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Optimized design and analysis of a compliant steering stage using hybrid actuation
Abstract：In this study， we focused on finely adjusting the angles of optical space instruments under various conditions. A symmetrical overconstrained compliant steering stage driven by a piezoelectric-electromagnetic composite was designed. Utilizing an elastic beam， pseudo rigid body theory and a transfer matrix， we established rotational stiffness analysis models for the compliant steering stage. The accuracy of the analytical rotational stiffness results obtained for this stage was validated via finite-element methods. The mapping relationships among the material and important geometric parameters and motion characteristics of the stage were explained by theoretical analytical equations. To enhance the overall characteristics of this stage， particularly with respect to the transmission ratio and natural frequency， we conducted topological optimization on the initial structural design. We also compared and examined the effects of load change on the motion performance such as tilt/tip angle， transmission ratio and cross-axis coupling of the stage. Finally， an experimental processing prototype was used to test the performance of the hybrid-driven steering stage. A finite-element simulation and experimental results revealed that the natural frequencies of the topologically optimized structure in the functional direction were 168.99% and 170.00% greater than those of the original structure. The average angular stiffness increased by 15.33%， and the maximum parasitic coupling ratio decreased by 20.29%. Moreover， the energized coil could effectively adjust the deflection angle toward the stage and resist the deflection loss caused by the load. Combining the finite-element method and the experimental results， the proposed design scheme for the target stage achieved both a high working frequency and high-precision positioning performance.Keywords：overconstrained configuration;electromagnetism;piezoelectric actuated;topological optimization;precision steering3879|2342|0
<HTML><L-PDF><WORD><Meta-XML>Updated：2026-09-11Domestic instrument industry in china： progress， challenges and outlooks
Abstract：This text highlights the value and importance of the instrument industry for economic and social development. It analyzes the current state of the global instrument industry and its economic contributions. Additionally, it discusses the challenges faced by the Chinese instrument industry, considering its historical development and existing issues. Strategies for overcoming current bottlenecks are presented, along with concepts and measures for the development focus of Chinese instrument enterprises. Finally, it outlines the opportunities and prospects for the Chinese instrument industry.Keywords：Instrument industry;Domestic instrument;Supply chain;Transformation of scientific and technological achievements;manufacturing process;Human resources3629|9730|2<HTML><L-PDF><WORD><Meta-XML>Updated：2026-09-11Virtual axis magnetorheological finishing of high-steepness curved optical elements
Abstract：In response to the technological constraints of traditional magnetorheological finishing machines， which typically feature an upper-mounted polishing wheel and encounter difficulties in processing optical components with significant steepness， this study introduces a compound linkage polishing technology. This innovative approach integrates a fixed mechanical axis with a virtual axis and employs an under-mounted fixed polishing wheel. Initially， a post-processing model for the compound linkage polishing of both the mechanical and virtual axes is established， informed by the structural characteristics of the under-mounted fixed polishing wheel. The model is articulated using the Denavit-Hartenberg （DH） method and is subsequently validated through geometric analysis. The accuracy of the established post-processing model is further corroborated by conducting spot-picking experiments on a virtual shaft concave spherical surface and uniform polishing experiments on a fused silica concave spherical surface， both with a diameter of 150 mm and a radius of curvature of 150 mm. Ultimately， a concave spherical surface crafted from molten fused silica， with a diameter of 170 mm， a radius of curvature of 158 mm， and a maximum normal angle of 32.54°， is polished and refined. Experimental results indicate that the PV value of the workpiece surface， with a trimming of 5 mm， converges to 0.04λ， while the RMS value converges to 0.005λ post-modification. These findings highlight that the proposed combined polishing model of the mechanical and virtual axes provides high precision and significantly enhances the processing capabilities for high-precision， high-gradient curved optical elements. This research contributes valuable insights into the application of magnetorheological polishing technology in the fabrication of complex curved optical elements with high steepness.Keywords：magnetorheological finishing;High steepness surface;Virtual axis;Under-mounted;Post-processing3411|2489|0<HTML><L-PDF><WORD><Meta-XML>Updated：2026-09-11Grating interferometric precision nanometric measurement technology
