A multimodal teaching advisor (MTA) that utilizes the work-site operator's know-how and robotic-systems information, including that from sensors, in a complementary manner has been enhanced and implemented with a wearable personal computer (WPC) which is thought of being advantageous to use in manufacturing field. The MTA's software was enhanced to acquire and monitor sensory and robot-motion data. As the MTA software components, graphical and voice use interface are implemented in WPC, MTA operation has been improved. Moreover, by adding to MTA software component to acquire and monitor logging information such as sensory data, MTA function was made full. Experimental results for a spatial-path-tracking task performed using a laser range finder showed that the MTA's operation was greatly improved. In particular, the simultaneous provision of support information via both the graphical and speech interfaces shortened the time taken to teach a robot by using a teaching pendant.
It has not been recognized that the contact length on the line of action elongates in the load meshing of gears. The elongation of contact length on the line of action is discussed with particular reference to roll forming of gears, and to dynamic behavior of the tooth in meshing. When thus phenomenon occurs in mesh at the tooth tip, the contact length on the line of action elongates more than kinematically calculated one. In rolling, the tool approaches to the. work, the center distance decreases small amount. But the elongation of contact length is sensitive. As the result, the contact point on the line of action can not understand exactly, and this fact confuses in tooth analysis. In this study this relation between the elongation of contact length and tooth space in small over the recess or before the approach are revealed by experiments and kinematic theory. This analytical result can explain not only in rolling, but also in which the single flank contact is done under constant center distance.
This paper proposes a method which approximates mesh data for measured points smoothly by iterative and local procedures. The method calculates fourth divided differences for u and v directions at each mesh point as a local fairness criterion, and modifies the central 9 points using 16 points from 5 × 5 mesh points for the point with the maximum local fairness so as to make their fourth divided differences zero iteratively. It repeats these procedures until the global fairness, which is the sum of the local fairness criteria, does not decrease. Then it fits the mesh curves locally with parametric cubic polynomials and obtains fifth-degree C2 parametric patches. Several examples demonstrate effectiveness of the method for the data with random errors and a few extraordinarily large errors.
In this study, a novel surface potential detection method is proposed, which introduces a heterodyne technique to a scanning force microscope (SFM). For observations of surface voltage at frequency beyond a cantilever resonance frequency, an amplitude-modulated frequency signal is used. By applying an AC voltage to the sample and an amplitude-modulated frequency voltage to the tip, the heterodyne beat signal corresponding to information of surface potential can be obtained. The tip-sample distance can be also obtained from the modulation frequency component, and is controlled by the z-piezo element in such a way that the component of the modulation frequency oscillation is kept constant. As a result, the simultaneous measurements of surface potential and profile of the sample have been possible without restriction of the mechanical resonance of the cantilever.
To maintain metal pipes, an electromagnetic coil is useful as the detecting device of the eddy current change in the metal due to the pipe defects and as the distance sensor of the clearance between the detecting device and metal wall. This type of sensor should be thin and smaller diameter for detecting by precise resolution and have large inductance and, small electrical resistance for high sensitivity and high S/N. In this paper, for the above requirements, a new planar spiral type of coil for higher inductance, and thicker coil for reducing the electrical resistance by using ultra thick photo resist SU-8 and Ni electroplating is proposed. Moreover the micromachining technology for the small size diameter and for automatic assembling was applied to the microcoil fabrication. As the results, the Ni microcoil of thickness 300μm and of the diameter 3mm was fabricated. The high sensitivity, big signal-to-noise ratio and wide bandwidth of the fabricated sensor were obtained to be 1.7V/mm, 75.6dB and 0Hz to 1500Hz, respectively. The distance between the sensor and metal could be controlled using the microcoil distance sensor.
