The purpose of this study is to propose a new numerical modeling of adhesive joint of CFRP laminated composites. The proposed model is constructed with shell and beam elements, that correspond to adherend and adhesive, respectively. In case that the new numerical model is applied to the eigenvibration analysis under the canti-levered condition, the validities are first checked by comparison with experimental results. Using this model, influences of adhesive and adherend properties and adherend thickness upon eigenfrequency are also discussed. Therefore hoop positions of the 1st and 2nd eigenvibration modes of CFRP adhesive joint are an free end of specimen and the adhesive, respectively. In particular, it is confirmed that the 2nd eigenfrequency depends on shear deformability in adhesive layer.

抄録全体を表示

Dynamic behavior of smooth hysteretic systems subjected to harmonic excitation is analyzed. Wen's differential equation model for hysteresis, which can be applied to a large class of hysteretic systems, is used. A piecewise power series expression for hysteresis, which was derived from Wen's model assuming a sinusoidal response and weak hysteresis in the previous paper, is extended to the case of the response expressed in terms of constant and higher harmonic components. The method of multiple scales is applied to the equation of motion with the extended piecewise power series terms and the second order approximate solution for the case of primary resonance is obtained. Phase plane trajectories and resonance curves obtained from the solution are compared with the results of numerical simulations and the second order averaging analysis in order to examine the validity of the present analysis.

抄録全体を表示

Dynamic behavior of smooth hysteretic systems subjected to harmonic excitation is analyzed. Wen's differential equation model for hysteresis, which can be applied to a large class of hysteretic systems, is used. Using the extended piecewise power series expression for hysteresis, the method of multiple scales is applied for the case of secondary resonance and the first and second order symmetric approximate solutions are obtained. The stability analyses for the solutions are also performed and the regions of non-symmetric solutions are determined. Obtained results are compared with those of numerical simulation and previous analysis using Floquet's theory and the method of harmonic balance in order to examine the validity of the present analysis.

抄録全体を表示

Characteristics of whirling motion of a vertical Jeffcott rotor contacting with an annular guard during passage through a critical speed accelerated by a power limited motor are investigated by experiments and numerical simulation. The results show that the rotor executes one of the three typical whirl motions according to the rotor unbalance. For large unbalance, the rotor continues a forward whirl with large amplitude, and for medium one, the forward whirl moves to a backward with large amplitude and frictional torque. The development of the backward whirl can be explained by a change of reflected angle of the rotor colliding with the guard due to the friction force.

抄録全体を表示

For high-speed operation of an electric railway, the contact loss of the pantograph is one of the important subjects. In 1st report on this research, through theoretical analyses and fundamental experiments, it is confirmed that the magnitude of the contact force fluctuation is proportional to the vertical velocity amplitude of the incident wave to the pantograph. In order to investigate the influence of the wave motion in a practical catenary-pantograph system, running experiments in the laboratory and field tests on Shinkansen line are carried out. From the results thereof, it is found that the backward wave incident to the pantograph is much more influential than the forward wave, and that the influence of the wave motion on the contact force fluctuation is large comparatively. A hanger developed to have spring and damping mechanism is found effective for reducing the wave motion of the contact wire incident to the pantograph and decreasing the contact loss ratio. It is expected that damping catenary vibration will contribute to speed-up in electric railway.

抄録全体を表示

Three-dimensional vibrations of the crankshaft system under running conditions were inves- tigated for an automobile engine, taking account of the dynamic behavior of cylinder block and torsional damper. To simplify the analyses, the crankshaft was idealized by a set of jointed structures consisting of simple round rods and simple beam blocks of rectangular cross-section. The main journal bearings were modeled by a set of linear springs and dash-pots. For the flywheel, the dynamic stiffness matrix was derived from FEM. For the cylinder block, the dynamic stiffness matrix was constructed from the modal parameters obtained from the experimental modal analysis because of the complicated structure. Then the dynamic stiffness matrix was constructed for the crankshaft-cylinder block system, by the principle of superposition. The three-dimensional vibra- tions of the crankshaft system were analyzed for the two cases in which a solid pulley and a crankshaft damper were attached to the crankshaft. The calculated results were compared with the experimental results. In the analysis, influence of the vibration amplitude and temperature of damper on the damper characteristics were taken into account. The influences of the dynamic stiffness of the crankshaft thrust bearings and the oil film on the vibrations behavior of the crankshaft system were also investigated.

