This paper describes a new trial system and experimental results for the three-dimensional position measurement. The principle is based on the well-known mathematical and geometric fact. It is possible to regard one point in three-dimensional space as an intersection of three planes. Then, the coordinates of it can be obtained by solving simultaneous equations of three planes. The system consists of three laser scanners, a laser detector on the target point and a computer. Each scanner is used to rotate the linearly spread laser beam called laser plane. When the detector is on the plane, each scanner to decide the equation of the plane measures the rotation angle. Ball type detector and hole type detector are developed in order to decrease the error by the incident angle. As a result of the experiment, following fact clarified. The detection range of incident angle in using the ball type is ±36 degrees. The range in using the hole type is ±60 degrees. The measurement accuracies of ±0.22mm in the small space (160mm height, 160mm width, 400mm depth) and ±0.69mm in the large space (600mm height, 600mm width, 800mm depth) are achieved. Main error factor is the coordinate error of standard point given for the calibration.
Adjustment of servo parameters of industrial mechatronic servo system is generally approached according to a certain empirical rule, but it is a hard work to achieve a high performance. This paper describes the contour control by the modified input data method for industrial mechatronic servo systems so that the adjustment of servo parameters is not required. Under a given set of servo parameters within an allowable range, the effectiveness of the proposed method has been verified by simulation and experimental study on contour control of an actual mechatronic servo system.
This paper describes the presumption method of the characteristics of the magnesium fresh surface in metal removal process that uses electronic states analysis by molecular orbital method. Recently, the demand of magnesium alloy has increased in connection with lightweight-sizing of home electronics. Under the cutting process of magnesium alloy, its activated fresh surface reacts with moisture in air. Therefore explosion accidents have occurred because of hydrogen generated in the cutting process. In order to perceive the risk of the magnesium fresh surface, we calculate the electronic states density of the fresh surface and the molecule existing in the environments close to the surface, and presume the characteristics of the fresh surface briefly. As a result, we find the useful index, moment of electronic states spectrum, to estimate the magnesium fresh surface characteristics, for instance, with the molecule of tool materials, air and water easily. Then the validity of the index is shown by comparison of experiment results, in which a cermet tool is suitable for magnesium cutting and the energy of the fresh surface becomes high in case of the cutting with segmental type chip or in the air.
This study deals with the improving method of ground surface roughness by numerical control function with a machining center. In the present report, we researched effective factors to improve the ground surface roughness after slant grinding by numerical control function. That is, we investigated the relationship between the surface roughness curves and slant grinding conditions. As a result, it is clear that there are two important parameters (hs: height formed by a cutting edge pre revolution and X0/Z0: incline of envelope curve of a cutting edge) to form the fine ground surface in slant grinding. Additionally, it was also confirmed that the wear of wheel was small in appropriate slant grinding conditions
The paper initially reviews γ-TiAl alloy. Experimental research is presented on the production of 3mm diameter holes in Ti-45Al-2Mn-2Nb+0.8%vol TiB2 using ultrasonic machining techniques. This entailed the use of a 20kHz piezoelectric transducer /250W generator, with both solid and hollow polycrystalline diamond (PCD) tools, operating in a boron carbide slurry. Fractional factorial Taguchi analysis was employed to evaluate 5 operating factors each at 2 levels, using an L8 orthogonal array with extensive replication. The data presented includes main effects plots for material removal rate (MRR) and tool wear rate (TWR), together with sample hole entry/exit photographs and corresponding workpiece surface roughness and surface integrity information (cross sectional mic rographs, microhardness depth profile plots and surface residual stress data).
High speed milling has been realized owing to a number of component technologies. The advancement of these technologies plays a pivotal role in practical application of high speed milling. Cutting tool is one of the most important component technologies among them. Especially, ball end mills, which are the central tools for die and mould machining, have wide usage. Therefore, ball end mills with long tool life and high machining performance are strongly demanded. However, the relationship between tool shapes of ball end mill and high speed milling has not been made clear since it is hard to analyze some complex tool shape parameters. The study focuses on the cutting edge shapes of ball end mills, and allows the creation of micro-lands on rake face and flank face in order to make tool lives longer and keep machining more stable. They are named Neg-land (land between cutting edge and rake face) and Pos-land (land between cutting edge and flank face). High speed cutting experiments enable us to recognize some specific cutting characteristics of created ball end mills. Based on the obtained characteristics, ball end mills with an original cutting edge shape (Opt-tool) are again proposed and produced. As a result, it is experimentally found that the Opt-tool shows the longest tool life and the highest machining performance in high speed milling.
