A novel design method of empirical if-then rules for diagnosis of plant start-up sequences is proposed. The rules dealt with in this paper take form of "If variable Y is out of the determined range when variable X becomes X_0, then raise alarm", which is one of the styles of rules commonly implemented in practical plant control logic. When sufficient number of normal and abnormal data is available, one can build empirical if-then rules for early detection of abnormal start-up sequences. Conventionally the rules are built by expert engineers based on their experiences, and inevitably in subjective way. Present paper proposes a design method which can objectively give an optimal rule. The first step of the proposed method is 'alignment' of data profiles using dynamic time warping. The second step is calculations of correlation ratios of data to find the best condition to distinguish normal and abnormal start-up sequences. A simulation study of a natural gas fueled plant is used as an example of applications of the proposed method.

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The casing of a large scale turbine generator is filled with hydrogen gas as a coolant. To prevent the hydrogen gas from leak, hydrogen-tight enclosures and seal rings are located at both ends of the casing. In some conditions, the gap between the seal ring and rotor shaft might be reduced to cause a rub. The rub sometimes cause a significant vibration. In order to solve the problem, we tried to make a guideline to evaluate the posibility of rubbing vibration occurrence by using each effective parameter with setting some assumption and confirming the consistency between analysis result and actual phenomena.

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In order to investigate effects of driving conditions and traffic environments on visual behaviour, a driving simulator experiment was conducted. Specifically it was considered how a visual field was influenced as a function of cognitive distraction, possibly resulting in a situation of look-but-did-not see, and crowdedness of other vehicles and pedestrians. Cognitive distraction was simulated by a experimental secondary task which was relevant to mental calculations. It was found that driver's reaction time to a target mark was increased resulting from cognitive distraction. This result may be explained from a driver's visual field point of view. That is a visual field for recognising a target mark got small when drivers was distracted with particularly driving on non-crowded road, compared with crowded road. Potential application of this research will be discussed.

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In this paper, a novel of detecting signs before wheel-climb derailment in scaled experiment is examined, and it is dedicated to the early signs detection of derailment for railway vehicles discussing a sensing method and a detecting algorithm for reducing the damage and aiming to avoid the happening of the derailment accident in advance. A scaled model of railway vehicle including one car body and two trucks as well as an original device that could simulate various wheel climb derailments only for the selective wheel were designed and made. Based on several patterns of derailment experiments, an algorithm for detecting signs of derailment beforehand was proposed. It was found and verified that the peak threshold of pitch angular rate and the integral threshold of roll angular rate of truck flame could be possible to detect signs before the wheel-climb derailment all the time during driving.

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In the sloshing analysis of liquid storage tanks by the finite element method, the displacement based fluid element based on the Lagrangian formulation is widely used in two and three dimensional problems. On the other hand, it has not been reported the application to the axisymmetric problem. This paper presents the applicability of the displacement based fluid element to the axisymmetric sloshing problem. The eigenvalue of elemental stiffness matrix is analyzed in order to investigate the characteristics of the rotational stiffness to the compressibility of the fluid. As a result, this method is found to be difficult to apply to the axisymmetric problem. However, it gives the highly precise response solutions if the sloshing modes are only taken into consideration.

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BTA deep hole drilling is used for producing holes of high aspect ratio. In this process, a chatter vibration sometimes occurs and a rifling mark is formed on the surface of the hole. The generating mechanism of the rifling mark in BTA deep hole drilling process has been studied as a self-excited vibration caused by time delay. In this paper, a BTA machining head which has two guide pads is treated, and countermeasures against the generation of rifling mark phenomenon are considered. The influence of the locations of the guide pads is analyzed. Also, the preventing method by an additional guide pad is proposed, and the effect of the preventing method is investigated. Furthermore, the optimal location of the guide pads is studied by quasi-static analysis. According to the numerical result, it was confirmed that the perfect prevention of the generation of rifling mark phenomenon was possible by using an additional guide pad and locating the guide pads appropriately.

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This paper deals with impact vibration in beam system excited by periodic displacement with cosine function. The analytical model is steady impact vibration for a cantilever beam. The beam collides elastically to clamped steel of unsymmetric faces at an arbitrary point of span. Tried to analyze by applying the Fourier series method for this system with assuming force of restitution has a triangle hysteresis loop characteristics. For verification of the analytical method, experiments are performed. The analytical results are in a fairly good agreement with the experimental ones. After that tried to analyze the infinitesimal stabilities for the approximate solution by Fourier series method by applying variation equation. As the result, experimental result appear at the stable solution region in the analytical solution.

