Recently, with the rapid progress of the computer hardware and 3D-CG software technologies, the 3D design system such as CAD and CAE, is popularized in manufactures. However, 3-dimensional data is produced now using man-machine interfaces, for example a 2-dimensional mouse and a keyboard, and using intricacy combined operations of those devices. So, designers said, it is far from sensate creation. Spark of imagination doesn't get interested. Therefore, little artistic especially jewel designers create using the 3D design system. In this paper, we describe the Virtual-glove using ERF (Electro Rheological Fluid) to feel the 3D virtual objects on operator's hand, propose the new actuator device for the small and lightweight virtual glove. Then we show the statistical analytical results about size of man's hands, and characteristics of ERF to reaction force. The results is shown the Japanese Boundaries Family was led, and the principle of reaction force using the device was clarified.

View full abstract

In structural designs considering thermal loading, maximization of temperature diffusivity in structures is one of the most important essential factors in reducing operating temperature and maintaining product durability, in addition to the usual maximization of stiffness that optimal designs achieve. In this paper, a topology optimization method is constructed for thermal problems considering generic heat transfer boundaries, including heat convection boundaries, based on the homogenization method. First, the topology optimization method for thermal problems is discussed using a homogenization method that assumes a continuous material distribution. Next, a new objective function that can take into account heat transfer boundaries, such as temperature-constant and heat convection boundaries, is proposed, based on the concept of a total potential energy maximization problem in the structural problem, and an optimization problem is formulated using the proposed objective function. An optimization algorithm is constructed using the Finite Element Method (FEM) and Sequential Linear Programming (SLP). Finally, several numerical examples are presented in order to confirm the usefulness of the proposed method.

View full abstract

Lost motion is one of the major disturbances to the contouring accuracy of NC machine tools. NC machine tools with large travel area sometimes show position-varying lost motion. Conventional backlash compensation with constant parameter applied to that lost motion causes contouring error due to inadequate compensation. This paper presents a model of a two-body system with a position dependent spring and position dependent friction that exhibits position-varying lost motion, and a compensation method for that lost motion introduced from the model. Tuning method for the compensation parameters is also proposed. Stiffness of the position dependent spring is calculated from specs of mechanical parts, such as a ball screw, bearings, a coupling, so on. The position depend friction is measured as a motor torque in a straight motion at a relatively slow constant feed rate. Contouring accuracy in a circular test of NC machine tools, measured by a two-dimensional grid encoder, demonstrates the improved performance of the proposed method.

View full abstract

We propose a design method of a nonlinear anti-windup controller for discrete-time systems subject to l₂ disturbances. The proposed controller is composed of a gain-scheduled feedback control law and a standard observer. The gain-scheduled control law has a structure that a high-gain control law and a low-gain control law are interpolated by a single scheduling parameter. The scheduling parameter is computed on-line by solving a convex optimization problem based on the information of the state variables estimated by the observer. We show that, by using the proposed control law, both a large region of attraction and high distubance attenuation performance can be achieved.

View full abstract

The authors propose here a new method for reducing both impulsive noise and white noise by use of M-transform and wavelet shrinkage. M-transform is a new signal transformation proposed by the authors, and any periodic time signal can be considered as the output of a filter whose input is an M-sequence. By using the properties of M-transform, it is shown that both impulsive noise and white noise can be eliminated by use of first M-transform and then wavelet shrinkage. This method is applied well to the signal obtained in Atomic Force Microscope (AFM) signal which sometimes contains many impulsive noise and white noise. From the results of the experiment, it is shown that the proposed method is very efficient for impulsive noise reduction.

View full abstract

It is specially analyzed about the problem of the pitch of stationary sound in the acoustic analytic subjects of brass instruments. It is modeled as a combination of the conical horn elements for the trumpet. First, the end of mouthpiece is set as the closed end, the resonance frequency is calculated as a characteristic value of the modeled trumpet by the technique of Cavity Resonance. Next, when it is played, the effective input impedance at the end of mouthpiece and those relative angles are calculated. Based on these characteristics, quantitative examined considerations are added to the playing methods, and a blowing pattern is set up. Furthermore, it is calculated the virtual additional length for the end of mouthpiece. It is examined correspondence with the playing methods of brass players. This playing method is taken into consideration, the CAD system for the pitch design of trumpet is built, and a suitable example to the pitch design is shown, with the utility of the system. The validity of a blowing pattern is shown.

