Traditionally, the metal mouthpieces of trumpets have been generally made of brass. However, for musicians who suffer from metal allergies, the use of the mouthpiece sometimes lead to inflammation of the lip if they are taking part in a long performance. This problem can be solved by using allergy-free pure titanium (titanium) and its alloys as the material for the mouthpiece. Therefore, a titanium alloy composed of non-toxic and allergy free elements has been designed. However, because their heat conductivity is generally poor, and they contain α phase with its HCP (hexagonal closed packed structure having structure, which restrict slip systems, forming them into suitable shapes can be very difficult. Therefore, precision casting method, where only final finishing was conducted by machining, applied for fabricating the mouthpieces of trumpets. Important considerations for use in musical instruments are the material characteristics and the sound characteristics of mouthpieces made of titanium alloy. Research on the material characteristics of titanium alloy mouthpieces is currently being undertaken. On the other hand, the sound characteristics of mouthpieces made of titanium alloy have not been examined sufficiently. In this study, the sound and the vibration characteristics of two kinds of mouthpieces made of titanium and Ti-Nb was examined. The adaptability of these materials for use in mouthpieces of trumpets was discussed by comparing the sound characteristics of mouthpieces of trumpets made of titanium, Ti-Nb, and brass.

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For robot-robot or human-human motion instruction, a reference motion pattern is required to show how to move. The reference will be an enhanced motion pattern because of time delay or latency of the closed loop system. In this paper, we propose ”Pseudo-reference” that is derived from an autonomous control system based on an orbit attractor. The nonlinear controller is decomposed into a feedback gain and pseudo-reference which is a virtual target posture. Even though the feedback controller is unknown, it can be estimated from the nonlinear controller, and pseudo-reference is obtained. The simulations using an inverted pendulum system show the appropriateness of the pseudo-reference for a reference pattern, and the experiments using a tap dancing robot demonstrates that the estimated controller also leads an appropriate reference pattern.

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The purpose of this study is reduction of both fuel consumption and battery deterioration by the suboptimal control for hybrid electric vehicles (HEV) which can be adapted for various driving situations and drivers as part of the emergent control system. From the rising price of fossil fuels and growing concerns on the environmental protection, HEVs are recently attracting attention. The HEV control system requires reduction of fuel consumption and battery deterioration, as well as adaptivity to dynamic environment and various drivers. However no conventional methods have taken this in account. Consequently in this paper, we use genetic network programming (GNP) as a method to find a suboptimal control of HEVs for various situations. GNP is one of the evolutionary computing methods, which has a network structure as its solution and is effective to dynamical problem because it implicitly depends on past information. We validated the proposed method by applying it to the driving simulation. Comparison to the conventional method proved the advantage of the new proposed method. We introduced new evaluation criterion “driving cost [¥/km]” in order to consider all the cost needed to drive; not only the fuel cost nor the battery cost. In addition, we validated the adaptivity to various driving situation and various drivers.

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The objective of this paper is to establish a concise structural model of the human musculoskeletal (HMS) system to be used for an exercise therapy of a malfunction or a distortion called Somatic Balance Restoring Treatment (SRBT). This model must be comprehensive for therapists while maintaining a theoretical thoroughness in mechanics. For this objective, a system approach called Interpretive Structural Modeling (ISM) has been applied to bridge multi-body dynamics and clinical observations. From a mechanical viewpoint, the HMS system can be treated as a collection of joint connected 15 rigid bodies in a topological tree. From a clinical viewpoint, joints are of major concern since most malfunctions take place at the joints. Based on clinical observation data accumulated for 36 years, we have discovered that all HMS motions can be constructed by a combination of 80 fundamental motion elements and that all motions are interacted with each other. By applying the ISM for the HMS system, we have obtained that an active motion element with intention induces associated motion element(s). In addition, the ISM yields a tiered structure of the fundamental motion elements according to the degree of activeness; and most importantly, an overall investigation of the matrix characteristics has revealed a fundamental structure of the SBRT.