This paper proposes an ultrasonic position measurement system for mobile robot moving in wide-area. The system uses ultrasonic receiver net which consists of many ultrasonic receivers with wide beam (100°) allocated at a constant interval on a ceiling. The ultrasonic receiver net covers all area where mobile robot moves. And two ultrasonic transmitters with wide beam (100°) are placed at rear and front of mobile robot to transmit ultrasonic wave toward ceiling alternately. Some receivers of receiver net can receive the ultrasonic wave, so the distances between transmitters and receivers can be obtained. Three optimal distances are selected to estimate the positions of the transmitters, and the posture of the mobile robot is estimated by the positions of the two transmitters. Theoretical analysis and experimental results show that the estimated position measurement error is φ 62mm and estimated posture error is ±4°. The ultrasonic receiver net can be expanded easily, making possible to measure position of a mobile robot moving in wide-area, especially in bad visible environment.
In this study, the technology for automatically detecting cracks, impurities, cavities, and surface scratches in a sodium lamp tube during production is developed. The specimen is illuminated from below with white transmitted light and the top of the specimen is viewed from above with a CCD linear image sensor. The viewed image is transferred into computer memory and smoothed with a 3 × 3 pixel smoothing operator. The above-mentioned four types of defects are detected using a subtracted image which is obtained by subtracting the original image from the smoothed image. The detected defects are classified into three groups based on their longitudinal length and the rotational length. Most impurities and cavities fall into the 1st group, and most cracks and scratches into the 3rd group. However, some impurities, cavities, cracks and scratches fall into the 2nd group where they cannot be classified with this machine. The defects in this group are subsequently classified into the 1st group or the 3rd group based on observation with the naked eyes. As a result, the 1st group contains impurities and cavities, and the 3rd group contains cracks and scratches. It is verified experimentally that this method is effective for the detection and the classification of the defects into two groups.
Micro-bimorph-type resonators, 1.014 mm thick, different widths, and made of 130-degrees-rotated Y-cut lithium tantalate piezoelectric materials with large piezoelectric effects and large Q-factors, have been developed for use in angular rate sensors. Their vibration characteristics were estimated by two laser-doppler vibrometers in order to determine the width of the resonator that can vibrate perpendicularly. The estimation showed that a 1.000-mm-wide resonator vibrated at an angle of approximately 56.9 degrees to the perpendicular axis but a 0.970-mm-wide resonator vibrated at an angle of approximately 3.33 degrees. In other words, the 1.000-mm-wide resonator cannot vibrate along the perpendicular axis but the 0.970-mm-wide one can. And it was found that mechanical coupling has a large influence on the 1.000-mm-wide resonator but has little influence on the 0.970-mm-wide one. It is thus concluded that since the 0.970-mm-wide resonator has desirable vibration characteristics, it can be used for a sensing element of an angular rate sensor.
Traditional observer design by Gopinath method is not easy to apply to the practical system because of sèveral design steps, and is difficult to understand its design structure. To overcome this disadvantage, a new design method is proposed based on the frequency domain, i.e., by using transfer function. This method is composed of a diophantine equation and only three steps are required in the design procedure. By choosing the order and coefficients of the equation adequately, various observers such as an n-th order observer, a reduced-order observer, a robust observer etc. can be designed in the same manner. The advantage of the new method is emphasized on its simplicity in construction and understandable structure.
This paper describes a key device for measuring three-dimensional surface profiles using grating projection method. In this system a structured pattern is projected onto the object and the pattern deformed in accordance with the surface shape is captured by a CCD camera. And the captured image is analyzed to get three-dimensional coordinates of the surface on the basis of phase shifting technique. A special grating is built-up which consists of an active-controlled liquid crystal (LC) aligned as stripes. This LC grating has the performances of 4bits gray levels and 50 micrometers of period. Experimental results are gotten by using this LC grating and improved driving method.