View full abstract

This paper proposes a new Electric Power Steering (EPS) control strategy that enables improvement on steering-wheel returnability. If we use a conventional EPS controller, frictional loss torque in the steering mechanism reduces steering-wheel returnability, which drivers occasionally perceive as unpleasant. To improve steering-wheel returnability for EPS-equipped vehicles, we analyze the relationship between vehicle parameter and returnability. According to this analytical result, we develop a new control strategy based on estimation of aligning torque generated by tires and road surfaces. We experiment with this proposed control algorithm using a test vehicle and confirm that it enables improved steering wheel returnability as well as better on-center feeling.

View full abstract

Nowadays, various suspension control technology have been developed such as active suspensions, active stabilizers. As an alternative to hydraulic actuator for suspension, electromagnetic device have been developed. Electromagnetic devices are attracting many researchers' attentions by their high responsiveness, controllability, energy saving performance, and so on. Besides these advantages, electromagnetic devices can be connected to each other very easily. Therefore, the authors focus on this characteristic of electromagnetic device and propose a method to use linked two electromagnetic devices as a roll stabilizer. Then the automobile can stabilize its rolling performance without a roll stabilizer, which increases the mass of the car body. Through basic experiments with two motors and control circuit, the performance of proposed system is examined. The results indicate the linked electromagnetic devices can be operated as the roll stabilizer. Numerical simulations of the turning automobile is carried out, and the results indicate the proposed system is effective.

View full abstract

It is well known that the vibration and the noise of agricultural machinery during running on a road is strongly influenced by the lug form of the tire. Many studies were carried out on the characteristics of Automobile Tire, but few studies have been carried out on Agricultural Tire. In this research, the vibration characteristics of an Agricultural Tire is studied by experimental modal analysis method. Then, the tire is modeled as a thin, cylindrical beam with multiple radial springs attachments to consider Tire Lugs, and a calculation procedure based on the receptance method for obtaining the natural frequencies is formulated. Furthermore, fundamental values of the tire are identified by the optimization method.

View full abstract

To reduce the running vibration of Shinkansen train, especially in tunnel sections, a potential of inter-vehicle lateral dampers installed between car-bodies is examined. Here, it has been regarded to be difficult to improve the ride quality in both open and tunnel sections only with lateral dampers or anti-rolling devices between car-body and truck. An equivalent single-car model, that represents an intermediate car in infinite-length train, is utilized to examine the effect of the inter-vehicle lateral damper and specify its damping coefficient. Then, a practical train model composed of eight cars is used to verify the tendency analyzed by the equivalent single-car model. As a result, qualitative effectiveness of the equivalent single-car model is confirmed, and it is shown that the inter-vehicle lateral dampers installed under the gangway have the possibility to reduce the vibration in tunnel and improve the riding comfort.

View full abstract

Hybrid magnetic bearing is recognized as an efficient one even with wide airgap and suitable for low loss and wide gap application. Previously sub-pole type IPM hybrid magnetic bearing has been proposed. However the sub-pole produces bias flux and cannot produce any control force. To overcome this problem, two new types of hybrid magnetic bearings are proposed which have permanent magnets within their stator cores. This paper introduces structure and principle of the proposed magnetic bearings. The geometric parameters of these new type bearings are optimized using FEM analysis. The experimental setups are made based on these analytical results. The fundamental characteristics are measured and compared with the estimated bearing performances. The results show stable levitation and good levitated rotation.

View full abstract

In this paper, we propose a design method of the fault detector of the injection unit. The injection unit is controlled as a speed control system with a reaction force sensor. We construct a residual generator by using a disturbance observer, and the residual signals are used for fault detection. The properties of the transfer functions from the sensor output and the control input to the residual signals are analyzed, and the frequency characteristics of the speed control system and that of the reaction force are utilized. We indicate the possibility of the fault isolation structurally by showing the design method of the post filter and the condition of the band width of the system. Our method can be executed on the normal operation mode. Usefulness of our method is verified by experiments for the actual system, and the fault detection and isolation for the several fault modes are demonstrated.

View full abstract

The paper proposed and developed a flexible ER microactuator called FERMA for in-pipe working micromachines, medical micro robots, and so on. An ER microvalve has a narrow flow channel with electrodes and controls flow of homogeneous electro-rheological (ER) fluid using the apparent viscosity change in an electric field. A conventional ER microactuator that consists of the ER microvalve and a fluid microactuator features simple structure, however, it is difficult to realize a flexible actuator due to the rigidity of the ER microvalve having sufficient channel length for pressure drop. To overcome the problem, we proposed an FERMA having a flexible ER valve called FERV inside a flexible tube. In the proposed FERV, an insulating thin flexible spacer with a slit was sandwiched by a pair of thin electrode sheets and they were wrapped by rubber. The slit in the spacer and two electrode sheets formed a flow channel for an ER valve. In this paper, we fabricated a two-port FERV with 4×3×9 mm³ in size and confirmed the low flexural rigidity and the static characteristics experimentally. Then, we fabricated a three-port FERV and clarified the static and dynamic characteristics experimentally. Finally, we fabricated an FERMA with the three-port FERV and a bellows type flexible tube with 8 mm outside diameter and 8 mm length and investigated experimentally the static and dynamic characteristics in linear and bending motions. The feasibility of the proposed FERMA was demonstrated.

