Recently, ultra high speed elevators are required for high rise building, where active vibration control mechanism is expected to improve the riding quality of them. Active mass dampers (AMD) are proposed as such control devices, and in this paper, we discuss the feedback control systems designed by optimal regulator. The reduced order models of the elevator were designed and verified through numerical simulations. As a result, it was confirmed that the reduced order control systems have enough performance and robustness against changes of mass, and that the design of the control systems could be very simple for an actual elevator system.

抄録全体を表示

This paper presents the vibration control system of a simply supported beam, which is subjected to external forces, and a simply supported rotating shaft which has unbalances. When a sustained disturbance is subiected to a flexible structure, the optimal control can't Provide significant reduction in vibration. For further reduction of the vibration, the disturbance cancellation control method is applied to a design of control system together with the optimal control. The disturbance cancellation control is introduced by estimating the position and magnitude of disturbance by sensing the acceleration of them. By carrying out numerical calculations, it is demonstrated that the present design approach is useful for reduction of the vibration in broad frequency band.

抄録全体を表示

Vibration control experiments of a simply supported beam using piezoelectric film (PVDF) sensor / actuator are carried out to verify that the triangular-shaped film pair is effective for multi modes vibration control in comparison with the rectangular-shaped film pair. In the experiment, analog circuits are used to implement DVFB (Direct velocity feedback) control law. Frequency responses of displacemet of a beam subjected to a concentrated harmonic force are measured with sensor outputs and feedback voltages, and those show good agreement with the theoretical results. As predicted theoretically, it is shown in the present experiments that all of the first three vibrational modes are efficiently controlled by the triangular-shaped film sensor / actuator, wheres the rectangular-shaped film sensor / actuator has no control effect against the anti-symmetrical vibrational modes, i. e., the second mode.

抄録全体を表示

In this paper, an effective method for the nonlinear vibration analysis of rotor system is proposed by using the Component Mode Synthesis method and the method of multiple scales. In that method, the system is divided into some components and a set of perturbed equation for every component is derived. The equation of motion for the whole system, then, is obtained by using the Component Mode Synthesis method. The dynamic analysis of rotor system is carried out by using the perturbation method. The distinguished feature of the proposed method is that the nonlinear restoring force term is represented by using modal coordinates in the convenient form. The order of the modal equation of motion and calculation time can, therefore, be reduced. In the numerical example, it is shown that the analysis method proposed in this paper is effective for the nonlinear vibration analysis of rotor system.

抄録全体を表示

The fundamental properties of active magnetic bearing controllers are investigated from the standpoint of output regulation in the presence of deterministic disturbances. A transfer function approach is used in the analysis. The variable to be regulated is selected from rotor displacement, coil current and bearing force. The treated disturbance is constant or harmonic ; the latter is caused by rotor unbalance. The essential properties of the controller achieving output regulation for constant disturbances are derived. Those for unbalance disturbance are also shown by using complexvariable representation, which makes the procedure of analysis similar to that for constant disturbances. The derived controllers for unbalance compensation are converted into two types of realvariable representation : state equation and convolution integral. It clarifies the equivalence between the independently developed unbalance compensation controllers. It is also shown that the obtained results can be utilized in designing controllers.

抄録全体を表示

The conventional type of large turbo machinery employing oil-film bearings is supported so stiffiy that the rotor is strong against earthquakes. However, there is concern about its reliability against rotors supported by Active Magnetic Bearings (AMB) because of its weak support. In this paper, a flexible rotor supported by AMB is selected for aseismatic evaluation. The shaking test using the actual earthquake Kobe and El Centro waves was done and the response vibrations were measured. The corresponding simulation was also done. According to experimental and calculation results, maximum response vibration is still less than the gap of touchdown bearing, i. e., norubbing vibrations and the safety requirement is thus satisfied. However, the response severity of AMB rotors is comparatively high with oil film bearing rotors. In order to reduce this sensitivity against earthquakes, we propose an additional control method using the feed forward excitation which force is proportional to the signal detected by the accelerometers attached on bearing housings. Since this addition can act as the cancellation of rotor vibration generated by the earthquakes, AMB rotor vibrations are successfully suppressed at a low level. The effectiveness of this AMB control method is proved for earthquake induced vibrations reduction.