This paper presents the effects of a wire running speed and a work feed rate on the multiwire saw slicing of 400mm-diameter silicon ingots from the viewpoint of the cutting force and the slurry layer thickness adhering onto the running wire. The cutting force, which becomes a cause of warp and waviness, is proportional to a work feed rate and inversely proportional to a wire running speed. The change of slurry layer thickness, which makes the global wafer thickness variation (GBIR), is derived from Navier-Stokes equation, and becomes more uniform along a cutting chord length at a higher wire running speed. By increasing the wire running speed from 500m/min to 850m/min (on an average) and optimizing the work feed rate, the GBIR and warp of the sliced wafers are reduced to half of the conventional products.
The authors recently found an interesting phenomenon in a glass lapping test with a silver lapping plate and n-dodecyltrimethylammonium chloride solution that the silver lapping plate was almost never worn during the lapping process even under the condition of large stock removal of glass. In order to apply this type of lapping to wide varieties of materials, it is indispensable to find out an appropriate surfactant which has the same effect as n-dodecyltrimethylammonium chloride does. If it is successful, the result would provide a key for clarifying the mechanism of this phenomenon. For that purpose, in the present work, the authors examined experimentally the effect of quaternary ammonium compounds solution on the glass and silver lapping behavior, and thus the following results were obtaind. When the silver is lapped using quaternary ammonium compounds having methyl groups, the same phenomenon as seen in the case when using n-dodecyltrimethylammonium chloride solution was clearly observed for any types of glass lapping plate.
This paper analyzes the adjustment of generating motion for hypoid gear with a modified roll, and investigates the effect of this roll on the adjusting result of this gear cutting by tooth contact analysis. By controlling the offset value and the third-order modification coefficient of this roll, the changes in the transmission errors and the bias-in of contact patterns can be adjusted from the toe to heel of tooth surface. If changing its second-order modification coefficient, the maximum of the transmission errors and the H value of V/H can be regulated obviously. In the tooth contact analysis, the instantaneous ellipses of tooth contact are simulated besides that the transmission errors and V/H value are determined. Moreover, the program for drawing the transmission error curve and the contact patterns has been developed. As a result, the detailed state of tooth contact can be demonstrated more clearly.
This study deals with the heat treatment on the edge of a die using YAG laser on-the-machine tool. First, the temperatures based on a theoretical model during laser irradiation were investigated in order to prevent the melting phenomena of the workpiece surface. Second, heat treatment experiments on the edge of a workpiece were carried out using this system. Quenched part was observed by an optical microscope. As a result, it was confirmed that the calculated results were in good agreement with the experimental ones. Finally, the edge of a lawn mower blade was treated by the selected condition from above results.
The machining noise produced in honing operation is honing sound. This study attempts to investigate experimentally the relation between the honing sound and the finishing performances of stones and to construct the neural network system to discriminate the finishing conditions. The main results obtained are as follows. When the stone pressure Pn is larger than the critical pressure Pc, the stone is on the condition of self-dressing and keeps the superior cutting ability. Then the honing sound with high sound pressure level is produced. The sound pressure becomes higher under the severer honing conditions. The honing conditions are grouped into three classes based on the magnitude of stone pressure; the low pressure condition (Pn is lower than Pc), the normal pressure condition (Pn is larger than Pc) and the severe pressure condition (Pn is much higher than Pc). The neural network system is constructed to recognize the frequency spectrum of the honing sound produced under these three conditions. The effects of cell number of hidden layer and of learning rate on prediction results are investigated. It is experimentally proved that the proposed neural network system has a high discrimination rate and the honing sound is applicable as a signal to monitor the finishing conditions of stones.
The fabrication of ULSI devices on a 12" silicon wafer requires a site flatness of within 0.1μm. However, the flatness is affected by the vacuum pin chucks used for planarizing wafers in optical lithography or for final polishing. This paper describes the contact between the pin tops and the wafer back-surface during clamping. Complete contact between the back-surface and the pin tops is difficult to achieve with a 775-μm-thick standard 12" wafer, even when the back is the mirror surface. The contact ratio between the wafer and the pin tops was measured. It depends on the wafer thickness. These experimental results closely agreed with theoretical results. The pin deformation that degrades the flatness was also analyzed. If the pressure loaded on all pins was uniform, the pin deformation is only 8nm. However, when the pressure loaded on each pin varied in peak to valley values by a factor of 16, the effect of the pin deformation on the flatness became significant.
