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WANG Chao, LIANG Yonghui, WANG Kemu, WANG Zhiguo
2026,46(4):1-16 ,DOI: 10.11823/j.issn.1674-5795.2026.04.01
Abstract:
This paper introduces the role of atomic vapor cells in hot-atom precision measurement systems and discusses the principal physical mechanisms governing atomic spin relaxation, as well as their effects on polarization lifetime, coherence time, system noise, and long-term drift. The processing characteristics, applicable scenarios, and development trends of conventional glass-fabricated vapor cells and MEMS-micromachined vapor cells are compared. The effects of material selection, structural design, wall-surface treatment, buffer-gas metering, and thermal and magnetic environment management on vapor-cell performance are also analyzed. Looking ahead, the development of atomic vapor-cell processing and manufacturing should focus on establishing an engineering-oriented characterization and evaluation framework based on intrinsic parameters, including atomic number density, spin polarization, and relaxation time, together with the performance requirements of representative application systems. Key error sources should be controlled at the stages of vapor-cell design, fabrication, and evaluation. By establishing the underlying physical correlations between manufacturing parameters and device performance, atomic vapor cells can be advanced toward standardized devices with reproducible performance, predictable service lifetimes, and compatibility with large-scale production.
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DONG Dengfeng, GAO Chao, LI Yang, WANG Shan, SHI Junkai, ZHOU Weihu
2026,46(4):17-45 ,DOI: 10.11823/j.issn.1674-5795.2026.04.02
Abstract:
To further promote the development and application of domestic laser trackers, this paper systematically introduces the laser tracker technology and the independent research and development progress of laser trackers achieved by the research team at the Institute of Microelectronics of the Chinese Academy of Sciences (IMECAS). The basic principles and structural components of laser trackers are elaborated, and key techniques including laser ranging, miss-distance detection, precision angle measurement, servo tracking, error compensation and calibration are analyzed in depth. The current domestic and international testing specifications and technical standards in the field of laser trackers are presented, performance evaluation methods for laser trackers are discussed, and approaches to improve laser tracker performance are analyzed from both theoretical and application perspectives. The typical applications are introduced, such as in-situ intelligent manufacturing, real-time dynamic robot calibration and large-scale networked measurement. A series of research accomplishments achieved by the team at the IMECAS are highlighted, including the development of six-degree-of-freedom laser trackers, the design of extended functional modules for laser trackers, and the construction of the industrialization system for laser trackers. The development trend of laser tracker technology is prospected. It is pointed out that various novel tracking and measurement methods and equipment derived from laser trackers will play a vital role in high-end equipment metrology and advanced manufacturing.
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ZHANG Luyan, JIA Linhua, ZHANG Fumin, MEN Lingling
2026,46(4):46-53 ,DOI: 10.11823/j.issn.1674-5795.2026.04.03
Abstract:
Current multi-channel laser ranging technologies applied in accelerator alignment suffer from high equipment costs and complex system deployment. To solve these problems, this paper proposes a frequency-sweeping laser interferometric ranging technique adopting spherical collimators. A frequency sweeping laser interferometric ranging system integrated with HCN (H13C1?N) gas absorption cells, optical switches and spherical collimators was constructed to realize high-precision absolute distance measurement over a large range. A spherical collimator compatible with the target base of corner reflectors for laser trackers was designed, which reduces equipment costs while ensuring the required measurement accuracy. System performance tests were performed in an experimental environment simulating accelerator alignment. The results show that within the measurement range of 30 m, the ranging error of the proposed system is not more than 30 μm, fully satisfying the requirements of accelerator alignment. This system provides a high-precision and highly adaptable solution for accelerator alignment, and possesses great practical value in engineering applications.
