wear of else showed to affect slightly the load flow at each load pressure and input displacement.Units driven by unsymmetrical actuators showed to have lower valve flow forces and higher valve efficiency than symmetrical actuators.The minimum flow gain and flow pressure coefficient are obtained when the load is symmetric.The study showed that the flow forces have two instability sources, decentering nature and similar values at different input displacements.The study discussed the selection of the pintle centering spring to overcome the problems of instability.

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Diesel particulate filter system is very effective for reducing the amount of particulate matter in exhaust emission of diesel engine.This system catches particulate by its filter and the filter is regenerated when it is fully loaded.To control effectively its filter regeneration, an accurate and reliable estimation of particulate accumulation is required.In this case it is desirable to employ an estimation method capable to compensate unknown factors in filter dynamics and operating conditions.In our previous work, the estimation problem was solved by feedforward neural network (FFNN), widely known of its capability to model nonlinear system.However using FFNN encounters both training convergence and structure design problems.This work is designed to solve both problems by employing a novel compact mehtod capable to conduct training while determine network efficient structure automatically.The experimental results verify the effectiveness of the method where an efficient structure is automatically obtained with desired training convergence.

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In this paper, the properties of a hybrid superconducting magnetic bearing (SMB) system are discussed.The hybrid SMB system consists of passive SMBs, active magnetic bearings (AMBs), a rotor, and sensors.The rotor position is controlled by a controller without bias current.Because the controller does not need bias current applied to the electromagnets, energy loss is considered to be less than that of other magnetic bearings.The displacements of the rotor are suppressed by both SMBs and AMBs.The superconductors of the SMBs were field-cooled.Compliance of the bearings, displacements of the rotating rotor, and energy loss of the hybrid SMB system were investigated.The results show that the hybrid SMB system has good perfoemances in these aspects.

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This paper is concerned with the positioning control of single link flexible arm using sliding mode control theory.We designed the control system using output feedback method.But the high gain sliding mode controller often causes the control system unstable based on spillover phenomena in higher frequency region.Therefore, we also design for the switching hyperplane using H_∽ control theory.But H_∽ controller has a problem of a big overshoot.Then we apply to Q parametrization which has a performance of H_∽ controller.In a word, nominal controller is the H_∽ controller.Q parametrization can satisfy some constraints, for example, norm, overshoot, settling time and so on.Q controller has a good performance.However, it becomes a high-order compensator.In this study, it becomes from the 6th to the 25th-order.

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In this paper, the nonlinear responses to uncertain excitations modeled by convex sets are discussed.First, the nonlinear differential inclusion problem is converted into a class of optimization problems to solve the worst response.Next, it is simplified to a two-point boundary value problem of nonlinear ordinary differential equations.Finally, as an example, the Duffing equation is considered to obtain the numerical results for the two-point boundary value problem using the shooting method.The worst response and the worst excitation at a given time are discussed.The results show that the worst excitation corresponding to the worst response is a rectangular wave, and not a sine or a cosine wave for maximum-bound convex excitations.The worst excitation of a linear system is a uniform rectangular wave with natural period, while that of a nonlinear system is not a uniform one.This nonuniformity is related to the nonlinearity, the initial conditions and the excitation bound of the system.Results of further analysis are consistent with the results of a classical nonlinear theory.

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Recently, we proposed a fuzzy Kalman filtering algorithm (FKF algorithm) which is formulated by embedding a set of parallel Kalman filters inside a fuzzy inference mechanism (FIM)⁽1)-(4).This paper proposes a version of FKF algorithm that directly determines the gain of each of the parallel Kalman filters.It fuzzifies both the modeling uncertainty of the dynamic system and the quality of each measured data to determine the Kalman gains.This can largely reduce the number of the parallel Kalman filters inside the FKF algorithm and the computation requirement.Monte Carlo simulations are conducted for observation and comparison.By adjusting the Kalman gains directly, the computation load is highly reduced with only slightly change in the filter performance.

