Equations of motion for one-dimensional continuous system are studied to identify unknown coefficients of that equation. Several new formulae are presented to calculate unknown coefficients. Experiments are achieved to verify accuracy of the present method. Good agreement suggests that the present method is reliable to identify unknown coefficients of the equation of motion. Following are applications of the present method. (1) Sound absorbing materials are tested. Complex sound propagation speed and complex effective density of the material are identified. (2) Wave dissipative offshore structure is also tested. Amplitude-dependent complex wave propagation speed in that structure are identified. (3) Perforated panels are tested to determine pressure loss coefficient under alternating flow condition. (4) Three-layered vibration damping steel beams are tested to determine complex equivalent flexural rigidity of the beam. Loss factor of the beam are measured in successive frequencies. (5) Cables with tension are tested. Both tension and flexural rigidity of the cable are identified using least square method from several resonance frequencies.

View full abstract

An analysis of vibration and damping of composite spherical shells with a constrained visco-elastic core are presented. The vibration damping properties are analyzed by means of the Ritz method. Displacement functions satisfied with boundary conditions are expressed by a power series. The elastic modulus of the core is treated as a complex quantity to take account of structural damping. The complex eigenvalue problem, which is derived by means of minimizing the energy functional, is solved to determine the natural frequencies, modal loss factors and mode shapes. The accuracy and validity of the present results are confirmed by the convergence study and comparison with published data. Numerical results are presented for different parameters, such as circumferential wave numbers, opening angles, ratios of core thickness to total shell one and the shear moduli of the core.

View full abstract

Free vibration of coaxial cylindrical shell made of the angle ply laminated of CFRP partially filled with liquid is analyzed by means of finite element method (FEM) using isoparametric elements. Liquid is assumed to be incompressible and inviscid. The theory is constituted for a coaxial cylindrical shell consisting of multiple walls, and is applied to the numerical calculation in the case of double walls. Bulging in the shell is simulated by FEM in the range of circumferential wave number n≥1, and boundary condition on the free liquid surface is taken into consideration. The ply-angle of the laminated composite, the stored liquid level between outer and inner shells, and the circumferential wave number are chosen as parameters to investigate their effects on the natural frequency and the mode of vibration in the shell. The maximum value appears in the frequency vs. ply-angle diagram for any mode of vibration. It is also shown that hydrodynamic pressure from the stored liquid significantly affects frequencies and modes of the system.

View full abstract

The new methods are presented for detecting Nonlinear Normal Modes (NNMs), which are defined as synchronous periodic motions of nonlinear systems, in modern analysis of nonlinear dynamics. In this work, NNMs in a three-degree-of-freedom (3 d. o. f.) vibration isolating systems, i.e., the vertical, horizontal and rotating vibrations, with '2-1-1' internal resonance are examined using this method as the examples of Non Similar Modes. The equations of motion of the 3 d. o. f. vibration system considering geometric nonlinearities are derived, and NNMs are investigated in the conservative nonlinear system. A forced oscillation of the nonconservative nonlinear system is analyzed with the method of multiple scales, in order to investigate the angular frequencies of excitation vs. amplitudes and phase characteristics. Moreover, the response curves are obtained analytically. Furthermore a 3 d. o. f. experimental equipment was set up, and the presence of bifurcation in the internal resonance was experimentally verified with the primary resonant excitation.

View full abstract

A method is proposed that precisely predicts natural frequencies for stiffness design of a deployable satellite antenna in a deployed configuration. Deployable satellite antennas are modeled as a coupled system; the reflector (an elastic body) is supported by a support structure or mechanism (a coil spring). The vibration equation is obtained by substituting kinetic and potential energies into Lagrange's Equation. It can be seen that natural frequencies of the deployable antenna depend on a parameter calculated from the modal momentum of the i-th mode and the moment of inertia of the reflector. The parameter represents the magnitude of the relative contribution of the i-th mode to the overall structural behavior around each coordinate axis. Therefore, this parameter can provide a useful indication of which modes we must consider from a prediction accuracy point of view. A numerical example shows that the proposed method is significantly effective for frequency prediction of deployable antennas.

