In the 1st report, the conceptual design and the sound information failure detection method for the plant inspection and diagnosis robot had been discussed. The inspection and diagnosis robot must monitor the condition of many plant machines at the same time. So it must not only inspect machine condition at prescribed inspection points, but also automatically move to a faulty machine after an abnormal state has been detected, in order to precisely identify faulty parts of the machine and failure types. This paper discusses (1)the calculation method of failure signal power from sound spectrum, (2)fuzzy navigation method for leading the inspection and diagnosis robot to the faulty machine by using the failure signal power. Furthermore, in order to verify whether the methods discussed in this report are effective, two examples of practical applications are shown.
This paper aims at establishing an accurate methodology to evaluate the friction torque of rolling bearing during the rotation of spindle. The technique adopted here basically depends upon the accurate measurement of change in the rotational spindle speed during free run by applying a reflective sensor system. The method developed here was adopted to evaluate the friction torque of angular contact ball bearing spindle under different operating conditions ; these are rotational speed, preload of bearing, amount of grease and misalignment of spindle. And it was clarified through experiments that the friction torque evaluated coincides with the measurement by torque transducer.
This study deals with an automatic scraping machine, namely a bearing recognition mechanism of scraped surfaces and a specially designed scraping mechanism. Authors tried to make a recognition system of the bearing in the scraped surface, comprised of a CCD camera, lighting unit and data processing unit. A photoflood lamp was used as a lighting unit, because of its sufficient brightness and uniform distribution in front direction. That was enable to eliminate other optical disturbance, so it was enough to recognize bearings of workpiece surface. The good contrast images were detected by photographs of the workpiece surface. Computer software was used to eliminate the influence due to uneven lighting, by means of the "P-TYLE" thresholding method. As the result, the high accuracy scraped surface with 16 bearing spots/in2 in 140 mm × 140 mm was enable to be recognized. Then the spot that must be scraped was identified, using a transformation system from image to space position.
Hardness both under test load and after unloading in three materials (pure gold, pure platinum and SK 5 steel), are obtained using an ultra-microhardness tester that directly measures the depth of concavity, using indenters (Vickers type and triangular pyramid). The influence of the radius of the indenter tip and differences in the classical method of measuring the concavity rim optically, also are investigated. The results obtained are as follows: (1) In hardness measurements both under test load and after unloading, correction of the radius of the indenter tip by comparison with the ideal shape, can remove the errors due to tip radius difference. (2) Correction of errors at the indenter tip and correction of errors due to "shallowing", coincide hardness measurements obtained from unloaded depth with hardness measurements obtained from the classical method. The correction proposed here for SK 5 steel, is effective for all indenter shapes and all test loads in this report.
The study deals with the development of control software to form a so-called character line, which means an intersectional line between two sculptured surfaces. The clear character line, one of the most impotant elements to make high quality die-mold products, is in general difficult to create by 3- to 5-axis control machine tools with conventional rotational cutting tools such as ball end mills because there remains hardly removable round on the character line. Thus, the round is normally removed by hand lapping, which requires the skill and experience of workers. In the study, a new approach is proposed to finish the character line by use of a non-rotational cutting tool, which is mounted on a 6-axis control machining center. Two machining methods to create the character line are investigated from the viewpoint of surface roughness and ease of creation, that is, one-path method and two-path one. The former gives priority to removing residuals formed in the previous rough-finishing such as ball end milling. The latter places emphasis on sharpening a character line. Based on these two methods, 6-axis control machining of character line was carried out. As a result, it is experimentally found that 6-axis control machining enables the creation of character line.
A new machining system for hard and brittle materials which makes it possible to achieve ductile-regime machining processes was developed. The machine is capable of cutting, grinding, or polishing brittle materials such as ceramics and glasses in ductile-regime. As a key component in building the system, giant magnetostrictive alloys with large output energy and outstanding elongation are employed to comprise an ultra-precision actuator. The actuator can be used not only as a fine positioning device but also as a high frequency vibration actuator. In this article, the results of the device viewed as a high accuracy positioning device in grinding processes are presented. Various kinds of hard and brittle materials were subjected to experiments whose results indicate that the newly developed machine is capable of realizing ductile-regime processes.
The slicing used diamond wire tool is considered as one of effective slicing methods for large size silicon ingot in the near future. As it is not necessary to use slurry with abrasive grains, the working ability after slicing process is good for operators. On the other hand, this method has some weak points such as diamond wire tool is expensive, reuse of broken wire tool is impossible and so on. Therefore, this study aims to develop the more excellent wire tool with regards to slicing ability. This spiral chip-pocket wire tool has such characteristics electrodeposited diamond grains in spiral on the core wire. In this report is described the outline of plating apparatus and the trial manufacturing method of spiral diamond wire tool. Behavior of breaking load, slicing ability and slicing accuracy of the trial manufacturing wire tool are studied through a series of experiments. It is clear that the trial manufacturing wire tool has high slicing ability, long-life and high strength compared with the ordinary diamond wire tool.
When the feed direction of the slides is changed, lost motion ensues in the feed drive system, of NC machine tools. Such lost motion is usually step type and easily compensated for by using the backlash compensation function of NC. However, special cases involve an exponential type lost motion which cannot be compensated for by this method. As a result, machining accuracy of the machine tools is adversely affected. Such lost motion often occurs in large size machine tools with linear ball guides and wiper seals. This paper presents research concerning the generation mechanism and the effective compensation method of the exponential type lost motion by using the existing large size machine tools and the teststands.