View full abstract

It is necessary to ascertain tactile texture recognition of humans in developing tactile devices that create or detect lifelike texture. Tactile texture has been researched in the field of psychophysics and neuroscience, but its function-structure relationship cannot be still uncertain by their method. In this paper, modeling of tactile texture recognition mechanism by numerical simulation system is discussed. The model is made of two parts ; reception part and perception part. Reception model is built by finite element model of human finger and filters emulating mechanoreceptors response properties. Perception model is built by feed forward type of neural network with 3 layers. This network is considered for configuration and module structure of primary somatosensory area. Finally, validity of the total model is confirmed by comparing output data of this model to the result of sensory evaluation.

View full abstract

The inverse dynamics based motor control strategy in human articulatory motion has been investigated. As the plant for this control application, dynamic model of human articulators consisting of lip soft tissue with related muscles and bones is introduced. The continuum of lip soft tissue is represented as a discrete model approximation composed of networked point masses interconnected via viscoelastic elements. Stiffness of every viscoelastic element is adjusted to ensure the compatibility in static deformation between discrete model and its continuum prototype. Simulation of forward dynamics by activating ingeniously selected muscle set induces a mimic of actual human speech articulation, called pseudo-speech motion. As a mathematical description of the human speech acquisition, articulatory control simulation based on iterative estimation of muscle motor command is presented. Inverse dynamics driving iterative estimation lets the articulator dynamic model put into practice an articulatory motion, induced by the estimated muscle motor command.

View full abstract

Lure fishing and fly-fishing have been positioned as sports deliberately different from the traditional Japanese fishing-style. In the case of fly-fishing, casting is the element which anglers must master in order to cast a fly, done so by using the weight of a line. This study uses experimental and computational analysis to investigate the dynamic behavior of a fly line. Fly-fishing constitutes various elements, but the importance that casting holds is extremely large. Fling speed, the casting process and the loop shape of the line while in flight are important for the proper presentation of flies. Moreover, the shape of a fly line is also important for a long cast or controlled cast. However, it is difficult to grasp the phenomenon or to make a numerical model because a fly line is an object of flexible string. Therefore, the most suitable casting method will be clarified from the viewpoint of sports engineering and human dynamics. In addition, measuring an angler performing movements with a flexible object such as a rod or a line is difficult. So establishing a method to measure the dynamic behavior precisely is also one of the purposes of this study. For the past study, motion of wrist and upper arm had been fixed to make a simple numerical model. However, upper arm, forearm and wrist move in the actual fishing field. In this paper, three input numerical model considering arm motion is established.

View full abstract

In this paper, we introduce a new mechanism of quasi-passive-dynamic-walking machine which uses actuators just only at ankle joints. First, we analyzed about basic mechanisms of passive dynamic walking. So, we made and modeled the passive dynamic walking machine that walks down the slope. Experiment of the walking was compared with the numerical analysis, which showed the validity of the model. And, these were analyzed from the energy point of view. Second, we proposed a new control method of quasi-passive-dynamic-walking based on the result of analysis of passive dynamic walking. The new method was confirmed by the numerical analysis on a horizontal plane. Finally, ankle-driven type of quasi-passive dynamic walking machine was designed and developed. Experiment of the walking on the horizontal plane was done. That result shows the validity of the idea.

View full abstract

In this paper, we demonstrate the effects of the affect display of anger by virtual facial image synthesis with facial color enhancement and expression on the basis of the analysis of facial color under the emotional change of anger. First, we examine the relationship between the change in the facial color and the physiological index of facial skin temperature, which indicates the change in the blood flux under the emotional change of anger. Second, on the basis of this result, we synthesize 11 enhanced facial color images by using an average facial image of 68 females with their eyes and mouth masked out ; we evaluate the effectiveness of these images through a sensory evaluation by performing a paired comparison. Further, we synthesize enhanced facial color images by using the average facial image in which only the eyes were masked out and evaluate the correspondence between the lip color and facial color after performing the enhanced facial color synthesis for an affect display of facial color through a sensory evaluation. Finally, we synthesize the facial expression of anger with enhanced facial color by using the average facial image and evaluate the effectiveness for the affect display of the image through the sensory evaluation of seven-point bipolar ratings.