View full abstract

Noise Control of the internal combustion engine in early design stage enjoins the analytical procedure to estimate the exciting forces, vibratory behavior of the engine block and the noise radiation properties. This paper presents a theoretical approach to predict the vibratory response of the engine block coupled with the rotating crankshaft considering the dynamic characteristics of the block, stiffness of the oil film and the main bearings, and exciting forces such as the gas force, inertia force, piston slap and so on. Engine noise radiated from the structure is estimated by use of the spatially averaged mean square velocity and the acoustic radiation efficiencies of the block surface. Numerical simulation offers the wave form of the vibration acceleration of the engine block and the estimated noise spectrum is compared with the measured one.

View full abstract

When a rotor system is supported by single-row deep groove ball bearings, nonlinear spring characteristics appear due to clearance of bearings. In such rotor systems, the vibration characteristics change due to the effect of nonlinearities. In this paper, we studied vibration control of nonlinear rotor systems with a dynamic absorber. We clarified that the nonlinearity influences on the vibration characteristics of controlled rotor systems. If the rotor system has a isotropic symmetrical nonlinearity, we cannot use fixed points theorem for the optimization of the dynamic absorber, because the vibration increases due to the effect of this nonlinearity. We also clarify that the vibration control of the nonlinear rotor systems with a dynamic absorber can be achieved by considering such effects of nonlinearity in designing the parameters of dynamic absorber.

View full abstract

The performance of an expansion chamber in a circular duct depends on the chamber length. If it becomes shorter than a specific length (so-called transition length from acoustically long to short), the chamber's property changes remarkably, and starts to act as a resonator muffler. While several researchers have investigated such short chamber's properties, the authors also treated them using experimental, analytical and numerical methods. Generally, their properties are realized using two interpretations: i.e., in contrast with a side-branch muffler (a quarter wavelength tube); or based on the cut-on phenomena of the radial modes in the chamber. However, no one has seemed to give any further description to bridge a gap between above two interpretations. In this research, for the purpose to clarify this situation and summarize short chambers' properties, comprehensive investigations are carried out for various sizes of the duct-chamber system and several (plane and asymmetric) mode waves incidence. Especially, in order to improve physical understanding, sound pressure distributions in the duct system are indicated using the numerical calculation (FDM) for various duct-chamber sizes.

View full abstract

Vibration isolation control of buildings is important for enhancement of safety for large earthquake. The sliding mode control theory which is one of nonlinear control theory has recently received attention in the field of active control. Although the advantage of the SMC method is a simple controller design and is capable of building a robust system against nonlinear characteristics of structures or devices, the disturbance is ignored or cancelled through the matching condition. In this study, a new method of the disturbance accommodating sliding mode control is presented, in which the disturbance is taken into account by augmenting the state space and the sliding mode is defined for the augmented state space. This method is applied to a base isolation control problem of a ten-degree-of-freedom structural model with active base isolator. In order to investigate the performance of the proposed method, computer simulations were carried out, and as a result, the effectiveness of the method was shown.

View full abstract

The sliding mode control theory facilitates the design of nonlinear control system and also has high robustness, which controls the left and right distribution of braking forces and the four-wheel-steering cooperatively. Using the sliding mode control theory, this paper proposes a practical method for improving the step response and stability of automobiles. Our theory is composed of the feed-forward control function on steering angle and the feedback control function through the differences of actual and target characteristics of vehicle dynamics, that are yaw rate and lateral acceleration. Computer simulation confirmed that when the vehicle applied this control system an improvement of the maneuverability and stability on cornering behaviors with braking was realized. In addition, our data suggest that this system makes it possible to achieve good control effects on low frictional road and the damaged road. Moreover, we report the result that was examined on the dynamic distribution method to make the load rate of four wheels with longitudinal and lateral forces uniform as much as possible, when the direct yaw moment element as the control signal is converted into the longitudinal force of each tire.

View full abstract

In recent years, many liquid container transfer systems used for the transfer of molten metal in the casting and steel industries have been studied. However, there are few studies to show the control system design method for real molten metal transfer although there are many for water, and it is highly demanded to realize the system in real plants. This paper gives the control system design method for molten metal transfer by using fluid behavior simulator, and realizes the molten metal transfer system. In order to design a feedback controller, sloshing phenomenon is analyzed by using Computational Fluid Dynamics (CFD) Model, and Hybrid Shape Approach is applied. The effectiveness of the proposed design method is shown through real experiment with water and the control simulations based on CFD with molten metal.