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This paper deals with the quenching problem of electromagnetic vibration of the motor using dynamic absorbers. The iron stator of motor is modeled by circular ring, and the two dynamic absorbers are installed on the outside of the circular ring. The solutions of forced vibration of the system are obtained by the theoretical analysis and the finite element analysis followed by the numerical simulation. Following was made clear from these analyses: (1) By installing two dynamic absorbers leaving an angle that is not equals to the one between any loops of the mode to be quenched, the amplitude of the iron stator becomes zero theoretically around the circumference of the circular ring, namely, the iron stator is perfectly quenched. (2) By installing two dynamic absorbers leaving an angle that is equals to the one between loop and node of the mode to be quenched, the quenched region near resonance frequency becomes the largest one. (3) In the frequency region that is higher than natural frequency, if manufacturing error is considered, the natural frequency of the dynamic absorbers must be a little higher than the frequency of electromagnetic force. (4) The results obtained by the theoretical analysis and those obtained by the finite element analysis followed by the numerical simulation were in good agreement qualitatively.

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Passengers boarding on a railway vehicle are usually treated as additional mass in designing carbody and the natural frequencies of carbody flexural vibrations are considered to decrease as the number of passenger increases. However, some previous studies indicate that on-board passengers behave not as additional mass but as damping. This paper examines the damping effect due to passengers by using actual railway vehicles and compares the measurement results to the cases that iron blocks or water tanks are loaded. A stationary excitation test in the rolling stock testing plant for a commuter-type vehicle and a running test on a commercial line for a Shinkansen-train were conducted. From both tests, relatively large vibration reduction effects upon different natural modes of flexural vibration of the carbodies and little change of their natural frequencies were observed when passengers were aboard. On the other hand, natural frequencies were decreased when iron blocks or water tanks were loaded. The authors also tried to develop a numerical model to express the flexural vibration of carbody with passengers. It was found that a simple 1-DOF mass-spring-damper system with low natural frequency and high damping ratio can simulate a passenger well. According to those measurement results, it is expected that a new and valuable damping device against carbody flexural vibrations can be realized if we can simulate or mimic the effect of passengers correctly. Some basic directions or policies to develop such damping devices were discussed.

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The predictive accuracy for the dynamic behaviour of a rotor under conditions of high-speed spinning depends on the accuracy of the numerical model of the rotor, the dynamic characteristics of the bearings and/or the seals, and the external force. In order to improve the accuracy of the numerical model, we propose a method to identify all characteristic matrices in the vibration equation of a rotor based on the information on rigid and elastic properties which can be obtained by a vibration test without spinning. The rotor is assumed to be composed of a shaft which can be modeled as beam elements and rigid discs. The proposed method can be applied for model reduction in which the reduced number of beam elements is feasible to calculate the dynamic behaviour of the rotor.

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It is necessary to know small but enough number of the subject for obtaining reliable design information from the sensory evaluation in mechanical engineering field. In this study, the sensory evaluation of the optimum diameter easy to grasp cylindrical object was performed and the relationship between the scale division ranks and the number of the subjects was investigated. The numbers of the scale division ranks employed were six, i.e., from 2 to 7, and the one hundred subjects were participated at the sensory evaluation tests. The mean values of the optimum grasping diameter were about 35mm for all division ranks. The distribution pattern of the subjective score of optimum diameter showed same with the kurtosis of 3 and the skewness of 0.3. Necessary time for the evaluation of the optimum diameter was increased with the scale division rank, but in the case of the scale division ranks over 4, the time necessary for enough high accuracy of the evaluation was the certain amount time. It was revealed that the numbers of the subjects needed for the evaluation with high accuracy were over 20 by using the ranks over 4 and over 10 by using the ranks over 6 and 7 division rank.

