Flow-induced vibration occurs in the structures subjected to annular flow such as elastic beam in the narrow passage. Once the vibration occurs, the vibration becomes larger. In this paper, active vibration control of the axisymmetric elastic beam subjected to annular flow is investigated. Fluid-structure coupled equations based on the Euler-Bernoulli type partial differential equation and Navier-Stokes equation are derived including control terms. In this paper, two kinds of control methods using piezoelectric actuator and air pressured actuator are proposed. Applying the optimal control law to the coupled system, the unstable behavior is stabilized. Simulation studies are performed to investigate the efficiency of the proposed control methods and the effects of the actuator position on control performance.

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It is known that, under appropriate condition, amplitude of vibration of some blades in mistuned bladed disk system become large compared to what would be predicted by an analysis of the perfectly tuned system. In this paper, the effects of the mistuning pattern on the natural frequencies and the frequency response of mistuned bladed disk system are investigated. It is shown that, in the tuned system, the excitation with the wavenumber k excites only the vibration modes with the same wavenumber and that, in the mistuned system, the excitation with the wavenumber k excites all vibration modes. The variations of the natural frequencies due to mistuning pattern are obtained by using sensitivity analysis. The relation between the mistuning patterns and the split of natural frequencies are discussed. It is noted that the mistuning pattern with the circumferential wavenumber 2k effectively splits the natural frequency of the vibration mode with the circumferential wavenumber k of the tuned system and that the amplitude of the responses of the system with the mistuning pattern with the circumferential wavenumber 2k subject to the excitation with the wavenumber k hardly become large.

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This study focuses on a calculated displacement from acceleration profile with double integration. Structural displacement and vibrational response are important informations for safety inspection of buildings. Such inspection system requires multi point measurement with accelerometers. Because of piece to piece variations, individual examination is necessary to use a large number of accelerometers. For the purpose of individual high accuracy sensor test, this study proposes a new exciter device which converts rotation motion to sine wave vibration with parallel link mechanism. The proposed exciter provides accurate acceleration and assured circular displacement for sensor inspection. Experimental results determine a matrix with real sensor direction vectors. Sensitivities are also measured for each sensor direction by matching integrated orbit for the reference circle. These detailed parameters of multi-axis accelerometer are what conventional methods cannot determine.

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When elliptical vibration with vertical vibration over the jump limit is given, works on a vibration table move right or left depending on whether they jump or not, and the works can be separated and transported. We investigated the phenomenon by which some works jump and others do not when there is vertical vibration over the jump limit. First, the pressure fluctuation produced in the contact surface between a work and a vibration table was measured. The negative pressure produced in the contact surface suppresses the jump of the work. It was then shown that the negative pressure was derived from the viscous damping which changes depending on the gap length in the contact surface. The gap dependence of viscous damping limits the generation of the negative pressure and produces the jump. Finally, the difference in the generating limit of the negative pressure was used to separate the works by the gap length.

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The main point of this study is to control both the end-effector motion of a flexible-base manipulator and the spatial force imposed by the manipulator motion on its base. Such simultaneous control, however, leads to the appearance of dynamic singularities. At the singularities, the control performance degrades and the system may be destabilized. In this paper, we introduce a trajectory tracking and reaction control method that ensures stable performance even for paths passing through dynamic singularities. In this way, the problem of reduced workspace due to the presence of such singularities can be alleviated. The results of simulation studies with a simple planar model and a realistic three-dimensional manipulator (JEMRMS/SFA) demonstrate the capabilities of the proposed controller.

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Parallel wire type positioning systems, which consist of several tensioned wires in the plane, have many practical applications in industrial fields. However, the conventional systems are easy to vibrate in the direction perpendicular to the wire plane, and this problem limits the use of the system, in spite of a lot of their advantages. For this reason, a new parallel wire type positioning system with a vibration suppression mechanism (tuned mass damper: TMD) is developed in this study. However the TMD is effective only for the object with a constant resonance frequency, whereas the parallel wire systems generally have a variable resonance frequency depending on the wire tensions. Therefore, authors have developed new technique which can control both the position (attitude) and the natural frequency of the object simultaneously. This paper first describes the detail of the proposed technique, then effectiveness of the technique is verified through several experiments.

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This paper presents research on a new vibration suppression method for stepping motors. A new compensation method for stepping motor controllers, which cancels out the cogging torque without using any additional electronic devices and mechanical parts such as angler position sensors, is proposed. This paper is organized as follows. First, a transfer function based on the feed-forward compensation that describes motions and electric circuits for tow-phase hybrid stepping motor is derived. Next, experiments for the motor drive controller conducted to evaluate the rotor vibration are presented. Then, computer simulation on vibrations for a print-head carriage system driven by a stepping motor is described to verify effectiveness of our proposed method. Finally, it is concluded that experimental and simulation results show that our proposed method is effective in the vibration suppression.