View full abstract

This paper mainly focused on the control system design and the control performance of the power assist lifting device used in power plant construction site. This device consists of several electric-chain-blocks, force sensors and a CPU. This mechanism is as follows. (1) Force sensors detect chain tension changes by human force. (2) The CPU calculates the required outputs from the force sensors. (3) Electric-chain-blocks move the object in the intended direction by human force. The control performance was verified through experiments using a 300 kg boiler panel that was suspended by the 2 electric-chain-blocks. A heavy control object could be moved, translated and rotated by human force using the proposed device. Positioning performance errors were suppressed to under 1 mm.

View full abstract

The head-positioning control system of a magnetic disk drive must enable precise positioning and high-speed access. To meet these control requirements, a Mode-Switching Control (MSC) system composed of two or three control modes and a mode-switching function has been used widely in current head-positioning control systems. One of the issues concerning MSC is to improve the transient response after it switches the mode. Although the mode switching is a non-linear action, the transient response can be improved if the control system considers the initial state response after mode switching. Initial-Value Compensation (IVC), which is based on this condition, can improve the transient response after mode switching. In the current study, we applied IVC to reduce acoustic noise during the seek operation of the head-positioning control system. Furthermore, we developed a new method for the mode switching condition; this method considers a trade-off between the peak value of operation current (which is an important factor in the reduction of acoustic noise during seek), the overshoot of displacement response, and the settling-time after mode switching. Acoustic noise during seek was experimentally found to be significantly reduced by IVC and the new switching method.

View full abstract

The neural network has been applied to many engineering problems such as pattern recognition, optimization, system identification and control because of its nonlinear mapping capability. Although the network has a great ability to acquire solution for a given problems through learning, however, several problems are known such as the convergence to a local minimum solution, and the tuning of network parameter manually to obtain desired accuracy. In the present paper, we deal with the self-organizing neural network where the spatially scattered neurons are connected automatically using Cellular Automata. The network is applied to the active noise control problem as an adaptive system, where the model consists of a simply supported plate embedded in an infinite rigid baffle above a rectangular cavity. The fully coupled acoustic-plate interaction equations including characteristics of piezoelectric transducers are solved using time-varying Green's function techniques, and the performance of the controller is discussed through numerical investigation as well as experiment.

View full abstract

This paper presents a method of simple adaptive control (SAC) for nonlinear systems using neural networks. The control input is given by the sum of the output of a simple adaptive controller and the output of the neural network. The neural network is used to compensate the nonlinearity of plant dynamics that is not taken into consideration in the usual simple adaptive control. The role of the neural network is to construct a linearized model by minimizing the output error caused by nonlinearities in the control system.

View full abstract

Wigner Distribution (WD) has recently attracted attention from many researchers as a tool for time-frequency signal analysis. WD offers higher frequency resolution but with interference terms for multiple frequency components. This paper first reveals that WD can be calculated as the convolution of Fourier Transform (FT), and then derives a series of transforms between FT and WD. A new method of spectral analysis as a hybrid of WD and FT is proposed for time-varying signals. The method offers higher frequency resolution with neither interference terms nor aliasing. Finally, we compare the proposed with FT and WD by a simple simulation and show its significance. This method is applied to measurement of a wave motion on the free surface of the Taylor vortex flow. Then we propose this new method is available to the time-frequency signal analysis.

View full abstract

Multi-media services such as audio and visual media are advanced rapidly. In addition to them, physical force information is expected as the next service, which may realize virtual reality service. Many reserches concerning the haptic interface as the force display have been reported. However, as they have not been studied specially from the control view point, control problems have not been clarified systematically. The purpose of this paper is to clarify the control problems of the haptic interface systematically, which includes not only the realization of the force display but also its stability and limitation. In this paper, two major control algorithms are investigated. The first type is the position control type, which realizes the position corresponding to user's force in consideration of the virtual environment dynamics. The second type is the force control, which realizes the force corresponding to operator's finger position. The following results are obtained. (1) Position control type: This type can realize the stable system for applied force. However, the force display does not show sharp linearity because it does not consider the force balance between the operator's finger and the interface. As the virtual environment dynamics must be used for realizing the Free Space, the unstable phenomenon occurs the continuation of the dynamic parameter is not guaranteed between the Free space and the Constrained Space. (2) Force control type: This system shows excellent performance as the force display because it actually generates the force by itself. However, the unstable phenomenon occurs when the force display becomes larger in relation to the user's finger reflecting force.

