[in Japanese]

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[in Japanese]

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The present paper deals with constructive method of three-dimensional shapes learned from nesting behavior of paper wasps. Paper wasps can construct comb of hexagonal cells with regular arrangement. This paper describes observation and analysis of nesting behavior. Observation results show that characteristic movements of antennae affect the shapes of nest and that nesting behavior connect with so called “taxis.” Computer simulation was conduct to ascertain relationship between constructed shapes and simple moving rules. The results are as follows : 1. Antennae are used in each process of nest construction as a wide variety of tools. 2. The simulation results show that simple moving rules such as “taxis” lead to the construction of straight line, curved line and hexagonal line, starting from the shapes of the base as a mark. 3. Construction algorithm of three-dimensional objects based on a simple moving rules is derived from analysis of paper wasps nest construction behavior. It is considered a method for construction of three dimentional shapes starting from an arbitrary base shapes as a mark.

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The use of the electric-mobility-classification method for sizing 0.1 μm mono-disperse particles was examined experimentally. It was suggested in a recent study that, in contradiction to the well-established theory of the electric mobility classification, the experimentally observed particle size depended slightly on the sample aerosol flow rate. In order to investigate this phenomenon, a statistically designed experiment was conducted in which precise setting of the air flow rates was made possible through a newly devised air flow configuration. It was confirmed that the measured particle size did decrease as the sample aerosol flow rate increased. The observed variation in the apparent size was about 0.7%, when the aerosol flow rate was varied from 0.3 L/min to 2 L/min.

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A new technique for reducing vibration of an objective lens actuator on a carriage is developed for optical disc drives. Phase disturbance at frequencies of several thousand hertz resulting from drive reaction forces is discussed. A practical method using only phase disturbance for evaluating modal damping in higher modes is proposed. Calculating modal damping in higher modes by this method is feasible for deciding the modal residue ratio and the level of vibration reduction. A simple structure for isolating the vibration of the drive reaction force of the actuator is designed. A new lens actuator which uses this vibration reduction technique has developed. And a thin-type optical disc drive has developed.

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A micro-step XYθ stage mechanism has been developed. This stage consists of three piezoelectric tube actuators fixed at one end to the vertices of an equilateral triangle on a baseplate. When a single cosine waveform voltage is applied to the three actuators, the quick bending motions in the same direction cause the sample to move forward by frictional force; quick bending motions tangential to the circumscribed circle cause the sample to rotate by frictional force. This stage can drive the sample two-dimensionally and rotate it in μm-order steps. The stage facilitates the positioning of the point to be measured in scanning probe microscopes (SPM). Subsequently, the sample is moved by the same actuators in the usual scanning mode and in precision Z-direction positioning. Thus this stage can be used as a micro-step XYθ stage and as a precision XYZ positioning stage, and also used as a micro-step XYθ stage for positioning a sample in optical microscopy and scanning electron microscopy.

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A fast and fine position control method of an ultrasonic motor has been already studied which uses phase shift input and applies a linear control system. However this method has a drawback in damage of the lining material because the rotor jumps slightly from the stator in an ultrasonic frequency in the neighborhood of a command position. So it is desired to cut down voltage input and to decrease the amplitude of the traveling wave after the coarse positioning is completed. This paper presents a new control method which uses not only phase shift input but also voltage input and varies them using a fuzzy controller. Besides a fast and fine positioning, prevention of abrasion of the lining material was achieved by applying this fuzzy control method.

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The purpose of the study is to measure axisymmetrical form, such as flat, spherical, and aspherical surfaces, by using a contact type form measuring equipment and to evaluate three dimensional form deviations. In the previous paper, the following process of the measurement was described; (1) Sectional curves along concentric circles and diameters are measured. (2) These sectional curves are combined on cross points by the least square method to compensate measuring errors due to tilts and lifts of a specimen. (3) A curved surface is generated by interpolation from sectional curves. In this paper, the accuracy of the experimental equipments is made clear by using an optical flat surface and a glass master sphere. The following facts are revealed by some experiments. (1) The accuracy in flatness measurement within a diameter of 42 mm is about 70 nm. (2) If a tilt of a tangent to a sphere is within 25°, the accuracy in the form measurement is about 110 nm.

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The inverse kinematics is a fundamental robotics. In order to control the position and orientation of the end-effector of a robot, the inverse kinematics solution is necessary. In this paper, work-space is used as the set of reachable positions and orientation of the robot's end-effector, and joint-space is used as the set of reachable configurations of the robot's joint limits. The position and the orientation of a robot's end-effector is defined by a set of the robot's joints angles, that is to say the position and orientation of a robot's end-effect is defined by the mapping from joint-space to work-space. A robot is assured to be non-redundant and the new method is proposed to classify the inverse kinematics solution, by resolving the Jacobian of robot. So the dimension of work-space is equal to the dimension of joint-space. First the method of manifold is used to make the character of joint-space clear. And then, the method of mapping is used to define shape-space that is the base-space in joint-space. And then, the method of mapping is used to make clear the number of inverse kinematics solution. In the last the method above is used to analyse the 2-joint (RR) SCARA type robot and the 3-joint (RRR) PUMA type robot.