抄録全体を表示

The double disk rotor model is used to analyse the second bending vibration mode generated by unbalance in a damper bearing-supported process compressor. First, a Q-factor map of the model is discussed. It has been shown that this type of map is a highly useful tool in selecting the most suitable parameter sets for rotor design. Secondly, a Q-factor map numerically generated by FEM is used to evaluate the model. The shapes of the Q-factor maps are classified according to vibration mode type. From this classification, the features of each vibration mode are extracted and the cause of the vibration can be analysed. The double disk rotor model is also used to decide on parameters for FEM calculation. The results suggest that the model provides a powerful tool for the simple creation of Q-factor maps.

抄録全体を表示

A detailed dynamic model of the curving of a non-pendulum rail vehicle was formulated and general equations of motion were derived considering both one point contact and two-point contact. Digital simulations of curving for a representative example were made. It was shown that two-point contact generated larger lateral wheel-rail force comparing one-point contact due to lack of self steering effect. Effect of forced steering on steady lateral wheel-rail force and effects of lateral stiffness of axle suspension and forced steering on dynamic lateral wheel-rail force when passing rail Joints and artificially generated random irregularity were examined. It was shown that forced steering had effect of decreasing both steady and dynamic lateral wheel-rail force, and smaller lateral stiffness of axle suspension had effect of decreasing dynamic lateral wheel-rail force when passing rail joints.

抄録全体を表示

In this paper, we will show the effect of vibration reduction of first-bending mode of railway car body by using coupling damper, from the results of calculated riding quality level and vertical acceleration peak for shinkansen vehicle. It is important to decrease this vibration because the natural frequency generally exists in the range that human feel it so sensitive that it has large effect on comfortability in riding. In this study, we make a train set model composed of five single car FEM models and coupling model, that is a linear spring and damper element connected parallel. From the resuits of calculation at several damping values, we find that this noticed vibration is decreased at all considered speeds (240, 275, 300, 320 km/h) but decreasing level is different at each speed. From investigation of vibration shape at natural frequency of noticed vibration (9.0 Hz), we make clear that difference of vibrated phase among each car make this phenomenon. On running 275 km/h, vibration level is too high, and vibration-reduction effect is small, because each car vibrates with same phase, as a result, relative velocity between each car is not effectively generated at each coupling damper.

抄録全体を表示

This paper describes a response analysis for a monorail car. The dynamic model of the monorail car, taking into account the influence of track irregularity on tire force, has been proposed A multi-body dynamics method was enhanced and applied to the monorail car system that included the proposed monorail car model. The equation of motion for this system was automatically derived using this multi-body dynamics method. Frequency response analysis in the lateral direction for the monorail car was executed and vibration mode of the monorail car was compared with that of a rail vehicle. The result showed that the acceleration of the rail vehicle was larger at 1-Hz frequency because of hunting motion. On the other hand, the acceleration of the monorail car was larger at 10Hz frequency because of the roll vibration mode of the truck produced by horizontal tire force.

抄録全体を表示

This paper describes traffic flow simulation by Cellular Automata, where the traffic flow emerges considering just interactions among each vehicle in the flow, and the flow is controlled by optimizing the period of traffic signals with the help of Genetic Algorithm. Cellular Automata are mathematical systems characterized by discreteness, local interactions and an inherently parallel form of evolution All the parameters in analytical space, time and state variables are treated as discrete ones, and the whole phenomena can be emerged considering just local neighbor rules among state variables defined on each divided area called "cell". In the present paper, various types of road module, such as crossing, straight road or T-type intersection were prepared as analytical space for Cellular Automata and the traffic flow was simulated on arbitrarily comPosed road module system. Furthermore, the period of traffic signals on the road system was optimized by Genetic Algorithm so that the number of moving cars might be maximized and at the same time the waiting cars minimized.

抄録全体を表示

A stable and accurate numerical simulation technique is proposed to investigate performances of the transfer system using a biased transfer roller (BTR) in electrophotography copier and printer. A one dimensional layer-structured model was used to calculate steady state distribution of electric field and current under gas discharge. Based on the discharge current, concentration of generated ozone was also calculated. As results of calculations using parameters based on a typical black and white laser printer, it was shown that (1) a transfer system using a semiconductive BTR under constant current operation was robust against variation of paper resistance due to changes in the environment and materials, (2) concentration of ozone in the BTR system was two orders lower than that in the system using a conventional corona device.

