This paper discusses a bandwidth extension of a spacecraft attitude determination filter. It supposes an offline determination by the ground processing with on-board sensor telemetry data. The bandwidth of the filter is extended via sensor fusion, where an attitude sensor, a low-bandwidth angular rate sensor, and a high-bandwidth angular rate sensor are used. The bandwidth of each sensor is different and each bandwidth involves a common frequency region. A high-bandwidth attitude determination filter is proposed. The angular rate input for the low-bandwidth attitude determination filter is extended to the high frequency range with a complementary fashion. The complementary filter has a flat gain property and a zero phase property. By numerical simulation of three-axis spacecraft attitude vibration, both the bandwidth extension and the accuracy improvement of the attitude determination filter are verified.

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The insertion of baffle plates in a duct is one of some countermeasures of the self-sustained tone generated from the duct with two tube banks. However the use of the baffle plate in the tube banks with cavity has unclear points in the baffle plate length and the insertion conditions. Then the aim of this study is to establish the best insertion condition of the baffle plate in the tube banks with the cavity. And the new idea has been verified by experiments that the suppression mechanism of the self-sustained tone is due to the decrease of the particle velocity and the Karman vortex. In the present experiments, the suppression effect of the baffle plate on the self-sustained tone has been examined. As a result, it was clarified that two peaks of fluctuation velocities appeared when the self-sustained tone occurred and one of them, which has a steep peak, was due to the occurrence of the self-sustained tone. It was also clarified that the self-sustained tone was occurred also by the selected resonance.

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The insertion of baffle plates in a duct is one of some countermeasures of the self-sustained tone generated from the duct with two tube banks. However the use of the baffle plate in the tube banks with cavity has unclear points in the baffle plate length and the insertion conditions. Then the aim of this study is to establish the best insertion condition of the baffle plate in the tube banks with the cavity. And the new idea has been verified by experiments that the suppression mechanism of the self-sustained tone is due to the decrease of the particle velocity and the Karman vortex. In the present experiments, the suppression effect of the baffle plate on the self-sustained tone has been examined. As a result, it was clarified that the insertion of the baffle plate only the tube bank is not effective for the suppression of the self-sustained tone in the case of plural banks with cavity. It was also clarified that the self-sustained tone disappeared when the baffle plate was inserted in and just down the tube bank where the fluctuation velocity was large.

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This paper proposes a method of acoustic vibration testing based on a point source generated by laser-induced breakdown in the air. A high-power Nd: YAG pulse laser is used in this system for generating the laser-induced breakdown in acoustic fields. Plasma formation can be realized by the laser-induced breakdown if the local intensity of the laser beam reaches 10¹⁵ W/m². The shock wave that is yielded by consuming a part of the plasma energy becomes a sound source. Assuming that the laser beam is focused to a small volume through a convex lens and the sound source by the laser induced-breakdown has nondirectional property, it is possible to create a point source with this technique. Securing the laser light path installs no device for acoustic excitation in acoustic fields. The system is validated by comparing the resonant frequencies of a micro-space measured by the laser-induced breakdown and calculated by theoretical model.

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As an important process for reverse engineering, automatic registration is usually divided in two steps, the coarse one and the fine one. In coarse step, an initial estimate for relative rigid-body transform can be brought to realization by searching some similar geometry, and guessing the corresponding region,. In fine step, highly accurate alignment can be achieved by searching an approximate correspondence repeatedly. For two steps, researching on the first one is more important, because the coarse step will requires more computation time and the accuracy will affect the next step. Various methods such as Genetic algorithms, geometric histogram, graduated assignment, feature matching were submitted or applied. However those methods either need large computing time or only can be used upon the satisfaction of some limited conditions. In this paper, a new method base on CDCP model, including location descriptors, classification descriptors and direction descriptor, was .location descriptors and direction descriptors can provide the necessary information for matching the corresponding points, and classification descriptors can make this process more accurate and efficiency. Experimental results of three 3D images taken by laser scanner are carried out to compare the registration results of proposed method with other twins, and proposed method can be confirmed make the coarse registration process be high speedily without any limited condition.

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In this paper, we proposed the real time robust tracking method which combined mean-shift using the spatiograms with the particle-filter, and the proposed method can continue to track non-rigid objects with a temporal occlusion. The proposed method is using a tracker representing the center of the object and samples. At first the tracker tracks the object by using the Mean-Shift algorithm based on the spatiograms. Then, to avoid to be trapped by occlusion, the true target position is searched by using the particle-filter. The proposed method needs only small number of samples so that the computational cost can be reduced largely. We conducted experiments in order to compare the proposed method with the conventional Mean-Shift. As a result, the proposed method was more effective than the conventional method, when the object moved rotation or moved rapidly and a temporal occlusion occurred.