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WANG Wei, LIU Jiamin, CUI Xue, JIANG Hao, LIU Shiyuan
2026,46(4):54-66 ,DOI: 10.11823/j.issn.1674-5795.2026.04.04
Abstract:
Existing calibration methods for ultra-micro-spot angle-resolved polarization scatterometers rely on rotating polarizers or liquid crystal retarders to calibrate the overall system parameters, resulting in complex operational procedures, difficulty in simultaneously decoupling multiple calibration parameters, and the introduction of additional error sources. To address these limitations, we propose an in-situ, stepwise calibration strategy for the system parameters of an ultra-micro-spot angle-resolved polarization scatterometer. Inspired by the principle of extinction ellipsometry, key system parameters — including the polarizer azimuth, ellipsometric parameters of the beam splitter in transmission and reflection, waveplate retardation and azimuth, ellipsometric parameters of the polarization beam splitter in transmission and reflection, and the orthogonally polarized transmittance of the objective lens — are sequentially calibrated with high precision. The proposed method was applied to calibrate a self-developed ultra-micro-spot angle-resolved polarization scatterometer, which was subsequently used to measure standard SiO2 thin films and rectangular grating samples. The results demonstrate that, after in-situ calibration, the instrument achieved a film-thickness measurement repeatability of 0.1 nm, and the extracted grating morphology parameters exhibited excellent agreement with standard values, thereby verifying the effectiveness of the proposed calibration method.
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HOU Guoyi, ZHAO Ziyue, LI Runrun, SUN Anbin, LI Shuanggao, HUANG Xiang
2026,46(4):67-92 ,DOI: 10.11823/j.issn.1674-5795.2026.04.05
Abstract:
Conventional digital measurement methods suffer from low efficiency in measurement field construction and poor coordination among multiple devices, which cannot satisfy the high-precision and batch measurement and assembly requirements for large complex structures of new-generation aircraft. To address the above limitations, this paper investigates the multi-system collaborative precision measurement technology, establishes an uncertainty analytical model for large-scale measurement fields, and proposes an adaptive planning method. A multi-mode datum conversion standard artifact was developed to improve the construction accuracy of collaborative measurement fields. Meanwhile, a measurement planning technology based on lightweight models and task-device collaboration was put forward to realize the automatic sequence generation and simulation optimization for multi-station and multi-task measurement. On this basis, a multi-system collaborative precision measurement platform for the assembly of large complex structures was developed, which integrates multi-device control, measurement planning, and data management and analysis, achieving closed-loop control of the assembly measurement process covering "model-planning-measurement-analysis". Comparative experiments were conducted to verify the platform performance. The test results demonstrate that the proposed platform remarkably improves the measurement accuracy and efficiency, providing strong technical support for advancing the precise measurement and assembly technology of large complex structures in the aviation industry.
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CHENG Yanbo, LI Tianfu, SUI Jinglin, TANG Xiaohui, XIA Meng, DONG Yongkang
2026,46(4):93-108 ,DOI: 10.11823/j.issn.1674-5795.2026.04.06
Abstract:
The basic concept, waveform construction, and time-frequency mapping mechanism of the optical chirp chain (OCC) are introduced, and the fundamental principle by which OCC improves the acquisition efficiency of Brillouin spectra is elucidated. The operating principles of optical chirp chain Brillouin optical time-domain analysis (OCC-BOTDA) and optical chirp chain Brillouin optical time-domain reflectometry (OCC-BOTDR) are described. Research advances in OCC-BOTDA are reviewed in terms of single-shot ultrafast measurement, long-range and high-performance sensing, suppression of transient effects and spectral distortions, vector measurement, polarization diversity, and denoising enhancement. Progress in OCC-BOTDR is summarized with respect to single-ended online demodulation and sensing-performance improvement. The measurement range, spatial resolution, measurement time, and other performance parameters of different approaches are comparatively analyzed. Future directions for OCC-based fast distributed Brillouin sensing are discussed. Further advances are required in high-quality OCC generation, coherent detection, and digital signal processing. Moreover, OCC-based fast distributed Brillouin sensing can be integrated with other techniques to enable long-range, coordinated sensing of multiple physical parameters, while improving the engineering applicability and reliability of measurement systems to meet the demands of multiparameter monitoring in complex engineering environments.