抄録全体を表示

This report shows an experimental study on the high damping characteristics of the U-bend tube bundle Steam Generators in PWR-type nuclear power plants. The tube bundle is tied up with a rodstructure called "anti-vibration bar (AVB)". Four test models which are the partial and the fullsize mock-up of the practical plants are excited with a three dimensional shaking table. It, at nrst, shows the basic characteristics of the tube bundle. Secondary, the quantitive estimation of the damping ratio is reported. The vibrational characteristics greatly depend on the exciting direction. Then, the estimation of the out-of-plane direction is 8%, and the one in the in-plane one is 15%. They are more than a present damping ratio, 1%.

抄録全体を表示

Mechanical models for the Sloshing in a teardrop tank widely used for spin-stabilized satellites are developed. The concentric case where the spin axis coincides with the geometrical centerline of the tank system is considered. In the past, analytical expression of the characteristic functions has been impossible for the present sloshing problem because the tank axis has a large tilt against the spin axis and the liquid volume is geometrically complicated, i. e., the domain surrounded by conical and spherical tank walls and parabolic liquid surface. Resort had to be made to time-consuming and expensive numerical approaches. This paper shows that an ingenious application of spherical coordinates according to the position of the contact line of the static liquid surface with the tank wall allows one to determine analytically the system of characteristic functions, and hence, to reduce the computation time and cost.

抄録全体を表示

We first searched global solutions of free giant swing motions of the two link model for a standard human body by forward dynamic simulations from all possible initial states within a specified region. Then we found that there are one free giant swing which exists in any motion Period and two others which appear in shorter period than 0.9 second. Next we investigated how we can efficiently obtain all of these global solutions by means of a numerical optimum trajectory planning method we have proposed in the previous paper. As a result, we propose a general search method to obtain all of optimum solutions including local optimum solutions.

抄録全体を表示

Wing in-Ground effect aircrafts have gained much attention during these thirty years because of their high efficiency. The aircrafts require active stabilizing controllers for safety maneuvering, which cause difficulties in designmg. In this paper, we apply simultaneous optimization technique to design Wing-in-Ground aircraft. It is shown that the simultaneous optimization on parameters of aerodynamics design and of stabilizing controller can give superior design to conventional methods. An example is given to illustrate the procedure of design and the effectiveness of simultaneous optimization.

抄録全体を表示

Focus is placed on the feedback (FB) active noise control (ANC) in order to reduce costs by simplifying ANC systems, because FB-ANC does not need reference signals. The purpose of this paper is to obtain a low order accurate model of an acoustic plant for FB-ANC and design a simple controller based on this model. The plant in this case is from the input to a single secondary loudspeaker to the output of a single error sensor (microphone). First, as a modeling method, physical modeling is applied. Second, Smith predictor is modified for FB-ANC to eliminate the influence of time delay in an acoustic field, and a PID controller is designed. Finally, effectiveness of the modeling methods and the proposed FB-ANC are demonstrated through numerical experiments using actual data.

抄録全体を表示

The pulsation attenuation capabilities of hydraulic silencers in real systems are investigated theoretically and experimentally in terms of the insertion loss characteristics, taking the every important circuirt-design factors including the pump and the load into consideration, so as to develop an useful CAE design tool for reducing the system audible noise level through the use of a fluidborne vibration control technique. Particular attention has been paid to the theoretical determination of the optimum insertion location where the potential attenuation capability of silencer can be brought out maximally. Theoretical model of the insertion loss characteristics is improved and validated by comparison with many experimental results obtained over the wide test conditions changing the insertion location variously for the different two branch-connection types of silencers under the different two load conditions. Additiollally, a new expression for the insertion loss characteristics for the branch-connection type of silerlcer is proposed which makes the physical elucidation of its complex characteristics easy and help to search for the optimum insertion location efficiently. The simulated results of the insertion loss characteristics from the Present theoretical model agree with the experimental results with sufficient accuracy for practical use up to around 5th harmonic (up to around 1.5kHz) of the pump induced harmonic pressure pulsations.

抄録全体を表示

This paper deals with an eddy current inspection for steam generator tubes of nuclear plants-A computational method is developed for detecting and characterzing material flaws inside and-or outside tubes. Those defects can be detected as a probe impedance traiectory by scanning a pancake type coil. The fuzzy system is used to evaluate position and size of a defecl in test samples. The iveness of the roosed method is demonstrated through computational experiments.