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A high-accuracy measurement technique for plate tension distribution on the process line would potentially lead to improved steel, aluminum and copper plate qualities. We propose an identification method by using natural frequencies and vibration modes, which are related to tension distributions of thin plate. In this paper, a new tension identification method in a thin plate using characteristics of vibration is investigated. We develop a simplified dynamic model of thin plate, and tension distribution is modeled by springs. A simplified model spring constants are obtained by the least-squares method to minimize the difference between a simplified model modal parameters and the given values. We apply the proposed identification method to a thin aluminum plate based on FEM analysis results. As a result, it is shown that identified tension distributions well corresponded to the FEM results.

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A 3-dof active scanning probe using a translational parallel mechanism (TPM) is proposed. In this paper, the characteristics of the mechanism, optimum design, prototyping, and accuracy of the TPM are introduced. In the proposed optimum TPM design, the manipulability of the mechanism is equal in all directions. This implies that the positional sensitivities of the TPM share an isotropic relationship. The positional resolution of the mechanism becomes 0.58 μm in a cubic working range with side length of 1.6 mm. An experimental mechanism using the proposed design is introduced. Relationships between positioning errors and mechanical parameters of the TPM are revealed by applying the error propagation analysis. In order to evaluate the accuracy of the TPM, we have developed an experimental system for the measurement of the position of the TPM using image processing. By applying mechanical parameters calibration, the accuracy of the absolute position of the TPM has been improved to 3.4 μm.

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In this study, the replica of the metal processing surface was produced using the transparent silicone. The new measuring method which examined the transmission image was proposed with a scattering of the spot light in the replica. The result was summarized in the following. It was able to be classified to four patterns of the transmission image from the replica reflection plane, that is to say, point pattern, circular pattern , elliptic pattern, diffractionpattern. It is possible that these patterns estimate the shape of the reflection plane, namely shape and processing method of the machined surface. The surface roughness by the diffraction was equal to the maximum height roughness by the tracer. In circular pattern and elliptic pattern, the empirical formula which showed the relationship between maximum height roughness and radius of gyration was obtained. In the point pattern, it was not possible to show surface roughness in the measuring range of this experiment.

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Sensing devices for intelligent tire that can measure friction coefficient of a road are researched so as to improve the performance of vehicle motion control systems such as ABS (anti-lock braking system). However, previous devices need complicated systems and do not have enough performance. This study proposes a simple tactile sensor that can measure the friction coefficient between a tire and road surface. The sensor is composed of a cantilever called “whisker” that is fixed to a base. The base is an elastic plate, and two strain gauges are attached to its surface. The whisker is passed through the hole opened to the tread of a tire and the sensor is attached to its inner surface. The whisker is covered by a domed rubber; the tip surface is used as the contact part. When the tire slips on a road and the contact part comes in contact with the surface, the vertical load and frictional force are applied to the contact part. Then, whisker is compressed and bended, so that the base is deformed elastically. The induced strains at the base from such deformation are measured by the abovementioned strain gauges. The study proposes the method determining the value of the vertical load and frictional force that acting on the tire from the measured strains and fabricates the prototype tactile sensor to confirm its availability.

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The purpose of this paper is to make a model for estimating a load variation on the back of supine persons which is induced by centrifugal acceleration during transportation by ground vehicles. First, the transportation experiment was conducted for 19 healthy subjects with normal body weight. A minivan without seats was used as an experimental car. In the experiment, the subject lied on the back in the center of the car with his/her eyes covered by an eye mask and the car ran about 820 meters in the range of lateral acceleration from -3 to 3 meters per second squared. At a sampling frequency of 100 Hz, the lateral acceleration acting on the supine subject was measured with an accelerometer and the vertical load acting on the scapula of the subject was measured with a load sensor. From the measured data, it was found that the vertical load variation was proportional approximately to the lateral acceleration. In response to this result, the model to estimate the vertical load variation was constructed as a linear system composed of a first-order lag filter, which eliminates high-frequency noises from the acceleration data, and a proportional gain, which converts the acceleration to the load variation.