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SUN Qian, MENG Xiangyue, LI Jing
2026,46(4):109-115 ,DOI: 10.11823/j.issn.1674-5795.2026.04.07
Abstract:
Currently, the heterogeneous node deployment schemes employed in sensor network applications for monitoring tasks suffer from suboptimal operational efficiency. To address this issue, this paper proposes the Optimal Deployment of Heterogeneous Node Positions in a Single-Sink Network (ODHNSS) algorithm. By jointly considering key performance indicators such as network coverage, the ratio of communication distance to communication radius, and the proportion of sleeping nodes, the algorithm establishes principled criteria for selecting optimal heterogeneous node locations, thereby enabling energy-aware optimization of heterogeneous node deployment in wireless sensor networks. Simulation experiments were conducted using MATLAB to comparatively evaluate the performance of ODHNSS against two state-of-the-art algorithms, Three-Tier Extended Energy-Efficient Clustering Hierarchy (TEEECH) and Optimal Deployment of Heterogeneous Nodes (ODHN). Results demonstrate that, relative to both benchmarks, ODHNSS significantly improves data transmission efficiency while simultaneously reducing overall network energy consumption, thus providing robust technical support for advancing wireless sensor monitoring network technologies.
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MIAO Biqi, TANG Zhaoxuan, ZHUO Lianghui, LI Zhenya, HE Wei, YUN Hao, ZHAO Kaifeng, YAN Zhipeng
2026,46(4):116-128 ,DOI: 10.11823/j.issn.1674-5795.2026.04.08
Abstract:
Aiming at the measurement errors caused by the resistance of high-temperature long wires and their temperature variations in long-distance strain testing of high-temperature structures for nuclear power applications, this paper proposes a strain correction method integrating strain gauge test data, measured strain gauge resistance and wire resistance values. The formation mechanism of strain measurement errors under long-wire transmission conditions is analyzed. By introducing resistance parameters of strain gauges and connecting wires, a unified correction model for measured strain is established to calibrate strain readings acquired at high temperatures. Based on the model, the thermal output curves and gauge factors are determined. High-temperature strain tests at 350 °C were performed to verify the effectiveness of the proposed method, which is further compared with the traditional three-wire method and half-bridge compensation method. The results demonstrate that the proposed method can simultaneously account for the coupled effects of wire resistance and its temperature drift, substantially reduce measurement errors, and improve the accuracy and stability of test results. This work provides critical technical support for enhancing the precision of high-temperature long-wire strain measurement in the nuclear power industry.
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LIANG Liang, WU Zhenghao, LI Shuhan
2026,46(4):129-137 ,DOI: 10.11823/j.issn.1674-5795.2026.04.09
Abstract:
To evaluate the aerodynamic performance and flow field quality of a full-scale test bench for a domestic high-bypass-ratio aero-engine, a computational fluid dynamics (CFD) simulation combined with measurement analysis was conducted. A three-dimensional model of the test bench, comprising an intake tower, silencing devices, a flow straightener, the aero-engine, an ejector duct, and an exhaust tower, was constructed using 3D modelling software. A refined mesh was generated, and the standard k-ε turbulence model with wall functions was employed to handle turbulence and near-wall flow. The flow governing equations were solved using the Semi-Implicit Method for Pressure Linked Equations (SIMPLE), and the distributions of velocity, pressure, and temperature fields, as well as natural convection characteristics, were analyzed. The results show that the ejection coefficient of the test bench reached 1.97, and the velocity non-uniformity at the cross-section 6 m upstream of the engine was 29.05%, which meets the relevant industry standard requirements. The flow straightener reduced the velocity non-uniformity by approximately 51.5%, significantly improving flow uniformity. The total pressure non-uniformity at the engine inlet was only 0.3%, indicating a low level of flow distortion. Under natural convection conditions, the wind speed inside the test bench remained below 2 m / s, and the impact of stack effect was limited. Overall, the test bench exhibits a reasonable aerodynamic design and excellent flow field quality, thus satisfying the ground test requirements for the domestic high-bypass-ratio aero-engine.
