Karman vortex occurs when the gas passes through the duct with tube bank of the heat exchangers, such as a gas heater and a boiler, and the very large noise called “Self-Sustained Tones” occurs due to the interaction of the vortex and the sound field in the duct. In general, baffle plates are used to suppress the self-sustained tone. However, it is difficult to use them effectively, because the insert condition is vague. We proposes that the rubber boards, flexible walls, are installed in both sides of the duct to suppress the self-sustained tones. Because we suggest the resonance of the duct perpendicular to the flow may be suppressed by rubber boards vibrating, when self sustained tones occur. The experiment was carried out to examine the suppression effect of the rubber boards installed. As a result, the suppression effect of the rubber sheet appeared when the tension of it is small and it is located at just the tube bank and downstream of the tube bank.

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An optimization method for multi-layered fabric sound absorbing structure is investigated using a multi-objective genetic algorithm (MOGA). Sound absorption coefficients of fabric materials are calculated by transfer matrix method using the Delany-Bazley model. For a feasibility study, a 3-layered-3-kinds structure of fabric materials was optimized, and results obtained by optimization agree well with experimental results. A 32-layered structure is thus optimized. The results show that relations between the layer pattern and frequency characteristics of absorption are consistent with the results of this 3-layered-3-kinds structure. Furthermore, the optimum flow resistivity distribution for noise reduction coefficient (NRC) is a ν shape, which is the same as the result obtained by using the gradient method.

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Gauge changing train is developed to realize through operation between standard gauge and narrow gauge. Axle of gauge changing train has lower torsional stiffness than solid wheelset or has clearances inside. Although running stability and safety at the target speed (270 km/h) have been validated through bench tests and on-track tests, theoretical investigations have only been carried out for limited conditions. This paper performs numerical simulations using simplified half-car model of gauge changing train at standard gauge mode and evaluates the influence of torsional stiffness or longitudinal and rotational clearance on running stability. Simulation result shows that low torsional stiffness has little effect on running stability. Longitudinal clearance causes small amplitude continuous vibration, whose wavelength is between axle and bogie hunting wavelength. Rotational clearance causes large amplitude, low frequency continuous vibration only if there is no friction on the rotational clearance. This low frequency continuous vibration is not the bogie hunting but a vibration mode of entire half-car system. For gauge changing train with improved axle (called “Type II” in this paper), critical speed of hunting is a little lower compared with the train with solid wheelset, but enough safety margin is secured.

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Numerical simulation of a tower crane cargo was performed to identify a velocity pattern by which residual oscillation was suppressed. Residual oscillation was sufficiently suppressed using a simple trapezoidal velocity pattern when a cargo's trajectory of swinging motion was symmetrical. A skilled operator, however, intentionally changes the swinging motion in the acceleration to monotonize the resultant swinging motion in the constant velocity rotation. Two-stage angular velocity pattern was then adopted to simulate manipulation of the skilled operator. Three parameters A, k and n value which determine the two-stage velocity pattern should be properly selected to suppress residual oscillation. A and k value was numerically determined and n value was analytically determined. Monotonic swinging motion in the constant velocity rotation was obtained under the particular velocity pattern. Deceleration timing to suppress residual oscillation was periodically obtained due to the monotonized swinging motion. The applicability of the proposed process optimized method was investigated by means of a scale model experiment. Numerical and experimental results showed well agreement in which residual oscillation of a tower crane cargo was sufficiently suppressed.

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This paper presents a controller design approach considering vibration suppression due to input saturation for load devices. In the target load device, a pneumatic actuator and a voice coil motor are combined as a dual-stage actuator to expand the servo bandwidth. However, since vibrations are excited by the input saturation in the voice coil motor, the vibrations deteriorate the force tracking performance for the desired load reference. In this research, therefore, a loop-shaping approach is adopted to suppress the vibrations, where a compensator is designed to improve the disturbance suppression performance at the resonant frequency of plant. The proposed approach has been verified by experiments using a prototype of load device.