A precise process for machining arrayed optical fiber ends to have tapered corners and slightly convex planes for use as the bare optical fiber connectors have been developed. The taper shapes are determined by the length L of the fiber from holder to the fiber ends, the height h of the holder, and number of revolutions. The underlying principle is that the machining amount is proportional to the product of the load and the work traveling length. The curvature radius (8 to 18 mm) of the slightly convex fiber end plane can be controlled by adjusting the polishing load. The polished plane with the silica abrasive lapping film has high optical return loss (55 to 60 dB).
Electrical and optical properties of amorphous silicon (a-Si) films fabricated at very high deposition rate using an atmospheric pressure plasma CVD method with rotary electrode were evaluated for applying to the electric devices. As the results, it was found that a-Si films with this method have good properties such as high photo sensitivity (σph/σd-106 at deposition rate of 0.3μm/s). And the optical gap (Eopt; determined (αhv)1/3 versus hv plot) was about 1.5 - 1.6 eV which were similar to those of a-Si films fabricated by the conventional plasma CVD method at low pressure. With increasing the deposition rate, the Eopt decreased and the hydrogen content in the a-Si films increased, and this tendency was contrary to that of the general a-Si films. These results indicate that the structure of a-Si films with this method include much disorder configuration which narrowed the Eopt. However, enough hydrogen in the films terminated the dangling bonds and caused the reduction of defect density. In conclusion, it was thought that the atmospheric pressure plasma CVD method could fabricate the device grade a-Si film at very high deposition rate.
This study deals with the characteristics of end-milling the hardened steels (SKD11 and SKD61: HRC53). The experiment under various cutting speeds was done in order to estimate the relationship between the cutting distance and the cutting speed. The cutting forces and the chip temperature were measured in the experiment. The hardness of the chip was also researched after cutting. The tooth form of the used tool and the cutting fluid were varied to estimate the deposition of the materials. Furthermore, the carbide including the chip was observed by AFM and the microscope. As a result, it is clear that the carbide included in SKD11 makes it difficult to end-mill comparing SKD11 and SKD61.
In turning of platinum alloy Pt850, the wear behavior of tools and the cutting characteristics of Pt850 are investigated experimentally. K10 carbide, cermet, ceramics and PCD are used as tool materials. K10 carbide and cermet are not suitable for the cutting of this material because severe wear on the tool flank was observed after a few second of cutting, that is, the width of the flank wear land was about 1 mm after 10 seconds cutting. The width of wear land of Al2O3 and Si3N4 ceramic tools was small compared with K10 carbide tool, but the cutting forces increased rapidly as the cutting proceed. PCD tool can be used for cutting of Pt850 because the width of flank wear land is much small compared with other tool materials used in this experiment and the increasing rate of cutting force is not so great. The influence of cutting speed on the flank wear of PCD tool is small. The surface roughness of work material Pt850 becomes lower when the smaller feed rate is chosen as a cutting condition and the cutting tool of larger radius corner is used.
A study on in-process detection of machining regime in micro-machining of optical glass (BK7) was conducted on ultra-precision lathe with a fast tool servo system. In micro-machining of optical glass, a brittle regime of machining can easily occur due to the wear of the cutting tool edge or change of depth of cut due to the irregularity of the workpiece. Brittle regime of machining must be prevented to keep the workpiece and tools from further breakage and hence an in-process monitoring system is needed. In this study, the following error signal of the fast tool servo is analyzed theoretically and experiments shows that it can be used as the signal for machining condition monitoring. Filtering and monitoring of following error signal based on the fast tool servo model is proposed to eliminate additional sensors. It is shown that the proposed monitoring method has the ability to detect a brittle regime machining status with a reliable speed and accuracy.