抄録全体を表示

The influence of the truck system vibration which exerts on self-excited vibration of driving axle shaft during slippage is investigated. The analyses of stability condition are performed using the analytical model vhich is composed of both the truck system and the driving axle system. These analyses reveal that the self-excited vibration is caused by the variation in axle load and the friction coefficient as a parameter has the critical value on the stability boundary. When the friction coefficient is less than the critical value, the system is stable, and in this case the system matrix is symmetrizable. Further-more, the novel method for the stability criterion is obtained by the use of the critical value map in the parameter plane of which coordinate axes are expressed by the ratios of the truck system eigenvalues to the driving axle system eigenvalues.

抄録全体を表示

Frequency parameters and modes of vibration are computed for thin laminated composite twisted cylindrical panels using the Rayleigh-Ritz method. Assumed displacement functions are taken to be algebraic polynomials. Comparison of frequency parameters obtained with avairable results in the literature shows that the method presented is effective for analyzing the vibration of thin laminated composite cylindrical panels. Effects of fiber orientation, sequence of laminate and initial twisted angle on the frequency parameters and modes of vibration are investigated.

抄録全体を表示

The modeling and formulation of simultaneous optimization problems with mixed 〓₂/〓_∞ norm objective function are discussed in the paper. They are applied to the simultaneous optimization of the cross-sectional parameters of a spring-supported beam and the parameters of the controller used to actively suppress the vibration of the beam. The weighted sum of 〓₂ and 〓_∞ norms of the transfer functions from external disturbance to measured outputs is used as the objective function. Simulataneous optimization is realized by iteratively executing structural optimization and controller optimization. Both serial and parallel approaches to combine structural optimization and controller optimization are investigated. The performance of both output and control input is improved significantly after simultaneous optimization. The simulation results show the great potential advantages of simulataneous optimization over tranditional design methods.

抄録全体を表示

This paper proposes a method to generate a position command which reduces both the time needed for a desired motion and the mechanical vibration. Based on the initially given position command, the optimal command is generated by scaling time axis. The criterion for the optimization is to minimize both the motion time and the high frequency component of motor torque including the mechanical resonance, under the constraints of limitations on motor torque and tracking error to the position command. Since the mechanical vibration is reduced by eliminating the high frequency component in motor torque, this method does not require detailed information about vibration characteristics of the mechanical system but approximate resonance frequency of it. Experimental results with two masses and a spring mechanism are shown to examine the effectiveness of the proposed method.

抄録全体を表示

For the purpose of suppressing all the vibration modes of a distributed parameter structure, this paper proposes a novel active vibration control called cluster feedforward control consisting of both the cluster filtering method presented by the authors and a feedforward control method based upon a filtered-x LMS algorithm. First, this paper derives the optimal control law of the cluster feedfor- ward control, a numerical example based upon the control law for eliminating all the structural modes of a planar structure being shown. Experimental results show the capability for suppressing a single cluster, then all cluster of a planar structure, that leads to the suppression of all structural modes. Finally, comparing the conventional multiple SISO feedforward control with the cluster feedforward control, the superiority of the cluster feedforward control is discussed.

抄録全体を表示

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 structural systems. This report proposes the method using a shaking table as the actuator so that the hybrid experimental method can be applied to a secondary structural system attached to a primary structural system. A response analysis method is proposed for this experimental method and its stability and calculation error are investigated 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.

抄録全体を表示

This paper is concerned with a computational method for detecting and characterizing defect shapes in conducting materials using superconducting quantum interference device (SQUID). The mathematical model is described by electrical potential problems with mixed boundary condition. The model output is then represented by Biot-SaYart's law. The estimation scheme is proposed for reconstructing defect shapes in sample materials with defect. Successful numerical results are reported in order to show the feasibility of the proposed algorithms.

抄録全体を表示

The dynamic problems of beams whose lengths change with time in longitudinal direction are often found in industrial manipulator systems. However, characteristic matrices of such system depend on time and the dynamic response analysis becomes very complex. Some works on such problems have been done for stringsre^(1)-(4), But there are not so many about the dynamic response analysis for beams with time-dependent changes of their lengths^(5)-(8). Though dynamic unstability may possible occur in such problems and be significant in practical problems but it has not been studied fully yet. Then the aim of this study is to present a convenient and effective dynamic response analysis method for such moving beams with time-dependent change of their lengths by making use of the developed method of dynamic analysis in our previous works for vibrating beams with longitudinal mass flow and to examine the dynamic behaviors through numerical examples by the method. Comparisions of the results by the proposed method with exprimental results done by us and with ones in other typical analytical study are made to confirm the validity and effectiveness of the method.

