Improve Processing Accuracy Research Articles

A rapid outliers detection and correction method for external ballistic velocity measurement data

Due to the influence of various sudden and abnormal factors during the tracking environment, equipment working conditions, and operation process, there are inevitable outliers in the tracking measurement process of aircraft such as carrier rockets, artificial satellites, and missiles. Therefore, the prerequisite for ensuring the reliability of processing results is to timely and accurately detect and correct outliers. In this paper, we proposed the sliding window-based variable degree B-spline function method (SWVD B-spline), which can handle isolated outliers and spotted outliers. SWVD B-spline uses variable degree B-spline function to model observed data in sliding windows, which can detect and correct outliers point by point along with window sliding. Then, we propose an initial window data selection method to remove outliers in initial windows to ensure the processing effect. In addition, because there are often inflection points in external ballistic velocity measurement data, differential evolution is used to optimize variable degree B-spline in windows that include inflection points to improve processing accuracy. The experimental results verify that SWVD B-spline can handle various outliers rapidly and efficiently.

Optimization of Levenberg Marquardt Algorithm Applied to Nonlinear Systems

As science and technology advance, industrial manufacturing processes get more complicated. Back Propagation Neural Network (BPNN) convergence is comparatively slower for processing nonlinear systems. The nonlinear system used in this study to evaluate the optimization of BPNN based on the LM algorithm proved the algorithm’s efficacy through a MATLAB simulation analysis. This paper examined the application impact of the enhanced approach using the Continuous stirred tank reactor (CSTR) control system as an example. The study’s findings demonstrate that the LM optimization algorithm’s identification error exceeds 10-5. The research’s suggested control approach for reactant concentration CA in CSTR systems provides a better tracking effect and a stronger anti-interference capacity. Compared to the PI control method, the overall control effect is superior. As a result, the optimization model for nonlinear systems has a greatly improved processing accuracy. With some data support for the accuracy study of neural network models and the application of nonlinear systems, the suggested LM-BP optimization algorithm is evidently more appropriate for nonlinear systems.

A Shunt-Assisted Silicon Electrode for Micro Electrochemical Machining

Abstract Stray current causes undesired material dissolution in micro-electrochemical machining (micro-ECM). The reduction of stray corrosion, caused by stray current, continues to be a major challenge for accuracy improvement. To limit the distribution of stray current, a shunt-assisted silicon electrode, with an auxiliary anode sharing stray current, is proposed in this study. The auxiliary anode is arranged outside the insulating layer of the sidewall-insulated electrode. It is proved in simulation that the auxiliary anode can help reduce the average material removal rate on the machined surface by 55% and improve processing accuracy. A fabrication process of shunt-assisted silicon electrode by bulk silicon process and thin film deposition process are presented. Microgrooves and holes are machined in ECM experiments. The angle between each side-wall and the vertical plane is less than 10 deg. The gap between the sidewall of the machined structures and electrode-outer-contour is about 30 μm±6 μm for the grooves and 45 μm±10 μm for the holes. These long-term experiments and consistent processing results show the shunt-assisted electrode is reliable in ECM process. But due to the stray corrosion induced by DC power supply and conservative feed method, the effect of the shunt-assisted silicon electrode in inhibiting stray corrosion is not significant. In the future, a micro-ECM system with novel power supply and active control methodologies is expected to better utilize the effect of the shunt-assisted silicon electrode.

MAda-Net: Model-Adaptive Deep Learning Imaging for SAR Tomography

The compressive sensing (CS)-based tomographic SAR (TomoSAR) 3-D imaging method has the shortcoming of low efficiency, mainly represented in two aspects: first, the CS solver requires iterative calculation and hence is computationally expensive; second, the CS solver needs hyperparameters’ selection, which commonly requires cost-inefficient try-and-error attempts. Recently, the iterative CS solver is suggested to be replaced by a deep learning network for a tremendous processing speed improvement. However, the existing deep-learning-based TomoSAR imaging algorithms suffer from the problem of model inadaptability, i.e., being inadaptive to the observation model and the signal energy model and hence is low accuracy. This article proposes a new model-adaptive network (MAda-Net) to implement deep-learning-based TomoSAR 3-D imaging with a much improved processing accuracy. First, a new adaptive model-solving (AMS) module is introduced to solve the problem of the observation model inconsistency between the real spatially varying one and the approximately fixed one used by the network. Second, a new adaptive threshold-activation (ATC) module is introduced to solve the problem of signal energy model inconsistency between the real backscattered echo and the simulated echo for network training. The effectiveness of the proposed method has been verified by the computer simulations and the real unmanned aerial vehicle (UAV) SAR experiments.