抄録全体を表示

A fuzzy servo system is described for a system with noises by using a stochastic fuzzy control method with some dynamic linear models. The present fuzzy servo approach is applied to the control problem of rotational angle for an omnidirectional mobile robot with three orthogonal-wheel assemblies. For the dynamic linear system with system and measurement noises, the optimal typel servo system is first derived by applying the estimate of Kaiman filter. Next, a multiple model servo system is considered under the hyposeses on the uncertainties of initial state and input distribution matrix. Furthermore, a stochastic fuzzy servo system taking account of dynamic models is derived by introducing the equality distribution on each multiple model. Finally, the stochastic fuzzy servo method and its modified method with a static evaluation on the model confidence are demonstrated through some simulations for the mobile robot.

抄録全体を表示

A system for measuring temporal variation of refractive index distribution has been developed. The system adopts six optical shearing interferometers or differential interfer ometers with doublefrequency diffraction gratings. They are arranged in six different directions. Each interferometer measures optical path diffemence between slightly sheared or displaced images. The image data are stored in image memories at the rate of 30 frames per second. Refractive index distribution on the sectional planes is calculated with the image data by using the algorithm of computed tomography. The temporal variations of refractive index distributions of gas flow flelds are reconstructed.

抄録全体を表示

A wheeled inverted pendulum (WIP), which is unstable and nonholonomic, with two servodriven wheeles is manufactured and used to confirm the proposed method for controlling its position and orientation. First WIP control system equipped with sensors such as a piezoelectric gyro to detect the tilt angle and two semiconductor photosensing devices to obtain the position and orientation is constructed. By using a distance variable the system dynamics is decoupled and an integral type optimum regulator is built up to reduce the influence of disturbance. Algorithms are proposed to cope with the singularity problem included in the control rule. Finally the WIP is effectively controlled starting from various initial position and orientation states to a specified final state.

抄録全体を表示

A learning control method using B-spline curves is extended to be applied to the tracking of specified spatial paths at arbitrary speed. This tracking control means the tracking of time scaled trajectories with geomemc path constraints. The proposed method obtains following results : (1) By using Time Scale Factor, dynamics of controlled system is described by two separate terms, a part defining a spatial path and the other one scaling time. (2) An algorithm is proposed to estimat coefficients describing the dynamics. (3) A gain matrix for learning control is expressed as a function of Time Scale Factor. (4) The learning control method is effectively applied to the control of a one-link flexible arm to track arbitrary trajectories which are determined by specifying spatial paths and scaling time.

抄録全体を表示

Noncontact manipulation of micro obiects has been studied experimentally using radiation force of ultrasound. In a standing wave field generated between a transducer and a reflector in water, it was possible to trap small objects at nodes of sound pressure distribution. A multi-electrode transducer used in the present experiment was a rectangle 20×40 mm in size with fifteen electrodes of 20×2 mm. A series of electrodes on the transducer was driven by a continuous sinusoidal signal of 2.1 MHz and alumina particles were trapped at the nodes of sound pressure in a standing wave fleld. They were transported laterally by changing the driving electrodes sequentially. The resolu tion in moving distance of particles is determined by the electrode interval. Then, a method to control the sound field with high resolution was studied. When the phase difference between the electrodes was altered, the peak of sound pressure observed by means of the schlieren technique moved smoothly and the particles were also transported smoothly in the lateral direction.

抄録全体を表示

Manipulator is widely used in industry. Almost all manipulators are equipped with end effectors which are suited for work, and contact with environments through end-effectors at the end link of manipulator. In this paper, a performance improvement method for redundant manipulator contacting with environment is presented. The environment inside of the space occupied by manipulator usually becomes an obstacle for manipulation. The redundant manipulator is useful to avoid collisions and meant to track a target al the other side of obstacle. But required actuator torques is easy to be short because of increase of parts of manipulator. To settle this problem, We propose the method that the redundant manipulator contacts with not onlye end-effector but intermediate points on some manipulator links. Redundant manipulator system is formulated kinematically in this paper. Contacting points are made to move along on environment surface, receive reaction force from environment to keep constraint on the environment surface.