抄録全体を表示

We have proposed the two-degree-of-freedom active noise control (2DOF-ANC) system, especially for active control of road noise inside automobiles. In this 2DOF-ANC system, the feedforward part is a conventional filtered-x LMS (least mean square) adaptive control and the feedback part is based on an Internal Model Control (IMC). The purpose of this paper is to apply the subspace method to the identification of an IIR (infinite impulse response) model for an acoustic field in the proposed 2DOF-ANC system. The IIR model is used to synthesize the feedback controller based on IMC and to reduce the number of arithmetic operations in feedforward control. The subspace method allows us to quantitatively determine the number of parameters in the IIR model. The effectiveness of the subspace method in the proposed 2DOF-ANC system is demonstrated through computer simulations using actual vehicle data measured in the experiment which simulates road noise in the cabin.

抄録全体を表示

This study is concerned with an adaptive rejection approach for periodic disturbance composed of multiple unknown frequencies components and its application to noise suppression in one dimensional duct system. We present a constant coefficient difference equation representation for sinusoidal signals. Then using this result, we obtain difference equation representation for periodic signal composed of multiple sinusoidal signals and derive the relationship between the coefficients of the difference equation and the frequencies of the multiple sinusoidal signals. Then algorithm is presented for the estimation of the frequencies of the multiple sinusoidal signals. We also propose an adaptive algorithm for generating a pseudo-feedforward control input signal such that periodic disturbance is eliminated by the response of plant. The results indicate that both the estimation algorithm of unknown frequencies is high precision and reference signal adaptive generation algorithm are stable. Finally, the approach is applied to a problem of periodic noise suppression in one dimensional duct system. Approximately 20 dB reductions of noise level were experimentally obtained both for two components of periodic noise. The experimental results show that the proposed algorithm is effective for suppression of periodic disturbance composed of multiple unknown frequencies components.

抄録全体を表示

A duct expansion, which has short axial length, acts as a resonator muffler. Generally, its property can be estimated by the numerical calculation which neglects sound damping in the expansion. But in the case of a slit, which is a duct expansion with very short axial length, the influence of sound damping is not negligible. Hence, in this paper, in order to consider sound damping, the slit was treated as a equivalent single-degree-of-freedom mechanical system. The equation to calculate the transmission coefficient of the slit Using this system was derived. By comparison between the solution of this equation and the measured value of transmission coefficient, the equivalent mass, damping coefficient and stiffness of the slit was obtained. It was found that each of these equivalent coefficients can be normalized as a almost fixed value by the slit size. Therefore the quantitative estimate of the slit property was established.

抄録全体を表示

This paper presents a large scale structural-acoustic analysis method in which, a cavity is divided into several acoustic fields. This system uses a transfer-function method to solve the acoustics efficiently. By solving simultaneous equations using the Gaussian elimination method for each pair of neighboring acoustic sub-fields in sequence, calculation time and memory requirements are reduced. Calculation accuracy is the same as when calculating the entire acoustic field without dividing it. We created a closed acoustic model (a cavity model) and carried out the numerical simulations. The results showed that the proposed method is effective for large scale structural-acoustic analysis.

抄録全体を表示

A new approach on modeling is put forward in order to compose the virtual prototype which is indispensable for fully computer integrated concurrent devolopment of products. A basic concept of functional model is proposed for embodying this approach. This model is used mainly for explaining and simulating the functions and the efficiencies of various machines which are composed of many mechanical, fluid-mechanical and electrical parts. All organizations and engineers of various specialties in charge of the development can collaborate with one another using this model. This model can be used in all stages of product development from the initial plan through the design to the trial testing. Models of parts compose an organic system in the total product model. Functional models of some simple mechanical, electrical and fluid-mechanical systems are illustrated, and its validity and usefulness of the proposed approach are demonstrated.