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It is generally known that tangential force characteristics of wheel/ rail have a great influence on the vehicle dynamics characteristic. However, according to one author's previous researches, it is difficult to estimate tangential force characteristics of actual-wheel/rail interface correctly, because the shape of contact patch of actual-wheel/ rail may not be a complete ellipse shape due to existence of fine unevenness on wheel tread. This paper presents the results of the laboratory experiments carried out in relation to tangential force coefficient between contacting two cylindrical test specimens under different surface conditions, and the numerical analysis results of hunting stability of railway vehicle with the fine unevenness on wheel tread. In the laboratory experiments, the tangential force coefficient of specimens with/without a variety of fine unevenness under different attack-angles has been obtained by means of a two-disk rolling contact machine. The experimental results showed, in the case of attack-angle is zero, the longitudinal tangential force coefficient becomes smaller when the fine unevenness is larger than the case without fine unevenness. On the other hand, in the case of the attack-angle is about 0.2deg, the lateral tangential force coefficient is small when the interval of the fine unevenness is large. Furthermore, a numerical analysis was carried out to estimate the relationship between a variety of fine unevenness and the hunting stability of railway vehicles. As a result of this study, it is clarified that the fine unevenness on wheel tread has an improvement effect on the hunting stability of railway vehicle.

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This paper proposes the measurement method of 3D posture using inertial sensors. The proposed method estimates the 3D posture (Roll-Pitch-Yaw angles in local coordinate) using the 3-axis angular velocity and the 3-axis acceleration. The 3D posture is compensated for the drift error of gyro sensor output by the translational and gravity accelerations of accelerometer output. The nonlinear state equation and the nonlinear measurement equation were established to estimate 3D posture. The Extended Kalman filter and the Unscented Kalman filter are applied to these equations. The measurement experiment was conducted to clarify the accuracy of proposed method using the experimental setup installing the rotary encoders. The results of the Unscented Kalman filter indicated higher than those by the Extended Kalman filter. In addition, the proposed method estimated the 3D posture compensating the drift error of gyro sensor in the measurement experiment generating the translational acceleration. Therefore, the proposed method can be used for the measurement of body motion.

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We have already proposed the method to transfer human skill to a robot through direct teaching. By using the method, we can automatically extract human skill including sensory feedback to adapt to environmental variation. However, we have not discussed what trajectory is robust against environmental variation. In this paper, we discuss the robustness condition of robot trajectories against environmental variation and how to derive the robust trajectory. We propose a method to determine whether a trajectory is robust or not. The method considers the probability of the environment variation uses the parameter space expression of trajectory in order to derive the robustness condition. We confirm the effectiveness of the proposed method through a case study on a typical assembly task, peg-in-hole.

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This paper reports experimental verification of nonlinear output regulation for an inverted pendulum system. The output regulation problem, which is alternatively referred to as servo system design problem, is posed so that the cart of the pendulum tracks an arbitrarily given sinusoidal signal while holding the pendulum up above. To solve the problem, it is necessary to solve the so-called nonlinear regulator equation and the computation for its solution is based on a newly proposed theory to approximate center manifolds in a system of ordinary differential equations. This computation theory, which was proposed by the authors previously, provides an iterative algorithm that enables one to obtain higher order approximations. The algorithm is suitable for computer implementation and a 7-th order polynomial state feedback law is obtained. The experiments show that the cart of the pendulum tracks sinusoidal signals with different frequencies. The paper also reviews the general theory of nonlinear output regulation as well as the theories of center manifold and its approximate computation.

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Small-size embodied interaction robots are required for use in home. These robots are expected to shake hands with human to promote embodied interaction. Therefore, in this paper, we develop a small-size handshake robot system for a generation of a handshake approaching motion. The handshake approaching motion has two motions. The first motion is a handshake request motion that the robot stretches its hand to a human as requesting a handshake. The other motion is a handshake response motion in which the robot responds a handshake when the human requests a handshake to the robot. In this robot system, a human hand position is estimated by using an image processing which is combined with a 3D arm model, and handshake approaching motions are generated using the estimated hand position. The effectiveness of the small-size handshake robot system is demonstrated by sensory evaluation of these handshake approaching motions.