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This paper presents a back-drivable two-fingered four-degree of freedom hand that can generate a large grasping force of 120 N and perform a high speed motion of larger than 750 °/s. All fingers are 98 mm in length and the weight of the hand is 1.2 kg. The hand can generate a large grasp force with a new force-magnification mechanism. The force-magnification mechanisms installed in our previous hands need a non-backdrivable element so that their high-speed drive mechanisms cannot be back-driven when the force-magnification mechanisms are activated, which results in low compliance. The new force-magnification mechanism in this paper uses a rack and pinion gear connection mechanism to establish the drive connection with the high-speed drive mechanism only when it is activated. Therefore, the high-speed drive mechanism can be back driven keeping high compliance. However, when the tooth crests of the rack hits that of the pinion gear, the connection mechanism is jammed. Therefore, a rack gear tilting mechanism is also proposed.

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When an elevator rope for a high-rise building is forcibly excited by the displacements of the building induced by wind forces and/or by long-period ground motion. In previous paper, when elevator cage is stationary, a new practical method for reducing the rope vibration by using vibration suppressors is proposed for relaxing the restricted elevator operation. The advantage of using the vibration suppressors for reducing the rope lateral vibration is demonstrated through numerical calculation. However, theoretical solution to the vibration of the rope with vibration suppressors has not yet been obtained. In this paper, a theoretical solution to the free vibration of the rope with vibration suppressors is presented, in the case of that vibration suppressors are arranged at equal intervals. Finite difference analyses of the rope vibration with/without vibration suppressors are also performed. The effect of the number of vibration suppressors on the natural frequency and rope deflection are clarified. The calculated results of the finite difference analyses are in fairly good agreement with the calculated results of the theoretical solution.

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This paper proposes a motion transformation method using nonlinear state-space mapping. A human motion is measured by a motion capture system and it is transformed to a “realizable” robot motion. “Realizable” requires existence of an input sequence that satisfies the dynamical consistency of the robot dynamics. The nonlinear state-space mapping is represented by a polynomial of power of state variable and its parameters are obtained so that the constrains of velocity and acceleration are satisfied, and the human motion is deformed simultaneously. Moreover, the transformed motion is decided by setting the reference kinetic energy. The proposed method is applied to a tap dancing robot and a robot motion is generated by an autonomous system based on orbit attractor.

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A project to develop a platoon system, called ”Energy ITS”, has been proceeding by NEDO (New Energy and Industrial Technology Development Organization). In a platoon, several automated vehicles run as one group. The current steering controller requires the information of a road like the cant and the curvature. Using the control law which does not require it, a steady lateral distance error appears. In this paper, a new steering control method which does not require the information of a road is proposed. MMAC (Multiple Model Adaptive Control) is applied to design the feedforward part of the controller by estimating the cant and the curvature. The effectiveness of the feedforward control part is evaluated by experiments on highway.

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This paper presents an application of the model predictive control to flexible spacecraft attitude maneuver. The objective of the study is to demonstrate an experimental feasibility of optimal attitude controllers suppressing the flexible appendage vibration under the actuator saturation. For the purpose, we study two approaches in the model predictive control framework. One is to use the frequency-shaped linear quadratic cost with finite horizon, and the other is to apply the robust control theory. Through ground experiments using a single axis air bearing table, as well as numerical studies for ETS-VIII spacecraft, their abilities are shown and compared.

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Impulsive force acting when the ball is hit with a baseball bat is interesting from the field of sports engineering. This study intends to develop an impulsive force sensor which can be attached to a column part of the baseball bat. The pipe surface sensor is a pressure sensor suitable for the measurement of high speed impulsive force. The pipe surface sensor consists of a thin pad sensor, a cover-plate and metal adhesive tape. The metal adhesive tape plays a role to wrap the sensor and cover-plate and fix these together to the bat tightly. First, a friction removal mechanism in contact interface, a bendable sensor configuration and a method of sensor installation on the surface of the pipe are discussed. Then, prototype sensors that can be installed on a pipe with diameter of about 70mm are made. The performance of sensor is investigated by the pipe punch test and the ball drop test. Then, the impulsive force is measured by the test that a batter hits the ball which the pitcher threw. A metal bat and a hard ball are used for the experiment of hit and bunt.