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In this paper, a method of the giant swing motion of a 2-DOF link horizontal bar mechanism using Delayed Feedback Control is discussed. Firstly, a kind of Poincare section to regard the system as a discrete-time system for evaluating its stability is defined. Meanwhile, a way to calculate numerically the transitional error matrix and the input control matrix is shown. Secondly, we investigate how we can obtain the gain of feedback on the basis of analysis about the stabilization of system under the control of delayed feedback. Finally, a simulation result to show the effectiveness of this method is represented.

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This paper presents a reduction method of system matrices for the absolute nodal coordinate formulation (hereafter called ANCF), in the case of planar flexible beam, by applying the component mode synthesis. We pay attention that the bending stiffness term expressed by the continuum mechanics approach of the ANCF beam element is constant, and apply Craig-Bampton method to this term. Numerical examples that compare the presented method and conventional ANCF are demonstrated to verify the validity of presented method. As a result, it is verified that the presented method represents the large deformation effect such as the dynamic stiffening due to centrifugal forces as well as the conventional ANCF. The presented method achieves the shortening of the computing time, while keeping the acceptable accuracy of the expression characteristics of ANCF on large rotation and large deformation.

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To increase the recording density of hard disk drives (HDDs), the gap between the magnetic head and the disk must be reduced less than 10nm. Due to the reduced gap, a lubricant film which is coated on the disk must be a monolayer with a thickness of 1-2nm and it should play more significant role in the lubrication of the head disk interface (HDI). For the lubrication design of the HDI by using monolayer lubricant films, it is essential to evaluate those viscoelastic properties under a shearing motion. However, a method that can be applied to the viscoelastic measurement of such a thin film has not yet been established. In our previous study, we have developed a highly sensitive shear force measuring method that utilized a ball-ended optical fiber as a shearing probe, which we called the fiber wobbling method (FWM). In this study, we expanded the capability of the FWM and achieve the viscoelastic measurement of monolayer lubricant films by developing new methods which realized the highly accurate gap control of 0.1nm order.

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It is easily expected that the evaluation of the sensibility will have an important meaning in the field of mechanical engineering. However, the quantitative evaluation of the sensibility is very difficult subject. So, our attention was paid to the position of the gaze concentration in the present study as a first step to evaluate the sensibility, and we tried to estimate the position of the gaze concentration by using the induction field in vision. In the present study, the hairstyles were chosen as the research topic and we gathered information by the questionnaire methods besides the analysis of induction field. As a consequence, we can find that the averaged value of the induction field has a strong relation to the results of the questionnaire. This result means that the induction field plays an important role to estimate the position of the gaze concentration.

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This paper describes first about the generalization of robot posture detection using inclination sensors, and second, the trajectory tracking control on a spiral road using that inclination sensor information. There is a cross talking, and the inclination sensor data does not show the robot posture angles directory. The relation between roll, pitch, yow sensor outputs and the three angles of the posture has been clarified. The result shows that there is a relation between these three sensor data. One of these three sensor data is subordination and two inclination sensors are enough for posture detection. The relation between the distance from the spiral center and robot posture on the spiral road is also clarified. The trajectory tracking control has been achieved successfully by using that trajectory radius and deviation angles detected by a couple of inclination sensors. This sensing method has an advantage because required data is obtained only from the road surface itself therefore there is no need of additional guiding road structure such as fences, center lines, or markings.

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This paper presents a cooperative control method for a multi-agent robot system. The concept of the method is based on evaluation information on an objective of multi-agent system. Robots communicate self-evaluation information on the objective each other. Each robot calculates global evaluation information using shared self-evaluation information of whole robot. The method enables robots to perform flexible cooperation in dynamic environment. Its usefulness is verified by applying the method to the soccer playing robots for the middle size league of RoboCup. It was confirmed that the effective and flexible cooperative behavior among the heterogeneous soccer robots are realized with proposed method.