Abstract：Grating interferometry is a crucial technology in precision nanometrology, valued for its high resolution, robustness, and adaptability for multi-axis measurement systems. It is essential in advanced semiconductor manufacturing and ultra-precision machine tools. This review first compares grating interferometry with laser interferometry and time grating, detailing their applications and performance. It then explains the two main principles: homodyne and heterodyne grating interferometry. The review also analyzes global development trends, highlighting key manufacturers and advancements in achieving nanometric to sub-nanometric precision in single and multi-axis systems. In addition, it examines error sources, classifications, and compensation methods in grating interferometry. Finally, it discusses the current state and future prospects of grating interferometers, offering insights for developing and optimizing measurement systems based on this technology.Keywords：precision measurement;nano measurement;grating interferometer;multiple degrees of freedom;error compensation2950|4585|9<HTML><L-PDF><WORD><Meta-XML>Updated：2026-09-11Development and prospect of hyperspectral polarization
Abstract：Hyperspectral polarization is a new technology that combines hyperspectral and polarization imaging. It has become a research hotspot in many scientific fields. The research progress of hyperspectral polarization technology is reviewed， and its future development direction is prospected. In this paper， we first introduced the basic principle of hyperspectral polarization technology， and explained the advantages of combining hyperspectral and polarization imaging. Then， the classification of polarization spectrum instruments was introduced according to different design principles. Next， the application of this technology in remote sensing， medicine， environmental monitoring， earth science and material science was discussed in detail. Through the review of case studied in different fields， the unique advantages of hyperspectral polarization technology in providing richer and more accurate information were demonstrated. Finally， the current challenges of hyperspectral polarization technology were analyzed， including the precision of instruments， the complexity of data processing， and the problem of effective integration with other sensing devices. In view of these challenges， the future technology development direction was discussed. Future research should focus on improving the hyperspectral and temporal resolution of the technology， improving the accuracy of data processing and analysis， and expanding the applicability of different application scenarios to better meet the needs of different fields. In summary， hyperspectral polarization technology， as a comprehensive and efficient means of information acquisition， had made remarkable research progress in many fields. By optimizing hyperspectral polarization technology to meet a wider range of applications， hyperspectral polarization technology was expected to become an important tool in future scientific research and practical applications.Keywords：hyperspectral;hyperspectral polarization;imaging technology;polarization spectrometer2483|5327|4<HTML><L-PDF><WORD><Meta-XML>Updated：2026-09-11Multimode composite guidance data fusion method and its experimental validation
Abstract：In order to improve the guidance accuracy and anti-jamming ability of optoelectronic precision guidance guides， a data-driven fusion method based on multimode composite optoelectronic guidance guides was established. First， the physical structure of the laser/millimeter-wave radar/infrared multimode composite precision guidance was analyzed. Then， the Lagrangian interpolation and coordinate transformation method was used to realize the multimode guidance data alignment. Finally， a multimode composite guidance information fusion method based on a novel Transformer model was proposed to realize the data fusion and interference identification of multimode composite guidance guides. In order to verify the effectiveness of the proposed method， an experimental system of the guide head hang-flying was constructed. The experimental results show that the multimode composite guidance information fusion method can realize the fusion of multimode guidance in the data layer， and compared with the mutual covariance fusion method， the root-mean-square error is reduced by more than 22%， and the probability of capture when interfered with is increased from 71% to 91%， which greatly improves the accuracy of multimode guidance and the anti-interference ability， and can satisfy the practical needs of the multimode composite optoelectronic precision guidance application.Keywords：multimode composite guidance;deep learning;data fusion;target tracking2377|1559|1<HTML><L-PDF><WORD><Meta-XML>Updated：2026-09-11MMShip： medium resolution multispectral satellite imagery ship dataset
Abstract：Considering that the existing remote-sensing ship datasets consist entirely of cropped images， the detection effect of the detection algorithm trained on the datasets is poor when it is directly applied to satellite images of the original scale. In this study， a multispectral satellite ship dataset MMShip with four bands of visible and near-infrared （NIR） light was established. The dataset includes both the original-scale data of satellite images and cut small-scale ship data. Owing to the introduction of multi-band information， this dataset compensates for the shortcoming that most of the existing datasets contain visible images， which are easily affected by illumination conditions. Sentinel-2 satellite images with cloud cover of <3 in the oceans worldwide were downloaded. After atmospheric correction， only four bands—red， green， blue， and NIR—with a 10-m resolution were selected， and the images containing ships were screened by scene. Next， the screened images were divided into a size of 512 × 512 such that the divided images do not overlap， and the images that did not contain the ship target were eliminated. The LabelImage software was used to label the small-scale data with a horizontal frame， and then the labeled data were converted to the original scale to obtain the labeling information under the original scale. Finally， several typical detection algorithms were used to perform visible-light， near-infrared， and multispectral comparison experiments on the altered MMShip small-scale dataset. In this study， a multispectral satellite ship target dataset covering different scenes was constructed， which included 497 original scale-labeled data and 5 016 groups of cropped ship target images. The contrast experiment confirmed that the addition of near-infrared band information can increase the accuracy of the ship target detection algorithm. The developed multispectral ship dataset MMShip can be applied to research on algorithms for multispectral ship target detection at the satellite-image and ordinary-image scales.Keywords：multispectral remote sensing;ship dataset;ship detection;sentinel-22221|2301|3<HTML><L-PDF><WORD><Meta-XML>Updated：2026-09-12Improved DeepLabv3+ semantic segmentation incorporating attention mechanisms
Abstract：To address the challenges of high computational complexity， limited detail extraction， and fuzzy boundaries in the current DeepLabv3+ semantic segmentation network， this study proposes an enhanced DeepLabv3+ model incorporating attention mechanisms. Specifically， the lightweight MobileNetV2 is employed as the backbone to balance high representational capacity with a significant reduction in model parameters. A parameter-free lightweight attention mechanism （SimAM） is integrated into the low-level features of the backbone network to prioritize key features and enhance feature extraction capabilities. Furthermore， the global average pooling in the ASPP module is replaced with Haar Wavelet Transform Downsampling （HWD） to preserve spatial information. An External Attention Mechanism （EANet） is also introduced after the ASPP module to leverage contextual information and achieve multi-scale feature fusion， thereby improving semantic understanding and segmentation accuracy. Experimental results demonstrate that the proposed model achieves a 2.82% improvement in mean Intersection over Union （mIoU） on the VOC2012 dataset compared to the original DeepLabv3+ model. This research enhances the precision of semantic segmentation and offers novel insights for advancing applications in computer vision.Keywords：semantic segmentation;DeepLabV3+;Haar wavelet transform downsampling;External Attention（EANet）;multi-scale integration2015|2726|4<HTML><L-PDF><WORD><Meta-XML>Updated：2026-09-11Solution of plenty of marks in photogrammetry by bundle adjustment
Abstract：How to calculate a plenty of marks in close range industrial photogrammetry was discussed. The optimization method of bundle adjustment was proposed when the number of marks was large. Firstly, the application of the elimination point by point in adjustment calculation was analyzed. The accuracy of adjustment optimization was improved by introducing 10 camera intrinsic parameters of lens distortion. Then, the random function was used to select many marks in the space for bundle adjustment. After several times of partial adjustment optimization, the result could be very close to the level of global adjustment optimization. This way of adjustment not only overcomes the difficulty on out of memory and calculation interrupt in traditional calculation, but also has a high computation speed. Finally, two experiments with 1 360 and 896 marks were performed and the results show that reprojection errors are 0.076 and 0.107 1 after reconstruction respectively. It indicates that the method has a great accuracy and can be used in the actual measurement.Keywords：photogrammetry;point to point method;elimination;bundle adjustment;forward intersection1899|2066|0<HTML><L-PDF><Meta-XML>Updated：2020-08-13Detection of seed viability by photoacoustic carbon dioxide sensing
Abstract：In order to investigate the relationship between variations in carbon dioxide （CO2） concentration and seed vitality during respiration， a CO2 photoacoustic sensing system utilizing a differential Helmholtz photoacoustic cell was designed. The system's performance was evaluated by measuring the CO2 production rate of south japonica rice seeds exhibiting varying levels of vitality. An independent signal processing module based on a field programmable gate array （FPGA） development board was developed to facilitate precise regulation of laser drive current and demodulation of photoacoustic signals. Through optimization of modulation frequency， laser modulation depth， working pressure， and other system parameters， optimal performance was achieved， with an integration time of 1 089 s and a detection limit of 0.6×10-6. In accordance with national standard GB/T 3543.1， a germination experiment involving 30 g of south japonica rice seeds was conducted. Linear fitting analysis was performed using CO2 evolution concentration data obtained from the photoacoustic sensing experiment. The results demonstrate that the seed respiration rate of south japonica rice is directly proportional to seed vitality， with a correlation coefficient of 0.979. This finding provides a valuable reference for assessing rice seed vitality through photoacoustic spectroscopy.Keywords：Photoacoustic spectroscopy;Seed viability test;Helmholtz photoacoustic cell;carbon dioxide1772|1390|2<HTML><L-PDF><WORD><Meta-XML>Updated：2026-09-11