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Spacecraft is exposed to the severe random vibration by acoustic during its launch. In the spacecraft design, random vibration of spacecraft components mounted on panel structure during launch environments needs to be predicted. In the present methods, SEA is the method for analyzing the high frequency band, FEA is for the low frequency band. This paper applies combination of FEA and SEA methods to predict the vibroacoustic response of spacecraft structure which may be extended to wide frequency range experienced during the launch. The combination methods focuses on the vibroacoustic prediction which keeps advantages to use detail model of structure expressed by FEA and statistical energy approach expressed by SEA of reverberant acoustic excitation. The combination method is applied to diffuse sound field excitation of honeycomb panel, and is compared with acoustic excitation test and the results from conventional approach of BEM ,joint acceptance and SEA.

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This paper proposes a method for designing an image-based fuzzy controller for trajectory tracking by using a genetic algorithm (GA). Although a controller designed by a GA cannot work well on real robots as same as simulations due to modeling errors, this paper tries to reduce the influence of the modeling errors by adding motion noises to the simulations in the design process. The proposed method is evaluated through some simulations and real robot experiments for a target trajectory consisting of a straight and a sine wave. It is shown from experimental results that the target trajectory can be tracked not only in simulations but also to a real robot by introducing an appropriate evaluation function for the GA and adding the amount of motion noises properly.

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Blood pressure fluctuations reflect the presence of a variety of dynamic response of the cardiovascular control systems to physiological perturbations to cardiovascular homeostasis. As in most biological processes, these fluctuations exhibit 1/f^α characteristic of the power spectrum under physiologic conditions. In recent studies of human blood pressure variability (BPV), the slope α of the 1/f^α relationship has been found to change in accordance with pathologic alternations of BPV, e.g. a selective loss of high frequency fluctuations associated with the inhibition of the control of arterial BP by means of autonomic nervous system. However, current experiments do not specifically address the origin of the corresponding change in the slope. In the present study, a time-discrete model of 1/f^α fluctuation generator consists of the aggregation of first order autoregressive (AR(1)) processes with different values of process parameters was developed to analyze the relationship between pathological conditions and the values of the BPV spectral exponent α. Results show that the present model well reproduced inverse power-low spectrum lines shifted more negatively in high frequency components, those are specific for BPV spectrum of denerved arteries. Spectral analysis using the proposed model may provide a useful means of identify and/or diagnose diseases those are apparently unrelated to the pathologic states of cardiovascular system.

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Visual servoing with a hand-eye configuration tends to be vulnerable for hand's dynamical oscillations, since nonlinear dynamical effects of whole manipulator and dynamical coupling among actuating joints stand against tracking ability—abbreviated here as trackability, i.e. a performance to keep a target object projected at the center of camera's view while the target moves. A proposal to achieve high trackability is that visual servoing of the hand and the camera be separately controlled independently by decoupling each other, and such controlling method is proposed in this paper. The effectiveness of the decoupled hand and eye-vergence visual servoing method has been evaluated through simulations incorporated with actual dynamics of 7-DoF robot with additional 3-DoF eye-vergence mechanism, where the stability of closed loop dynamics has been verified by Lyapunov analysis.

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In order to develop scapula motion support equipment for the athlete to learn proper movement of his shoulder in such sports and games as baseball and tennis, a measuring method of the skeleton position and posture is necessary for automation of teaching training. The paper proposes a method for measuring the position and posture of the shoulder skeleton using parallel links. The proposed method is noninvasive and simple, and employs linear encoder. Measurement experiments of the position and posture of the scapula were conducted using this method, and obtained results were compared with previous results obtained by X-ray radiography, and the validity of the proposed method was demonstrated.