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ZHANG Longci, CAO Xizheng, LEI Duncai, GONG Xuan, HE Yu
2026,46(4):138-147 ,DOI: 10.11823/j.issn.1674-5795.2026.04.10
Abstract:
To address the challenging measurement of oil-gas two-phase parameters in the return oil pipeline of an aeroengine lubrication system, a testing system for oil-gas two-phase flow of aeroengines based on electrical capacitance tomography has been developed. The cross-sectional phase fraction measurement is achieved using electrical capacitance tomography technology, and the flow pattern is regularized through a rectifier to enhance measurement accuracy, at the same time, the Venturi technology is utilized to achieve total flow measurement, ultimately leading to the measurement of gas-liquid two-phase flow. A calibration device for oil-gas two-phase measurement has been set up based on the field test bench for comparative testing of the measurement system. The results indicate that the maximum measurement error for liquid phase flow rate is 7.26 %FS, and the maximum measurement error for gas phase flow rate is 6.56 %FS under six experimental conditions. The research presented in this paper plays a crucial supporting role in the design of lubrication systems in the aeroengine field.
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WANG Menghui, ZOU Qiao, ZHOU Zhixin, DONG Jigang, WANG Yahai, ZHAO Rui
2026,46(4):148-155 ,DOI: 10.11823/j.issn.1674-5795.2026.04.11
Abstract:
To achieve accurate dielectric constant measurement of liquid and powder materials in the millimeter-wave band, this paper proposes a measurement method based on corrugated transmission lines. A dedicated test system was built using a customized polytetrafluoroethylene (PTFE) container and matched with vector network analysis technology for experimental testing. The Gated-Reflect-Line (GRL) calibration technique was adopted to mitigate measurement errors arising from multiple signal reflections and scattering between the container structure and the test samples. Following calibration, liquid or powder samples were loaded into the container, and the reflection S-parameters captured by a vector network analyzer were utilized to calculate the sample dielectric constant. Solid PTFE was tested as a standard sample to verify the feasibility and reliability of the established test system. Further experiments were conducted on quartz powder and dimethyl synthetic silicone oil within the frequency range of 75～110 GHz. The test results show that the maximum deviation of measured data from the average value is merely 5%, which verifies the superior accuracy of the proposed method. This study offers a crucial technical reference for millimeter-wave dielectric constant measurement of liquid and powder materials, supporting technical development in food processing, biomedicine and other related fields.
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JIANG Tao, QIAO Lu, XIAO Qiong
2026,46(4):156-166 ,DOI: 10.11823/j.issn.1674-5795.2026.04.12
Abstract:
To promote the layout of standard essential patents in China's aviation industry and enhance the integration of patents and standards in the high-end equipment manufacturing sector, this paper takes enterprises in the aviation industry chain as the research perspective to conduct patent retrieval and statistical analysis based on patent databases and industry standards repositories. The results show that patents within the aviation industry chain are insufficiently integrated with international standards, and their industrial adaptability remains weak，with room for improvement in quantity, track selection, mechanisms, operation and maintenance, and synergy. Based on the above analysis results and the domestic policy environment, application strategies and layout paths for standard essential patents are proposed. It is pointed out that efforts should focus on niche tracks with strong interoperability and that a multi-party collaborative whole-chain working mechanism should be established. This research can provide a reference for promoting the deep integration of patents and standards in the aviation industry and for high-end equipment manufacturing industry groups to carry out relevant domestic business.
Volume 46,2026 Issue 4
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ZHANG Shuming, LIU Chunhong, XUE Weijun
Abstract:
As a highly complex integrated system, aircraft structural integrity remains a critical objective in the aerospace industry. The load spectra serve as a key linking operational missions, load transmission, structural responses, and damage evolution. Its accuracy and representativeness directly determine the reliability of structural integrity assessments. This paper comprehensively reviews recent advances in aircraft load spectrum research both domestically and internationally, with a focus on its essential role within structural integrity frameworks, innovations in measurement technologies, cutting-edge methods for multi-source data fusion and intelligent processing, and their practical engineering applications, aiming to provide theoretical support and technical references for structural integrity design, service life management of aircraft in future, and effective implementation of Structural Integrity Programs in terms of load spectrum data acquisition.