A softened affected layer generated in electrolytic grinding at higher electrolytic voltage could not be removed by a spark-out grinding without electrolysis in the previous report. In this report, the electrolysis controlled spark-out grinding is developed in order to remove completely an affected electrolytic ground layer at any electrolytic voltage. Effects of the electrolysis controlled spark-out grinding on finished surface characteristics are experimentally proved by investigating ultra micro hardness on machined surface, surface finish and so on. Main conclusions obtained in this report are as follows: (1) The electrolysis controlled spark-out grinding can prevent the finished surface hardness from decreasing at higher electrolytic voltage in which affected layer is remained after spark-out grinding without electrolysis. (2) A surface finish and an effective spark-out grinding time decrease by the spark-out grinding with an optimum electrolyze-out time. (3) An optimum electrolyze-out time decreases with increasing electrolytic voltage and becomes negative at electrolytic voltage over 7V.
This report aims to clear the influence of wheel speed on the ductile_mode grinding of hot pressed silicon carbide ceramic with the metal bond diamond wheel of mesh #140 grain size. The experiments are executed by plunge grinding method with surface grinder. The wheel speeds used are 20, 50 and 85m/s. The ground workpiece surface is observed with a differencial interference microscope and SEM, and its roughness is measured with a ordinary stylus profilometer, a interferometric surface profiler (WYKO) and AFM. The ductile_mode grinding without brittle fracture is possible at higher table speed or larger speed ratio (table speed/wheel speed) for higher wheel speed. The surface roughness parallel to grinding direction attains to below 10nm (Ry) or below 2nm (Ra) with decreasing the table speed or the speed ratio. The surface roughness normal to grinding direction, on the other hand, is saturated to about 200nm (Ry). The wheel speed has little influence on the surface roughness normal to grinding direction.
This paper deals with the optical telemeter system in which data-transmission and power-supply through cylindrical surface of rotating spindle are realized. Data-transmission is carried out by means of one LED on the cylindrical surface of rotating head and enough numbers of PD facing to LED rotational locus. Non-contact powersupply is carried out by means of two pairs of coil and ferrite-core arranged on the rotating side and the stationary side respectively. These schemes through cylindrical surface are realized in a demonstration unit to clarify the effectiveness of the newly developed system. The measurement accuracy of the developed system is superior than 0.05°C for 0-50°C range from the view point of temperature change.
This paper deals with an accurate cutting force prediction method of end milling in the finishing operation. In order to evaluate the finishing process of end milling, it is necessary to model the workpiece surface precisely. Thus, a cutting process model is proposed. It is based on the actual depth of cut, where the effect of elastic recovery, ploughing force and tool deflection is taken into account. The cutting process in surface generation is investigated from the viewpoint of depth of cut. Three cutting phases, that is, burnishing, rubbing and cutting, are introduced in order to describe the surface generation. Next, a new simulation model is proposed. It is based on the evaluation model of cutting force ratio and actual cutting depth according to three cutting phases. Furthermore, a new procedure of cutting force calculation is proposed in order to consider the effect of error on workpiece surface. The effectiveness of the proposed method is demonstrated by developing the prototype simulation system and making cutting experiments with straight flute end mill, where it is difficult to predict the cutting force by conventional simulation methods. The cutting force measured in the, experiment shows a good qualitative agreement with the predicted one.
Pad conditioning is one of significant subjects to keep constant polishing rate and polishing uniformity for CMP(Chemical Mechanical Polishing). To achieve constant pad conditioning, the following three factors are indispensable: (1) Formation of stable contact condition between pad and conditioner, (2) Real time pad condition, (3) Conditioning uniformity within the whole area of the pad. In order to meet their factors, pad conditioner with abrasives on retainer surface, which was termed `conditioning retainer', has been developed to realize stable polishing performance for CMP. The conditioning retainer carrying out simultaneously both pad conditioning and wafer polishing has a great deal of stiffness enough to keep horizontal contact to the pad against continuous friction resistance during pad conditioning. In addition, surface of the double layer pad conforms to surface of the conditioning retainer, so that contact configuration between conditioning retainer and pad has been kept to be constant. For uniform pad conditioning, the shoulder slope shape was formed on the assist pad to compensate the excessive wearing on the pad edge. The shape relieving polishing pressure at the pad edge corresponds to retainer trajectory density on the pad. The measure resulted in uniform pad wearing and the continuous uniform polishing profile.
It is desirable to increase the number of cutting edges per bob revolution as much as possible to reduce the burden of each cutting edge and the polygon error caused in bobbing process. But, it is difficult to increase the number of cutting edges because interference between the grinding wheel and the following cutting edge in relief grinding of the hob is apt to occur. A method for finishing the hob cutting edges by plunge grinding without relieving motion is proposed. In the method, the cutting edge is finished when the grinding wheel and hob work are in a static position. In this paper, the calculation method of the grinding wheel profile to finish the cutting edges, the optimum static position to obtain the desirable clearance angle, and the effects of the positioning errors of the grinding wheel on the accuracy of finished cutting edges are investigated.