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Legged locomotion is high environmental adaptability by the effect of ability to choose landing positions freely. But the conventional legged locomotion machines have not been able to do high efficient legged locomotion, because most of actuator outputs are wasted to support upper body weight. In this case, the methods are pointed to be effective that compensating upper body weight by mechanical device, but it has not succeeded by this method. So, we propose it with passive gravity compensation mechanisms. First, we analyzed load shifts of legs, and it is clarified that this shifting needs two compensation mechanisms on each leg. One of the two is used to support the upper body, another is used to idle leg. Second, we develop novel two mechanisms, one of the two can change in the size of the compensation force. Another can change in the direction of the compensation force. Finally, we create the desired device by combination of those mechanisms, and measure compensation force throughout the walking motion. In conclusion, the novel system enabled upper body weight-free legged locomotion by means of using most of the actuator output for walking.

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Legged locomotion is high environmental adaptability by the effect of ability to choose landing positions freely, but low transfer efficiency. Because, the output is consumed by supporting upper body. In this paper, we propose a passive walking assist device with two air cylinders and surge tanks. This new device has three advantages in comparison with conventional devices. (1): The proposed device can effectively assist than conventional devices that are arranged spring element series to leg, because it has a twist arranged spring in parallel without interfering swing motions. (2): The weight is very light (1.5kg) and assist force is powerful (about 20～40 N / leg), using the system it runs by air. (3): The assist force is not from the electricity, from the loss of walking. Demonstrating these effects, we create the device and measured feelings and assist powers, Feeling are measured throughout the walking motion and bends by each load condition. Assist power are measured by a device that reproduces the walk. From result of this, it is expected that leg power can be assisted effectively.

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Learning is essential for human being. In this article, we analyzed the human learning strategy in the multi-movement discrimination by learning machine. Especially, the leg movements' discrimination using Self Organizing Mapping was taken as an example. Firstly, based on the experiment by ten healthy subjects, learning strategies were divided into two strategies; Convergence strategy (improving the repeatability of each movement) and Independence strategy (conducting different movements). Secondly, a child with severe impairment conducted similar experiments. He selected Convergence strategy and his index values to evaluate the degree of convergence and independence of his leg's movements were quite similar with healthy subjects' value. The generality of Convergence and Independence strategies was suggested in multi-movement discrimination task.

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The purpose of this paper is to develop a mechanical regulator and a robot motion control scheme for a human-robot cooperative task in stiff environment. The proposed mechanical regulator realizes the stable motion of the robot in the stiff environment by regulating dynamical interference between human dynamics and robot dynamics. The proposed mechanical regulator is composed of following components: (i) the motion-detecting system that detects relative positional deflection data between the human motion and the robot motion; (ii) the mechanical load regulating device that regulates an operational load of the robot motion for the human; (iii) the mechanical gravity canceller that reduces a dead load with the mechanical regulator when an operator manipulates the mechanical regulator. In addition, a switching control scheme of impedance parameters is proposed to realize the human-robot cooperative task in the stiff environment. To confirm the effectiveness of the proposed mechanical regulator and the proposed switching control scheme, experiments of the human-robot cooperative task in the constraint state are carried out. The experimental results show that the proposed mechanical regulator and the proposed switching control scheme are effective for the human-robot cooperation in the constraint state.

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This paper proposes a cooperative transfer control method by using three wheeled mobile robots (WMRs). One WMR is designated as a leader, and the other two WMRs are followers. A carrier platform is supported by links with passive joints on the WMRs. The carrier platform is always kept levelly when WMRs run along a straight path on a slope. The level control of the carrier platform is achieved by a position control of WMRs. The positions of the followers are controlled by using a fuzzy set theory to level the carrier platform, while the leader runs along the target path. Membership functions of the fuzzy set theory are designed by using a genetic algorithm. The usefulness of the proposed method is demonstrated through simulation and experimental results.

