Special issue

1 Research on calibration technology for high-precision spherical coordinate scanning measurement systems

SUN Anbin , WANG Jihu , CAO Tieze , FAN Jingjing , GAO Ting , LIU Yuwei

2026, 46(2):155-170. DOI: 10.11823/j.issn.1674-5795.2026.02.14

[Abstract](59) [HTML](142) [PDF 53.37 M](80)

Abstract:
The metrological standards of high-precision spherical coordinate scanning measurement systems are mostly limited to evaluating simple geometric features, making it difficult to meet the traceability requirements for full-field scanning accuracy of complex surfaces. Meanwhile, large curved surface standard devices face a bottleneck in maintaining high precision during calibrating high-precision spherical coordinate scanning systems due to the influences such as gravity and ambient temperature. To address the above difficulties, this paper proposes a calibration scheme based on large-scale physical surfaces. A large-scale combined standard device integrating concave, convex, and planar surfaces was innovatively designed to achieve comprehensive evaluation of the contour scanning performance of the measurement system. The proposed "segmented fabrication-precision assembly-thermal expansion release" structural design scheme utilizes an invar frame and an independently suspended thermal expansion release mechanism to suppress environmental thermal stress and gravity-induced deformation, enabling high-precision assembly of the large-scale standard device while ensuring long-term stability compliance. A high-precision reconstruction method for large-scale geometric digital models was developed to achieve accurate calibration of the high-precision spherical coordinate scanning measurement systems. Experimental results demonstrate that this method can control the assembly error tole-rance within 0.05 mm and reduce the RMS error to less than 0.01 mm, effectively supporting the establishment of accuracy traceability for the measurement system.

2 Online measurement and compensation of six-degree-of-freedom errors for Z-axis of micro-nano CMMs

LI Jie , ZHANG Chengyao , LIN Rongwei , LI Ruijun

2026, 46(1):160-168. DOI: 10.11823/j.issn.1674-5795.2026.01.11

[Abstract](221) [HTML](126) [PDF 10.34 M](312)

Abstract:
There is a lack of a universal and readily integrable online measurement and compensation scheme for six-degree-of-freedom (6-DOF) errors along the Z-axis of micro-nano coordinate measuring machines (CMMs). To address this challenge, this study introduces a synchronous measurement method for the axis of micro Z-axis linear and angular errors based on laser interferometry and autocollimation principles，and establishes a spatial error compensation model under Z-axis 6-DOF influence based on the Abbe principle and the Bryan principle. An in-situ and on-line Z-axis 6-DOF error measurement system based on the measurement method was developed and applied to a micro-nano CMM. Measurements were performed along the Z-axis on a grade 0 gauge block with a nominal thickness of 8 mm using the CMM. The results show that the measurement standard deviation and indication error are reduced by 54.6% and 54.3%, respectively, after compensation. This method, compensation model and the system provide a reliable solution for improving the measurement and machining accuracy of coordinate measuring machine(CMM) and other precision equipment.

3 Analysis of calibration error propagation in the kinematic chain of a six-DOF robotic manipulator's end-effector pose

JIANG Wensong , WANG Yan , LUO Zai , FENG Siqi , YANG Li , ZHANG Penghao

2025, 45(2):48-55. DOI: 10.11823/j.issn.1674-5795.2025.02.05

[Abstract](552) [HTML](183) [PDF 2.88 M](893)

Abstract:
To study the nonlinear impact of calibration errors on the positioning accuracy of a robot's end-effector, a linkage analysis of end-effector pose calibration errors for a six-degree-of-freedom robot was conducted. Using the modified Denavit-Hartenberg model (MDH) constraints, a kinematic parameter model for a six-degree-of-freedom robot was established to analyze the spatial geometric relationships of the end-effector's pose transformation. The sources of robot calibration errors were examined, and the functional relationships between the coordinate systems of the measurement system were derived. Based on this, a calibration error propagation model for the robot's end-effector pose was constructed. A calibration system for a six-degree-of-freedom robot was set up to conduct experiments. Experimental results indicate that the primary sources of calibration error in robotic end-effector positioning include link length errors, joint offset errors, joint twist angle errors, and zero-position errors. The combined calibration error was measured as 2.66 mm, with relative uncertainties in the x, y, and z directions of 0.09%, 0.37% and 0.46% respectively. The research findings provide technical references for achieving precise positioning control of the robot's end-effector.