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The purpose of this study is to investigate proficiency process of a human motion skill for the robot operation and a relationship between the activity level of the higher brain function and the human-robot cooperative positioning operation in which mechanical positioning supports assist operator's motion with a 1-DOF linear track robot. In this study, to reveal the proficiency process for the robot operation under the impedance control, a quantitative evaluation analyzing both time-normalized trajectories of operator's motion and the activity level of the higher brain function is carried out. Using the time-normalized trajectories, the quantitative evaluation can be carried out among several experimental conditions and data obtained from various operators and trials. Experiments were conducted to elucidate the relationship between the proficiency process for the robot operation and the activity level of the higher brain function. In the experiments, different three types of mechanical positioning supports are introduced to reduce operator's work load and to increase positioning accuracy in the positioning cooperative task between the human and the impedance-controlled robot. The introduced mechanical positioning supports in this paper are as following: i) active positioning support utilizing additional force; ii) passive positioning support using a variable viscosity; iii) frictional positioning support by Coulomb-like virtual friction. In addition, the activity level of the higher brain function in the experiments was measured using NIRS measurement system. The experimental results show that the relationship between the activity level of the higher brain function and the proficiency process for the robot operation on the human-robot cooperative positioning task is observed.

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In order to keep a highly safe and reliable system of car driving, it is important that the system would be considered as a man-machine system including not only the feature of vehicle movement but also human perception, cognition, and motion of a driver. In this paper, it is examined to clarify the relation between feature of eye movements and driving behavior in conventional and unconventional situation by the experiments using the driving simulator and the eye tracking system. The measurements of time histories of eye movements were performed in the situation of different traffic regulation by the simulator. It is recognized in both turns that typical patterns of eye movements in horizontal axis appeared between the start and end of the turns. It is found from the time histories of eye movements by synchronizing that of vehicle data that the appearances of fixations were distributed uniformly on the trajectories of vehicle by trained drivers from the start of turning to the end, while the appearance of fixation by untrained drivers are concentrated in the beginning of turning or the end. These facts mean that the untrained driver did not receive visual information during the operation of turning, therefore the trajectories of vehicle by untrained driver showed the overshooting in the right turn and undershooting in the left turn.

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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 considering added mass effect of air. As a result, it is shown that identified tension distributions well correspond to the FEM results.

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Pneumatic isolation tables are generally used in the fields of manufacturing and measuring precision components, and several methods by which to achieve active control of pneumatic isolation tables have been proposed. In these studies, the internal pressure of the air springs is actively controlled by using servo valves in order to suppress micro-level vibration. On the other hand, so as to suppress millimeter-level vibration and obtain low cost equipment, several methods by which to achieve active control using on-off valves instead of servo valves have been proposed. In these investigations, a switching control method based on the Lyapunov function exhibits performances that are superior to the other methods. However, the switching control method suppresses vibrations in only the vertical direction. Therefore, improvement of the vibration suppression performance is required in not only the vertical direction but also the rolling and pitching directions. Thus, the purpose of this study is to obtain high vibration suppression performance for a pneumatic isolation table with three degrees-of-freedom using on-off valves. The switching control method is extended to multi-input system, and it is shown that the extended method is suitable for control of a pneumatic isolation table with three degrees-of-freedom. The effects of the extended method are verified by numerical simulations and experiments.

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In this paper, a compact range image sensor for measuring objects in a short distance is constructed using a multi-slit laser projector. When a robot executes a task such as grasping an object or avoiding an obstacle, three-dimensional (3D) information of the target is usually necessary. A humanoid generally carries a vision sensor at its head and recognizes, grasps or avoids objects using the vision sensor. Measurement with a sensor attached to a robot's body is often suffered from occlusion by its hand just before grasping an object. The constructed sensor is compact enough to be attached to a robot's hand and thus occlusion can be avoided. The compactness of the sensor is achieved by using a small CMOS camera and a laser projector and setting the baseline length between them as short as possible. The short baseline length also enables measurement in a short distance. Some experiments verify that the constructed sensor can obtain 3D information of objects appropriately in a short distance.