View full abstract

Determining joint angles and velocities of a redundant robot system is so far a difficult control issue, especially in attempting to generate natural motions. This paper presents two conventional control methods for a redundant upper limb robot system utilizing the change in manipulability of the finger to execute a task in a free space as well as in a restraint space. In order to clarify and compare characteristics of these algorithms, theoretical analysis and experimental results are demonstrated and evaluated under (1) the viewpoint of giving motion priority to arm or finger, and (2) the calculation viewpoint between a Heuristic Method, which is based on approximate estimation, and a Steepest Decent Method. Two new control methods reducing disadvantages of the above conventional algorithms are also proposed and their utility is verified.

View full abstract

We propose a pressure distributed sensor as a tactile sensor for a five-fingered robotic hand like a human hand. The sensor has simple, three-layer structure, which composed of an urethane gel, a pressure sensitive rubber under the gel, and an electrode sheet at the bottom. The arrangement brings high productivity and smooth maintenance. The electrode sheet also provides high ratio of the detection area to the sensor and high sensitivity. First, the characteristics of response time and accuracy are investigated by ground tests. Secondly, a shape recognition method with the sensor is proposed. Finally the effectiveness and validity of the proposed method are demonstrated through laboratory experiments.

View full abstract

Inspection of industrial piping is a well-known and highly practical application of robotic technology. The present study examines a mechanism that allows a pipe inspection robot to move along the outside of a pipe. Robots especially designed to inspect the surface of piping have recently been realized by some companies, and are in practical use as mechanical piping inspection devices in various plants. These robots are equipped with ultrasonic diagnostic equipment that can measure the thickness of the pipe along its surface. However, they are able to move by manual operation only. Such robots cannot be applied to pipes with flanges and valves, etc. In this paper, we have designed a mechanism that enables robots to traverse flanges, rise along vertical flanges, and move along the underside of the piping. The proposed robots are composed of three connected units. Our robots move by means of magnetic elements (magnetic wheels or electromagnets).

View full abstract

A compensator, which can support the collaborative work of human and machine in order to improve the maneuvering performance and the response of human-machine system, has been proposed and named as “collaborater”. In this study, human dynamics is proposed as the modified Delayed Feed-Forward (DFF) model which is identified by both the experiments and the numerical simulation concerning to the manual control for the single arm type rotating handle machine. Using the modified DFF model, the collaborater can be designed based on the 2D0E-PID controller design technique. The performance of proposed method examined through the experiments.

View full abstract

Continuous Passive Motion (CPM) is a surgical treatment or physiotherapy after surgery or trauma. Most of the CPM devices used for treatment of the elbow joint have one degree of freedom in flex-/extension. For this reason, the patients are limited in pro-/supination of the forearm with flex-/extension of the elbow joint according to the arm movement of the CPM device. In this paper, a novel impedance control scheme of pro-/supination is proposed for CPM device with flex-/extension and pro-/supination. Impedance control is designed for the reference trajectory measured from a normal subject, and the parameters for impedance control are designed in order to suppress the excessive force at the limitation of range of motion. The effectiveness of the proposed scheme is evaluated by experiments.

View full abstract

This paper aims at acquiring robust feature for rotation-, scale-, and translation-invariant image matching from a space-variant image by a fovea sensor. A proposed model of eccentric compensator corrects deformation in a log-polar image when the fovea sensor is not centered at a target image, that is, eccentricity exists. An image simulator in discrete space implements this model by its geometrical formulation. This paper also proposes Unreliable Feature Omission (UFO) using Discrete Wavelet Transform. UFO reduces local high frequency noise appeared in the space-variant image when the eccentricity changes. It discards coefficients when they are regarded as unreliable, based on digitized errors of the input image by the fovea sensor. The first simulation estimates the compensator by comparing with other polar images. This result shows the compensator works well and its root mean square error (RMSE) changes only by up to 2.54 [%], in condition of the eccentricity within 34.08 [°]. The second simulation shows UFO works well for the log-polar image remapped by the eccentricity compensator, when white Gaussian noise (WGN) is added. The result by Daubechies (7.9) biorthogonal wavelet shows UFO reduces the RMSE by up to 0.40 [%] even if the WGN is not added, when the eccentricity is within 34.08 [°].