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This paper describes 3D scanning by a 2D laser range sensor and rotating curved mirrors for taking 3D laser reflecting points of objects in real space. I developed a 3D laser range sensor system, in which the 2D laser range sensor and the curved mirrors rotated about the sensor. The 2D laser range sensor takes reflecting points in 2D plane and widefield area around the sensor. The rotating curved mirrors reflect the laser from the 2D laser range sensor, and change direction of the laser radially from 2D plane to 3D wide-field space around the 3D laser range sensor system. I designed the curved mirror by reflected and changed radiate direction of the laser from 2D plane to 3D space. I made up hardware and software of the sensor system to control the sensor system. I checked scanning accuracy of the curved mirror in the sensor system. I took actual reflecting points in real space experimentally by using the developed sensor system. The results have shown the usefulness on the real environmental measurements.

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Robotics has attracted much attention from the planetary surface exploration community ever since NASA 's Pathfinder Mission opened a new door for the subject. In order to collect geological samples, 3D surface information of the environment and the targets, in general, has to be obtained so that a manipulator can successfully grasp them. Measurement accuracy and robustness are key issues for the realization of autonomous sample acquisition. A stereo camera is generally a useful device for 3D surface measurement; however, it may not be robust enough to handle unknown natural objects that exhibit a great deal of similarity and where there is uncertainty over their texture. In this paper, we focus on the robustness and accuracy of a measurement method using a stereo camera, and we propose Shadow Casting Stereo Imaging (SCSI). In use, SCSI casts the shadow of the manipulator (or a stick-shaped object) on a target surface, and then the 3D information can be measured using conventional stereo imaging by utilizing this cast shadow. The shadow creates a featured area on similar textures under harsh lighting conditions, because it produces a darker area on the textures as feature points for image processing. In addition, this technique reduces the search area for the template matching, and lowering calculation costs. We evaluated the performance of SCSI by comparing the measured results with conventional stereo imaging. Our results show that SCSI has advantages in terms of accuracy, robustness, and calculation cost against similarity of a natural object under various lighting conditions.

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We have developed two technologies for 3D magnetic microstructures, with a wide size range between 5μm to 2mm. The first technology enables us to obtain density controlled 3D magnetic microstructures. The size of this structure is approximately 500 μm. In this scale, controlling density is vital for magnetic micro actuators, because the effect of gravity is strong. To adjust density, we developed the world's first “density controllable magnetically modified photocurable (DMPC) polymer.” In addition, we succeeded in 3D velocity control of a screw-type magnetic micro actuator with neutral buoyancy in water. The second technology realized a 5μm magnetic micro actuator, which is a combination of a 3D transparent structure and 2D magnetic structure. Furthermore, we have succeeded in 2D driving a ferromagnetic micro actuator, whose diameter is as small as 1 μm. These two fabrication processes will become key technologies in the medical field, because they can supply a wide variety of 3D microstructures with small effort.

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Weave, yarn density, yarn count, fiber material and so on of woven fabrics greatly affect their surface characteristics. Surface characteristics of a fabric are important factor for consumers and textile producers in order to evaluate its fabric hand. However, there is no simple system to easily measure its surface characteristics. This study uses a simple tactile sensor that can measure the friction coefficients of fabric surfaces and tries to evaluate their surface characteristics from obtained values. We traced surfaces of plural fabrics that differ in yarn, weave and yarn density with the tactile sensor, and measured variation of the friction coefficients with respect to the trace distance. This study introduces some evaluation values from the measured variation of the friction coefficients and compares them with results by KES, which is the ordinary system to evaluate surface characteristics of a fabric. As a result, the study confirmed that proposed method easily evaluates the geometrical and frictional properties of woven fabrics as their fabric hand, and also can estimate the yarn density of woven fabric by analyzing the oscillation period of variation of friction coefficient.