抄録全体を表示

There is no report regarding the specific design method for Spring Balancer. I investigated the basic issue of design in one of the balance systems. Using balance equation and principle of conservation of energy, the decrease of potential energy in a weight is conserved as elastic strain energy in spring, I discovered that the pulley for spring is of special spiral shape. Also I realized that the volume of spring is directly proportional to the maximum potential energy and the maximum potential energy function can be used as the design formula. This makes the Spring Balancer design easier. Also I calculated the generalized formula of inertia force for both Gravity Balancer and Spring Balancer. The result shows that Spring Balancer is suitable for miniaturization and weight reduction, because of the fact that the inertia force is smaller when the travel distance of weight is shorter.

抄録全体を表示

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 robust performance of two types of controllers, a sliding mode controller and an adaptive sliding mode controller, is compared using simulation.

抄録全体を表示

Damage detection and warning for space debris collision is one of the most serious problems for space systems operations. Estimation of impact force and its location is necessary for such systems, which can be realized by inverse analysis. However, this analysis requires an enormous amount of computation time, which may preclude on-board processing. To overcome this problem, this paper presents two improvement procedures based on an inverse analysis by using a priori knowledge on duration of impact force that is assumed much shorter than measurement time. Improvements are demonstrated in terms of calculation time and the effects of errors in coefficient matrix on estimation accuracy are analyzed based on the analytical solutions of the structure vibration model with acceleration data corrupted by white noise.

抄録全体を表示

The main feature of one-shot thrusters is discreteness in both time and space domain. In a previous paper, we limited our analysis to only the time discreteness by applying discrete-time sliding mode control to the attitude control of a spinning vehicle. In this paper, we will consider the space discreteness by applying a simple genetic algorithm (SGA) to the selection of the set of one- shot thrusters prearranged on the vehicle in order to generate the control force. We adopt a regulator scheme to reject disturbances of precession for a LUNAR-A type penetrator, and conduct numerical simulations of the problem to show the effectiveness of the proposed control algorithm for one-shot thrusters. Improvements in the calculation time of the SGA by using shortening chromosomes are also demonstrated.

抄録全体を表示

In this paper, we deal with fixed order H_∞ controller design, based on bilinear matrix inequalities (BMI). Firstly, we propose a new algorithm for solving LMI/BMI problems, which is theoretically applicable to nonlinear matrix inequality problems. Secondly, we demonstrate by simulation the algorithm to be numerically stable and reliable, as far as LMI/BMI problems are concerned. Lastly, making use of the present algorithm, we obtain the fixed-order H_∞ controller for 2-mass-spring systems, which implies the practicability of BMI based design methods for fixed-order H_∞ controllers.

抄録全体を表示

An optical servo system is a novel and attractive control system which can be used in hazardous environments. In our previous paper, we built two types of optical servo system which consist of a photo-fluidic interface, two booster amplifiers and a pneumatic cylinder. One type is the cart position control system in which the optical signal is fed back directly and the other type is that in which the optical signal is fed back indirectly. It is strongly desired to analyze the control system in order to make the control performance higher and to design the control system. This paper describes a theoretical analysis of the tested optical servo system. First, the opto-pneumatic servo system and its operating principle are explained briefly. Second, an analytical model of the tested control system is proposed. And, it is shown that the static and dynamic characteristics predicted by the proposed analytical model agree well with the experimental results. Finally, the simulated results of the indirect feedback position control are compared with the experimental ones. It is shown that the positioning accuracy of ±0.15 mm which is almost the same as that in the usual electro-pneumatic servo system can be obtained.

抄録全体を表示

An optical servo system, which can be used in hazardous environments, is a novel and attractive control system. In our previous paper, we proposed an analytical model of a tested optical servo system which consists of an optical servo valve and a small pneumatic cylinder in order to improve the position control performance. This paper describes an extension of the optical servo system to a more normal scale system using a normal pneumatic rodless cylinder with the full stroke of 600 mm. First, two kinds of opto-pneumatic servo system using the rodless cylinder are explained briefly. Second, the control performance of the first system which uses two flow amplifiers on market is investigated. Finally, the optical servo valve is designed and improved by using the analytical model proposed previously. And the control performance of the second system using the improved valve is investigated. As a result, it is shown that the improved optical servo valve is more useful in a normal scale control system compared with the flow amplifier.

抄録全体を表示

In knowing the movement of a car, it is extremely significant to measure forces which act between tire and road when the car is traveling. Therefore, we considered method for measuring these forces in a short section of the road in wide range of speed from very low to high. We contrived structure of the force plate for which strain gauges were used. Finally, we successfully made the force plate whose characteristics were wide response range from D.C. to high frequency, enough sensitivity and very small cross-axis sensitivity. In this paper, we describe structure and characteris- tics of this force plate and examples of measurement results.