抄録全体を表示

A robot makes to be enhanced sensing capability to discriminate surface unevenness of an object by means of equipping an optical three-axis tactile sensor. The single sensor cell of the sensor was comprised of a columnar feeler and 2-by-2 conical feelers. Three-axis force and displacement were estimated from the area-sum and area-difference of contact areas of the conical feelers. To perform surface detection experiments, the optical three-axis tactile sensor was mounted on the wrist of a robotic manipulator having five degrees of freedom. The robotic manipulator rubbed the tactile sensor on three brass plates with step-heights δ=50, 100, 200 μm and a brass plate with no step-height. We proposed the virtual PSD (position detective device) method capable of processing rapidly image data to obtain distributions of three-axis force. Experimental results indicated that the optcal three-axis tactile sensor was able to detect the distribution of the coefficient of friction in spite of existence of step-heights. This tactile sensor was able to detect fine step-heights in the range of from 50 to 200 μm and to detect inclinations of the brass plate in the range of from -0.38 to 0.38°.

抄録全体を表示

An electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the autonomous assembly tasks using hydraulic manipulators. In this report, we applied a compliance control which is based on the position control by a disturbance observer for our manipulator system. And a reference traiectory modification method is proposed in order to achieve accurate force control even though the stiffness and position of environmlent change. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved under various environment conditions. Finally this proposed force control algorithm is applied to the approaching of bolt and the wrenching of nut task as one typical task in the maintenance work of live power electric line and is experimentally confirmed very effective by this task.

抄録全体を表示

Motions of a space manipulator cause dynamic disturbances to the spacecraft attitude. This paper proposes a method of path planning for space manipulators to reduce such dynamic disturbances. The method is based on the concept of the Enhanced Disturbance Map where the direction of joint movements that causes zero disturbance to the spacecraft attitude is given in the joint space. In this paper, this approach is applied to the path planning of space manipulators. The proposed method determines the direction of small joint movements at each step that causes zero atteitude disturbance and moves the end effector toward a desired position. The path planning algorithms are presented first for the case of non-redundandant DOF space manipulators and, then, for redundant DOF space manipulators. The present method also avoids the singular points in the joint space by means of the singularity low-sensitive motion resolution method. Results of numerical simulations are presented for a two-link planner space manipulator system and for a three-link redundant system.

抄録全体を表示

This paper describes autonomous acquisition of target approaching behavior for a distributed autonomous robotic system on a water surface. The robot is a distributed controlled swimming one which has redundant linkage structure. Being located under unstable and uncertain floating environment, it is difficult for the robot to control itself. However, in this paper, we propose a method being simpler than those already proposed. That is, oscillation action patterns are preset heuristically, and simple Q-learning is employed to realize the target approaching behavior. The robustness of the behavior acquired by this simple scheme is shown by the observed fact that the behavior is environmental oriented, and the behavior is used recursively by the swimming robot.

抄録全体を表示

Conventional golf swing-robots are generally used to evaluate the performance of golf clubs and balls. Most of the robots have two or three joints with completely interrelated motion. Therefore, subtle adjustments in swing motion that advanced golfers make according to the characteristics of individual golf clubs are not possible. Consequently, golf swing-robots can not accurately emulate the performance of advanced golfers, which is a problem for evaluation of golf club performance. In this study, a new golf swing-robot that can adjust its motion to both a specified value of swing velocity and the specific characteristics of individual golf clubs was experimentally investigated. This robot utilizes the dynamic interference force produced by swing motion and shaft vibration like advanced golfers. Thus, this new robot can emulate the performance of advanced golfers and can therefore be used for accurate evaluation of golf clubs.

抄録全体を表示

Steering stability of tractor-trailer vehicles has been studied in general by root locus analysis of lateral motions, or measuring their damping ratios. However, in actual driving, it is necessary to establish a handling performance index taking driver's maneuver and off-tracking of trailer into consideration. By the analysis of a driver-tractor-trailer system, an appropriate index for objective handling evaluation is proposed and three types of safety drive limit are investigated. Consequently, many design parameters can be easyily optimized for better handling performance.

抄録全体を表示

A powertrain simulator with a simplified automatic transmission model was developed to aid the development and verification of control schemes for automatic transmission systems. To simplify the model, characteristics of engagement, slippage and release of clutches and one-way clutches were described approximately as a single model of clutches and one-way clutches respectively. And a conventional mathematical model for geartrains which was described by 79 equations was replaced by a model which was described by 9 equations. Algebraic loops was removed in the new model, and as a result, the run-time of the simulator was reduced by about one-sixth. This simulator was used to simulate acolal simple clutch pressure control during shifting and it was confirmed that this simulator was capable to examine the effect of shift shock reduction control.