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It is a useful tactic that punctual flight services result in high customer satisfaction to against low cost carrier. However, today about 50% of flights are frequently delayed or canceled by irregulars. These irregulars must be dealt with by rescheduling to maintain a high-level customer satisfaction. Rescheduling is a highly complex problem since flight services have a large number of elements that are directly or indirectly involved in each other. And it is always dealt with by operator's implicit knowledge that is cultivated from his/her long experience. For these reasons, a flight rescheduling support system is strongly desired to support the difficult rescheduling problems. Our research proposes a support system of flight rescheduling. This system represents flight service as a service model consists of three sub services: (1) transportation service, (2) operation service, and (3) maintenance service. Based on the modeling of flight services, we focus on the relationships of flights to describe the rescheduling of flight service. Our research also proposes an algorithm of flight rescheduling by using these relationships. Then an automatic planning system and evaluation method for the flight rescheduling results is proposed to support operator's decision making. At last, a prototype system is shown as a case study by using an actual data of flight service.

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This paper discusses a level set-based topology optimization method for the design of negative bulk modulus acoustic metamaterials. Acoustic metamaterials are engineered materials that are designed to have extraordinary acoustic properties, such as a negative effective bulk modulus and effective density. Novel applications such as sound isolation devices, acoustic cloaking, acoustic superlenses, and others have been proposed using such acoustic metamaterials. Most metamaterials consist of periodic structures of unit cells that are adequately small compared to the wavelength of target frequency. The overall structure of such periodic structures can be considered as an effectively homogeneous acoustic structure, and behaves as a material having negative effective properties exhibited globally. The purpose of the optimization problem here is to find optimized configurations of acoustic metamaterials composed of rubber and epoxy that achieve a negative effective bulk modulus. In the design of acoustic metamaterials, the presence of grayscale areas in an optimal configuration significantly affects its performance, so we use a level set-based approach that inherently avoids the grayscale problem. The effective bulk modulus of the acoustic metamaterials is computed based on the reflection and transmission coefficients and the optimization problem is formulated to minimize the effective bulk modulus. Optimization algorithm uses the adjoint variable method (AVM) for sensitivity analysis and the finite element method (FEM) for solving the acoustic wave propagation problem, the adjoint problem, and the reaction diffusion equation to update the level set function. Finally, several numerical examples are provided to confirm the utility and validity of the proposed method.

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This paper presents a topology optimization method for fluid problems using the lattice Boltzmann method (LBM). In the field of computational fluid dynamics, the LBM is a new approach for calculating viscous fluid behavior that replaces the classical formulation employing the Navier-Stokes equation. Since the LBM is formulated with a linear equation rather than the nonlinear Navier-Stokes equation, the LBM algorithm can be easily constructed. Therefore, the explicit scheme of the LBM makes it especially suitable when implementing large-scale parallel computations. In conventional approaches, since the optimization formula is constructed using a discrete governing equation, the adjoint equation typically includes a large-scale asymmetric matrix in the sensitivity analysis, which severely inflates the computational cost of solving an optimization problem. To overcome this, we construct a structural optimization problem governed by the continuous Boltzmann equation so that an adjoint equation that uses the same framework as that of the Boltzmann equation can be derived. Due to the framework characteristics, the adjoint equation can be calculated explicitly, as with the lattice Boltzmann equation. In this paper, we construct an optimization formula based on the lattice Boltzmann equation and the adjoint lattice Boltzmann equation. Furthermore, in order to obtain clear boundaries in the design domain, we use level set boundary expressions.

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A flat thrust bearing, that has a structure which generates a pressure flow by using the discontinuity of shear flow rate between a water-repellent surface and a hydrophilic surface, was developed. In this study, ultrasonic pulse echo technique was employed for the investigation of the film thickness influenced by the static contact angle θ (≅10°, 60°, 110°) and the water-repellent area ratio β(=0.25, 0.5, 0.75). Since the occurrence of the slip of water at a water-repellent surface having 110° of static contact angle is easy, observed lubrication film thickness is thicker than that of θ≅60°, and the film thickness at θ≅10° becomes thinnest. The film thickness is different by the area ratio β of water-repellent region against a bearing surface area, and it thickens in order of β=0.25, 0.75, 0.5. Thickest film is formed around of the β where the area of water-repellent region is equal to hydrophilic area. Calculation results of the infinite long bearing approximation, which considered the slip on a wall, agree with the characteristics of measured film thickness mentioned above. Therefore this thrust bearing operates under similar mechanism with conventional bearing having lubrication surfaces which shapes a wedge film. The order of measured film thickness agrees with order of satisfactory bearing of friction characteristics in each bearing tested. Consequently it can be conclude that the main factor of which coefficient of friction under a same load and speed is different by static contact angle θ and water-repellent area ratio β is a variance of film thickness in each bearing.