抄録全体を表示

This paper presents an accurate AFM used in liquid that is free from the Z-directional disrortion of the servo actuator. Two correcting methods are employed in this AFM. One is the external- monitoring method, and the other is the in situ self-calibration method. The external-monitoring method is based on the fact that PZT actuators from the same class show similar hysteresis patterns. The same voltage signal used to control the servo actuator is applied to another PZT actuator which is called as the reference actuator. The displacement of the reference actuator is measured by a displacement sensor. As a result, the distortion of the AFM image can be corrected satisfactorily. In the in situ self-calibration method, the derivative of the calibration curve function of the PZT actuator is calculated from the profile measurement data sets which are obtained by repetition of measurement after small Z-directional shift. Input displacement at every sampling point is approxi- mately estimated first by using a straight calibration line. The derivative is integrated with referring the approximate input to get the approximate calibration curve. Then the approximation of input value of every sampling point is improved with the obtained calibration curve. Next the integral of derivative is improved with the newly estimated input values. Repeating these improving process the calibration curve converges to the correct one, and the distortion of the AFM image can be corrected. Principles and experimental results of the two methods are presented.

抄録全体を表示

We propose a Whole Finger Manipulation (WFM) to improve robustness of manipulation by multifingered robot hand. The WFM is characterized by (1) multiple contact points between an object and surfaces of the inner links of multifingered robot hand, (2) a manipulation by utilizing a sliding at each contact point. This paper presents a dynamics of the WFM. The kinematics and dynamics of the multifingered robot hand and the multiple contacted object by the inner links are explored. The condition which is that the WFM is a model determinancy is shown using Kuhn-Tucker conditions. The conditions of an arbitrary manipulation for the WFM are derived using the duality theorem of linear programming problem. The dynamics of the WFM is demonstrated by computer simulations graphically.

抄録全体を表示

We have proposed a Whole Finger Manipulation (WFM) to improve robustness of manipulation by multifingered robot hand. The WFM is characterized by (1) multiple contact points between an object and surfaces of the inner links of multifingered robot hand, (2) a manipulation by utilizing a sliding at each contact point. In this paper, considering the kinematics and dynamics of the WFM, we propose a control scheme which guarantees the manipulation stability. The proposed control law consists of both tracking control of multifingered robot hand and impedance control which enforces the motion of the contact point in the normal direction and internal force. The minimal internal force is defined as the internal force which generate the minimal contact force at the instant. The conditions for being manipulated an object stably are presented. The experimental results to verify the validity of the proposed control law are shown.

抄録全体を表示

Digital control of robot manipulator employs discrete-time robot model. It is important to explore effective robot model in order to achieve good control performance. This paper presents a new type of discrete-time robot model using trapezoid rule to approximate the convolution integral term, and eliminating the nonlinear force terms in robot dynamical equation. The new model obtained is characterized with its simple structure. From the control application point of view, the model's properties were examined. A control system for 2-1ink vertical manipulator was designed, and simulation results demonstrated the good properties in the trajectory following and the robustness towards system uncertainties and disturbances.

抄録全体を表示

We introduce a new type of space robot system, called a tethered robot system. The tethered robot system comprises a tethered robot, i.e. a body equipped with manipulator arms, which is attached to a main spacecraft through a tether. By operating the manipulator arms, the tethered robot can grasp an object which is located far away from the spacecraft. Task performance, however, is complicated due to the presence of external forces, such as gravity, centrifugal and tether- tension forces. In this paper, we propose decoupled control of tether tension and robot motion around an equilibrium point at the tether end. First, we examine rotational and translational motion of the tethered robot caused by the external forces. Then, it is noted that the tethered robot can be controlled in a way similar to a free-flying robot, by proper operation of the tether attachment point. Therefore, the control of the tethered robot with respect to its mass center should be composed of two subtasks: the end-effector motion subtask and the tether attachment point motion subtask. The effectiveness of the proposed approach is confirmed by computer simulation.