4 Precision femtosecond laser ranging based on electro-optic sampling and its applications

QIU Zhifeng , SUN Shichao , LI Boyao , GU Chufang , SUN Jinghua

2025, 45(2):80-87. DOI: 10.11823/j.issn.1674-5795.2025.02.08

[Abstract](560) [HTML](222) [PDF 6.76 M](1045)

Abstract:
In order to research high precision and high speed laser measurement technology, this study explores precision ranging using a femtosecond optical frequency comb based on electro-optic sampling timing detection technology. The optical frequency comb ranging system integrates a fiber Sagnac interferometer, electro-optic modulators with dynamic phase bias, non-reciprocal static phase biasing units, and optical pulse time-of-flight detection, offering advantages of high precision and speed. The system achieves a 45 nm single-point ranging uncertainty within a 26 ms integration time. Coupled with a two-dimensional scanning translation stage, it enables precise measurements of step heights on gauge blocks and surface morphology of coins. Additionally, it dynamically detects the diffuse reflections from a metallic film 3 m away influenced by nearby speaker sound waves, faithfully reproducing the played music signals. This study demonstrates the great potential of electro-optic sampling timing detection technology in high precision and high speed distance measurement, playing a significant role in advancing the field of precision ranging.

5 Frequency scanning interferometry method for distance measurement based on electro-optical intensity-phase cascade modulation

DENG Zhongwen , LIU Chuanfeng , ZHANG Hengkang , SUN Haifeng , ZHANG Shuwei , LI Xiaoping

2025, 45(2):68-79. DOI: 10.11823/j.issn.1674-5795.2025.02.07

[Abstract](573) [HTML](212) [PDF 5.64 M](795)

Abstract:
Frequency Scanning Interferometry (FSI) absolute distance measurement technology exhibits significant potential for applications in advanced manufacturing and aerospace technology. To address the issue of significant measurement errors in traditional FSI systems under high-dynamic conditions, this paper proposes an FSI distance measurement method based on electro-optical intensity-phase cascade modulation. Based on the theoretical derivation of the amplification effect of optical path difference variation in traditional FSI systems, a double-sideband FSI distance measurement system with electro-optical intensity-phase cascade modulation was designed. The system employs a single photodetector for photoelectric detection of the frequency-scanning interference signal, and uses all-phase fast Fourier transform (APFFT) to extract the phase information of the interference signal with high precision, enabling the simultaneous high-accuracy measurement of both absolute distance and relative displacement of the target. Simulation results show that the standard deviation of the absolute distance measurement of this method can reach below 10 μm, and the standard deviation of the relative displacement measurement can reach below 10 nm, which effectively verifies the feasibility and accuracy of the proposed method.

6 Research on measurement method of aeroengine blade roughness

ZHANG Xueyi , HE Xiaomei , WANG Yizhang , MA Pengmou

2023(2). DOI: 10.11823/j.issn.1674-5795.2023.02.05

[Abstract](976) [HTML](337) [PDF 3.52 M](1354)

Abstract:
The surface of aero-engine blades has large bending and torsion, and it is difficult to ensure consistent surface roughness during machining. In view of the lack of definitions of measuring position and direction in the current roughness measurement method when measuring blades, which leads to the problem that the measured roughness value cannot determine the eligibility of blade roughness, the research on blade roughness measurement method is carried out. Based on the measured section data of blades, using the roughness probe carried on the CMM, the blade roughness measurement method is obtained by carrying out multi-position and multi-direction roughness measurement experiments on different types of blades and analyzing the difference of the roughness measurement results in different positions and directions. This method associates the blade roughness with the blade profile, and solves the problem that the measurement position and direction of blade roughness are not standardized. The research results are of great significance to accurately and effectively evaluate the qualification of blade surface quality.