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Recently, Quad-rotor type helicopters which are representative of Multi-rotor type helicopters have been extensively developed over the world. The Multi-rotors are expected to replace Single-rotor type helicopters as an industrial helicopter because of their simplicity of the structure and good maintainability. In this paper, we focused on the operation problems of previous industrial helicopters and applied the Multi-rotors by a generalized design method. The generalization of the design method is performed considering variation of requirements of airframe specifications. In addition, we considered using commercial components rather than customized components in each process, so we achieved cost reduction compared with previous study. At first, we introduce the required specifications of a small pesticide application in this study and present the airframe design method. And then, we tuned parameters with presented simulation model and implement a multi-rotor type helicopter following the design method. Finally, we show the flight result and present the effectiveness of the design method.

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Finger deformities refer to the symptoms where a flexed or extended joint becomes fixed in one direction and is prevented from returning to a normal state due to muscle or tendon abnormalities around the joint as a result of trauma or a pathological abnormality. The deformities exist in numerous forms, and their causes are known to be either a muscle imbalance or tendon rupture. We focused on the finger deformity forms of the boutonnière and swan-neck deformity. To clarify the formation mechanisms of these deformities, conventional studies have used cadaveric fingers whereas in this study we used the finite element method to model the mechanism of human finger flexion and extension (extensor tendons, flexor tendons, phalanges, tendon pulleys, and ligaments). Using this model, flexion angles of the distal interphalangeal (DIP) and the proximal interphalangeal (PIP) joint were calculated with conditions for a tendon (central band, lateral band, flexor digitorum superficialis tendon) rupture and tendon tension abnormalities. The results have shown that the conditions which most resembled the boutonnière deformity were those of the central band removal model, and the conditions which most resembled the swan-neck deformity were those of the flexor digitorum superficialis tendon removal model and the tendon tension abnormalities. These results are in agreement with those from clinical observations and cadaveric finger experiments, and demonstrated that the finite element method was effective for clarifying the mechanisms for finger deformity formations.

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In this paper, we analytically considered the effects of the in-plane stress of the disk on the changes of modal shape. The purpose of this study is to confirm whether the modal shape changes according to the in-plane stress. The results make it clear that the in-plane stress changes the modal shape and its curvature. The curvature of the modal shape is proportional to the reciprocal number of the bending stiffness. Thus, it is confirmed that the in-plane stress serves to change the bending stiffness distributions on the disk. Moreover, the natural frequencies of the disk are evaluated by two energy methods in which the variations of modal shapes are considered or not. The difference in the natural frequencies from two energy methods shows the effect of the changes in the modal shape of the disk due to the small difference in the results of the energy methods (maximum difference of strain energy: 7.1%). Finally, the two energy methods are compared to investigate the effects on the natural frequencies with hammering test. The experimental results show the traditional energy method is allowed to evaluate the natural frequencies practically.

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Power assist systems have been introduced to reduce workers' load in industrial production. The author has studied on control systems for power assisted conveyance of flexible structures. Generally, the systems include influences of various kinds of uncertainties. One of them is vibration influence of controlled objects to operators. Another one is structured uncertainty such as nonlinear friction or parameter variations. The author's previous paper proposed a robust assist system design by taking these uncertainties into account. It consisted of an impedance controller, a disturbance accommodating optimal controller, a disturbance observer and a reaction force controller. However, the nonlinear friction such as Coulomb friction often induces chattering motion. Such a motion may cause a controlled object spill-over instability because the previous control system design does not take influences of unstructured uncertainties into account. Therefore, this note provides a modified version of the previous design by using the frequency-shaped disturbance accommodating optimal control. This note adopts the same controlled object as the author's previous paper. The effectiveness of the modification is verified by simulations.

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This paper proposes a Sequential Approximate Optimization (SAO) for the discrete design variable problems using Radial Basis Function (RBF) Network. We consider that there are two important keys for SAO: One is the parameter adjustment for good approximation, and the other is to explore the sparse region for global approximation. The authors have proposed the simple estimate of the width in the Gaussian Kernel for good approximation. In addition, in order to explore the sparse region, we have developed the density function. The density function with the simple estimate of the width works well in the case of the continuous design variables. However, a simple application of the density function to the discrete design variable problems will cause some difficulties. In order to overcome these difficulties and find the sparse region of the discrete design variables with the density function, the new variables for the discrete design variables are introduced. By using the new variables, it is possible to find the sparse region of the discrete design variables. A simple sampling algorithm is shown, in which the Discrete Differential Evolution (DDE) for the discrete design variables is employed. Through typical numerical examples, the validity of proposed approach is examined.