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For the past several years, large scale earthquakes happened. A lot of industrial facilities were damaged. For example, a lot of power plants were stopped in The 2011 off the Pacific coast of Tohoku Earthquake or The Southern Hyogo prefecture earthquake in 1995. These earthquakes have larger acceleration level than the seismic design level. Therefore, the earthquake proof measures are required. There are many dampers as the energy dissipating device. For example, oil damper, visco-elastic damper, magnetic damper, friction damper, elasto-plastic damper, and so on. The friction damper and elasto-plastic damper are utilized for the large scale earthquake. This paper deals with the response reduction effect by elasto-plastic behavior. Elasto-plastic behavior is expected to absorb the seismic energy. In this paper, R-O model are focused as the elasto-plastic model. There are two types of elasto-plastic behavior. One is elongation type and the other is elongation-compression type. At first, the comparison of the characteristics of these types is taken place. Next, the seismic response reduction effect is clarified.

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A spring constant of railway vehicle is deteriorated as operated either since newly built or lately inspected. The existing system to detect the deterioration of coil springs for railway vehicles depends on periodical inspections at factories away from operational rail tracks. It is costly and time consuming work. In this respect, this paper applies the theory of detecting 3-D locations of the center of gravity for detecting the deterioration of coil springs for railway vehicles, which was invented by the second author of this paper and abbreviated as D3DCG. D3DCG can detect not only the center of gravity of railway vehicles but also the lower limit of unstable zone for the center of gravity by which the deterioration of cars underneath the vehicle can be measured on the moving vehicle. In order to apply D3DCG, the authors measured the vertical acceleration and the roll rate of moving railway vehicles commercially operated and was successfully able to find that the lower limit of unstable zone decreased according to operational years of the car since newly built or lately inspected.

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The authors' group has been developed an LDA flow rate meter based on laser-Doppler anemometer (LDA) for an instantaneous fuel injection rate measurement. This flow rate meter that does not affect the downstream spray can realize the simultaneous measurements of the dynamic fuel injection rate and of the spray characteristics. The transient flow rate can be useful to understand the spray characteristics. The LDA flow rate meter only measures one point time-series velocity on the center of circular pipe. It provides instantaneous time-series flow rate and integral mass of the fuel flow. In this paper, the LDA flow rate meter measured the high pressure injection system for the direct-injection gasoline engine. The pipe diameter of the measuring section of the LDA flow meter is tested for improving the measurement accuracy of the high pressure fuel injection rate. In the measurement, the fuel pressure is changed from 5MPa to 20MPa and injection time is changed from 0.5ms to 5ms. The integral masses by the LDA flow meter are compared with the results by a mass balance.

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A Consideration of latent functions at the conceptual design stage has become increasingly important from the perspective of product safety and sustainable design. This paper discusses reasoning processes of latent function at the conceptual design stage. First, the function dividing process is systematized from a linguistic viewpoint into two function operation types; those are decomposition-based dividing and causal-connection-based dividing. Then, reasoning processes of latent function is formulated on each function operation types. Finally, a computer system to carry out reasoning of latent function is developed and a case study is conducted by using the system. The case study shows the feasibility of using the proposed model to help designers to consider latent function on function dividing process.