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This paper presents a path following feedback control method with a variable velocity for a cooperative transportation system with two car-like mobile robots. The path following feedback control method previously presented makes all the state variables of the transportation system be asymptotically stable by feedback control except its position along a path under the precondition that its moving velocity along the path controlled by feedforward is non-zero constant. In order to enable the transportation system to make a smooth start and stop, it is necessary for it to vary its moving velocity continuously. Especially, the slippage between the driving wheels of the transportation system and the floor causes its moving velocity to be slower than its desired moving velocity so that it has a deviation of its position from its desired position along the path by feedforward control. Therefore, we modify the feedback control method previously presented. In the modified feedback control method, all the state variables of the transportation system are controlled by feedback and their asymptotical stability is guaranteed and furthermore, the deviation of its position from its desired position along the path because of the slippage between its driving wheels and the floor is compensated and such deviation is converged into zero by a new feedback control loop in which its moving velocity along the path is variable. We have developed an experimental apparatus of the transportation system and verified the validity of the feedback control method with a variable velocity experimentally.

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A passive running robot can run down a gentle slope with no energy source without gravity. The trajectory of its running motion is a limit cycle. Therefore, passive running may give us an important insight to develop the biped running robots. For example, when we throw a bar to the ground, it can jump rotating. This phenomenon is called "hinged-movement". In this paper, we focus on passive running based on the hinged-movement. First, the hinged-movement is confirmed by experiment, and is modeled. Secondly, passive running based on the hinged-movement is demonstrated by experiment. Thirdly, the fixed point of passive running is derived analytically. Finally, the stability of the fixed point is demonstrated by simulation.

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This paper considers the problem of controlling both the planar position and the attitude of an underactuated airship with a reduced number of actuators in the presence of a persistant wind disturbance. The airship is a nonholonomic system described by a set of nonlinear equations. A smooth and time-varying coordinate transformation and an integrator are utilized to reduce the disturbance rejection problem of the airship to a simple stabilization problem of a linear time-invariant system. A new feedback controller with integrator provides both global stabilization of the airship system and global asymptotical rejection against the wind disturbance. The proposed design method is simple and straightforward. Experiments are performed to validate the effectiveness of the proposed controller.

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In this paper we address the development of a finish machining support system that can operate without machining mistakes for the limited production of diversified products. The machining is supported by a haptic device. One challenge is that it is necessary to separate the force sensor output that exists in the operation force from the machining influence force. We propose a control method to remove the influence of the rotation tool disturbance force from the operation force by using adaptive modeling, which estimates the force of rotation tool friction torque in the tangential direction of the machining side from the contact force in the normal direction of the machining side. The effectiveness of this research is shown by a machining experiment.

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Driving attendant-propelled wheelchairs has large physical and mental burden. So its usage is limited in short time and small area. To reduce the burden, it is very important to employ auxiliary assisting device to assist propelling. The development of the device according to attendant's performances, needs well-organized estimation of the propelling load under various operation. To validate the load in various conditions on real road is difficult to carry out. We propose a newly motorized treadmill to simulate the various road conditions based on an attendant-wheelchair model. We investigate and organize the various propelling load on the treadmill, then develop an attendant model for design of auxiliary assisting device. From our results, we found that attendants autonomously regulate propelling force by subjective physical load, and validated the model. Finally, our proposed attendant's model can successfully estimate the propelling load on various roads, and apply for the design of assisting device.

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In this paper, we propose a passive gravity compensation mechanism with a slider crank mechanism and a compression spring, which named "Compression Type Mechanical Gravity Canceller (CT-MGC)". The CT-MGC has several advantages in comparison with the original MGC. First, the new mechanism generates accurate weight compensation torque as same as the MGC without wire and pulley, because it consists of rod-driven mechanism. Second, the new mechanism can be installed into heavy manipulators or carry heavy loads while ensuring high rigidity and safety, since there is no risk for amputation of wire. From development and experiments of a single link model equipped with the CT-MGC, it is clarified that this revolutionary device succeeds to shift basic concepts of weight compensation mechanism from "raise tension" to "push up".