In order to simplify the treatment of coolant in production systems, the superfinishing characteristics under the condition of water-solution type coolant are investigated experimentally. This type of coolant is inferior to an oil type coolant in removing chips from the stone because of its poor permeability. Electrolytic in-process dressing is applied to promote the self-dressing of diamond stone. As work materials, alumina which is sintered under atmospheric pressure and soft steel (equivalent to 0.15% carbon steel) are used. The results obtained are as follows. Electrolytic in-process dressing makes it possible to use the coolant of water-solution in superfinishing. The suitable conditions in electrolytic in-process dressing depend on the machinability of work materials. The soft steel whose chips are easy to make a loading on the working surface of stone needs the stronger dressing. A concentration of some percent is sufficient for a coolant to maintain its essential properties. The electrolytic in-process dressing is more effective for harder or finer stone, because it can control the cutting ability of the stone.
In order to efficiently operate FMS with the AGV's driving, it becomes important to control AGVs driving. This paper represents a method of autonomous driving for multiple AGVs equipped with FMS. It is assumed that an FMS model has a one-way driving lane for AGVs and neither passing nor encounter between AGVs is allowed. AGV is modeled by SLA (Stochastic Learning Automaton) to have a capability of making driving decision by itself. Such a capability is accomplished by the stochastic learning process of SLA. Numerical experiments show that AGV can learn proper driving actions and operate its run in the shortest possible distance.
This paper addresses a method for systematic checking of dimensional errors such as over and deficient dimensioning in mechanical part drawings drawn with CAD systems. A rule-based procedure automatically finds out dimensioning characteristic points in a three-view drawing which are connected into pairs by dimension lines. The dimensioning characteristic point stands for a vertex and the dimension line stands for an edge of a topological-graph model. Checking of deficiency and redundancy of dimensions is based on Graph Theory. A method for checking of chamfer dimension is also presented. A prototype system has been developed to perform the check of over-dimensions and deficient dimensions in three view drawings. The feasibility of this system has been confirmed with respect to various types of mechanical part drawings.
Robot manipulators are coupled and non-linear systems which are difficult to control at high speed operation. So the dynamic modeling of robot manipulator is important from the view point of design of contouring control. This paper presents an influence of coupled torque on the trajectory error in the contouring control in open-loop robotic mechanism and closed-loop robotic mechanism. Especially, the contouring control in two kinds of trajectories is investigated. The one is trajectory of straight motion, the other is trajectory of right angled turn motion. In our study, first, the equations of torques are derived from the Lagrange's equations of motion with offset length between arms. Their equations are verified by the experiment of straight motion. As experimental results, the coupled torques of each mechanism are revealed. Next, the influences of their coupled torques on the trajectory error are revealed from the simulation of right angled turn motion. The design procedure are provided for obtaining the influence of coupled torques on contouring control by the simulation in each manipulators' configuration.
When a circuit pattern is detected by an image sensor, degradation of the modulation of the detected image is inevitable. For automatic detection of defects in a pattern by image processing, a less degraded image is desirable. This paper presents a simple method to restore degraded modulation of a detected image. The method is intended for a practical image processing system. Its feature is that modulation compensation can be performed in real-time by a hard-wired logic circuit, so it can be implemented as a relatively simple circuit.
Resolution of interferometers reaches to a few nanometers or less with the phase shifting or other interpolation techniques. However the accuracy of them could not approach to their resolution because any accurate standard for calibration could not be found. The present paper proposes a self-calibration method which can determine the interpolation error between fringes of the interferometer without using any standard. An interferometer of Michelson type has been developed with the phase shifting by a piezo electric actuator. The interpolation error due to the phase shifting actuator has been calibrated by the proposed self-calibration method. The reliability of the calibration result is estimated to be about 0.2 nm from the reproducibility error of the calibration. It has been confirmed that the proposed method can calibrate the interpolation error with the accuracy of the limit given by the resolution or the stability of the interferometer itself.
This paper presents a new automatic 3D-measuring system, using a developed three dimensional coordinate measuring machine (3D-CMM) by two image processors (a CCD camera and a laser microscope) and a work station (WS), for the dimensional inspection during the production of small molded electronic parts. Generally, in the measurement of small molded electronic parts, a 3D-CMM by an image processor (CCD camera) is rather suitable than a 3D-CMM by a probe, because a probe may damage some portions and unable to enter narrow spaces. But it is less accurate in vertical direction than it is in length and breadth directions. Also it takes much time to make a measuring program. So it is difficult for the system using only a 3D-CMM by an image processor to shorten the process time of the dimensional inspection. At this stand point, in the developed system, a confocal scanning laser microscope and a WS are appended to a 3D-CMM by an image processor to get the required vertical direction accuracy and to save the process time as much as possible. The former ensures the vertical accuracy, and the latter shortens the process time 45% than the previous one.
When a solid sample is scratched by an abrasive grain, a series of pit(5-30μm) array can be observed to form, and a series of light pulse array corresponding to the pit array has been found to emit. The pulse has about 10ns half-value width and repetition intervals of 0.3-1μs. Spectral measurements were made for these short pulses applying an experimental set using band-pass filters. A method obtaining the maximum transient temperature of the fracture part by the spectral data is discussed. The obtained maximum temperatures of metal samples are 1400°C : steel and 3000°C : Mo. A fused quartz sample showed a noticeable result; many sharp lines at 300-400nm were observed suggesting gasification of * O2 of SiO2. The micro-fracture process and the mechanism are discussed based on the obtained results.