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New method for measuring the circular interpolation errors of high precision NC grinding machine is proposed. The measuring device consists of Capacitance Ball Probes, CBP, and capacitive displacement meter. A precision steel ball A is set on the table of the NC surface grinding machine and the other ball B is mounted at the end of the wheel head.While the ball B circles the ball A, the capacitance change due to the motion errors is detected. Since the obtained data are also affected by the floating capacity, which is generated among ball A and wheel head etc., the clearance between two balls, d, has to be set at a very small value, such as d=10μm. When auxiliary poles are set beside the ball A, the floating capacity can be effectively suppressed. Two-orientation method is also proposed to improve the accuracy in measurement. In this method, two sets of data are obtained before and after the change in direction of each ball, and the differences in data between the two are Fourier transformed. The true motion errors are then determined by phase operation. The calculation error originated from this method is assessed and the effectiveness of this process is confirmed by the computer simulation.

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An electrostatic paper feed device was proposed, developed and tested. The device consists of a single 3-phase electrode structure stator sheet which drives paper directly via electrostatic forces. This device's simple structure offers much better space usage than traditional friction roller devices. Moreover, since frictional forces are not essential for operation, this device can transport low friction materials. Because the electrostatic forces are distributed over the entire paper surface, it can also drive paper that is both thin and delicate. PPC paper, printer paper, magazine paper and Japanese washi paper have been tested as transport material and each type could be propelled when the relative humidity conditions were less than 30%, 30%, 40% and 50%, respectively. Since performance is sensitive to humidity changes, this electrostatic technology cannot be expected to replace traditional devices in all circumstances. However, in the case of business machines such as copiers, the merits of employing a much more compact electrostatic paper feed mechanism are clear. In addition to the paper feed applications, it is also expected that this technology can be applied to precision paper positioning systems.

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A new measuring method is proposed for estimation of robot positioning accuracy. The principle of the method is that one point in 3-dimensional space can be regarded as an intersecting point of three intersecting planes. The coordinates of it can be obtained by solving simultaneous equations of the three planes. According to the principle, a system consisting of a laser detector on the target point, two horizontal scanners, one vertical scanner and a computer has been developed. Each scanner is used to rotate the linearly spread laser beam called laser plane. The rotation angle of the laser plane can be measured with high resolution (0.26'') by using rotary-encoder and time-conversion method. Laser detector is set at each target point. When the laser plane is detected by the detector during scanning for each scanner, the rotated angle of the plane is measured to give equation of one of three intersecting planes. Finally, the coordinates of target point can be obtained by solving equations of the three laser planes determined above. Experimental results show that the 1-dimensional measuring accuracy is ±30 μm and the standard deviation of it is 10μm within a range of 1 m at the distance of 2 m from the scanner.

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A new soft-handed vacuum chuck has been developed to allow the precise measurement of the placement accuracies of X-ray masks and wafers, which are deformed by stresses in processes. As their thicknesses are thin, it is difficult to clamp them without deformation. The chuck has three vacuum pinpads that prevent lateral movement and enable a vacuum seal. This set-up enables a lateral clamping force that can bear an acceleration of 0.3 g and clamping without deformation. Deflections of a 3-inch silicon wafer and an X-ray mask substrate with a 30-mm-square window calculated with the finite element method were minimized at the support radius of 24 mm and 29 mm. Using this chuck with a NIKON 3 I laser interferometry coordinate-measuring machine, we can measure the placement accuracies of an X-ray mask and a reticle with good repeatability at less than 20 nm (3σ).

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Selective laser-hardening of steel sheet has been developed. By this method, only selected region of steel sheet can be hardened. So, forming process can be followed by hardening process. It is very effective, because steel sheet can be formed while it is ductile and after that the only region required to be hardened can be heat treated. It is necessary to develop two core technologies ; (1) uniformly heating of selected region of steel sheet and (2) realizing the optimized heat cycle for laser-hardening. As for (3), the special integration mirror for shaping a uniform laser beam of 25 mm × 25 mm square has been developed based on the ray-tracing method. Moreover, the combined optical system, which enlarges the uniformly heated area 9 times as large as the case of a uniform heat source, has been designed based on the heat conduction model for laser static heating. As for (2), the optimum heat cycle including soaking for hardening has been determined. And, in order to realize this heat cycle, a control system consisted of a non-contact temperature detector, a PID (proportional integral differential) controller and a laser power regulator, has been developed. Finally, by this selective laser-hardening method using the special integration mirror and the heat cycle control system, hardness of test piece of steel sheet has been increased from 130 to 200 in Vickers hardness.