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In the medical field, plastic syringes are used with silicone oil for the sliding area between a barrel and gasket, where barrels are typically plastics such as PP (Polypropylene) and gaskets are made of TPE (Thermoplastic elastomer). However, silicone oil is considered to have some demerits: accumulation in the body and adsorption of medicine's constituent. Therefore, the development of unlubricated plastic syringes is desired. We reported in 2009 that the friction coefficient between TPE and PP flat specimens without silicone oil at normal load of 1 N was decreased by 50 % by photochemical fluorination of TPE. The test with an actual syringe, or the indentation of a fluorinated TPE gasket into a silicone oil-free PP barrel showed that the resistance force during indentation was decreased from 50.7 N to 30.4 N; the reduction ratio of resistance force was 40%. In this work, the effect of gasket deformation ratio α (=[D_G-D_B]/D_G×100 %, D_G: diameter of gasket, D_B: inner diameter of barrel) on the fluorination effect in silicone oil-free syringes was further investigated by changing the inner diameter of barrel so that the contact pressure between gasket and barrel are changed. As a result, it was confirmed that the reduction ratio of resistance force due to photochemical fluorination increased from 43 to 75%, with the inner diameter of barrel D_B changed from 20.3 mm (α=2.64 %) to 20.7 mm(α=0.72 %) against a fixed gasket diameter of D_G=20.85 mm. At the inner diameters D_B≥20.65 mm (α≤0.96 %), the resistance force between fluorinated gasket and barrel was less than 10 N, which is the maximum acceptable value for practical syringes. Moreover, at the inner diameter D_B=20.65 mm (α=0.96 %), leak load, above which water leak occurs between gasket and barrel during indentation, was more than the minimum acceptable value of 76.9 N for practical syringes. In other words, the requirements for practical syringes in the resistance force and leak load were both satisfied at α=0.96 % with fluorinated gaskets; on the other hand, these requirements were not satisfied together at any α values with non-treated gaskets.

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We have developed a method to diagnose damage using a laser beam. Our method can be explained as follows: First, a tooth surface is irradiated by a zonal laser beam from an oblique direction, and then the irradiated laser beam line is shifted along the surface of the tooth according to gear revolution. The variations of the laser reflection between the initial and the present conditions are compared. And then it can estimate the condition on the tooth surface such as initial or abnormal abrasion, pitting, spalling, etc. To apply this method for a helical gear, the arm for setting the laser sensor was assumed as the special closed-loop serial-linkage, and the structure of the arm was proposed. By using these proposals, the data calculated from laser reflection and measured with caliper were compared. As a result, we could diagnose the helical and/or profile shifted gear as well as a spur gear, and the difference was up to 8 [%].

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In this research, I investigated the design of non-circular pulley for a force/torque profile adjustment mechanism. I proposed the generalized analytical design method of the non-circular pulley applicable to the majority of structures. By using this design method, the torque acting on the non-circular pulley and the force acting on the flexible part twisted around the non-circular pulley can be converted mutually to obtain a desired torque/force profile. Also I demonstrated the design of the non-circular pulley for a spring balancer and for an arm weight compensation mechanism. Furthermore, I investigated the design limit of the non-circular pulley, and showed that too long effective radius, too long offset length, and too short radius of curvature cause the problem of impractical non-circular pulley shape. From the analysis of the occurrence condition of each case, it became clear that the derivative of the effective radius is important for avoiding too long offset length and that the effective radius and the second derivative of that are important for avoiding too short radius of curvature.

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This paper reports in-process detection of tool wear by using tool-work contact electric resistance as a sensor signal in face milling. The change in the tool-work contact resistance was estimated from the change in the tool-work contact area according to the progress of the tool flank wear by using Holm's contact theory. As a result, it has been understood that the tool-work contact resistance changes by several milli ohm due to the progress of the tool flank wear. We calculated the tool-work contact resistance by using Ohm's law from the tool-work thermo electromotive force (E.M.F.) and the tool-work thermal current. The variations of contact electric resistance calculated from both the E.M.F. and the electric current reveal that the electric resistance decreases as the tool flank wear progresses because contact areas between tool and workpiece increase. We developed an in-process measurement system of variations of the contact resistance during face milling process. From the result in progress of tool flank wear and tool-work contact resistance under several cutting conditions, it has been confirmed that this method is effective for tool wear detection, that is difficult to monitor in traditional external detection sensors under the finish intermittent cutting.

