The oxygen content in bio-reactors is an important parameter to judge the status of bio-reactor operation, but the oxygen content data is finite in experiment. In order to find the distribution of oxygen content in bi...
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ISBN:
(纸本)1424411351
The oxygen content in bio-reactors is an important parameter to judge the status of bio-reactor operation, but the oxygen content data is finite in experiment. In order to find the distribution of oxygen content in bio-reactors, the interpolation algorithm is introduced in this paper. At first, according to the characteristic of experimental data field, the bio-reactor domain is grided to hexahedron, the space of bio-reactor is reconstructed through the hexahedron element mesh of the scattered data field, and the region mapping algorithm is used to interpolation calculation. This integrate algorithm is good for the data field reconstruction and interpolation, which the field is belongs to the three dimensional space of bio-reactor.
Aiming at the problem of acceleration and jerk fluctuation caused by the discontinuity at the corner of the tool path in the continuous short-line machining process, a real-time corner smoothing and interpolation algo...
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Aiming at the problem of acceleration and jerk fluctuation caused by the discontinuity at the corner of the tool path in the continuous short-line machining process, a real-time corner smoothing and interpolation algorithm for realizing the continuous motion of the tool axis jerk is proposed. In the corner smoothing process, the C-3 continuity of tool path is realized by constructing a symmetrical PH transition curve satisfying the maximum approximation error constraint between adjacent short lines. In the interpolation process, based on the flexible acceleration and deceleration control method, the feed rate, chord error, acceleration, and jerk constraints are considered. For the smooth C-3 continuous path, the acceleration and deceleration profile with jerk-continuous is used for velocity planning and interpolation, and the continuous motion of the tool axis jerk is realized. In this paper, the proposed method is compared and analyzed with the C-2 continuous algorithm and the traditional point-to-point interpolation algorithm through simulation and experiment for the same tool path. The results show that the jerk fluctuation of the proposed algorithm is reduced by 60.36% on average compared with the C-2 continuous algorithm, and the processing time is reduced by 19.5% compared with the point-to-point interpolation algorithm. It proves that the proposed algorithm can effectively reduce the vibration of the machine tool and improve the processing efficiency.
The existing interpolation algorithm cannot meet the need of high-speed and high-accuracy machining of a free-form surface. So this paper proposed a correcting and compressing interpolation algorithm. Depending on the...
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The existing interpolation algorithm cannot meet the need of high-speed and high-accuracy machining of a free-form surface. So this paper proposed a correcting and compressing interpolation algorithm. Depending on the distance and angle evaluated from the adjacent command points, the machining path of free form can be divided into two machining types. For those regions where the accurate figure is critical such as corners, the convention linear interpolation is performed exactly between the adjacent command points. For those regions having a large radius of curvature where the smooth figure is critical, firstly, the interior point selection method based on circle transition is derived to reduce the tolerance between the machining path and the original surface;secondly, the interior point correction method based on the least-square method is proposed to reduce the calculation error and round-off error in the interior point and estimate the first- and second-order derivative vectors of the interior point;thirdly, the shape-defining point is selected by the bend direction of the machining path and fitted to a quintic spline curve which has the C2 continuity;fourthly, the fitting accuracy controlling method is proposed to ensure the machining accuracy;lastly, the curve interpolation is performed on the fitted smooth curve. Machining tests carried out on a vertical machining center show that the proposed algorithm can improve the machining efficiency and machining quality of a free-form surface.
In this paper, a novel and accurate real-time non-uniform rational B-spline curve interpolation algorithm is proposed. This algorithm not only considers chord errors, feedrate fluctuations, jerk-limited, and accelerat...
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In this paper, a novel and accurate real-time non-uniform rational B-spline curve interpolation algorithm is proposed. This algorithm not only considers chord errors, feedrate fluctuations, jerk-limited, and acceleration/deceleration (Acc/Dec) capabilities of the machine, but also optimizes the look-ahead process. In the meanwhile, it improves machining efficiency by adding the circular buffer and pre-interpolation (non-off-line) and enhances the real-time performance by removing the time-consuming calculation from the interrupt service routine. Furthermore, the proposed interpolation algorithm can interpolate both the long spline and the short spline with uniform method. The advantages of the proposed method were confirmed by the simulation results.
In this paper, a jitter measurement circuit for mixed-signal production test based on the interpolation algorithm is presented. By utilizing the limited sampling points per cycle, the original signal under test is rec...
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In this paper, a jitter measurement circuit for mixed-signal production test based on the interpolation algorithm is presented. By utilizing the limited sampling points per cycle, the original signal under test is reconstructed with a high accuracy. From the reconstructed signal, most timing jitter features can be characterized. To validate the design effectiveness, comparative studies have been performed between this jitter measurement method and other standard jitter characterization instruments.
interpolation algorithm is the critical algorithm to achieve good dynamic performance of machine tools. However, due to complex kinematic constraints and calculation conditions, high-order continuous inter-polation al...