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This paper presents a simple robust PID tuning method for force control of ionic polymer actuators. The model is represented by a linear-time invariant system which consists of electrical and electro-mechanical models. The uncertainty is represented by an interval polynomial set of the closed-loop characteristic equation. Using Kharitonov's theorem, we show that just one Kharitonov polynomial stability critevion is necessary and sufficient for satisfying the robust stability of the system. The PID gain is determined by pole placement based on the derived Kharitonov polynomial. Experimental results show the effectiveness of the PID force control by the proposed method.

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We have already developed an active roller guide system to suppress the elevator lateral vibration. In this system, sky-hook control theory was applied because it has been well realized in any other fields and reliable. However, the optimality of the controller design was not verified. So it requires further investigation how suitable for active roller guide system it is. In this research, the application of robust control theory to active roller guide system is dealt with, so that the validity and limit of robust control approach is investigated. Particularly, we describe the influence of car weight parameter change. Finally, experimental results are provided to demonstrate the effectiveness of the proposed mu synthesis control and to make its problems clear.

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Pedestrian collision avoidance in urban environments is an important active safety technology to protect vulnerable road users and realize zero-traffic-accident society. Especially, reduction of vehicle-pedestrian collision accidents at intersections by using vehicle control engineering approaches in a promising approach. This paper focuses on the right turn driving situation which drivers need to negotiate pedestrians near crosswalk region. Using a micro electric vehicle as an experimental vehicle, this paper describes an autonomous collision avoidance by braking. The intensity of braking maneuver is determined by Potential Fields. A LIDAR is used to detect pedestrians and measure their speed and position in intersections. The proposed system consists of the risk assessment in consideration of pedestrian motion and an algorithm to minimize the collision risk which changes dynamically associated with changes of pedestrian behavior. Finally, the effectiveness of the autonomous collision avoidance system is verified by driving experiments using the micro-scale electric vehicle.

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The development of a clean and fuel efficient diesel engine control method is required for the purpose of global environmental protection. However, in the EGR control of turbo-charged engines, the system has nonlinear characteristics, and there is mutual interference between the EGR valve and the VNT guide vane. We propose a cooperative control method to deal with the nonlinearity of the diesel engine. In this paper, a method for model identification and ILQ (Inverse Linear Quadratic) design is introduced. As the result of using this method, which can be systemized from model identification to the mapping of the controller gain, high environmental performance and efficiency are achieved.

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In this paper, we present a position and yaw angle controller for a four-rotor mini helicopter, which is designed via the backstepping methodology. In order to avoid a singularity problem caused by using of Euler angles, only quaternion is employed to represent the attitude of the airframe. Although the use of quaternion makes it difficult to obtain a desired attitude in a step of the back-stepping procedure, a geometrical approach gives an effective solution for the problem. It is shown in some numerical simulations that the proposed controller can achieve global tracking to demanded position and yaw angle simultaneously.

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This paper presents a people tracking system with multiple sensor nodes allocated in an environment. Each sensor node consists of a two-layered laser range sensor (LRS) that detects the positions of heads and knees of people. From the laser images of the people, heuristic-rule-based and global-nearest-neighbor (GNN)-based data association can identify a large number of people in crowded environments. The identified people are tracked via a model-based tracker; the interacting multiple model (IMM) estimator is applied to track people suddenly changing in motion, such as walking, running, going/stopping suddenly, and turning suddenly. Simulation and experimental results validate our people tracking method.

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We propose and develop a standing assist robot, which is attachable to the motorized bed, for the elder at hospital or home. Especially, the target user of the robot is the elder who can walk indoor independently, but can not stand up because of his or her muscle strength ability. The developed robot has three degree of freedoms (two active joints for rotation and translator and one passive joint for the rotation) which promote trunk's forward tilting and elevate the center of gravity by assisting to extend the knee and hip joints. We confirm that the developed system is attachable to the typical motorized bed using the space under its bed. The myoelectric signals of Tibialis Anterior (TA), Rectus Femoris (RF) and Erector Spinae (ES) are measured to analyze the effectiveness of the developed standing assist robot. As a result, the myoelectric signals of TA, RF and ES with using the developed system are about from twice to three times smaller than those in normal standing. In addition, the myoelectric signals of RF and ES are the almost same as those during the walking. In other word, it is confirmed that the burden for the muscle is suitable, because the target user can walk and can not stand up. Therefore, this result shows the effectiveness of the proposed concept and developed prototype that the robot is attachable to the bed.