抄録全体を表示

This paper describes a modeling method for simulating the traveling characteristics of Rubber Tire-mounted Gantry (RTG) cranes. The modeling methods of the gantry frame, tires, and driving motors are introduced, since these are the primary factors affecting the crane traveling performance. The dynamic simulation is based on the Finite Element Method. Simulation cases for different trolley positions and gantry traveling speeds are developed and compared with experimental results. The effectiveness of this simulation method is proven by the strong correlation between the simulation and experimental results. The effective factors on RTG traveling performance (straight traveling and turning) are discussed regarding the RTG's structural characteristics.

抄録全体を表示

Rubber Tire-mounted Gantry crane (RTG) is designed in a big gantry structure, and features some degree of flexibility and high position of its center of gravity. This results in a large influence against the travelling performaoces. The main factors affecting on the crane behavior (pitching romng and yawing) are the torque variation of the gantry-travel motors due to the road roughnes and inclination and the dynamic interactive forces between the tires and runway surface during the travelling motion. Based on both the experiments by actual RTG and simulation analysis, this paper clarifies the influence of the crane behavior on the travelling traiectory during straight travelling.

抄録全体を表示

Rubber Tire-mounted Gantry (RTG) cranes are not equipped with the mechanical steering device, but steered by means of the differential rotational velocity of the driving wheels on right and left sides. Accordingly, the power line design is the most important for the optimization of RTG's travelling performance. Herein this paper, the characteristics of the driving motors and tires, and the dynamic analysis with FEM in travelling are described. The effects of them over the straight travelling perfomance are discussed. As for the tire characteristics, the effectiveness of rolling resistance, friction coefficient, cornering stiffness and rolling radius are proved to be mostly concerned to the straigh ttravelling performance. The four corners drive system is proved to improve the straight-travelling better compared to the two opposite corners driven system.

抄録全体を表示

Perceptional characteristics of both hand and arm regarding the externally applied vibration and torque were investigated to design the information tool for physically handicapped people who lost their visual sensation or hearing. Perceptional characteristics of vibration were varied by the direction of vibration source, the frequency and the amount of weight. Perception of the torque that rotates the right arm anticlockwise seemed to become indistinct when the moment of inertia of rotating element was small. These results were thought to be caused by the area covered with the palm on the handle and the link mechanism of both ulna and radius bones. It was possible to recognize positions of the vibration through piezo plates on the skin of the palm. However, the perception was affected by the input frequency and voltage to the piezo plates.

抄録全体を表示

On sport players using raket and bat and general persons, sensory evaluation of the optimum diameter in grasping cylindical object and the movable angle of wrist joint under the grasping were investigated, and the effcts of the fingers in the six movements of wrist joint (Horizontal movement : Palmar-flexion and Dorsi-flexion, Vertical movement : Radial-flexion and Ulnar-flexion, Twist movement : Supination and Pronation) were investigated using stress sensors attached on the fingers. The subjects were ordinary persons and players of badminton, baseball and tennis, and the obtained data were compared to each other. The optimum diameters of the grasping evaluated by sport players were ranging from 30 mm to 40 mm, these values were same as that of ordinary persons, and the average values of optimum diameter were almost same as grip diameters of raket and bat. About movable angle of wrist joint under the grasping, badminton players could move horizontally and twist at larger angle and fielders could move vertically at larger angle. About the grasping force of fingers, the maximum force was exhibited at the tip of index finger for sport players, on the other hand, it was exhibited at the tip of middle finger for ordinary persons. It was considered that the specific training has effect on the sport players in the movable angle of wrist joint and in the finger's way of using at the movement of wrist joint.

抄録全体を表示

The influence of sliding conditions on pitting fatigue strength has been investigated. In order to elucidate the influence of sliding conditions, fatigue tests were carried out on various conditions of specific sliding (0∼-82%) and rolling velocity (500∼5000 rpm) with carburized SCr420 Steel rollers. As the results, there were two pitting forms, internal initiation and surface initiation. In the case of 0% specific sliding, internal initiate pitting occurred. The crack initiation depth and the fatigue strength of internal initiation coincided with the values estimated from shear stress and shear strength related Vickers hardness. In the case of -8∼-82% specific sliding, surface initiate pitting occurred. The fatigue strength was related to specific sliding rather than rolling velocity, surface friction coefficient and surface temperature, and the fatigue strength decreased as specific sliding increased.

