Wrinkle patterns which are decorative texture and have the function to hide surface damage are formed on exterior surfaces of industrial products. To enhance product value, it is required to generate various wrinkle patterns having different impressions for meeting diverse needs of customers. The wrinkle patterns are usually designed as copies of leather and peel wrinkles, etc. so that designed patterns are limited. The objective of this research is to develop a system for designing various wrinkle patterns with unique and natural impressions. The properties of “fractal” and “1/f fluctuation” which are involved in nature are applied for realizing a computer algorithm to generate wrinkle patterns with natural impressions. The developed system allows everyone to design various wrinkle patterns easily using the user-intuitive interface, and check patterns in real time.
In the field of a precise positioning, an active isolation system, which is arranged 6 acceleration sensors in total in the horizontal and vertical direction, is generally installed and measures the movement of 6 degrees-of-freedom. In this case, the body supported by isolation unit has inclination Θ of the direction of pitch or roll, inclination components are superimposed to the acceleration sensor output of horizontal direction. When this component is canceled by high pass filter, the body oscillates in the cutoff frequency of the filter. Therefore, the inclination angle Θ is measured by position sensing devices equipped with isolation unit, and the inclination component can be correctly compensated. Then, the necessary performance for isolation unit is able to be achieved.
In this paper, we propose a parallel processing technique for creating animation of swaying trees in the wind based on physical simulation. Our technique independently assigns each tree to computation nodes. The each node processes not only parallel rendering for tree shapes, but also parallel simulation of the wind and bending of branches. This independency reduces data traffics between nodes and realizes efficient parallel processing. When the each node independently simulates the wind, it is necessary to consider wind interactions between the upper and the lower side tree. Therefore, we realize cooperative wind simulation with independent cluster nodes, by inventing a novel method for estimates of wind velocity of lower-side trees from simulation results of upper-side trees. By synthesizing rendered images from each cluster, our system generates animations of swaying trees. Through many experiments using these techniques, it is shown that the efficiency of parallel processing for animation of swaying trees is verified.
In designing a holder part of a large stamping die, designers must consider not only the functional property of the holder, but also its manufacturability. The holder part is produced by cutting and engraving table, wall, slot and pocket features into the raw cast shape. Since designers do not always have enough knowledge about the manufacturing method, they sometimes design a part with some unmanufacturable features. The author develops a new system for suggesting a design modification method to eliminate such unmanufacturable ones. This system automatically determines some optimum positions of a cutter for completely machining the unmanufacturable feature. Such cutters in the optimum positions have interferences with the holder part. Our system visualizes the interference volume between the cutter and the holder part. The designer can determine the design modification method of the holder part based on the interference volume.
The purpose of the study is to develop an evaluation system for the operations involving forearm torsion, such as screw driving and knob turning, for digital human model. In the previous report, a model was proposed to estimate the rotational range of the object rotated by the hand. The purpose of this report is to propose a decision rule for the working postures of the upper limb for torsion operations. The working postures were measured for various positions of the object. The results demonstrated that the upper limb took the posture so as to decrease slightly the maximum degree of coincidence of the upper limb. A digital human model was developed for evaluation of the operations involving forearm torsion based on the results.
This paper considers finite word length (FWL) effects when implementing discrete-time transfer functions in delta form. There are power/size and price/cost constraints in realizing embedded control mechatronic systems such as humanoid robots. To meet these specifications, fixed-point microprocessors with a short word-length are suitable for the control. Fixed-point controller implementation including those using a delta form may suffer from underflow and overflow in the numerical calculations. To solve this problem, a new numerical integration method for fixed-point microprocessors named Variable Modulation Method (VMM) was previously proposed. The present report shows that the basic principle on the improvement of the numerical accuracy relies on the bias modulation in the every sampling period and its mathematical proof is given. From this basic principle, the controller input/output modulation and the high-pass filter are not necessary. Furthermore, in order to improve the numerical accuracy, this simple methodology is extended. As an illustrative example, a fourth-order Butterworth filter is considered. The simulated results show that modified VMM can improve the numerical accuracy the same as VMM. Also, the implementation of modified VMM is very simple, and becomes almost the same as the conventional delta form.