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Abstract:
Cold atom interferometers use laser-cooled atomic ensembles as test masses and convert gravity-induced phase shifts into absolute acceleration measurements. Their low drift, absence of mechanical wear, and capability for continuous observation make them suitable for precision gravity metrology, static gravity monitoring, and dynamic gravity measurement on moving platforms. This review introduces the basic principle and technical characteristics of cold atom interferometric absolute gravimetry. It summarizes recent progress in gravity metrology and metrological traceability, ground static measurement, transportable and field measurement, shipborne measurement, and airborne measurement. It also discusses prospective underwater and spaceborne applications. The review compares the system configurations, error correction methods, vibration compensation strategies, data processing procedures, and performance evaluation methods used in different application scenarios. It further summarizes engineering progress from the AVIC Changcheng Institute of Metrology & Measurement in quantum absolute gravity traceability, validation of static quantum gravimeters, shipborne dynamic measurement, and airborne dynamic measurement. Current developments show that cold atom absolute gravimeters are moving from high-precision laboratory instruments toward metrological, product-oriented, and multi-platform engineering applications. However, further improvements are still needed in domestic core components, long-term reliable operation, environmental adaptability, dynamic compensation accuracy, data fusion, and evaluation standards. Future work should coordinate the development of core devices, complete instruments, platform adaptation, data processing, and metrological evaluation for stationary stations, field surveys, vehicle-borne measurements, shipborne measurements, airborne measurements, underwater platforms, and spaceborne missions. These developments will support gravity reference maintenance, geophysical exploration, marine gravity surveys, and airborne gravity measurement.
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ZHANG Lei, ZHOU Wenbin, YANG Zhenqi, LV Qingbin
Abstract:
To meet the demand for simultaneous real-time monitoring of CO? concentration and gas flow velocity in flue gas streams for industrial emission monitoring, this paper presents a synchronised measurement system based on tunable diode laser absorption spectroscopy (TDLAS). A distributed feedback (DFB) laser with a centre wavelength of 2004?nm was employed as the light source. The system retrieves CO? concentration by exploiting the characteristic absorption lines of CO? molecules in the near-infrared band, and determines the flow velocity using a dual-path compensation algorithm, thereby enabling collaborative sensing of key flow-field parameters. Experiments for simultaneous measurement of CO? concentration and velocity were conducted under various flow-rate conditions in an annular wind tunnel, and the results were verified by comparison with reference instruments. The experimental results show that, under different flow velocities, the velocity measurement deviation ranges from 0.11 to 1.04?m/s, with a maximum measurement variance of 1.27?m/s; for the two independent optical paths, the CO? concentration deviation lies between 0.06?% and 0.09?%, with a maximum variance of 0.06?%. The system operated stably throughout the tests, exhibited good measurement repeatability, and the correlation between concentration and velocity data was consistent with theoretical expectations. The proposed device enables simultaneous on-line monitoring of key flue-gas parameters without disturbing the flow field, providing a reliable technical means for combustion diagnosis and quantitative emission control.
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ZHANG Chenglong, WANG Liang, LIU Feng, WEI Chunfeng, CHEN Jichi
Abstract:
To improve fault feature representation and diagnostic performance for bearing fault diagnosis, this study proposes a fault diagnosis method that integrates time-frequency analysis, deep feature extraction, feature selection, and ensemble learning. Continuous Wavelet Transform (CWT) converts bearing vibration signals into time-frequency images and preserves fault characteristics in both the time and frequency domains. A pretrained model extracts deep features from the generated images and improves fault feature representation. Feature selection algorithm based on nearest neighbors (ReliefF), maximum relevance minimum redundancy, and least absolute shrinkage and selection operator remove redundant features and retain discriminative features. Random Forest, eXtreme Gradient Boosting, and Light Gradient Boosting Machine (LightGBM) classify bearing faults. This study compares different combinations of feature selection methods and diagnosis models and evaluates their diagnostic performance. Experimental results show that the combination of ReliefF and LightGBM achieves the highest diagnostic accuracy of 95.72%. This method provides reliable technical support for fault diagnosis, condition monitoring, and health management of rotating machinery and promotes the development of intelligent fault diagnosis technologies.