7 Research progress of depth measurements of high aspect ratio microstructures

WU Yuesong , WANG Zizheng , SUN Xinlei , WU Feiyu , HUO Shuchun , HU Chunguang

2023(1):3-17. DOI: 10.11823/j.issn.1674-5795.2023.01.01

[Abstract](3229) [HTML](453) [PDF 3.98 M](4520)

Abstract:
High aspect ratio hole/slot microstructures are now widely used in the fields of micro-electro-mechanical systems (MEMS) and three-dimensional integrated circuits (3D-IC), and are fundamental process structures for micro and nano devices. With the development need for miniaturization and functionalization of devices, the depth-to-width ratio of hole/slot microstructures is constantly increasing. As an important parameter, depth has a direct impact on the device processing and device performance. The accurate measurement of the depth of micro-hole/slot structure is of great significance, but the measurement method faces great challenges and has become one of the difficult problems in the field of measurement. To address this issue, the measurement methods are divided into two major categories according to the non-optical and optical measurement methods, and the working principles of measurement methods such as scanning electron microscopy, scanning probe technique, white light microscopic interferometry, confocal microscopy and reflection spectroscopy are introduced. The research status of the depth measurements of micro hole/slot is introduced, and the advantages and disadvantages of each measurement method are summarized. Finally, the future development trend and research focus of high aspect ratio microstructure depth measurement are discussed to help the future research of high aspect ratio microstructure depth measurements.

8 Inner diameter measurement based on dispersive confocal principle

LIU Hange , YAN Yufeng , TANG Wei , HAN Jiahao , PAN Guotao

2023(1):128-136. DOI: 10.11823/j.issn.1674-5795.2023.01.12

[Abstract](1103) [HTML](265) [PDF 2.03 M](1105)

Abstract:
In order to meet the requirements of high-precision and non-contact measurement of small diameter deep hole parts, a set of high-precision optical measurement system suitable for large measurement range was developed. Based on the principle of dispersion confocal measurement, a micro displacement system is established, and a high-resolution optical measurement system is formed by combining the spectral analysis technology. Firstly, based on the dispersion confocal principle, the structure of dispersion objective lens is designed by using Zemax software. Secondly, the creeping structure is designed, and the motor is used to drive the reflector rotating to complete the radial geometric dimension measurements of different sections of the deep holes. Thirdly, the system error is analyzed by least square method and is compensated. Finally, an experimental platform was built to verify that the measurement range reached 5 mm and the measurement accuracy was better than 3.3 μm. It has the advantages of high measurement accuracy, large measurement range and compact structure, which is of great significance to solve the problem of the measurement of the inner diameter of small size deep hole parts.

9 Research on relative pose measurement method of space target in complex light environment

DING Yibing , WANG Haiming , SU Zhenhua , YIN Liang , LUO Ying

2024(2):56-69. DOI: 10.11823/j.issn.1674-5795.2024.02.07

[Abstract](899) [HTML](260) [PDF 3.54 M](1429)

Abstract:
To solve the problems of difficulty in measuring the relative pose of the target spacecraft caused by differ- ent illumination, information distortion and incomplete feature of the image obtained by the visible light camera under complex lighting conditions in space, a binocular vision relative pose measurement method based on image enhancement and arc feature was proposed. An adaptive image preprocessing algorithm based on multi-scale Retinex with chromaticity preservation (MSRCP) was applied firstly to improve the image quality in the environment of spatial dim light and local strong exposure. Secondly, an ellipse detection algorithm based on the edge arc support line segment was applied to ex- tract the arc segment features of the docking ring on the surface of the target spacecraft and fit them into an elliptical con- tour. Finally, a binocular vision camera was used to build a physical simulation platform for relative pose measurement, and a binocular space elliptical conic measurement model was established to calculate the six degrees of freedom relative pose. The relative pose of target spacecraft was achieved in normal and dim light scenes at close range. The experimental results showed that the average error of relative position is better than 20 mm and the average error of relative attitude is better than 0.3° under normal lighting condition, and the average errors of relative position and pose are better than 30 mm and 1° , respectively, under dim lighting condition. The research results provide a reference for the identification and measurement of targets in on-orbit service missions such as close-range space rendezvous and docking, and have techni- cal reference value.