Design and Manufacturing of a High-Sensitivity Cutting Force Sensor Based on AlSiCO Ceramic.

On-line cutting force measurement is an effective way to monitor processing quality, improve processing accuracy, and protect the tool. In high-speed and ultra-precision machining, status monitoring is particularly necessary to ensure machining accuracy. However, the cutting force is very small in high speed and ultra-precision machining. Therefore, high-sensitivity cutting force sensors are needed. Current commercial cutting force sensors have defects such as large volume, low compatibility, and high price. In particular, the sensitivity of cutting force sensor needs to be improved for high-speed and ultra-precision machining status monitoring. This paper provides a possible solution by embedding the sensor in the tool and selecting sensitive materials with high piezoresistive coefficient. In this paper, the structural design of the sensor and the fabrication of the sensitive material SiAlCO ceramic are carried out, and then the sensor is packaged and tested. The test results show that the cutting force sensor’s sensitivity was as high as 219.38 mV/N, which is a feasible way to improve cutting force sensor’s compatibility and sensitivity.

Tooth crest chamfering method of spiral bevel gear using ball end milling cutter

A chamfering method is proposed in order to improve processing accuracy and efficiency of tooth crest chamfering of spiral bevel gear. Coordinates of discrete points of upper and lower edges of chamfering surface are calculated based on the mathematical model of tooth surface and face cone. Distances between center of ball end milling cutter and upper and lower edges are set equal to radius of the ball end milling cutter, chamfering tool path is generated by particle swarm algorithm solving, both sides of tooth crest can be chamfered simultaneously to ensure processing efficiency. Direction angle of the cutter axis is calculated based on the relationship between direction of the cutter axis and contact positions of the cutter surface. Aiming to prolong service life of cutter, direction angle varies uniformly within the feasible region and contact positions distribute evenly on the cutter surface. Pinion without tooth crest chamfering is installed on four-axis CNC machine tools, edge detector is used to detect axial and circumferential cutter positions, then chamfering experiment is completed. Widths of chamfering surface are measured on different measuring positions, maximum error is 0.08 mm compared with design width 1 mm which appears at tooth crest inner end of convex side. Measuring results show that chamfering error is much smaller than that with manual chamfering, which indicates that the chamfering method is feasible.

Optimal design of cathode based on iterative solution of multi-physical model in pulse electrochemical machining (PECM)

In pulse electrochemical machining (PECM), the control of pulse parameters would result in designing the cathode shape according to a given anode shape more complexly than in direct current electrochemical machining (DC-ECM). To solve the problem, a numerical approach is proposed to achieve optimal design of cathode. A gap model is proposed to describe the influence of pulse parameters on gap size and a multi-physical model is introduced to describe the influence of pulse parameters on the distribution of electrolyte conductivity which can reflect the distribution of gap. An optimization method based on iterative solution of multi-physical model is presented to improve design accuracy of cathode shape. The experiments are conducted to illustrate the method of cathode design in PECM process. The results show that the proposed method can effectively improve processing accuracy.

Planetary and lunar ephemeris EPM2021 and its significance for Solar system research

AbstractWe present an updated public version of EPM (Ephemerides of Planets and the Moon). Since the last public version, EPM2017, many improvements were made in both the observational database and the mathematical model. Latest lunar laser ranging observations have been added, as well as radio ranges of Juno spacecraft and more recent ranges of Odyssey and Mars Reconnaissance Orbiter. EPM2021 uses a new improved way to calculate radio signal delays in solar plasma and has a major update in the method of determination of asteroid masses. Also, a delay-capable multistep numerical integrator was implemented for EPM in order to properly account for tide delay in the equations of the motion of the Moon. The improved processing accuracy has allowed to refine existing estimates of the mass of the Sun and its change rate, parameters of the Earth–Moon system, masses of the Main asteroid belt and the Kuiper belt; and also to raise important questions about existing numerical models of solar wind.