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Power assist systems have been introduced to reduce workers' load in industrial production. The authors have 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 uncertainties such as nonlinear friction or parameter variations. This paper shows a robust assist system design by taking these uncertainties into account. It consists of an impedance controller, a disturbance accommodating optimal controller, a disturbance observer and a reaction force controller. The first and second elements have already been applied to the authors' previous paper. In addition, the disturbance observer is needed for eliminating the influence of the structured uncertainties. Moreover, taking the characteristic of the controlled object model into account, the simple reaction force controller is applied in order to eliminate the influence of the reaction force from the vibration reduction actuator. As a controlled object example, this paper adopts a power assist cart with a vibration system. The effectiveness of the proposed control system is verified by experiments and their corresponding simulations.

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Improvement of value-added steering maneuvering is required more than ever, for wider range of passenger vehicles. Steering is one of the key systems to achieve better vehicle maneuvering. Sensory evaluation of “steering feeling” can hold contingency designing strategy. But, uncertainty of human factors should be taken into account for estimation of physical quantities. Some methods that specify relation between “steering feelings” and performances of vehicle dynamics have been proposed but not practical for actual design of steering components. In this paper, the theoretical method with detailed steering model that specifies quantitative performances and physical quantities for steering components is proposed.

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This paper describes the utilization of the product model by SysML as a joint platform for distributed design. We introduce a typical design process involving distributed design teams. In particular, this process allows a thermal design of cavities, i.e., air space inside the enclosure, in terms of flow rate, acoustic radiation resistance and so on. Then, we investigate a module-based design optimization approach defining cavity as a module to efficiently support such processes. Authors propose structural and functional modeling that enables all the distributed design sites to share the design information with the product model. Using this design framework, it will be possible to prevent performance defects due to physical coupling between modules, and thus, reduce the iteration of work.

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A multi-objective particle swarm optimization (MOPSO) is known as a multiple point search-based meta-heuristic approach to find diverse Pareto solutions efficiently for design problem consisting of continuous design variables, but has difficulty to handle the constraint conditions. Overcoming the disadvantage, this study proposes a hybrid algorithm incorporating MOPSO and sensitivity analysis on constrained conditions. When design candidate with constraint violation appears during searching process, the design candidate is moved to the feasible domain using gradient information of the constraint conditions. Then, the design candidate is moved to the feasible boundary using the bi-section method. The forced transferee is applied to the design candidate in MOPSO algorithms. The proposed approach is different from the other hybrid approaches that the Pareto candidates are improved by local searching algorithms. Rather, the approach recovers the violated design candidate to the Pareto candidate by moving to the feasible boundary. This approach is useful for the design problem such as most structural design problems that the constraint sensitivity is easily obtained and that the Pareto sets will exist on the feasible boundary. Through several numerical examples, the diversity and convergency of the Pareto solutions as the performance of the proposed method are investigated.

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In the present paper, WCA (Wants Chain Analysis) is proposed by extending CVCA (Customer Value Chain Analysis). CVCA is a method for visualizing relationship among stakeholders for analyzing existing social systems and designing new social systems. WCA is a method for visualizing wants and needs of stakeholders in CVCA utilizing Maslow's hierarchy of needs. In WCA it is shown that people's wants or needs are finally realized through the looped and linear chain of relationship among stakeholders. With various examples, effectiveness of WCA is shown by describing that characteristics of business/social systems structure can be clearly visualized using WCA. It is described that WCA is useful for analyzing social systems. “Think of others” should be more and more important for humans' satisfaction and happiness in the near future. WCA can be a tool for clarifying what is for others.

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Level set-based shape and topology optimization methods get attention as a new type of structural optimization. However, the structural optimization methods cannot treat explicitly a design dependent load, such as pressure load, because the finite elements for solving the equilibrium equation are fixed during the optimization process. On the other hand, Boundary Element Method (BEM) is only required boundary elements to solve a boundary value problem. Therefore, some complicated numerical techniques for re-meshing process are not required. This paper presents a level set-based topology optimization method using the BEM for three-dimensional problems. First, we briefly discuss BEM for three-dimensional elastic problems and the topology optimization method using the level set method and the Tikhonov regularization method. Second, the minimum mean compliance problem with volume constraint is formulated. Next, an optimization algorithm and numerical implementation for generating boundary elements based on the level set boundary expressions are shown. Finally, we show some three-dimensional numerical examples including design dependent load problem and discuss effectiveness and adequacy of proposed method.