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An innovation estimation scheme is conceived to solve the intial and divergent problems for an all-accelerometer inertial navigation system (INS).The reformulated unobservable system with six accelerometers mounted diagonally on each surface of a cubic is investigated.An own-ship trajectory estimator produces extra pseudo measurements in position and velocity of the vehicle to help the Kalman filter in achieving convergence subject to unknown initial values.It also provides an upperbound value for the initiation of the platform attitude.A simulation case with arbitray initial values verifies the effectiveness of using this information infusing concept in obtaining a convergent INS state estimation.

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In the present paper, we propose an H-slit beam which can be effectively utilized to achieve a highly unidirectional deformable structure.The outlines and characteristics of a 3-axis force / torque sensor based on the above proposal is also reported.This sensor can measure very small reaction forces and torques generated by the motions of a robotic manipulator having its degress of freedom in only one plane.For such an application, a sensor structure which accepts no effect of gravitational force on the manipulator is needed.The important point to consider is that the sensor should be sensitive only in the direction of measurement of force / torque, and very stiff in all other directions.To achieve this goal, we propose the H-slit structure as an extension of the parallel beam structure.The idea behind is the formation of a 4-link closed structure, the joints between the links are deformable, hence the strain gauges can be fixed at these positions.By changing the dimensions of links, a variation in sensitivity and directional stiffness is possible, and by changing the dimensions of H-slit, a mechanical over-load protection is also achieved.

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We propose the Planning of Landmark Sensing (PLAS) considering environmental conditions for autonomous mobile robots.When a robot moves, the robot usually resets accumulated position errors by sensing the landmark.In previous works, these errors are estimated based on robot models, and Kalman Filter is used to reset the errors after the landmark sensing.Based on this method, only the relation of the robot and the landmark position is considered to influence the observation noise of Kalman Filter.But in the actual visual landmark sensing, environmental conditions, like position of lighting and brightness of room, are likely to cause the misrecognition of landmark.Then we consider environmental conditions for the observation noise.This helps our system to recognize the possibility of the misrecognition in bad sensing environments.As a result of the consideration of the environmental conditions, our navigation system can navigate robots precisely, even if the environments are not suitable for the landmark sesning.

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The "pneumatic wobble motor", a new type of pneumatic stepping motor, has been developed.A pneumatic wobble motor consists of a donut shaped wobble generator made of silicone rubber, a wobble ring made of metal, and an output shaft.The output shaft is encased in the wobble ring which the wobble generator covers.The wobble generator has six chambers and injecting air into each sequentially causes the wobble ring revolution, which makes the output shaft to rotate.In this report, first, the driving principle and design of this motor are presented.Next, its characteristics are analyzed theoretically.Two prototypes with different designs are fabricated and tested.The experimental results are promising.The features of pneumatic wobble motor are(1)big torque (more than 10 times that of conventional small-size electromagnetic motors).(2)simple structure and(3)waterproof and dustproof.

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"Bubbler, "a new type of pneumatic rubber actuator realizing linear motion, has been designed and developed.Bubbler consists of a silicone rubber slab, and its interior is divided into many chambers.When pressure is applied to successive chambers sequentially, the surface of the rubber slab produces linear traveling waves which drive objects placed on the actuator.This actuator can be applied as a mobile robot base or a conveyor.The mechanism and characteristics of this actuator are discussed in this report.The characteristics of the actuator can be estimated by applying a simple linear analysis mehtod for various driving conditions:frequency, length, and duty ratio of the generated waves, vertical loads, and horizontal loads.Slip ratio or the error between the theoretical and experimental velocity of the actuator is within 20%.Experimental results are very promising.The walking speed of the prototype, 63mm×60mm×9mm in size, was found to be 4.7mm / s and the load-to-weight ratio in the order of 40:1.

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Determining the load distribution on a contact line of a bevel gear and the tooth root stress distribution are very important on strength design.However, it is not easy to request them, because the mesh is three-dimensional and the tooth thickness and the height of tooth become large from the toe through the heel, unlike a cylindrical gear.Therefore, in a previous report by using approximate equations of deflection-influenced functions and the bending moment-influenced functions of a tooth of a bevel gear, we proposed the method to calculate the load distribution on the contact line of a tooth of bevel gear and the tension-side root stress.In this report, we examined the influence of number of teeth and gear ratio for them.