View full abstract

This paper describes a non-linear auto-tuning controller for a pneumatic servo system. The pneumatic servo system has essentially non-linear elements such as compressibility of air, friction between cylinder and piston. Therefore, we propose a two-degress-of-freedom control system in which a non-linearity is compensated by neural networks. This proposed control system uses two controllers. One is a reverse system controller, which improves the tracking performance for the reference input, and the other is a feedback controller, which restrains the non-linear disturbance input. In particular, the reverse system controller identifies the plant automatically by a two layers neural network, and the feedback controller compensates for the non-linearity with a three layers neural network. Further, the effectiveness of the proposed control system is confirmed by experiments using the existent pneumatic servo system.

View full abstract

ETS-VII is a test satellite to perform in-orbit demonstration of rendezvous docking (RVD) technology, which will be necessary for advanced space activities in the early 21^st century. ETS-VII successfully performed autonomous RVD in the first experiment flight. But in the second experiment flight, seberal times of Z-thruster misfiring occurred and they prevented for ETS-VII to accomplish docking for three weeks. To verify all technical items, the third experiment flight was replanned on condition that firing Z-thrusters should be minimized. And we modified on-board software to continue approach in case that Z-thrusters misfiring occur. ETS-VII succeeded in the third experiment as the result of these countermeasures. We present replanning of the third experiment flight and its result in this paper.

View full abstract

This paper is concerned with behavior acquisition of mobile robots based on multi-objective behavior coordination. Based on the concept of structured intelligence, the intelligence of a robot emerges from the interaction among simple functional mechanisms. The multio-bjective behavior coordination plays a role in integrating behavioral modules. A behavioral weight is assigned to each behavioral module represented by a fuzzy controller. To situate its action to the facing environment, the robot dynamically updates behavioral weights according to spatio-temporal context of the environment. The purpose of this paper is to discuss the effectiveness of the multi-objective behavior coordination through the behavior acquisition from the viewpoint of the structured intelligence.

View full abstract

A new hierarchical functional model of power train is constructed in this report using modeling approach proposed by the authors. A fundamental concept on hierarchical structure of virtual prototype of automobile and virtual testing using this prototype is presented by the authors' modeling approach. Function of automobile running is deployed from this concept, and government equation expressing this function is given. A basic functional model of power source is constructed by this deployment. It is made evident that this model has enough flexibility and applicability to express general power source, and can be used for wider purpose in power train development than usual ones.

View full abstract

The hierarchical functional model of power train is materialized in this report by attaching the mechanism model. The mechanism model representing nonlinear torque generation mechanism is made with torque curve chart, and is taken into the functional model as the side load. A simulation result using this model shows broad behavior of total power train. In order to examine function and efficiency of engine in actual development, the mechanical model has to reproduce them faithfully and in detail. Mechanism models of idle speed controller and reciprocal engine are presented as examples of detail mechanism model, and simulation results using these models are shown.

View full abstract

Hierarchical functional models of coupling and transmission that compose drivetrain are constructed in this report by the new modeling approach proposed by the authors. Mechanism models of a hydrodynamic power transmission and an automatic transmission are combined with the functional models to give characteristics of the mechanisms to the functional models. It is shown that hierarchical structure gives meanings to the relationship between these functional models organized as several kinds of sets of model elements, and that generality and concreteness are given to the functional model of drivetrain by this model organization.