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In the design of emotional qualities, which are evaluated by the customer's subjective impressions, feelings and emotions, such as a feeling towards product sound, a designer needs to find the design factors that affect the emotional quality and determine the characteristics of their effects. The authors previously proposed a method for extraction of potential emotional factors by analyzing human sensitivity towards unexplored design and applied the method for designing product sound quality. From the result using vacuum cleaners as a case study, the authors found that the existence of prominent peak tones in sound around 500Hz has the potential to improve sound quality. However, prominent peak tones are usually regarded as a factor of annoyance. In this paper, we propose an indicator for adjusting the frequency and level of peak tones to improve a product sound quality. We have assumed that the harmonic features of peak tones in noise can be used as the indicator. We created vacuum cleaner sounds having three peak tones whose harmonic features such as tonal consonance and modality are different. To evaluate the effectiveness of the harmonic features, we conducted a pairwise comparison-based sensory evaluation with two groups of participants, one consisting of those who play some musical instrument and the other of those who do not. From the experiment, we found that the peak tone harmonic features can be perceived by both groups of participants and significantly decrease their annoyance at vacuum cleaner sounds.

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A robust topology optimization approach in consideration with random field uncertainty in loading condition is proposed in this paper. The proposed method integrates the level set-based topology optimization and the robust design method using stochastic process model. The stochastic process model is applied to describe the uncertainty of design parameters with nonuniform distribution in space with a reduced set of random variables. The robust optimization is formulated to minimize the robust compliance that is defined as a weighted sum of the expected value and the standard deviation of mean compliance under volume constraint. The standard deviation of mean compliance is approximated by the first-order sensitivity with respect to random variables that are described through the assumed spectral distributions from Wiener-Khintchine theorem. As a topology optimization, a level set-based approach incorporating a fictitious interface energy proposed by parts of the authors is applied. The method has several advantages to makes it possible to change structural topology as well as boundary shapes and to control the geometrical complexity of the optimum configuration qualitatively. Through numerical examples, the efficiency of the proposed robust topology optimization approach is demonstrated by comparing between the deterministic and robust optimum configurations.

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In recent years, sustainable materials using natural resources have been developed to alleviate environmental problems. Bamboo has especially drawn attention because it has the fastest growth rate among various natural materials, and its fiber also has high specific strength and stiffness like glass fiber. Previously we proposed a high quality bamboo fiber extraction method with a machining center that overcame issues including lower shape accuracy and inefficiency caused by conventional extraction methods. In this paper, we implemented a fabrication of self-adhesive products using only bamboo fibers extracted with a machining center. Moreover, mechanical properties such as Young's modules and tensile strength of the product were investigated. In addition dumping characteristics were also studied. Influences of moisture rate of the products on the properties were evaluated by concerning a practical use. Finally, possibility of the product for bamboo fiber recycling in order to reduce environmental burdens in manufacturing phase was also addressed. As a result, it was found that the self-adhesive products using only bamboo fibers show some reasonable performances.

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A ball bearing is grouped under radial bearing and it rotates with supporting radial load. When a radial force is loaded to a ball bearing, the spring constant of the rotating ball bearing will change periodically assuming that the force is static and fixed, because the stiffness of the bearing depends on the positions of rolling elements. Thus, it can be expected that the radial vibration increases. However, there are few reports on the rotational accuracy in case that a radial force is loaded to a ball bearing. Therefore, in this research, a measuring device for rotational accuracy was developed and the influence of radial load to a ball bearing was analyzed experimentally. Axial and radial forces can be loaded at the same time in the developed measuring device. Consequently, it was verified that the increment of vibration got fewer for smaller variation in radial stiffness of the ball bearing although the radial vibration increased with radial load. In addition, this phenomenon corresponded with the tendency proposed in a previous report by the authors for the number of rolling elements to get high rotational accuracy.

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In the present paper, a mathematical model was developed to represent the pitch error of the axes of rotation of five-axis machining centers having a tilting rotary table. The parameters used in the model were determined based on data measured for simultaneous three-axis motion. In experiments and simulations, the center offset and half apex angle of the cone-frustum are varied. In addition, the sensitive direction of the ball bar is varied to be either perpendicular to the conical surface or parallel to the bottom surface of the cone frustum. The simulation results obtained for different half apex angles, center positions of the cone-frustum, and sensitive directions of the ball bar are in good agreement with the experimental data. Then, the effects of the friction torque of the linear axes and the backlash and pitch error of the axes of rotation are simulated in order to analyze the experimentally obtained circular trajectories. When the center position of the cone-frustum is located far from the center line of the axis of rotation in the Y direction, the circular trajectory is affected by the sensitive direction of the ball bar and the half apex angle of the cone-frustum. In particular, for the case of a half apex angle of 45 degrees, the trajectory is strongly affected by the errors of the axis of rotation.