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Cross-section roundness profile measurement is generally considered a significant procedure in the processing of parallel rollers requiring the highest quality in dimensional accuracy.This becomes a difficult procedure due to the fact that such rollers show extremely small dimensional error, resulting in expensive and time consuming measuring methods or, in most cases, the ignorance of the procedure itself.This report deals with the development of a roundness measurement system for high-precision parallel rollers based on a V-block double enlargement device.The measuring principle of the V-block method is described, followed by details of our proposed double enlargement device.Cross-section profile measurements are conducted on JISP1 grade parallel rollers, and these results are further compared to results obtained from a contemporary radius measurement method to demonstrate the validity of the device for such application.

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In the present work a theoretical method has been proposed to predict the starting torque characteristics of constant difference epitrochoid generated orbital rotary piston hydraulic motors.For the analysis of such class of Low Speed High Torque(LSHT)hydraulic motors, design and manufacturing data of a few variety of products have been used in the computer calculations to estimate the variation of torque with shaft position over a power cycle.Effects of various factors such as fitting of the rotor-stator (i.e., star-ring), drives, interchamber leakage and their variations with shaft positions have been considered.Finally experiments have been conducted to establish the theoretical model.Experimental result have good agreement with theoretical predictions.

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Results of theoretical investigations of the stability characteristics of an actively controlled externally pressurized air journal bearing are presented.The proportional and derivative control is used for the control algorithm of the active air bearing.The stability characteristics of the actively controlled bearing for zero steady-state eccentricity are investigated with the step jump method.The speed at onset of instability is increased for both proportional and derivative control of the bearing.The proportional control increased the stability threshold without affecting the whirl raito.However, for the derivative control of the bearing, stability threshold increase is accompanied by a parallel reduction of the whirl ratio.Results show the active control of bearing can be adopted for the stability improvement of air journal bearing.

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At the conceptual design stage, design process is not always logical because of lack of design criterion, procedure and knowledge clearly established.This process is dependent on the individual designer with specific design experience.It is important to consider the designer-dependent subjective aspects.In this article, we discuss an artificial design assistant for conceptual structural design, and its personalization to individual human designer.In this framework, the rule-based inference is used to generate and to evaluate the design candidates from multiple criteria to be considered by the human designer.The generic operations combined with the genetic case-base are used to suggest the candidate to the human designer.The progress of the design process is managed by the human designer through the interaction with the artificial design assistant.The preference of the artifical design assistant has been adjusted to meet that of the human designer in terms of the parameters for the genetic operations.Proposed idea is implemented and examined for the conceptual design of skeletal bridge structure.Case studies demonstrate the effectiveness of the artificial design assistant with the personalization capability.

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Reliable stress analysis of a bone requires the precise finite-element model.This study deals with an automated method of an individual finite-element model of a bone based on the X-ray CT data.The method consists of two processes.The first process produces an approximate finite-element model of a bony shape with small tetrahedral elements.For the modeling, various types of tetrahedral elements with almost same volume were provided.The second process transforms the approximate model so that the model is fitted to the outer shape.We applied the method to a human lumber vertebra and a human mandible.The proposed method successfully generated the exact finite-element models of the bones.

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Fixtures that constrain the unwanted motion of a workpiece are important tools in automated manufacturing today.In this paper, we analyze the stability of clamping with passive friction force.The concept of the instant center of rotation is applied to transform the stability analysis into a search for a static equilibrium state.Many properties related to be stability analysis are studied.According to these properties, we design an efficient algorithm for searching the static equilibrium state.The maximum allowable cutting force or the minimum normal stress, which are key concerns in automated design of fixtures, can be calculated precisely by using the search operation.The algorithm can also be extended to the case of multiply distributed friction forces with differently configured clamping areas.Several examples are provided to illustrate cutting force design for different fixture conditions.

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