The authors propose 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. In this paper, the proposed noise reduction method is applied to electromyogram 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.
Linear motor drives became main streams of high-end lithography tool for semiconductor manufacturing. However ball screw drives with rotational motors are still important for rough layer lithography. A limitation of ball screw drives is due to stiffness of nut and screw. This stiffness will be changed gradually in use. Therefore its control gain has to have enough margins in order to keep robustness in industrial usages. This paper intends to improve the ball the screw stage stability using a small linear motor as an electromagnetic damper. This method can combine advantages of rotational motors and linear motors. The former is high efficiency, low cost and the latter is high stability because of direct drive. After detail experiments we found suitable control structure of electromagnetic damper which is inspired from grease characteristics in slide screw stages. It makes high accuracy and high throughput stage at the same time.
This paper describes an instrument for 3D edge profile measurement of diamond micro-cutting tools used for ultra-precision fabrication of micro-structures. The measurement targets of this instrument are round-nose tools with nose radii of less than 100 μm. The core elements of the instrument are an atomic force microscope (AFM) for profile measurement of the tool edge and an optical sensor for alignment of the AFM cantilever tip with the tool edge. A three-axis closed-loop controlled PZT scanner is employed in the AFM for high-accuracy profile measurement and DC-servo-motor-driven stages are employed in the alignment mechanism for automatic alignment. Measurement experiments of micro-tools with nose radii of 30 μm and 8 μm are carried out, respectively. Cutting edge radii, nose local radii and edge contour roundness are evaluated based on the 3D edge profile measurement data.
In the laser forming of a metal plate, the bending process is caused by the thermal stresses which are produced in the plate by the laser irradiation. In the present study, the finite element method (FEM: LS-DYNA) is used to analyze the laser forming, in which the laser beam is modeled by the Gaussian distribution, then the bending deformation of the plate is estimated by the FEM. Comparing with the experimental result, the validity of the proposed analytical model of the laser forming is evaluated. In the numerical example, the distribution of the strain in the metal plate is clarified in the laser forming.
In this paper, it is described that it makes the basic characteristics of electrolyzed water of dilute NaCl clear. First, the structure and the characteristic of the equipment which makes electrolyzed water were described. At the same time, the way of making electrolyzed water of dilute NaCl were described. The equipment of the electrolyzed water for this study is the type which has 3 bathtubs. Next, as for the relation between the electrolytic-current and the characteristics of electrolyzed water, it made clear experimentally. In the same way, it made the change of the characteristics of electrolyzed water by the elapse in the time clear. Also, it measured about the dissolution hydrogen concentration and the hydrogen grade scale in electrolytically reduced water, and the dissolution oxygen concentration in electrolytically oxidized water, too. Lastly, using the etching experimental results to the oxygen-free copper material, it proved the characteristics of electrolytically oxidized water.
Chatter vibrations limit machining productivity and sometimes result in reduction of tool life in the end-milling process. There are two major types of chatter vibrations, i.e., forced and self-excited types. Their generation mechanics are different, and thus their characteristics and strategies to avoid them are also different. It is, therefore, needed in practice to understand their relationship and to select efficient milling conditions to stabilize the process for the self-excited chatter vibration and to minimize the forced chatter vibration at the same time. However, most of past research works have been focused only on the self-excited chatter vibration, and detailed analysis of the forced chatter vibration and its relationship to the self-excited chatter vibration can not be found in the literature. Thus, an analytical model of the end milling process with the forced chatter vibration is developed and verified experimentally. Then, the characteristics of the forced type and its relationship to the self-excited type are clarified, and the milling conditions to avoid the both types are clarified by utilizing the analytical model developed here and the model of the self-excited type developed in the past research.
Spinning with diode laser is newly proposed and experiments on AISI304, magnesium and titanium alloy plates are carried out. The sizes of the plates are 0.3, 0.4 and 0.5mm in thickness and 70 mm in diameter. The laser is scanned on lines of 1, 2, and 3mm away from the circumference. An AISI304 plate of 0.3mm thick can be formed into a shape of head of vessel of the diameter of 66mm, and a height of 2.0mm. The bending angle is about 90 degrees. Titanium alloy plates are difficult to form. Magnesium alloy plates are easy to form; however, the surface layer occurs to melt.