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An austempered ductile iron (ADI) exhibits the excellent mechanical properties and the wear resistance. However, ADI has generally the very poor machinability due to the characteristic. This paper describes the tool life behaviour and the wear mechanism, when turning ADI with ceramic cutting tools such as zirconia toughened alumina (ZTA), alumina containing TiC etc. Al₂O₃-TiC tool has the longer tool life at low cutting speeds. In contrast, Al₂O₃-ZrO₂ has the longer tool life at 150 m/min or more, further, the flank wear rate per a cutting distance decreases as rising cutting speeds. In order to investigate this reason, the reaction tests between ceramics and ADI were carried out at 773 K and 1 273 K, in addition the transformation of ZrO₂ contained in ZTA ceramic tool was examined. ZrO₂ consists of a tetragonal phase (T) and a monoclinic phase (M) and the T-phase increases at high temperatures. Therefore, it is assumed that the wear resistance in ZTA ceramic tools depend on a value of T-phase which influences on tool hardness.

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The study deals with a new machining concept by making use of 6-axis control. 6-axis control implies that a cutting tool allows three rotational movements for positioning as well as three translational ones. A 6-axis control machining center equipped with a main spindle capable of tool orientation in addition to conventional 5-axis control structure is developed. A non-rotational cutting tool is mounted at the main spindle to carry out 6-axis control machining, which allows a variety of machining possibilities. In the study, a control software to finish workpieces with sculptured surface in the coarse pickfeed is presented together with cutting experiments. As a result, it is found that 6-axis control machining reveals the possibility of effective finishing.

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Ultra high speed grinding has been attracting attention as a processing method for improving the productivity and for quality on the surface of work. Present study focuses on grinding characteristics of an optical glass under high speed region. Grinding has been carried out using NC grinding machine with a magnetic bearing and also new type grinding wheels have been made in which metal beryllium is used as the core of wheel. Three kinds of wheel have been produced. Experiments are conducted under the conditions ranging from conventional grinding speed to 12000 m/min. It is found that grinding mode varies with increasing the revolution speed of wheel from conventional to ultra high speed one. Ductile mode appearance on the surface ground under the ultra high speed can be seen in which traverse grinding is made using a metal bond wheel.

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Increase in aspect ratio, the ratio of hole length to hole diameter, inevitably results in difficulties with micro drilling of multilayered printed circuit boards (PCBs) such as damage to inner walls of holes, drill breakage and reduction in yield rate and productivity. This paper presents the experimental analysis of a chip flow mechanism for micro drilling of typical composite material PCBs consisting of copper foil, woven glass fiber and polyimide resin, from the view point of the cutting force. Measurement of the cutting force revealed that a complex chip flow peculiar to composite materials results in a sudden increase in cutting torque and thrust, bringing about the above-mentioned damage. This damage can be diminished by smoothing the chip flow during drilling. As a result, through-holes with superior quality inner walls have been achieved, which are free from resin smear on the cut surface of the copper foil, tears at the drilling end, deformation of the copper foil and scoops on the inner walls.

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The analytical method for the prediction of the mechanical state of machined surface layer was proposed. The residual stress and strain are caused by both the mechanical and the thermal state of cutting processes. Thus elastic-plastic deformation analysis and thermal analysis of cutting processes were simultaneously carried out using a finite element method. The tensile residual stress in the cutting direction was generated within the numerically machined top surface. At high speed cutting the flow stress of the primary shear zone ahead of the cutting edge increased because of increasing of strain rate. Furthermore the tensile stress parallel to cutting direction generated just behind the cutting tool was further increased by shrinkage of workpiece surface in cooling process. Thus the residual stress at high cutting speed became larger than that at low cutting speed. The curvature of the machined workpiece after unchucked increased with cutting speed, too. The residual stress and the temperature of the finished surface calculated were in good agreement with experimental data.

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This paper describes the development of a new laser soldering technique for surface mount assemblies. The new technique, which uses a YAG laser beam, has a superior performance. It can be applied to tape carrier package (TCP) assemblies for fine pitch leads and offers a no-bridge soldering process. This paper describes fluxless laser soldering developed for the no-clean assembly process. In this technique a focused YAG laser is used to remove oxides and other contamination from the soldering surfaces. First, the removing process induced by lasersputtering, is experimentally evaluated. The fluxless laser soldering concept is proved by Auger electron spectroscopy (AES) analysis of the oxide film on laser-sputtered solder. Second, the reducing atmosphere (H₂-N₂ gas) is shown to acheive high solderability. The experimental results are comparable with laser soldering in air using a rosin mildly activated (RMA) flux. From these experiments, this fluxless laser soldering technique offers the ability to assemble high lead count and fine pitch ICs for use in TCPs.

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