Study of a quantitative screening method of magnetotelluric sounding curves

An accurate tensor estimation function is a guarantee for acquiring a reliable underground electrical structure model. The past studies regarding transmission functions aim at obtaining smooth and continuous sounding curves through the time domain by data screening means such as least square, robust and remote reference processing methods as well as digital filtering techniques such as wavelet denoising, empirical mode decomposition and Hilbert–Huang transform denoising. As SNRs in different field measurement sites are different, if different data processing algorithms like single-site processing, remote reference processing, magnetic field correlation-based remote reference processing and magnetic channel sharing are used for data processing at the same measuring site, 3N-2 groups of sounding curves with different qualities will be obtained. Manual screening method has been mainly used in the past for screening of the abovementioned 3N-2 groups of sounding curves. If the quantity of sounding site is large, this manual screening method is of low efficiency without quantitative screening indexes. In this paper, discrete Frechet distance is mainly utilized to carry out quantitative screening of 3N-2 groups of sounding curves processed through the abovementioned four processing methods in order to obtain smooth, continuous and reliable sounding curves, thus avoiding subjectivity and low efficiency problems in the past manual screening. A quantitative sorting of all kinds of data processing results can be conducted, and the optimal sounding curve is finally picked out for data inversion. The above sounding curve selection result has improved processing accuracy of magnetotelluric data.

Experimental Study of Electrochemical Micro-milling of Silicon

Electrochemical machining (ECM) is a common method of silicon micromachining, but it is difficult to be directly used for three-dimensional processing. Therefore a new electrochemical micro-milling (ECMM) method is proposed. The method combined electrochemical machining and milling processes technology. Micro-removal of materials can be achieved by electrochemical machining technique, while milling processes enable three-dimensional machining. ECMM utilizes the passivation of silicon in sodium hydroxide solution to reduce electrochemical stray corrosion and improve processing accuracy. Experiments showed that the ECMM technology can limit the electrochemical stray corrosion to less than 10 μm. This method can be used for the machining of tiny three-dimensional structures of silicon materials.

A New Square Grid-Based Method for Identifying Solar Activities

The FITS is widely used as a common file format in astronomy. However, how to detect an effective celestial event from large-scale astronomical images with complex background is a thorny issue. This paper proposes a square grid structure for target detection (GSTD) of solar activities, inncluding the separation of the target area and the deletion of the background area. This kind of processing can greatly reduce the storage cost of the data set, while the solar activity area can be well preserved. The solar image is operated through an equally sized square grid to separate the solar activity target area and the background area to speed up the processing of images, improve processing accuracy, and effectively prevent image noise interference. The experiment results have shown that this method delivers satisfactory performance in accuracy and time-cost. Through the anti-jamming processing of image noise, the accurate positioning and effective recognition of solar activities are realized. This method has been proved to achieve good image segmentation recognition of solar phenomenon in the research of various types of solar activities. Moreover, it can provide a feasible way to reduce the storage occupancy of Content-Based Image Retrieval (CBIR) systems.

Precision milling method for face-gear by disk cutter

In order to accelerate the engineering application of face-gear, a precision milling method for face-gear by disk cutter is provided in this paper. Based on the principle of face-gear drive, the principle of face-gear milling by disk cutter is analyzed, and the mathematical model of the disk cutter is presented according to the meshing principle. Taking the milling needs into account, an innovative machine tool is developed, and the movement control method of face-gear milling by the disk cutter on the special machine tool is provided. For the comparison of tooth surface accuracy, the equation of face-gear tooth surface is calculated, and the 3D model of face-gear is established based on CATIA software. To verify the feasibility of the method, a simulation of face-gear milling is put forward based on VERICUT software. To optimize machining parameters and improve the machining accuracy, an error analysis model of face-gear milling is established, and the corresponding error influence rule caused by installation and movement parameters is obtained. In order to verify the theory, the experiment is carried out, and the completed specimen is detected by coordinate measuring machining (CMM). Finally, the processing parameters are amended according to the detection results and the error influence rule, and the maximum dimensional deviation value of specimen face-gear tooth profile is reduced from 181.2 to 30.4 μm. The result shows that the method of errors amendment can improve processing accuracy, and the generating milling method by disk cutter is an effective approach to achieve the precision face-gear.