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Brake pads are phenolic resin composites which contain several ingredients such as metal fibers, inorganic fillers, organic fillers, and so on. As previously reported, wear tests showed that pad wear varied with the type of metal oxide. Low wear was observed with the addition of metal oxides which were hardly reduced. This behavior was attributed to the frictional mechanism accompanying the tribo-degradation of phenolic resin which reduces the metal oxides at friction surface. The reduction of metal oxide associated with friction was defined as tribo-reduction. In this paper, two experiments were performed to demonstrate tribo-reduction in the friction of phenolic resin composite materials. In the first set of experiments, wear tests were conducted between cast iron or copper as disk material and pad materials to which different types of metal oxides were added. Results showed an increase in wear amount when the disk metal and the metal of the metal oxide added to the pad material were the same. This means that the reduction of metal oxide changed the friction system into similar metal contact. In the second set of experiments, samples composed of the same amount of metal oxides and phenolic resin were heated to test the chemical reactions between them. X-ray diffraction analyses showed that the metal oxides were reduced. From these results, it is clear that tribo-reduction takes place during friction of phenolic resin composite materials because of the degradation of phenolic resin.

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In this study, a calculation efficiency for the authors' previously proposed reliability-based multiobjective optimization (RBMO) algorithm is discussed. The RBMO algorithm integrates the hybrid multiobjective particle swarm optimization (MOPSO) for handling the constraint satisfaction technique using gradient information of constraints with a concept of the single-loop-single-vector method (SLSV). Though the method requires iterative evaluations for moving the design candidate with constraint violation to the feasible region, the algorithms totally have a good convergence performance for the most design problems. For example, Pareto solutions that lie on the feasible boundary are found in the early stage. However, some design candidates require the large numbers of iterations until the candidate moves to feasible region under the case where the violated constraint conditions are shifted frequently during the constraint satisfaction process. This study proposes the improvement method by eliminating such deteriorating iterations based on an idea from the modified SLSV method or the conjugate mean value method. The key idea of the proposed method is to select a kind of average direction of the previous searching directions as the current moving direction, when the deteriorating iteration occurs. The efficiency of the proposed method is demonstrated through several benchmark design problems by comparing the convergence property of the improved method with that of the original hybrid MOPSO with SLSV method.

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This study is related to automation of polishing process by using an industrial robot. In polishing process, full automation of polishing operation has not been achieved due to the difficulty in visual inspection. Judgment of polishing sufficiency has been performed by skilled workers. In this study, the surface after milling process is the target for polishing. In the previous report, the generation of robot program for polishing operation based on CAD data was already proposed. Focusing on the periodicity of cutter mark patterns on milling surface, we proposed an automatic judgment of polished surface quality. This method is based on the image processing which uses Discrete Fourier Transformation. In order to capture images of the polished surface, a CCD camera was mounted on a 6-axis controlled robot hand. However, the image processing method proposed in previous report could not judge the curved cutter mark patterns because the periodicity of those patterns is not uniform. The objective of this report is the development of automatic judgment method for non-periodic cutter mark patterns. We developed a judgment method which uses statistical pattern recognition as a means to judge the existence of cutter marks. As a result, a system that allows the automatic polishing that includes the surface quality judgment is developed.

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Constant-flow hydrostatic water bearings have advantages in sustaining stiffness, cooling capability, temperature independence of viscosity and environmentally friendliness for ultra-precision machine tools. However, there are only a few cases that the hydrostatic water bearings are applied for machine tools and there are few reports concerning the constant-flow hydrostatic bearings. In this paper, the authors propose a simple analytical model for estimating sustaining force of the constant-flow hydrostatic water bearing equipped with a rectangular pad. The solutions derived from the simple analytical model are validated using numerical results computed by ANSYS FLUENT. As a result, it is clarified that the simple method of estimation provides the highly accurate solutions for rectangular pads.