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The purpose of this study is to investigate the 3-D flow of lubricants around the mesh-ending region of a rotating helical gear pair. It has been revealed that there are air-flows around the meshing region, so effective lubrication should be considered with the flow, especially in severe condition of the transmission by gears, such as a high circumferential velocity or wider tooth width. In this paper, a simulating experiment is introduced, in which an acrylic helical gear pair is immersed into the water, and driven. This experiment makes phenomena slower than actual lubrication in the air, so observations become easier. Stainless particles are injected into the mesh-ending region like lubricants against meshing direction, and suspended sparsely in the water. The motions of the particles are captured by a high-speed camera. The camera is located to be able to look into the space between the teeth. Optical astigmatism is introduced intentionally into the system for the observation with the high-speed camera. With this optical system, distorted elliptic images of the particles are observed when the particles are out of focus. Numerical procedure is investigated to evaluate the positions of the particles along the optical axis from the distorted particle image. The tracings of the particles injected from various nozzle positions are shown in this paper, and hitting locations of the particles on the tooth surfaces are found out as lubricated region.

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The cutting performance of indexable insert drill that has non-axisymmetrical geometry for drilling of difficult-to-cut materials is investigated. A twisted drill is also used to compare the cutting performance. The cutting characteristics are evaluated by tool flank temperature at peripheral corner edge θ_α, thrust force F_t, chip geometry and surface roughness R_a. The temperature of cutting tool is measured using a two-color pyrometer with an optical fiber. As work materials, the carbon steel, stainless steel, titanium alloy and nickel-base alloy are used. The θ_α and F_t of indexable insert drill are lower than that of solid drill in cutting of titanium alloy and nickel-base alloy. In the case of titanium alloy, the F_t of indexable insert drill is only 40% in the case of solid drill. On the other hand, this tendency reversed for stainless steel, and θ_α and F_t of indexable insert drill become higher than that of solid drill. The chip geometry by indexable insert drill is divided into parts in fragments so that there is chip breaker on the rake face of insert while the chip geometry by solid drill is continuous and long. The difference of surface roughness by the indexable insert drill and solid drill is negligible in the cutting of difficult-to-cut materials.

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Recently titanium alloys and nickel alloys have become widely used for making aeronautic and astronautic parts. During machining of those metals, most of the cutting heat generated is severely conducted to the cutting tool as the thermal conductivity of those materials are very low and resulting the shorter tool life. It is required for a durable tool with excellent cooling capacity. Thus, in this research, cutting technology in strong alkaline water for machining of titanium alloys and nickel alloys was developed and evaluated by experiments. Firstly, the corrosion characteristics of titanium alloy and some other materials were investigated using water and strong alkaline water. Then, durable cutting tool with high and efficient cooling capacity was developed. This cutting process was taken inside the vessel filled with strong alkaline water. The tool life and cutting accuracy with applying proposed method are investigated by experiments using Ti6Al4V. From the results, it is concluded that; (1) The cooling capacity of the new tool using strong alkaline water is very effective for maintaining the longer tool life, (2) The developed new tool is effective for high speed cutting of titanium alloys and nickel alloys, (3) The proposed new tool and compulsory cooling system are economical and eco-friendly.

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Generally, rolling bearings are fixed at both ends of a rotating axis and a reference target is provided to give allowable fixing error of the bearings as appropriate according to the category and application. The allowable fixing error of a spindle, in which high rotational accuracy is required, should be very small. However, there is no research report which investigates closely the relationship between the fixing error and the rotational accuracy. Thus, eventually, this research intends to clarify the relationship between them and this report describes the relationship between the inclination error in bearing unit and the non-repetitive run-out using small ball rolling bearing. Consequently, using a measuring equipment of rotational error for single ball bearing, it was made known that the amplitude of the ball-cage rotation becomes very large when the inclination error increases. Thus, the conclusions of this research are as follows. (1) When the inclination error increases, the amplitude of frequency of cage rotation becomes large even supposing that the inclination error is in an allowable range. (2) When the inclination error increases, the amplitude of the doubled frequency of cage rotation becomes prominent. (3) When the number of rolling elements becomes large, the increment of variation of rotational period for the ball-cage is small.

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Recently, the direct molding machine of the metal product is utilized, but the fabricating device and the materials are very expensive, also the kinds of the materials are limited, in comparison with the machining of bulk material. In this paper, a new metal laminating modeling by using an arc discharge is proposed to achieve the near-net-shape molding. On this process, as the heat input from arc discharge is large, some cooling should be necessary to prevent overheating of the fabricating product and the machine. But the cooling rate of the molten pool, where the molten metal is dropped from the tip of the welding torch, affects the shape of the fabricated product. Then the laminating characteristics of the two types of cooling, namely water cooling and an air cooling were investigated. It was shown that the laminating height becomes high and the width becomes narrow when the cooling rate of the molten pool is higher. These results can be helpful for higher modeling accuracy using this direct metal lamination process.