抄録全体を表示

A hybrid control method for a flexible manipulator based on an angular velocity control is presented, which is applicable to curved constraint surfaces. The error of contact force is converted into a velocity vector according to the force/velocity conversion law which consideres both force respose characteristics and variational angular velocity with respect to normal direction of the surface. The velocity vector which is tangent to the constraint surface is calculated using the velocity control law. The desired velocity vector is obtained as a sum of the above two velocity vectors, and is converted into angular velocity vectors. A vibration control law is proposed to reduce overshoot of end point velocity response. The desired angular velocity vector is obtained as a sum of the above angular velocity vector and vibration control term. Motion and force controls without calculating inverse dynamics is performed using DC motors whose desired values are equal to the above desired angular velocity vectors. Computer simulations and experimental analyses are carried out to clarify the validity of the proposed method.

抄録全体を表示

A new type of pneumatic stepping motor, named pneumatic wobble motor was developed. Pneumatic wobble motor consists of a donut-shaped wobble generator, which is made of silicone rubber, a wobble ring, which is made of metal, and a rotor. The rotor is encased in the wobble ring, which is covered by the wobble generator. The wobble generator has six chambers and injecting air into each sequentially exerted on the wobble ring, causing its revolution, which makes the rotor 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. Experimental results are very promising. The features of pneumatic wobble motor are (1) big torque, (2) simple structure, and (3) water-and dust-proof.

抄録全体を表示

In this paper, we consider virtual sports training system as a useful application of virtual reality. For such an application, the force display system especially needs two abilities of high speed motions and a large motion area, in addition to some general abilities for it. To satisfy those abilities simultaneously, one of good ways is to adopt parallel wire mechanism because this mechanism has good characteristics of low inertia and low viscosity. However, it have not been investigated which control method is better for this system. In this paper, firstly we reveal two problems on controlling this system under high speed motions: elasticity of this mechanism and influence of handle dynamics. For such problems, some control methods are proposed. Since proposed control methods are quite simple, it is easy to implement them. Some basic experimental results demonstrate effectiveness of those methods.

抄録全体を表示

A compliant wrist which combines passive compliance and active sensing is proposed to provide the necessary flexibility for force and contact control. This paper describes a mechanical design and a sensing technique of the compliant wrist. The compliant wrist has a three degrees of freedom parallel mechanism which has consists of two platforms connected by three serial chains. The kinematic equations for use of the wrist are derived, and the simulations are performed to estimate the performance of the proposed compliant wrist. It is shown that using the design method we can construct a compliant wrist which has a desired Cartesian stiffness and a suitable motion space.

抄録全体を表示

In general, it is said that the pneumatic servo system is unsuitable for complex controls and limited in application. However, from the characteristics of the air compression, it is desirable that the pneumatic robot develops for the flexible manipulation. The main problems which exist in the pneumatic servo system are the existences of both solid friction and a dead time. This paper proposes a design method of robustness servo controller to solve above problems. The design method of robust servo controller for pneumatic manipulator is described as follows. First, the model of the pneumatic manipulator is derived and the influence of the solid friction is examined on the position control. Second, the design specification of control system are drawn up, and then it is shown that the robust servo problem is reduced to the mixed sensitivity problem. Third, the design technique of the controller is proposed based on state feedback H^∞ control theory. From the viewpoint of robustness, this technique has the superior advantage, comparing with the other technique estimating plant like the disturbance observer and the adaptive control. Finally, the characteristics of the H^∞ servo control system is analyzed, and the effectiveness is verified through the experiment and the simulation.

抄録全体を表示

An integrated control system of active rear wheel steering and yaw moment control using braking forces is presented in this paper. Because of the tire nonlinearity that is mainly due to the saturation of cornering forces, vehicle handling performance is improved but limited to a certain extent only by steering control. Direct yaw moment control using barking forces is effective not only in linear but also nonlinear ranges of tire friction circle. The proposed control system is a model matching controller which makes the vehicle follow the desired dynamic model by the state feedback of both yaw rate and side slip angle. Computer simulation is carried out and shows that vehicle handling performance is much improved by the integrated control system.

抄録全体を表示

In this paper, a design method of trajectory control for automated vehicle system is proposed. Many articles have been published about this theme. However, in these studies, only lateral deviation models have been considered and the trajectory between straight road and curve road has not been specified clearly, On the other hand, in our study, we pay attention to this trajectory. We specify desired yawing motion to satisfy objectives (tracking to the desired trajectory, maintaining comfortability in riding, etc.) and construct a yawing motion control system. The yawing motion control system is synthesized by 2-degrees-of freedom control system and included in the preview control system. In the overall system, desired yawing motion and optimal preview time are calculated by the analysis of steady state of automated vehicle system. Finally the usefulness of the proposed control system is demonstrated by the numerical simulations.