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Abstract:
This review presents the research background and current state of novel nanoprobe technologies for nanoscale measurements. It discusses the limitations of conventional characterization methods in terms of spatial resolution, environmental adaptability, and multidimensional information acquisition, and analyzes the critical role of nanoprobes as functional units in overcoming these bottlenecks. Focusing on two core objectives, namely improving spatial resolution and enhancing signal sensitivity and signal-to-noise ratio, this paper systematically summarizes representative advances in plasmonic nanofocusing probes, ultrasharp probes, dynamic feedback control techniques, as well as surface plasmon resonance enhancement, probe structural optimization and noise suppression, and signal amplification and conversion strategies. The design principles, technical characteristics, and application scenarios of various probe types are examined in detail. Moreover, this review points out that current nanoprobe technologies still face significant challenges in reproducibility, environmental stability, and multimodal signal interference. It is proposed that future efforts should be directed toward establishing standardized performance evaluation systems, developing multimodal signal decoupling algorithms, and advancing intelligent adaptive probe technologies. In parallel, refining the precision of probe fabrication processes and enhancing the efficiency of functional integration will further improve the comprehensive performance and application potential of nanoprobes in single?molecule detection, in?situ characterization, and measurements in complex environments.
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Abstract:
This paper proposes an immersion and invariance theory-based prescribed-time adaptive control method for a series elastic actuator system with parametric uncertainties. A newly designed time-scale transformation function is employed to overcome the singularity problem caused by traditional time-scale transformations near the prescribed time. Then, the parameter estimation structure of the immersion and invariance method is introduced, and a prescribed-time convergent adaptive law is developed to guarantee the prescribed-time convergence of the parameter estimation error. Furthermore, a prescribed-time sliding mode surface is designed to ensure that the tracking error of the system converges to a given small neighborhood within the prescribed time. Besides, the stability of the closed-loop system is validated via the Lyapunov method. Simulation results verify the effectiveness of the proposed method.
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Abstract:
Heterodyne laser interferometers serve as core instruments for ultra-precision displacement measurement. The main bottleneck restricting their measurement accuracy lies in nonlinear errors (NCE) induced by non-ideal characteristics of optical systems, which are typically manifested in three features: unequal amplitude, DC offset, and non-orthogonality. Based on a rigorous derivation of the series model for nonlinear errors in heterodyne interferometry, this paper compares and analyzes the inherent limitations of traditional analytical compensation and ellipse-fitting methods. It is pointed out that both methods essentially belong to passive mathematical fitting and can hardly eliminate residual harmonic fluctuations under dynamic displacement conditions. To address this issue, an active feedback compensation strategy based on an improved polarizer rotation method is proposed. A closed-loop regulation structure is constructed using a quarter-wave plate and a controllable rotating polarizer. By means of the independent-variable physical freezing mechanism, dynamic nonlinear errors that fluctuate sharply with displacement are equivalently converted into static constant offsets. Combined with static pre-scan stripping and Fast Fourier Transform (FFT), high-precision calibration and initial alignment of the system initial phase offset ??are achieved. Simulation results preliminarily verify the theoretical feasibility of the proposed method under ideal conditions, which can effectively suppress first-order nonlinear errors from the nanometer scale to below 0.1 nm, restore the Lissajous figure to a standard unit circle, and bring the measurement accuracy close to the noise limit of the Cramér-Rao Lower Bound (CRLB). At this stage, this work focuses primarily on theoretical modeling and simulation analysis. This research introduces a new concept for eliminating nonlinear errors at the hardware closed-loop level, and an experimental platform will be constructed for hardware validation in future work, which is expected to offer theoretical and technical support for realizing ultra-precision and high-linearity displacement measurement.