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Baby strollers are essential tool for transportation of infants. However, present public environment is hardly comfortable for baby stroller users. So, the stroller users sometimes feel danger and physical strain, because they can not handle the strollers. This research shows that operability of the baby strollers in several environmental conditions, such as cross slope and ruggedness road, can change by adjustment of the baby stroller dimension. First, a usability criterion using a manipulating force ellipsoid is designed and a variable dimension stroller developed. Next, by using the criterion and the stroller, its turning motion on flat plane and straight motion on both cross slopes and ruggedness roads are measured and evaluated. Then, it is confirmed that operability of the stroller in each movement can change by adjusting the size parameters of the stroller. Finally, the relationship between environmental conditions and stroller features is clarified, and guidelines for appropriate usage in consideration with physical characteristics of the user are provided.

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Herringbone grooved aerodynamic journal bearings have better stability characteristics than plane aerodynamic journal bearings. In addition, the use of the flexibly supported bearings is one of the efficient way to improve the bearing stability. Therefore, the combination bearing systems have prospects of realization of ultra-high-speed operations. The purpose of this work is to evaluate the effect of the external stiffness and damping elements on the bearing stability. The Voigt rheological model was used for the external elements, in which the stiffness and the damping were treated as the linear elements. It was cleared that the stability boundary of the herringbone grooved aerodynamic journal bearings supported by the suitable stiffness and damping elements can be heightened more than three times compared with the rigidly supported bearings.

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The characteristics of monolayer liquid lubricant films coated on magnetic disks are basically determined by their interactions with disk surfaces. If the strength of the interactions could be patterned by ultraviolet (UV) irradiation through a photomask, it would be possible to attain desired tribological performance by rational design of the pattern. In this research, we developed coarse-grained molecular dynamics simulations to investigate the effect of masked UV irradiation on the distribution of monolayer lubricant films coated over solid surfaces. Consistent with experimental results, the simulation results showed that masked UV irradiation induces molecular flow from non-irradiated toward irradiated areas, and thereby a patterned surface structure with thicker lubricant in the irradiated area than in the non-irradiated area. The lubricant films, however, remained monolayer even in the UV-irradiated area. Our simulation results demonstrated that, rather than stacking of lubricant molecules, the patterned surface structure is caused by the stretch of the lubricant molecules in the film thickness direction following the increase of molecule density in the irradiated area.

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The lapping process is one of traditional finishing process for improvement of geometrical tolerance and surface roughness. Most of lapping process is conducted by skilled worker as a manual process at present. So, productivity of this process is very lower than other mechanized process and difficult to control. An automated lapping system and optimized lapping slurry for this system were developed from these reasons. The cemented carbide (V 10) was lapped as mirror-like surface using the system with best condition decided from several pre-experiment. In this study, we propose an estimation approach of limit surface roughness and improvement speed of surface roughness on each material without pre-experiments. The limit surface roughness of lapping theory is compared to experimental value. A time constant of improvement curve of surface roughness is estimated experimentally from lapping conditions. Relationship between initial surface roughness Rz_<ini> and limit surface roughness Rz_<lim> was researched. Finally, the estimation approach of them was established by confirmed experiment. It is concluded from the result that; (1) Limit surface roughness is calculated according to the lapping theory. (2) Time constant of improvement curve of surface roughness can be also estimated by lapping conditions. (3) It was become possible to lap without the excess machining and the worsening of form accuracy.

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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 either vulcanized rubber or 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. In this study, in order to decrease the friction between barrels and gaskets under unlubricated condition, we treated PP and TPE for medical use by a surface fluorination with PFPE (Perfluoropolyether) and excimer lamp. The effect of the treatment was estimated by making friction test, analyzing FTIR spectrum and measuring surface free energy. As a result of experiment, it was confirmed that the friction coefficient between fluorinated TPE and non-treated PP is decreased by 50%.

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In this paper, we examined the relationship between surface roughness and particle adhesion behavior by a proposed experiment. Five kinds of SiO_2 spherical powders (powder diameter: 0.2, 0.5, 1.0, 1.5 and 2.0μm) and stainless steel plates with seven kinds of surface roughness were used for the invetigation. The effect of humidity, electrostatic force and van der Waals force on the particle-steel adhesion behavior was also examined. The experimental results showed that van der Waals force was relatively important to the adhesion behavior compared with two other effects. The adhesion ratios of SiO_2 powders to polished stainless steel plates were measured. The adhesion ratios depend on the surface roughness and the particle diameters. The adhered particles on the steel plate were observed by SEM in order to examine the adhesion mechanism of SiO_2 particle on the polished stainless plate substrate. As the result, 0.4-1.0μm particles were easy to adhere independent of surface roughness and nominal powder diameter. The result indicates that adhesion behavior of powder depends on the adhesion force of 0.4-1.0μm particles that are changed by the surface roughness of the steel plate.