10 Dual-band microscopic interferometry for nondestructive testing of three-dimensional morphology of microstructures

HUO Xiao , GAO Zhishan , YUAN Qun , GUO Zhenyan , ZHU Dan

2023(1):70-80. DOI: 10.11823/j.issn.1674-5795.2023.01.06

[Abstract](1122) [HTML](272) [PDF 5.54 M](1690)

Abstract:
Functional microstructure has the function of regulating light field or electronic conduction, and generally contains regular geometric shapes. Based on the ratio of depth to line width, it can be divided into high/low-aspect-ratio microstructures. At present, the detection of the geometric characteristic parameters of the microstructure is mainly conducted by SEM, which belongs to the destructive detection. The production line urgently needs non-destructive testing technology to monitor and improve its manufacturing process. This article systematically summarizes the progress made by the author's research team in the low-coherence microscopic-interference technology for nondestructive testing of three-dimensional (3D) morphology of microstructures in the past ten years. The white light microscopic interferometer is used to detect the 3D topography of ultra-smooth surfaces, steps, micro optical elements, micro mechanical elements and other low aspect ratio microstructures. A near-infrared micro interferometer is used to detect the 3D morphology of silicon based high aspect ratio microstructures. In this paper, the key technologies of the two band microscopic interference system and the tests of typical samples are described. The results show that white light micro interferometer and near-infrared micro interferometer are two kinds of high-precision nondestructive testing instruments. They can detect the 3D morphology of the microstructures with aspect ratio ≤4, and ≥20, respectively. The 3D topography data obtained by the microscopic-interference nondestructive testing technology will effectively promote the optimization of the manufacturing process of the microstructure and the further improvement of the performance of related devices.

11 High-precision ultrasonic thickness measurement system based on LMS adaptive time delay estimation algorithm

YANG Dingqiang , LIU Jibing , WANG Nian , LI Ruijun

2024(4). DOI: 10.11823/j.issn.1674-5795.2024.04.05

[Abstract](611) [HTML](171) [PDF 1.36 M](1097)

Abstract:
A high-precision ultrasonic thickness measurement system based on the least mean square (LMS) adaptive time delay estimation algorithm was developed, addressing the issue of low accuracy of the existing ultrasonic thickness measurement systems. The ultrasonic transmitting and receiving circuits were designed. The high-speed data acquisition and transmission system based on field programmable gate array (FPGA) was developed. The host computer signal processing software based on MATLAB was developed. The ultrasonic time of flight (TOF) was calculated accurately and efficiently by LMS adaptive time delay estimation algorithm, so as to realize high-precision thickness measurement. The simulated echo simulation experiments were conducted. The results show that the LMS method has more advantages in time delay estimation than the peak method, envelope method and correlation method. An ultrasonic thickness measurement system based on LMS adaptive time delay estimation algorithm was built, and the thickness measurement experiments were performed on gauge blocks. The results show that the relative error of thickness measurement is less than 3.77%, the standard deviation of repeated experiment is not higher than 0.2 μm, and the maximum relative measurement uncertainty is 1.4%. The ultrasonic thickness measurement system based on LMS adaptive time delay estimation algorithm can be applied in the fields such as plate thickness measurement, which is conducive to promoting the development of high-precision ultrasonic thickness measurement technology and has important technical reference value.