综合评述
“量子增强检测技术前沿与应用”专题 客座主编：肖连团
计量、测试与校准
理论与方法
"精密测量"专栏
理论与方法
"精密测量"专栏
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A Modal Analysis Method for Industrial Robots Based on Multi-Posture Model and PLSCF Method
Abstract:
The dynamic characteristics of industrial robots are pivotal in governing operational accuracy, stability, and system reliability. Generally, low-order modes demonstrate significant posture-dependent behavior and multi-joint coupling interactions. To accurately represent the dynamic characteristics, a modal identification method is proposed, incorporating a multi-posture model and the Poly-reference Least Squares Complex Frequency-Domain method (PLSCF). For a typical six-degree-of-freedom industrial robot, a multi-posture model is constructed according to its representative operational postures. Modal experiments are conducted using impact hammer excitation and shaker-based excitation methods. Based on the obtained frequency response functions, modal parameter identification is calculated using the PLSCF, extracting the first three natural frequencies and corresponding damping ratios. Consequently, the second and third natural frequencies vary by approximately 20%. The corresponding mode shapes are then constructed, with the underlying evolution mechanism investigated. In addition, a modal assurance criterion (MAC) is introduced to evaluate the correlation of mode shapes and to assess the influence of posture variations on the local modal coupling behavior of the robot. The result presents that the proposed method effectively captures the dynamic behavior of industrial robots, offering a reliable basis for dynamic modeling and analysis and facilitating applications such as structural optimization, trajectory accuracy improvement, and intelligent operation and maintenance.
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A Method for Coordinated Scanning Planning of Robot-Positioner under Scanning Geometry Constraints
Abstract:
To tackle the challenge of planning coordinated movements between robots and positioners during robot-assisted 3D measurement, we propose a robot–positioner collaborative scanning motion planning method based on the geometric relationships of four key points. Using four points—the turntable center A, the scanner center B, the robot base C, and the positioner base D—we construct a fixed main plane and a dynamic probe plane. Candidate positioner angles are geometrically pre-screened using lateral position relationships and plane deviation angles. Following the principle of ''robot first, positioner support,'' the positioner’s zero position is preferred, and angle searching is initiated only if geometric pre-screening or reachability verification fails. For continuous scanning paths, a unified positioner angle is chosen to reduce turntable switches. Simulations on typical complex surface parts show that this method is quite feasible. In experiments with 12 scanning viewpoints, the planned trajectories achieved a 100% success rate for inverse kinematics and collision checks, with a scan coverage of 82.13%. This approach efficiently plans positioner angles and ensures smooth transitions for continuous trajectories while maintaining scan coverage and path executability.
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Research on Surface Defect Inspection Technology for Rubber O-Ring Seals Based on Machine Vision and Laser Scanning
YANG Ying, ZHEN Xiaojuan, ZHOU keping, WEI fen, LUO Cheng, LUO Ting, LIU Weijun
Abstract:
Rubber O-ring seals are widely used in high-demand industrial sectors such as aerospace and petroleum energy, where surface defects directly affect sealing reliability. To address the low efficiency of manual inspection, the missed detection of micro-defects, and the difficulty of quantifying defect depth, a surface-defect inspection method integrating machine vision and laser line scanning is proposed. For flash defects, sector-shaped ROI segmentation, piecewise edge fitting, and abnormal-contour discrimination are employed. For pits, short shots, and adhesion defects, multi-light-source temporal differencing, Gaussian-high-pass composite filtering, and Sauvola adaptive thresholding are combined. For pit-depth evaluation, maximum-similarity template matching and least-squares curve reconstruction are used. Experiments were conducted on 75 samples containing flash defects and 106 samples containing pits, short shots, or adhesion defects. The detection rate for prominent flash defects was 100.00%, and the overall detection rate for pits, short shots, and adhesion defects was 97.24%. The relative errors of area measurement for all four defect types were below 10%. For ten repeated measurements of the same pit, the mean absolute deviation was 13.94 μm and the standard deviation was 1.21 μm. Double-sided inspection of five samples required approximately 2 min. The proposed method integrates micro-defect recognition, area measurement, and depth evaluation, providing a quantitative basis for O-ring quality grading
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