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Applications of biomass-based materials have drawn attentions as a future material technology due to the green as well as the sustainable developments. Wood biomasses have a great abundance on the earth, and many studies aiming at an industrial use of wood biomass have been done by means of the physical and the chemical processing. Our previous study showed that untreated various biomasses including solid woods got improved fluidity under a temperature range from 160 to 180 °C with a moderate moisture condition, and injection-molded products could be obtained with a comparatively high density and hardness than the raw material. In this study, the injection molding of several wood biomasses, namely solid Japanese cedar, bamboo and rice straw, were performed to investigate the possibility and problems in the production of an industrial applicable material. Furthermore a pre-treatment of wood biomass by steaming was conducted as a preliminary trial to improve the injectability and the mechanical and physical properties of the products. The results showed that there might exist optimum conditions among the mold temperature and the mold nozzle size for wood biomasses with a given moisture level to make a complicated shape cup. The injected products showed average hardness of about 19HV (cedar), 24HV (bamboo) and 13HV (rice straw) with above 1.35 g/cm³ of the bulk densities. It was found that the pre-treatment by steaming of the wood biomasses was effective at decreasing pressure required for the injection molding, and attained the products with improved size stability against water.

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This paper deals with the investigation conducted on the mechanism of the polishing technology, to which AC electric field is applied. For the analysis of the slurry dynamical behaviors, we used a digital image processor. In this research, we have also worked to develop a novel high-efficiency polishing technology applying AC electric field for the glass substrates for IT devices. When AC electric field was applied to, the slurry behavior was found to have better stability than the one without AC electric field. Furthermore, good polishing rates were obtained under high-relative rotation speed between the glass substrates and polishing pad. This suggests that the friction heat generated between the glass substrate and polishing pad, which promote tribochemical reactions, improves polishing rate. This latest polishing technology makes the removal rate two times better than the conventional polishing and produces excellently smooth surface.

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Significant hardened structures were achieved through frictional stir burnishing (FSB) process. FSB is a process where the rotated at high revolution speed burnishing tool rubbed and stirred the thin surface layer of workpiece. FSB process also give the workpiece surface the heat caused by friction and deformation. On the low processing temperature condition, very hard region which hardness is approximately 900HV and thickness is approximately 20 μm was formed on the surface of 0.45% carbon steel. On the other hand, another type hard layer which hardness is approximately 800HV and thickness is approximately 200 μm thickness was formed with high processing temperature condition. This hardened layer also has corrosion-resistant characteristics, which cannot be etched by acid etchant. The factors of hardened the surfaces are grain refinement or martensitic transformation.

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Metal spinning is a plastic forming process for forming rotational shapes. In this process, a sheet metal blank attached to a rotating mandrel is subjected to a force by a roller tool and formed into a desired shape. This process is more suitable for high-mix low-volume production than press forming. Former studies on forming nonaxisymmetric shapes encountered the problem that the shapes were limited to noncylindrical shapes. In this study, we propose a synchronous multipath metal-spinning method for nonaxisymmetric shapes with vertical sidewalls. The tool trajectory changes from the flat shape of the blank gradually to fit the shape of the mandrel surface. Linear interpolation between the blank and mandrel shape along normalized planar paths, which constitute curved- and straight-path elements, is used to calculate the tool trajectory in three-dimensional space. The cross-section shape of the mandrel is measured by touching it with the roller using force control. It is possible to independently handle the mandrel shape, blank shape, and the paths for interpolation in this method. Cylindrical and rectangular box shapes are successfully formed from thin aluminum sheets in forming experiments.

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The purpose of this study is to acquire design method of machine tools with higher chatter stability. This study focuses on stiffness of main structures and friction damping in a slide of a machine tool, because the stiffness and the friction damping are considered to have major influence on the stability. A 2DOF vibration model of the machine tool with friction damping was developed, and it was applied to the chatter stability analysis. A testing machine was developed and the model parameters were identified. The chatter stability was predicted using the developed model and the identified parameters, while cutting tests were carried out using the developed machine tool to verify the model. The predictions and the experiments were in a good agreement, and therefore it is considered that the model is effective to improve the chatter stability in the machine tool design. For example, the results indicate that higher stiffness does not always lead to higher stability, and that the optimum friction force exists at every stiffness condition.

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