High-efficiency approach for fabricating MTE rotor by micro-EDM and micro-extrusion

Micro-gas turbine engine (MTE) rotor is an important indicator of its property, therefore, the manufacturing technology of the microminiature rotor has become a hot area of research at home and abroad. At present, the main manufacturing technologies of the MTE rotor are directed forming fabrication technologies. However, these technologies have a series of problems, such as complex processing technology high manufacturing cost, and low processing efficiency, and so on. This paper takes advantage of micro electric discharge machining (micro-EDM) in the field of microminiature molds manufacturing, organizes many processing technologies of micro-EDM reasonably to improve processing accuracy, presents an integrated micro-EDM technology and its process flow to fabricate MTE rotor die, and conducts a series of experiments to verify efficiency of this integrated micro-EDM. The experiments results show that the MTE rotor die has sharp outline and ensure the good consistency of MTE rotor blades. Meanwhile, the MTE rotor die is applied to micro extrusion equipment, and technologies of micro-EDM and micro forming machining are combined based on the idea of the molds manufacturing, so the MTE rotor with higher aspect ratio and better consistency of blades can be manufactured efficiently. This research presents an integrated micro-EDM technology and its process flow, which promotes the practical process of MTE effectively.

Research on the Cutting Process Simulation Based on Finite Element Analysis

The blade is a complex mechanical structure model which has two processing methods. One is making mold blade using the electrochemical methods and forming the blade molding using precision casting methods. But the cycle of this processing method is long and the process is complex and difficult to control. The second method is cutting the blade directly. The cutting force and the friction between tools and blanks can affect the machining accuracy of the machining. We should timely adjust the cutting parameters and cooling model to improve processing accuracy.

Автоматизація процесів подачі аркушів листових друкарських машинах

Designed to automate the process of controlling the supply of the paper in sheet-fed printing machines to improve processing accuracy of measurements, which provides objective measurements in real time based on digital media measurement and processing. Automated delivery system using a sheet of digital software control of technological parameters and their stabilization can prevent paper waste and reduce the chance of stopping the printing machine in real time. Application of statistical processing of measurement results can improve the accuracy of determining the number of pages taken from the feeder sheet printing machine.

505 短パルスレーザによるステンレス基板へのマイクロプリズム加工 : 加工精度の向上(OS7-2 オーガナイズドセッション《精密/微細加工と評価》)

The recursive mirror comprised of dozens of re-entrant pyramids as large as about 300 μm in length is applicable to the optical measurement of soundness of structures. To make such a micro shape directly on a stainless steel substrate, the structures with a mirror device may be able to be used for many applications under special circumstances, such as high pressure, high temperature, and radiation fields. To improve processing accuracy in the microfabrication of microprisms by near-infrared short-pulse irradiation, we introduced an in-situ observation apparatus and finishing processes. As a result, a three-dimensional structure was constructed from three layered triangles with about 420 μm in width and about 56 μm in depth. Although the re-entrant pyramid structure with smooth surfaces was achieved after the finishing process, it is necessary to improve the surface roughness with a reflectivity of a few percent or more, for practical use.

Finite Element Analysis and Optimization of Long-Span Gantry NC Machining Center Structure

The use of finite element theory and modal analysis theory, the structure of the machine static and dynamic performance analysis and prediction using optimal design method for optimization, the new machine to improve job performance, improve processing accuracy, shorten the development cycle and enhance the competitiveness of products is very important. Selected for three-dimensional CAD modeling software-UG NX4.0 and finite element analysis software-ANSYS to set up the structure of the beam finite element model, and then post on the overall structure of the static and dynamic characteristic analysis, on the basis of optimized static and dynamic performance is more superior double wall structure of the beam. And by changing the wall thickness and the thickness of the inner wall, as well as the reinforcement plate thickness overall sensitivity analysis shows that changes in these three parameters on the dynamic characteristics of post impact. Application of topology optimization methods, determine the optimal structure of the beam ultimately.

Finite Element Analysis and Optimization of Structure for Large Blanking Machine Equipment during High-Speed Blanking

This paper reviews the background and significance to investigate the high-speed speed blanking process modeling simulation and optimization of large blanking machine equipment for CNC uncoiling, leveling and shearing line. And a powerful tool has been providing to of heavy machinery optimal design specifications. The finite element model of beam structure has been established by using a three-dimensional modeling software UG NX4.0 CAD and finite element analysis software ANSYS. Then the static and dynamic characteristics results of the whole beam structure have been simulated. On the basis of analysis results, the optimal static and dynamic performance of square cross-section of the beam structure has been obtained. Drawings at the design stage of large blanking machine equipment for NC uncoiling, leveling and shearing line, the use of finite element theory and modal analysis theory, the structure of the blanking machine static and dynamic performance analysis and prediction using optimal design method for optimization, the new machine to improve job performance, improve processing accuracy, shorten the development cycle and enhance the competitiveness of products is very important.