View full abstract

We propose a method to control: the right and left torque distribution system of braking/driving forces, the four-wheel-steering and the active suspension cooperatively to concurrently improve maneuverability/stability and ride comfort for automobiles. Using the LQ control theory, we obtained the integrity control rule by which both the body slip angle and the yaw rate characteristics to steering input were made not only to follow the target values, but also control the swing of the body. Computer simulation confirmed that when the vehicle applied this chassis integrated control system, the effects of control for improving the vehicle performance were greater than that of the active suspension control alone. In addition, our data suggest that this system makes it possible to achieve good control effects under bad conditions such as a variety of rugged roads and the μ turbulence roads. Moreover, because this system can greatly decrease the amount of steering work required of the driver, a reduction in physical and mental load can also be expected.

View full abstract

It is important to optimize the combination of specification parameters of carbody, truck, and their connecting elements to reduce bending vibration of railway carbody and to improve riding comfort. This paper presents the optimization of the specification parameters using the genetic algorithm (GA). The riding comfort level (L_T) at the center of carbody is used as the objective function and the specific parameters are taken as design variables. A beam model, in which the carbody is treated as an elastically supported beam, is used to calculate L_T. The effects of carbody and truck connecting elements, such as traction links and anti-yaw dampers, are taken into account in the calculation model. It is shown through numerical calculation that bending vibration can greatly be reduced and L_T is also improved as a result of the optimization method presented in the paper. A running test for a real Shinkansen train is also carried out to confirm the effectiveness of the method. It is found that the bending vibration is reduced to a large extent and L_T can be improved by 2 dB or over, in the case, where the specifications of traction links and anti-yaw dampers are modified based on the result of GA optimization.

View full abstract

It's important to separate, transport and operate a micro-object such as a microbe with high speed and high purity for examination of newly developed or discovered microbe. However, it is difficult and takes much time to separate a single target microbe. Here we designed a new separation cell, with which we can separate the target microbe based on the continuous sample liquid injection. We integrated the Laser Manipulation and fluid flow control in the micro capillary for the single target manipulation. We fabricated a disposable type separation cell by the polymer and succeeded in the separation of a microbe within 30 seconds.

View full abstract

To evaluate the performance of photovoltaic systems, it is necessary to estimate detailed characteristics of solar radiation which varies with seasons, time, and weather conditions. The objective of this paper is to propose a method of evaluating the performance of photovoltaic systems, using probabilistic characteristics of solar radiation estimated at an arbitrary location by combining rough data observed meteorologically at the location with detailed data measured at another location. A case study on the electric power supply to a condominium is conducted. The validity and effectiveness of the method is clarified, by comparing the purchased and reversed electric power estimated by the proposed probabilistic method and calculated by the deterministic method with measured solar radiation. The performance of photovoltaic systems is also clarified in relation to the area and tilt angle of the photovoltaic array as well as the weather conditions of some locations.

View full abstract

In this study, a novel hybrid vehicle is proposed. The vehicle has a flywheel-engine hybrid system. Flywheels are more effective as energy charge systems than electric batteries in a respect of output power density. However, transmissions to effectively drive flywheels are very complex systems such as CVTs (Continuously Variable Transmissions). In the proposed hybrid vehicle, Constant Pressure System is employed, which is hydraulic power transmission. Using Constant Pressure Systems, hydraulic CVTs are easily realized with variable displacement pumps/motors. In this paper, firstly, the proposed flywheel hybrid vehicle making use of Constant Pressure System is described. Secondly, fuel consumption characteristics of the flywheel hybrid vehicle are experimentally examined with the stationary test facility, which employs a flywheel as a load emulating vehicle inertia. Finally, the experimental results and discussions are described. Fuel consumption of 26 km/L is expected for 10 mode driving schedule with vehicle mass of 1500 kg.

View full abstract

To reduce the spin-off of lubricants, which is caused by the radial component of air-shear force on a magnetic disk, we analyzed the air-velocity distribution and the air-shear force by using the three dimensional large eddy simulation (LES) and the finite-element method. A sensitivity analysis of five design parameters showed that disk/arm clearance and arm thickness had greater effect on the mean radial air-shear force than the other three parameters. The air-shear force was decreased when these two parameters became small. The force on the disk with the optimum parameters is 12% less than the force on a current design disk. The optimized drive can thus be operated at 14% higher rotational speed with the same reliability as current drives.