View full abstract

The degradation of tooth surfaces and the abnormal tool wear sometimes occurs in dry hobbing. This paper investigates the transient phenomenon of chip formation and behavior in simulation tests of hobbing by using a high-speed video camera. The jamming of the chip between the tooth surface and the cutting edge causes scratches on the tooth surface and the chipping of a cutting edge so on. The figures of chips produced by hobbing are classified roughly into the “U”, “J” and “I” types. This paper presents findings of the “J” and “I” type-chip movements in flytool simulation tests. The “J” type-chip is removed with the two cutting edges both top and a side edge. In the “J” type-chip, a part of end side of the chip produced by the top cutting edge is often jammed into the finished surface by pushing from the chip at the side cutting edge. The “I” type-chip flows from the root to the tip side of the cutting tooth, and the pointed end of the chip is jammed into the space between the finished surface and the relief face of the cutting tooth, in down cut. In up cut, the chip flows to the root side of the rake face, and possibility of jamming is shown as well as the case of down cut.

View full abstract

Electro-Rheological Gel (ERG) is a functional material which changes its surface frictional property according to applied electric field. The one-sided pattern electrodes is a very useful idea to free sliding or rotating parts from wiring arrangements and contribute to extend the application field for ER materials. Application device of ERG is classified into two main groups; linear motion type and rotating motion type. In order to obtain the high ERG effect in the applications, it is necessary to design the pattern of one-sided electrode in which electric field is efficiently applied to ERG. In this study, equivalent circuit model of one-sided pattern electrodes on condition of using the opposite metal plate is proposed for these types of application. On basis of this proposed model, the one-sided pattern electrodes are designed and the validity of this electrode design method using the proposed model is verified by means of a numerical and experimental analysis. The general-purpose tool for the analysis of electric and magnetic field 'ANSYS 9.0' is used.

View full abstract

Several methods of measuring the bolt loads were already proposed and some of them have been commercially used. To measure bolt loads accurately acting on the bolts profile curves of bolt top surfaces were measured with a stylus profilometer. In the experiments the bolt top surfaces were ground or polished. The bolts were also grooved on the bolt bearing surfaces to promote the deformation of the bolt heads. A special loading device to apply tension load to the bolts was built up on the mechanical stage of the profilometer. The profile curves of the bolt top surfaces were measured at the various tension loads. On the other hand, finite element analysis was conducted to obtain the profile curves of the bolt top surfaces. The measured profile curves of the bolt top surfaces were fairly in good agreement with the calculated ones. There was a less variation in the measured profile curves in the case of bolts with groove.

View full abstract

Almost holes such as cooling channels of a mold or hydraulic equipments are machined by drilling process. It is desirable to establish a cooling channel located within a constant distance along a curved surface of a cavity or a core. However, the drilling process cannot make curved holes. Therefore a curved hole machining technique is required. Some kinds of curved holes machining process have been proposed, but they have not reached the practical level. The objective of this study is to develop a curved hole processing method using the electrochemical machining with an electrode posture control system. The posture of an electrode is controlled with a stepping motor and the wire. A simulation technique to predict the electrode position in a hole and the hole path was also developed. It was shown that the proposed system is able to make curved holes with the reasonable efficiency and accuracy.

View full abstract

Warm press forming is very effective to improve draw ability of magnesium alloy. Generally, increasing the temperature of metal makes it soften. In warm press forming, heating the blank on the die decrease its deforming resistance. On the other hand, cooling the blank on the punch increases its tensile strength of sidewall of the product. Draw ability is increased by these methods. But there is a forming limit in this process. Because, excessive high heating of the die increase the temperature of the sidewall, then its strength is decrease. Similarly, high punch speed increase the temperature of the sidewall, then draw ability is decrease. In this study, warm press forming of magnesium with assist of direct cooling and induction heating is investigated. Sidewall of the product is directly cooled by water. Temperature of the blank on the die is increased very quickly and locally without increasing the temperature of the side wall by induction heating. The optimum condition and its performance of this forming system are fisrt investigated by FEM simulation. And real press test is performed for confirmation. It is concluded from the results that (1) Warm press forming with assist of direct cooling and induction heating can increase draw ability from D. R. 3.0 to 4.0 and D. R. 2.4 to 3.2 each punch speed 2.5 and 10 mm/s respectively, (2) Scheduled induction heating power that decided using FEM simulation improves the thickness distribution of sidewall of drawing cup.

View full abstract

A diamond blade is widely used as a cutting tool for slicing materials such as stones, ceramics and glasses in a straight line. Generally, it has many slots and their functions have the effect of reducing cutting resistance and increasing the tool life. Against this background, the application of photocurable resins to the blade with slots has been examined on both single-layered blade and multi-layered blade. In this paper, a combined-structure blade was proposed and experiments were performed to investigate cutting characteristics during dicing. As the results of a series of cutting tests on silicon wafers utilizing the combined-structure blade, the remarkable improvement of cutting performance was verified.

View full abstract