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In shearing, the crack occurrence may be controlled by elevating a hydrostatic pressure of a material near tool cutting edges. In the progressive die forming, shearing phenomena is affected by pre-punching station. Then the influence of pre-punching on shearing characteristics was investigated by the experiments and FEM analysis. The results of this study clarified the followings. With increasing of diameter of pre-punched hole, die side crack earlier occurs and punch side crack later occurs. This tendency agrees with the magnitude of hydrostatic pressure at punch and die cutting edges. Change of hydrostatic pressure mainly depends on decreased rigidity of pre-punched hole material to be sheared. It was also ascertained that the counter punch mainly affects the punch side crack occurrence.

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In this investigation a high efficient mirror machining process with providing above 20kHz ultrasonic vibration and 20-50Hz low frequent vibration to fine abrasive stone, has been created and named "Superposition superfinishing (SSF process)". This machining process consists of the first cutting process (SVC process: superposition vibration cutting) and the second mirror machining process (SF process: superfinishing). To finally obtain a high efficient and high precision mirror surface with smoothness, more fine uneven surface roughness on first cutting process is desired, because the mirror finishing time on second process can be reduced. Until now, in several experiments it was practically observed that surface roughness by superposition vibration cutting is smaller than that by superfinishing without stone loading. In this report, some experiments have been examined to confirm this inproving effect in detail. Experimental conditions are as follows: Rotational frequency of work: 60-950min^<-1>, Work diameter (material): φ35mm (SKS3, H_RC47), Frequency F and Amplitude A of Low frequent vibration: 0-25Hz, 0-1mm, Frequency f and Amplitude a of ultrasonic vibration: 0-46kHz, 0-7.5μm, Stone Pressure P: 24.5-196kPa, Stone: WA(600-3000)RH(20-80)V, Machining fluid: Light oil. In this paper, it is confirmed with analyzing and experiments that surface roughness by SVC process can be improved in comparison with SF process without stone loading.

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Cu and Fe shape-memory alloys, as well as Ni-Ti shape-memory alloys, have been developed thus far, however, their workability is poor. An attempt has been made to improve the drawability of shape-memory alloy wire by conventional wire drawing and roller die drawing. We prepare Fe and Cu shape-memory alloy wires. The results are summarized as follows, 1) By removing the brittle layers on the Fe alloy wire surface, thereby, the drawability can be improved. 2) Under optimum drawing conditions, the drawing limit of Cu shape-memory alloy wire could be raise by up to 90%. 3) The shape-memory alloy wires obtained are expected to be applied to various fields, such as springs that can be used as actuators.

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Shear spinning is usually performed while the flange of the workpiece is kept in flat and perpendicular to the rotational axis. This paper proposes a spinning method using force control with a coordinate transformation for shaping products which have inclined processing part, and evaluate the basic feature of the process by forming of obliquely truncated cone shells. The thrust force along a flange of a product is maintained constant value using impedance control method, while the position of the roller is constrained on the inclined flange plane. This process is also able to apply for a non-axisymmetric die, and neither three-dimensional data of a die nor tool trajectory data is needed. The effectiveness of the proposed method is experimentally verified in forming of pure aluminum sheets of 150mm diameter and 1mm thickness. In comparison with the known process which can make similar shape proposed by authors, this method can form desired shapes with higher profile accuracy.

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This study proposes a calibration method of parallel mechanisms for machine tools by response surface methodology (RSM). RSM finds the optimum solution by employing a response surface that approximates an input-output relationship of a certain problem. The methodology obtains the response surface from a small number of data that are selected by experimental design. The present study approximates a relationship between the target postures and the output errors of a parallel mechanism by response surface. Furthermore, the calibrated control values are obtained from the response surface. It is beneficial that the output errors of a parallel mechanism can be estimated from a small number of measured data by RSM because the measurement of its posture is so difficult. This study shows the proposed method can distinctly improve the positioning accuracy of a spatial 3 dof parallel mechanism from a small number of the measured data by numerical simulation, and the availability of the proposed method is actually confirmed by the calibration of a machine tool consisting of the parallel mechanism.

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