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interpolation algorithm is the critical algorithm to achieve good dynamic performance of machine tools. However, due to complex kinematic constraints and calculation conditions, high-order continuous inter-polation algorithms for six-axis machine tools are relatively rare in the literature, although they can greatly improve motion stability, reduce motion impact, and inspire motion performance. This paper develops an interpolation algorithm with jerk continuity for six-axis machine tools. A C3 continuity corner smoothing method of six-axis path is achieved by locally inserting two specially designed symmetrical quintic Bezier curves into the transition corners of linear commands. The pose in the six-axis path is converted to Euler angle with three parameters, and the synchronization of the position and pose are mathematically guar-anteed at the junctions of the linear and curve segments. The proposed corner smoothing method can calculate all control points of Bezier curves under the constraints of approximation error and path curvature analytically, which makes it suitable for online calculation. A quintic-polynomial feedrate schedule is uti-lized to meet the jerk continuity of the motion, and the concept of equivalent jerk is proposed to simplify the schedule calculation and smooth the velocity curve. In this way, the jerk continuity of the algorithm is achieved both at the geometric level and the feedrate level. The developed algorithm is verified to have more advantages than low-order continuous algorithms by simulation and comparison, and can improve the motion continuity of six-axis machine tools.& COPY;2023 CIRP.
In orthogonal frequency-division multiplexing (OFDM) digital communication systems, an uncorrected frequency offset can lead to a severe degradation of the system performance. This paper describes a technique to mitig...
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In orthogonal frequency-division multiplexing (OFDM) digital communication systems, an uncorrected frequency offset can lead to a severe degradation of the system performance. This paper describes a technique to mitigate the influence of frequency offset on system performance by applying a weighted discrete Fourier transform (DFT) to a novel OFDM frequency-assignment scheme in which null carriers are regularly inserted among modulated data carriers. This frequency-assignment scheme makes possible the application of a window, function at the demodulator to broaden,the signal spectrum and renders the demodulated signal more immune to the influence of frequency offset. In addition, a variant of this frequency-assignment scheme also leads to a DFT-based measurement technique for, easy and accurate determination of the frequency offset. interpolation algorithms and frequency-assignment schemes suitable for both initial frequency acquisition and subsequent frequency tracking are described in detail. The Rife and Vincent (Class-I) windows are examined and their estimation results are obtained for an additive white Gaussian noise (AWGN) and a multipath fading channel.
Wave absorbing material is an important functional material of electromagnetic protection. The wave absorbing characteristics depend on the electromagnetic parameter of mixed media. In order to accurately predict the ...
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Wave absorbing material is an important functional material of electromagnetic protection. The wave absorbing characteristics depend on the electromagnetic parameter of mixed media. In order to accurately predict the electromagnetic parameter of mixed media and facilitate the design of wave-absorbing material, based on the electromagnetic parameters of spherical and flaky carbonyl iron mixture of paraffin base, this paper studied two different interpolation methods: Lagrange interpolation and Hermite interpolation of electromagnetic parameters. The results showed that Her mite interpolation is more accurate than the Lagrange interpolation, and the reflectance calculated with the electromagnetic parameter obtained by interpolation is consistent with that obtained through experiment on the whole. (C) 2015 Elsevier B.V. All rights reserved.
The mechanical equipment fault spectrum often contains random noise, and traditional spectrum estimation methods introduce large errors in the fault diagnosis of mechanical equipment including gas blower. Accurate fre...
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The mechanical equipment fault spectrum often contains random noise, and traditional spectrum estimation methods introduce large errors in the fault diagnosis of mechanical equipment including gas blower. Accurate frequency estimation of multi-frequency signals that are contaminated is a common problem. To address the fault spectral characteristics of gas blowers, a novel discrete Fourier transform interpolation algorithm is presented based on traditional practice. The algorithm combines the zero-complement technique and the main lobe fitting technique. The accuracy of the spectrum correction was improved greatly with the new algorithm, and it could effectively promote fault pattern recognition. Application examples and simulation results showed that the new algorithm is very successful in the fault pattern recognition of gas blowers. Under noise conditions, the proposed algorithm has a smaller estimation error than conventional algorithms and could achieve high precision, strong compatibility, and robustness. Theoretically, the algorithm has attained a higher level, and its application in engineering practice is also quite impressive due to its highly expected values.
An interpolation algorithm for finite-duration real sequences using the discrete Fourier transform is presented. The proposed method is shown to result in a significant saving of computational labour over the discrete...
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An interpolation algorithm for finite-duration real sequences using the discrete Fourier transform is presented. The proposed method is shown to result in a significant saving of computational labour over the discrete version of the time-domain classical interpolation formula. Estimation of inbetween samples for large sequences is possible within a mean square error of 0.00114 with this method. Some considerations with regard to the computation of FFTs are also discussed.
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