View full abstract

The clamping force of a bolted joint is usually controlled by torque or angle at tightening. However the fatigue failure of bolted joints occures if the clamping force is loosened in service. Therefore the clamping force in service after tightening must be checked to avoid failure of bolted joints. In this study, a new method to detect the clamping force of bolted joints after tightening has been proposed, in which the clamping force is detected by pulling the protruding thread of the bolt through the nut on a bolted joint. The relationship between the pulling force and the displacement at the pulling point is measured to detect the apparent spring constant of the bolt. When the pulling force reaches the clamping force of bolted joint, the apparent spring constant varies markedly. Thus the clamping force of the bolted joint can be defined on the basis of the variation of the apparent spring onstant. The basic theory and the experimental verifications are presented.

View full abstract

In centerless grinding, the axis of regulating wheel is tilted at a small angle of less than 1° with respect to the axis of the workpiece. In order to ensure in-line contact between a cylindrical workpiece and the regulating wheel, the regulating wheel is dressed with a barrel shape. As a result, the radius of the barrel-shaped regulating wheel varies along its axial direction, which leads to the variation of relative peripheral speed between the regulating wheel and the workpiece along the workpiece length. This relative speed variation results in uneven wear on the regulating wheel along its axis direction, which in turn results in dimensional errors on the workpiece. In this paper, the mechanism of wear deviation on the regulating wheel is discussed and its effect on the workpiece accuracy investigated. It is found that wear deviation results in the workpiece to be produced in a conical shape and to vibrate to increase its roundness error. A technique for reducing the wear deviation is then propused by setting the workpiece at an appropriate position in its axial direction at which the radius of the regulating wheel is smallest.

View full abstract

Various models are considered for the generation of the ground surface topography to predict the surface texture of workpieces in terms of the wheel topography. Both topographies of ground surface and wheel surface exhibit the self-similar structure and can be quantitatively characterized by the fractal dimension, so that the mathematical model can be built based on the empirical results by using the group method of data handling. Again, since it is possible to represent the self-similar wheel surface topography by a probability function which gives the fractional Brownian motion, a method of simulating the generation of the ground surface texture with the artificial wheel surface is proposed.

View full abstract

Magnetic abrasive finishing is one of the surface finishing methods, in which a workpiece is polished by special abrasives held in a magnetic field. Since these abrasives are not connected mechanically one another but only supported by magnetic force, they can change the position to fit the workpiece surface. Therefore, this process is applicable to curved surfaces or inside of tube, which cannot be finished with conventional processes. However, as regards finishing mechanism, behavior of abrasives during working has not been explained well. In order to clarify it, a new mechanism for this process based on energy principle was proposed and discussed in this paper. Apparatus for plane finishing was made and nonmagnetic stainless steel sheet was polished. Under the assumption that abrasives were arranged between magnetic poles in such a way that cohesive energy became minimum, movement of abrasives in contact with workpiece was explained by means of equilibrium of forces. Normal force, horizontal force and distribution of normal stress in the contact area were measured with specially designed jigs. They were increased with increasing current to the electric coil or the amount of supplied abrasives, due to increase in intensity of magnetic fields or cohesive density of abrasives, respectively. Mean surface roughness was measured and found to be improved from 0.1 μm to 0.04 μm after about 10 minutes working.

View full abstract

An automated design of bending process was carried out by using an artificial intelligence. This design which is to decide an optimum order of edges to be bent can be considered as a kind of traveling salesman problem. A genetic algorithm was applied for a solution, where a gene is an edge to be bent and chromosome is an order of gene. If an interference occurred due to an ill-considered order, a process cannot be carried out. The interference would to be known at the beginning of a design, while it often occurs at the end of a process. In order to design efficiently a practice of an inverse process design, which means not to decide a beginning order from a raw material to a product but to do a development order from a product to a raw material. Automatic design of two product profiles were carried out in the condition that two crossovers were examined and a scaling changed and it done successfully in the case of combination of two point and permutation crossover and gradual change of weight of a scaling. A fitness function was composed of five process factors which include a interference.

View full abstract

Finish machining used to be carried out in grinding, but it is being replaced by cutting with very small undeformed chip thickness. In ultra precision process, the effect of the cutting conditions and the complicated factors on the machined surface integrity is a serious problem. In this research, work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal cutting. As a result, it was found that work hardened surface layer was affected not only by the shear angle varied under the cutting conditions and the thrust force of cutting resistance, but also by the thrust force action point, coefficient of thrust force and the compressive stress equivalent to the bulk hardness. Furthermore, these mechanical factors acting on the depth of the work hardened surface layer were investigated with the calculation model.