抄録全体を表示

Recently, environmentally-friendly absorption chillers/heaters have become popular as air conditioning/heating sources. This system is free from CFC use. In this way next improvements such as a system for maintenance, including failure diagnosis, are needed to be considered. The authors earlier proposed a failure diagnosis system for absorption chillers/heaters that is compact and sufficiently accurate. The system uses linear or curvilinear quantitative relationships derived from experiments grounded on qualitative knowledge. These quantitative relationships, however, are only effective in steady-state. Therefore, under the condition of large state-transitions, the possibility of erroneous daignosis exists. In this paper, we propose a compensation method that allows the failure diagnosis system to be effective even under large state-transitions. The method eliminates possibil- ities of fault judgements.

抄録全体を表示

These days, requirements of the machine become more and more complicated and we need to satisfy many of those requirement simulataneously. In such cases, it would be rational and reasonable to carry out multi-objective optimization. However, in the conventional decision making problems, we need to give preference according to local information such as trade-off. But, it is not that easy to give proper preference from such local information. If we can give multiple acceptable designs to the designers, it will be great help for them to give preference, because they will give something like map of the design space. However, to give multiple Pareto solutions, we need to carry out a great number of scalar optimizations, and it is unrealistic. In order to give multiple acceptable designs by single optimization process, we simulate adaptation strategies of wild lives combined with genetic algorithms in the previous study. We have succeeded in keeping variation among population and directions to give multiple acceptable designs, but we failed in controlling of the number of population. As a sequence of the previous study, we focus our attention mainly to adaptation of foraging and try to simulate the evolution of species as the changes of searching ranges for design variables. The goals of the proposed method lie in finding multiple acceptable designs, keeping variation of population and see the changes of searching range for each objective functions to give clear map to the design space to the designers. In this study, the proposed method are analyzed using a simple two-variable, two-objective problems whose analytical solution is available.

抄録全体を表示

It has been said for so long that it is important to apply optimization from the primary parts ot design to obtain the sophisticated design results. However, it is not so easy to quantify things that we treat in these processes that the techniques of optimization are not applied in these processes. In order to overcome these situations, we have developed qualitative optimization using qualitative sensitivities which don't need such a distinct quantification of the design objectives. In this study, we applied the proposed method in "KANSEI" design which made it possible to consider human sensuous impression or emotion into design and which become more and more important for the better design these days. We propose the new Kansei estimation method based on binary questionnaire for deriving qualitative sensitivities which are key in qualitative optimization. As an example, we designed a chiar which derive high efficiency in office work and showed the effectiveness of the proposed method.

抄録全体を表示

Highly variable deformations of a human anterior cruciate ligament (ACL) cannot be adequately quantified by one-dimensional, localized measurements and/or analyses. This paper describes a new structurally-motivated phenomenological approach. Such assumption was made that the ACL ligament can be idealized as being composed of a homogeneous matrix in which two non-interacting families of densely distributed extensible fibers are embedded. A non-linear stress-strain characteris- tic exhibited by multiple collagen fibers was represented by the multi-linear curve. Then a constitutive equation for the ACL composite was formulated. Using the finite element method, finite deformation and stress distribution of the ACL as a function of knee flexion were introduced through simulation.

抄録全体を表示

Belt side tracking caused by the helix angle of the tooth trace of a helical synchronous belt under no load was investigated in the present study. Belt side tracking is an important problem because it influences the transmission characteristics, belt life and noise characteristics. Experimental results of belt side tracking were correlated the force on the belt tooth when the belt tooth began to mesh with the pulley tooth. It was confirmed that the amount of belt side tracking is proportional to the magnitude of the installation tension and the helix angle, and is inversely proportional to the belt width.

抄録全体を表示

In order to elucidate the influences of particle size of powder and relative radius of curvature on surface durability of induction-hardened sintered powder metal rollers, the rollers with a diameter of 30 mm and 60 mm made by three kinds of particle sizes were fatigue-tested under a sliding-rolling contact condition using two cylinders testing machines. The three kinds of particle diameters were under 45 ixm, 75μm∼106μm and 150μm∼250μm, respectively. The surface durability of the roller became higher as the relative radius of curvature decreased. The surface durability of the roller made by the smallest particle size was almost equal to that of the roller made by the intermediate particle size. While the surface durability of the roller made by the largest particle size was inferior to those of the other rollers. The smaller the particle size became, the smaller the pore size became and the lager the pore cluster factor by fractal dimension became. The failure mode of all rollers was spalling. The minimum depth of the spalling crack agreed almost with the depth of the peak amplitude of the ratio of orthogonal shear stress to Vicker's hardness. It was understood that the pore size and the pore cluster factor were important parameters to evaluate the surface durability of the sintered powder metal rollers.