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Recently, many developers have begun paying more and more attention to multi-joint dual-arm robot, and it is expected the robot will reclaim its place in the field of new automation. Industrial dual-arm robots have therefore gained attention as new tools to control both linear motion and rotational motion accurately. On the other hand, the five-axis control machining center controlling the motion of three translation axes and two rotary axes has put into wide practical use. However, a one problem has been that it may be the difficult to measure the synchronous accuracy of two rotary axes without high accuracy gyro sensor. In the present report, we proposed a novel method to measure the synchronous accuracy of two rotary axes of machine tool table with a ball, which keeps a ball rolling around a circular path on the working plate by dual-arm cooperative control. As a result, we investigated an influence of each axis motion error on a ball- rolling path, and demonstrated this method made it feasible to estimate the synchronous accuracy of two rotary axes of machine tool table.

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In the field of micro chemical process, the research on slug flow chemical process becomes attractive. The slug flow is a flow in which two liquids appear alternately, forming striped pattern on a flow line, and it is effective to realize efficient chemical reaction. We have developed a micro three-port valve that aims controlling freely the length of the slug flow. However, the working performance of previous valves depends on the characteristics of fluids and driving conditions. The goal of this research is the development of a slug flow generation system using a new electro magnetic valve, which realizes slug flow with desired length without depending on the characteristics of liquids and pressure fluctuation by segment number change of slug flow.

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The present paper describes a systematic and comprehensive evaluation method of product development process based on the product definition at the early stage of product development in order to reduce the development time in large-scale and complicated product development with technology risk. The proposed evaluation method focused on the redesign and retrial of product components due to complicated relationship among components as the development risk leading to development delay. This proposed method evaluated the quantitative development risk using the product worth flow analysis which calculates the strength of interaction between components from the view point of engineering interaction and importance of customer worth and supported to decide the product development process and development strategy of each component. The paper shows two case studies in 2 types of micromachining system (lithography technology and cutting technology) developments. This proposed method contributes to the reduction of the feedback relationship across the product modules by technological alliance between the manufacturing process development in manufacturing firm and development of main components of manufacturing tool in comparison to the conventional manufacturing firm-led development process.

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In this paper, the influence of fullerene as an additive in cutting oil on flank wear and crater wear of TiN- and (Al,Ti) N-coated tools, and finished surface roughness were investigated with minimal quantity lubrication (MQL) system in hobbing when changing the cutting speed. Experiments were conducted by simulating hobbing by fly tool cutting on a milling machine. The following results were clarified; (1) Fullerene decreases the flank wear compared with cutting oil for MQL on the market under the various cutting speeds tested. The flank wear obtained with the (Al,Ti)N-coated tool is smaller than that obtained with the TiN-coated tool. (2) Although the cutting speed was varied, fullerene is effective for the crater wear and the finished surface roughness compared with the cutting oil. (3) From the viewpoints of flank wear, crater wear and finished surface roughness, fullerene is available for MQL system in hobbing.

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For non-heating sterilization, the use of various radiations including gamma-ray irradiation has been approved in the United States, Europe, and China, whereas legally prohibited from the safety perspective in Japan. Previously we reported the development of a fine grinder for dry tea leaves, implying the occurrence of sterilizing activity that has not been found in conventional grinding procedures. The present study aimed to elucidate the mechanism of occurrence of sterilizing activity in the use of the developed apparatus “Batch-type Vertical Rotation Planetary Ball Mill (VPBM)” and to realize a non-heating sterilizer for Dried micro powder foods. First, a method of enhancing sterilization was devised and successfully tested in a validation experiment. Subsequently, the generation of ultraviolet rays by the enhancing method and enhanced sterilization were assumed and verified in a qualitative validation experiment. As the wavelength of relaxation frequency on the gradual extinction of electronic polarization, a dielectric polarization, is within the range from visible rays to ultraviolet rays, it was hypothesized that if similar phenomena (generation and gradual extinction of electronic polarization) occur in the VPBM-specific crushing mechanism, ultraviolet rays may be most probably generated from dried capsules and cell walls of bacteria. Thus, final validation experiments were carried out on dried and pulverized food materials containing a lot of bacteria, with favorable results. Mechanical energy may have been converted into electric energy, then to chemical energy for non-heating sterilization.

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