In-process tool life detecting system has been developed. To detect tool life during cutting operation, a belt type TiN thin film having good electric conductivity was coated parallel to cutting edges on flank face of a ceramic insert having no electric conductivity. Width of the thin film from the cutting edge was adjusted to the maximum flank wear width which is a criterion of tool life. The electric resistance of the thin film, which is damaged by tool wear, was observed during cutting to detected the tool wear. A coil and a capacitor were connected in series to the sensor insert and made a series resonance circuit, and a sensor head coil with high frequency oscillator was coupled to the coil connected to the tool electromagnetically. An electromagnetic induction between two coils was used to take the signal from the tool with the thin film out to adopt the system in face milling cutter and/or automatic tool changer system in which it could not connect lead wires directly to the tool. The series resonance circuit of the tool was tuned into the frequency of the sensor head coil so that the sensor head coil was influenced by the condition of the circuit of the tool. The system developed in this study showed good stability for electric noises from an environment especially machine tools.
This paper proposes a quantitative model, for description of driver behavior. Three results are introduced for perceptions of unsafe relations between the first and the second party vehicles at intersections; result y stands for existence of the relation, n for non-existence, and u for lack of information. Accident occurrences are expressed in terms of these results and absence of avoidance actions. An acceptable risk region is introduced and the perception results are shown to locate on boundary points along a hyperbola. Superficial human error probability is inversely proportional to a priori probability of unsafe relation. Perception and judgment error ratios derived from the model are consistent with actual data. The maximum risk level turns out to be a very small number around the order of ten to the minus seven. Crossing collision safety devices are required to demonstrate an extremely high alarm reliability for its effectiveness of decreasing the collisions.
This paper proposes a new way of motion guidance mechanism of microscopic slider, in which the frictional directionality of textured surface is utilized and there is no geometrical constraint. When a slider slides across the ridge of line-and-space texture, extra force is necessary to overcome the strong pull-off force at the line contact in addition to the shearing of the adhesion in contact that also acts along the texture, thus the sliders motion is constrained along the texture. This paper proposes a model that describes the equilibrium of force and moment, and a design guideline was also proposed based on the model. Experimental result proved the validity of the model and the design guideline.
Robust design is an experiment-based method for reducing the dispersion of a system's quality characteristic through sensitivity reduction and, if necessary, noise source control. Sensitivity reduction is to select the values of the control factors so that the quality characteristic should become as insensitive, or robust, as possible to the variations of the noise factors of the system. Noise source control is the costly effort of reducing the variations of some noise factors themselves within a certain limits. In addition to a traditional overall dispersion measure like SN ratio, this paper first introduces multiple dispersion measures each of which evaluates the robustness of the quality characteristic to each noise factor. Then it presents a new approach to robust design using these multiple dispersion measures. When there are more than two noise factors, manipulating the values of some control factors so as to reduce the sensitivity of the quality characteristic to a certain noise factor will not always lower the sensitivities to the other noise factors, but may increase some of them on the contrary. That is, there can be trade-off relationships among sensitivity reductions of the quality characteristic to various noise factors. The proposed approach enables the designer not only to capture but also properly deal with these trade-off relationships. As a result, the noise source control required for reducing the dispersion of the quality characteristic down to a satisfactory level will be less expensive than the case where the traditional approach is used. The power of the proposed approach is illustrated with an example.
In this study, an articulated mobile robot was developed for inspecting the inside of the chemical plants or the nuclear power plants. Although, it consisted of only six segments connected by five pitch joints, it was able to climb over the obstacles such as the stairs and the large block. It was also able to climb up a vertical narrow passage such as ducts and pipes, but it must continue to press both walls by making at least one triangle with two links. Because the robot supported itself using at least two links, it was limited the degree of freedom to move. This paper deals with mobility of this robot against some obstacles in the narrow passage such as projections, corners and steps. We proposed overstriding methods and analyze the maximum size of these obstacles that the robot was able to overstride.
The visually handicapped persons are often inconvenient to distinguish the color in the daily life. We have developed the portable color identification equipment. At first, it measures the surface color in the same way as the photoelectric colorimeter. Next, it translates the measured RGB data into the color name so that we can image the color easily. The color name is expressed by adding a modifier about lightness and chrome to 13 basic color names. Finally, it informs the color name by the voice for the visually handicapped persons. This equipment contains automated calibration system in order to make a measurement result be steady. The effectiveness of this system was shown by the experiment under various conditions of a temperature and illuminants.