抄録全体を表示

In order to elucidate the influences of particle size of steel powder on the surface durability of induction-hardened sintered powder metal gears, the gears with three kinds of particle sizes were fatigue-tested using a power circulating gear testing machine. The three kinds of particle diameters were under 45μm, 75μm∼106μm and 150μm∼250μm, respectively. The surface durability of the gear with the smallest particle size was almost equal to that of the gear with the intermediate particle size. While the surface durability of the gear with the largest particle size was inferior to those of the other gears. The smaller the particle size became, the smaller the pore size became and the lager the pore cluster factor by fractal dimension became. The failure mode of all gears was spalling with pitting. It was understood that the pore size and the pore cluster factor were important parameters to evaluate the surface durability of the sintered powder metal gears.

抄録全体を表示

The influences of the oxidized and nonmartensitic layer, produced during carburizing process, and surface roughness on pitting fatigue strength have been investigated. In order to elucidate the influence of the oxidized and nonmartensitic layer, carburized SCr420 steel rollers were fatigue- tested after chemical polishing that remove the oxidized and nonmartensitic layer and were compared with the ones without chemical polishing. In order to elucidate the influence of surface roughness, shot-peening was applied before carburizing to make the surface rougher. The results show that the pitting fatigue strength became decrease when the oxidized and nonmartensitic laver remained at the end of the test. In the case that the oxidized and nonmartensitic layer was not removed before the test and the initial surface roughness R_y is more than 4μm, the surface layer wore drastically during the test. Therefore, the oxidized and nonmartensitic layer wore out and the final surface roughness was smaller. The final surface roughness determines the pitting fatigue strength and so the pitting fatigue strength can be predicted using the relationship between initial and final surface roughness.

抄録全体を表示

In this paper, we numerically analyzed the static and dynamic characteristics of step, taper, taper fiat and herringbone bearings and compared their optimal performances in terms of application conditions for hard disk spindle. The first three types of bearings are designed to have thick grooves which can separate each bearing part into independent one so as to generate only positive pressure. The effects of separating groove depth on radial and tangential stiffnesses are made clear. The optimal values of design parameters of each type of bearing in terms of both maximum radial stiffness k_rr and maximum ratio of k_rr to friction torque T and bearing characteristics in both cases are calculated. The stability comparison of these five types of bearings were also carried out. It is found that herringbone bearing is superior to the other three types of bearings in terms of the maximum k_rr. However, the taper-fiat bearing is superior in terms of the maximum k_rr/T and whirl stability

抄録全体を表示

A new measurement method of bolt tightening forces by simultaneous loading of torque and compressive force to a bolt has been developed. By simultaneous application of torque and compres- sire force to a bolt, the friction coefficients in threads and bearing surfaces are accurately detected separately in the process of tightening. Thus, the present method can control the tightening force of bolts within the error of ±10% for wide tightening forces under oil-free or lubricated conditions. The working efficiency of the present method is much better than that of the angle control method or the torque gradient control method because it is not necessary to measure the tightening angie and the friction coefficients in advance.

抄録全体を表示

In order to perform a precise positioning, flexure joints having backlash-free and frictionless are suitable in micro positioning mechanisms. In the case of flexure joints, relative angular displace- ments at the joints are small. Therefore many flexure joints are used to obtain a large output displacement from a small input displacement in the mechanisms, and they are used within the linear elastic region. In this paper, large-deflective elastic hinges are proposed instead of revolute pairs. They are movable connections between links, and can eliminate an input displacement magnification mechanism and a stress concentration problem at joints. As a result, the length of pseudo-links that considered with geometric relation of hinge's deformation is changed. To solve the nonlinear large- deflective elastic hinge problem under a concentrated load and a moment, the large deflection theory, namely, elastica is used. Also, a concept of movable pseudo-revolute pair to analyze a hinge in the kinematic aspect is proposed, and the validity of the concept is confirmed theoretically and experimentally.

抄録全体を表示