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In this paper, we propose evaluation and verification about the MDA development by UML which aims at the improvement in productivity and maintainability of MES. We consider why MDA (Model Driven Architecture) is not widely spread in the development of MES (Manufacturing Execution System) and propose a method to overcome the problem which prevents the developers of MES from adopting MDA. The method makes it possible to apply the MDA development with UML (Unified Modeling Language) to the development of MES by introducing additional documents to supplement. We evaluated the proposed method by using the prototype system which was developed with a UML modeling tool and Excel macros. The application of the system to a practical example showed that the proposed method required about half number of documents and software development workers of the conventional one. It is expected that the MDA development of MES with UML and the proposed supplemental documents encourage the reuse of the documents and the productivity and the maintainability are remarkably improved.

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Damaged clutches that were returned from the field typically had 3 types of symptoms: 1.Only the friction material was damaged, 2.Only the mating plates were deformed, 3.Both symptoms were observed together. Root cause identification of these symptoms by relationship with the difference of operating application is the purpose of this paper. Field load frequency of each application was organized and the life time of the friction material and the presence/absence of the mating plate deformation were determined by the original calculations. The result were: 1.On the application that the clutch absorbed the energy during short term, the mating plate deformation was dominant, 2. On the application that the clutch absorbed the energy during long term, the friction material life was dominant.

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Unexpected disruptions, such as delays of manufacturing processes, addition of emergent jobs and failures in manufacturing equipment, often occur in the actual manufacturing systems, and a predetermined production schedule may not satisfy given constraints due to the disruptions in the manufacturing systems. This research proposed a new reactive scheduling method using the co-evolutionary genetic algorithm. The proposed method alternately modifies the loading sequences of jobs and the machining sequences of jobs in a very short time, in order to improve the disturbed production schedules without interrupting the progress of manufacturing process. A prototype of an extended reactive scheduling system is developed to evaluate the effectiveness of the proposed method. Some computational experiments are carried out for unexpected delays of manufacturing processes.

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This paper deals with the state of the thermal crack development on the rake face of cemented carbide hob material, P30, whose flank face was coated with TiN and (Ti,Al)N films when changing the hob feed in the cases of dry and MQL system in hobbing. Experiments were carried out by simulating hobbing by fly tool cutting on a milling machine. As a consequence, the following points were clarified: (1) The number of thermal cracks obtained with MQL system is smaller than that obtained in dry when using both TiN- and (Ti,Al)N-coated tools, irrespective of changing the hob feed. In the case of MQL system, however, the delamination occurs on the thermal crack. (2) The thermal cracks begin to appear at a distance of contact length with chip from cutting edge, which develop toward the cutting edge. The thermal cracks also occur almost perpendicular to the top cutting edge, the roundish portion and the side cutting edge. (3) The occurrence directions of thermal cracks agree approximately with the directions of chips which flowed out perpendicular to the three cutting edges of hob tooth.

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The robust topology optimization method integrates the level set-based topology optimization that introduces fictitious interface energy to regularize the optimization problem and the sensitivity-based robust optimization method that the objective function is formulated as the weighted sum of the mean value and the standard deviation of the compliance energy. Accordingly, the robust topology optimization method has two parameters, the regularization parameter and the weighting factor. This study investigates the effects of the two parameters of the level set-based robust topology optimization method on the structural configurations of the optimum designs and values of objective function through numerical examples.

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[in Japanese]

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