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Most transmissions that use a traction drive mechanism also have a gear train to transmit power to the outside. In these transmissions, traction oil is used both as the working fluid and gear lubricant. Since precedence is given to the performance of traction oil as a working fluid, its performance as a lubricant is generally inferior. The traction coefficient of traction oil is higher than that of automatic transmission fluids (ATFs), so it is thought that the power loss of meshing gears under traction oil will be larger than that under ATF. In this paper, we experimentally compare the power loss of meshing gears between use with traction oil and with ATF and show that the power loss with the former increases by approximately 0.5% compared with that found for ATF. And also, it is shown that the magnitude of the power loss depends on the gear dimensions and operating conditions. The one of authors proposed the new estimation formula of friction coefficient and confirmed the usefulness of this formula under ATFs. In this paper, the usefulness of proposed estimation formula is also confirmed under traction oil.

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In sliding friction of elastomers, the effective static friction coefficient μ_s^eff observed is not necessarily equal to the inherent real one μ_s possessed by the material; usually μ_s^eff < μ_s because of the elastic deformations of sliding objects and the propagation of shear fracture in the contact area. This indicates that focusing on elastic deformation of sliding objects can derive a new criterion of μ_s^eff for machine design. In this study, mainly through numerical simulations for a physical model assured by experiments in which measuring frictional force and observing contact area were carried out for a longitudinal line contact of polymethyl methacrylate, it is found that the stiffness ratio κ = K_b^tot / K_c^tot (where K_b^tot and K_c^tot are the total bulk stiffness and total tangential contact stiffness of the elastic sliding object, respectively) dominates the value of μ_s^eff.

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To measure true values of kinetic friction coefficient in a force balance between the frictional force and spring force, an anti-vibration tribometer (AVT) has been developed. The AVT utilizes a novel principle that an angular misalignment between the two velocities (i.e., the driving velocity of one of contact surfaces and the moving velocity of the other surface) produces a positive damping effect to stabilize the equilibrium point and suppress frictional vibration autonomously. For example, when a sliding contact between a steel ball and a steel plate is lubricated by glycerin, the AVT provides a force balance situation at a misalignment angle φ = 30° (i.e., an anti-vibration setting), although strong frictional vibration occurs at φ = 0° (i.e., a conventional setting). By comparing the kinetic friction coefficients obtained at φ = 0° and 30°, it has been found that frictional vibration can lead to a serious error of measuring kinetic friction coefficient (e.g., a 35% underestimation at a low driving speed).

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A novel portable friction tester was developed for the measurement of skin friction at various points on the human body. The tester consisted of a handle attached to a measurement head and a main housing body. Normal loads and frictional forces were measured by a two-axis load cell equipped with strain gauges. A PC was connected to the device to process the output signal. In order to compensate for interference from the dead load due to handle rotation, an acceleration sensor was built-in. A linear equation showing the relationship between the acceleration and dead load was derived so that dead load could be compensated for at any angle. The results obtained for a curved surface showed the importance and effectiveness of this method. Also, the validity of the coefficient of friction obtained using the portable tester was verified with a stationary pin-on-plate tribotester. The portable tester was applied to a skin friction measurement.

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After products have been released to markets, from marketing competitions, not only functional improvements but also cost reductions are requested in improvement designs. But many of engineers are feeling difficulties to satisfy both of them at same time. We propose a process for improvement designs to satisfy these different kinds of features by using information integration method. Information Integration method is an evaluation way which is based on concept of Shannon's information theory. In this method, different kinds of features can be compared in a common measure called “Information”. We apply this method to evaluate functions and costs in improving designs. We also propose an optimizing process for improvement design based on this method. By comparing evaluation items in this method, next target for improvement can be automatically selected without personal subjectivity. We have confirmed effectiveness of this process in a case study of electric shaver's improvement design. This study also makes up practical design processes with our previous studies “Practical Cost Reduction Methods based on TRIZ” and “Functional Improvement Methods based on Expert Engineers' Thinking Way”.

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