View full abstract

In the ultra-precision machining, the smaller the undeformed chip thickness is, the more the machined surface integrity is affected by the cutting edge roundness of the cutting tool. In this research, the work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal cutting. In the case of a rounded cutting edge, unlike a sharp one, it makes the generation mechanism of the work hardened surface layer complicated. Therefore, it is difficult to predict the depth of the work hardened surface layer by using the previously presented prediction equation for the sharp cutting edge. However, it is possible to predict it by using the ratio of the undeformed chip thickness to the cutting edge roundness. That is because the equivalent shear angle changes according to the ratio of the undeformed chip thickness to the cutting edge roundness.

View full abstract

A new forming process, upsetting-burring process is proposed to produce the parts with a flange from a thick plate. The usual burring operation used in the sheet forming was applied to the thick plate forming and the flange shape can not be obtained satisfactorily. The feature of the newly devised upsetting-burring process has been investigated in detail by FEM analysis and verified by a series of experiments with the aluminum plate. In the upsetting-burring process, the plate is upsetted partly and the upsetted material flows into the flange portion. By changing the upsetting height, width and the taper angle of the lower upsetting die, a flange with sufficient height and good shape accuracy can be formed successfully.

View full abstract

This paper deals with the performance of water-soluble cutting fluid for hobbing in terms of tool life (flank wear), crater wear and finished surface roughness using TiN and (Al, Ti)N coated tools, in order to develop water-soluble cutting fluids which have more superior cutting ability than that of water-insoluble cutting oils. Experiments were carried out using a fly tool. As a consequence, the following points were clarified: (1) When using the TiN coated tool, the soluble cutting fluid used in this test prolongs the tool life in comparison with the cutting oils up to a cutting speed of 117 m/min, but at a high cutting speed of 159 m/min, its tool life becomes shorter than that obtained with the cutting oils. (2) With the (Al, Ti)N coated tool, the tool life obtained with the soluble cutting fluid is longer than that obtained with the cutting oils at all cutting speeds tested. (3) From the view points of the tool life, the crater wear and the surface finish, the soluble cutting fluid prepared in this experiment is more effective than the cutting oils when using the (Al, Ti)N coated tool.

View full abstract

New product development of machine tools is always costly and risky for machine tools manufacturers; nevertheless, there have been few academic studies on the product development process in order to establish the product development methodology for machine tools. Successful product developments were found to be related to perceived superior skills and resources within the objective machine tools manufacturer. In this study, therefore, the success factors in new product development of machine tools have been identified based on the results of the interview and questionnaire investigations with experienced engineers in Japanese machine tools manufacturers. Furthermore, a structured method for identifying the success factors in new product development has been proposed. Furthermore, it has been verified that the proposed method has an effective means to realize the success of new product development.

View full abstract

A direct and intuitive 3-D geometric operation interface using various-shaped deformable real objects as input tools is proposed. Elastic-conductive material block itself is used not only as a structural body but also as 3-D deformation sensor. To use various-shaped blocks as input tools other than simple parallelepiped ones, neural network is introduced to learn relationships between 3-D deformation of the blocks and measurements of their resistance change patterns. Also, a neural netwerk optimization algorithm is proposed for semi-automatic determination of the number and arrangement of wire terminals to measure 3-D deformation of the input tool. The measured and calculated deformation of the input tool is mapped to the object shape on a computer display using free form deformation. This interface enables users to use input tools of suitable shapes for their purposes, from a simple shape for general purposes like cubes to a specific shape like a doll figure.

View full abstract

Manufacturing system engineering process (MSE process) is investigated to establish a systematic and computerized support system for planning, design and evaluation processes of the manufacturing systems. A description method is proposed to describe the MSE process. The proposed method is applied to description of the MSE process for the automotive parts manufacturing system. According to the analysis of the description, a prototype of a computerized support system is developed for MSE processes in order to support the manufacturing engineering processes.

View full abstract