抄録全体を表示

In order to elucidate the influence of case hardness on pitting fatigue strength, fatigue tests were carried out with carburized SCr 420 steel rollers that tempered at various temperatures to adjust case hardness. The resuits on 0% specific sliding condition show intemal initiation pitting form and the fatigue strength increases with case hardness. The results on -25% specific sliding condition show two pitting forms ; internal initiation and surface initiation. In the case of internal initiation on -25% specific sliding condition, the fatigue strength increases with case hardness as 0% specific sliding condition. The fatigue strength of internal initiation on both specific sliding conditions coincides with the values estimated from shear strength related case hardness. In the case of surface initiation, the fatigue strength decreases with case hardness. It becomes clear that the pitting from showed on -25% specific sliding condition is lower strength form which internal initiation or surface initiation, that relationship depends on case hardness.

抄録全体を表示

In order to elucidate the influence of residual stress on pitting fatigue strength, fatigue tests were carried out with carburized SCr 420 steel rollers on various conditions of shot peening. The resuits for rollers with the oxidized and nonmartensitic layer show that the fatigue strength increases with shot peening, and it is remarkably in the case that the oxidized and nonmartensitic layer wore out during the test. On the other hand, the resuits for rollers, that the oxidized and nonmartensitic layer was removed in advance, show that the fatigue strength decreases with shot peening. However, in each case, it is necessary to deduct influence of surface roughness and hardness, so it is becomes clear that residual stress makes the pitting fatigue strength improve. In the case that the fatigue strength decreases with shot peening, the effect of residual stress is regarded less than that of surface roughness and hardness.

抄録全体を表示

Robust error compensation algorithm for tooth form grinding works of an involute spur gear is proposed. The proposed algorithm is insensitive for the measuring error of the tooth form profiie data. Relationship between indirect measuring quantity ; the grinding error and direct measuring quantity ; the tooth profiie data are expressed by an implicit function. Error propagation analysis for the implicit model is derived using implicit derivative of the model function. Error ellipsoid of the indirect measuring quantity which express the projection of the error hyper sphere of the direct measuring quantity is defined. By taking the structural restrictions of the grinding error model into the least square calculation of the error estimation, the primary axis length of the error ellipsoid became smaller, which means the algorithm became more insensitive for the measuring error. Proposed algorithm was implemented on a in-process measuring system with personal computer. Accurate grinding error compensation was confirmed by experimental results.

抄録全体を表示

Recently, hard thin films are often used to improve the tribologicaI performance of machine elements or cutting tools. When the films are subiected to sliding, cracks are often generated by a normal and a friction forces because of the brittle nature of the fiims. However it has been unknown that whether or not the cracks affect the detachment phenomena of the fiims from the substrate, which cause drastic deterioration of the sliding surfaces. In this paper a stress analysis of both several hard thin films and the substrates, especially the analysis of the interface between them, is conducted to examine the influence of a crack existing in the fiim on the detachment of the film. The crack is supposed to be normal to the sliding surfaces since the fiim thickness is very thin compared to the contact width. A two dimensional FEM method is used for the analysis. The calculated results suggest that the normal crack greatly affects the detachment phenomena of the films under the conditions of high coefficient of friction and thinner film thickness. On the other hand the crack chip is closed and has no influence on the detachment phenomena when the film is thick even if such normal crack is present. The detachment of the film is dependent on the coefficient of friction.

抄録全体を表示

The friction and pull-ff forces were measured between an atomic force microscope (AFM) probe made of Si₃N₄ and submicron-size asperity arrays on a single crystal tungsten plate, a silicon wafer, and a platinum film. A focused ion beam was used to produce two-dimensional asperity arrays. The tip of the AFM probe had a flat, square surface measuring 0.7×0.7 μm². The pull-off force was proportional to the curvature radius of asperity peak, but was not affected by microroughness on the Peak. The friction force was proportional to Pull-off force. These suggest that Laplace pressure of condensed water was predominant as the pull off force and the Pull-off (adhesion) force worked as an extemal normal load for the friction. The friction coefficients calculated by regarding the pull-off force as the external normal load were compared between the platinum and silicon patterns, which proved that the friction coefficient on silicon was about twice higher than platinum.

抄録全体を表示

For survey of new solid lubricants which are effective in high temperature, 18 oxides were examined on stainless steel in high temperature up to 1000°C. Test equipment used was a ring / disk type friction tester, and test condition were 10 mm/s in speed and IMPa in contact pressure. The results showed that potassium tungstate allowed smooth sliding up to 1000°C without seizure. The combination of acid oxide and basic one causes low friction, and coefficient of friction shows relation to the difference of Ionic Field Strength.

抄録全体を表示

A numerical method of analysis for unsteady elastohydrodynamic lubrication of point contacts was developed with consideration of direct contacts. In order to make the analysis possible, three states of the contacting regions are distinguished, i. e., the hydrodynamic-fiim-formation, the direct contact and the cavitation regions, to which different equations are applied, respectively. In piace of Reynolds equation applied to the hydrodynamic-film-formation region, elasticity equation is used as the governing equation of the direct-contact region. Not only pressure and fiim-thickness, but also the oil mass quantity at each point in the calculation region are always grasped and used to decide the state of the point and the goveming equation. The results by this method are presented for the case of starting from Hertzian contact condition with zero velocity and for periodically varying velocity between zero and 50 mm/s. It is shown that increase in pressure at the contact points is not so large even when direct contacts occur.

抄録全体を表示

A double cavity half toroidal contimlously variable power transmission transmits input torque through a pair of variable units and changes its speed ratio by controlling attitude angels of four power rollers. One power roller among them is controlled by a hydraulic servomechanism and the others are followed it under the control principle of equal force transmission. Synchronization of four power rollers is guaranteed by safety wires, however nonlinearities of friction force on the control pistons or pressure delay in hydraulic lines due to air mix or pipe length cause instability of the speed ratio servomechanism through the safety wires. This paper focuses the relation between the synchronization and stability of the CVT by making bond graph analyses and experiments, and shows design guidelines on the stabilization of the double cavity half toroidal CVT.

抄録全体を表示

Piston motion which interacts with lubrication characteristics including friction force between the piston and cylinder has been measured in order to prove the oil whirl phenomena in an axial piston pump and motor which had been found theoretically in the previous paper. The piston motion has been measured by means of eddy current displacement sensors, comparing with calculated results. It has been verified that the piston has whirled in the cylinder under certain operating conditions and specifications, similar to the oiI whirl phenomena as self-excited vibration in journal bearings. The phenomena have not occurred for wide clearance and short sealing part between the piston and the cylinder as the previous paper predicted them. The period of piston whirl has coincided with that of friction force variation.

抄録全体を表示

We propose a new transit system to equip the magnet belt. We made two types of the magnet belt in order to account the thrust characteristics. In these magnet belt, we measured the characteristies of the slip rate, the adhesion coefficient and the efficiency. We understanded that these are a small slip in ordinary and the action of the pulling apart in belt do not reduce the efficiency.

抄録全体を表示

Braking tests under overloading were carried out using large one-piece brake disks having eyebrow-shaped holes as decoration. When the number of braking was greater than five, permanent deflection of the disks was observed. When the number of braking was less than six, no appreciable deflection occured. The experiment revealed that such deflection occurred during the cooling process after the final braking cycle. The mechanism for this phenomenon is explained based on the deflection-time record in conjunction with the temperature distribution of disks and its variation with respect to time. The key for this phenomenon is yielding in tension at the bridges between holes. The deflection occurs due to elastic-plastic buckling caused by shrinkage of the flange. Numerical simulations were successfully conducted by using a general 3 D FEM in consideration of geometrical and material non-linearities.

抄録全体を表示

In order to reduce the aerodynamic noise of lathe chuck rotating at high speed, an air flow around jaws and front face of a three-jaw scroll chuck is observed by means of the tuft and tracer methods. Flow visualizations are carried out when heights of the jaw are 10, 20 and 40 mm and also the chuck rotating speeds are 1000, 2000, 3000 and 4000 min^-1 . A characteristic vortex-like flow can be observed around the suction surface of the jaw and also at the outer surface of the chuck body closer to the front face. In addition, the region of the vortex-like flow spreads with the increasing Reynolds number and reduces with lowering the height of the top jaw. And the air flows around jaws and the front face of the chuck are classified into two types, i. e., the flows caused by the top jaw acting like a centrifugal pump and by the difference of pressure such as the vortex-like flow and the separation.

抄録全体を表示