Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an op...Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an optical fibre displacement sensor(OFBDS)with simple structure and high measurement accuracy,the unified model of the commonly used OFBDS structures was proposed and the feasibility of the intensity⁃modulation of multi⁃structural optical fibre bundles was analysed based on the arrangement characteristics of the fibre bundle end⁃face.The intensity⁃modulation characteristic of different fibre bundles was analysed,and the single coil coaxial fibre bundle was chosen as the fibre probe in this study.The sensor hardware system was designed.Lastly,the calibration experiment,temperature interference experiment,changes of measured plane surface area,and the dynamic experiment were conducted.Results showed that the sensor linear measurement range was about 3 mm,and the sensor system had excellent static and dynamic characteristics.展开更多
An on-machine measuring(OMM)system with a laser displacement sensor(LDS)is designed for measuring free-form surfaces of hypersonic aircraft’s radomes.To improve the measurement accuracy of the OMM system,a novel Iter...An on-machine measuring(OMM)system with a laser displacement sensor(LDS)is designed for measuring free-form surfaces of hypersonic aircraft’s radomes.To improve the measurement accuracy of the OMM system,a novel Iteratively Automatic machine learning Boosted hand-eye Calibration(IABC)method is proposed.Both the hand-eye relationship and LDS measurement errors can be calibrated in one calibration process without any hardware changes via IABC.Firstly,a new objective function is derived,containing analytical parameters of the handeye relationship and LDS errors.Then,a hybrid calibration model composed of two kernels is proposed to solve the objective function.One kernel is the analytical kernel designed for solving analytical parameters.Another kernel is the automatic machine learning(AutoML)kernel designed to model LDS errors.The two kernels are connected with stepwise iterations to find the best calibration results.Compared with traditional methods,hand-eye experiments show that IABC reduces the calibration RMSE by about 50%.Verification experiments show that IABC reduces the measurement deviations by about 25%-50%and RMSEs within 40%.Even when the training data are obviously less than the test data,IABC performs well.Experiments demonstrate that IABC is more accurate than traditional hand-eye methods.展开更多
The surface quality of a corrugated plate directly determines the heat transfer property of the thermal power mechanical apparatus.Traditional detection methods are impractical for real-world production,being slow and...The surface quality of a corrugated plate directly determines the heat transfer property of the thermal power mechanical apparatus.Traditional detection methods are impractical for real-world production,being slow and destructive.In contrast,the point laser displacement sensor,employing the optical triangle method,emerges as a promising device for assessing parts with variable curvature and highly reflective surfaces.Despite its benefits,high-density sampling by an innate frequency introduces challenges such as data redundancy and a poor signal-to-noise ratio,potentially affecting the efficiency and precision of subsequent data processing.To address these challenges,adjustable frequency data sampling has been developed for this sensor,allowing adaptive sampling for corrugated plate digitization.The process begins with surface digitization to extract discrete points,which are transformed into intersection curves using the B-spline fitting technique.Subsequently,dominant points are identified,considering multigeometric constraints for curvature and arch height.Finally,the sampling signal is adjusted based on the distribution information of dominant points.Comparative results indicate that the proposed method effectively minimizes redundant sampling without compromising the accurate capture of essential geometric features.展开更多
An improved self-mixing grating interferometer based on the Littrow structure has been proposed in this Letter to measure displacement.The grating is integrated inside the interferometer to reduce the impact on the vi...An improved self-mixing grating interferometer based on the Littrow structure has been proposed in this Letter to measure displacement.The grating is integrated inside the interferometer to reduce the impact on the vibration parameters of the object caused by the grating attached to the vibrating object.The+1 st diffracted light returns to the laser cavity after being reflected by the target object,and self-mixing interference occurs.The displacement can be reconstructed by processing the self-mixing signals.The feasibility of the proposed interferometer is demonstrated by experimental measurements,and results show that it can achieve micro displacement measurement with the maximum absolute errors of less than 50 nm.展开更多
How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel principle and device is developed to solve the problem. Firstly, the working principle of the...How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel principle and device is developed to solve the problem. Firstly, the working principle of the device is introduced. When three or four displacement sensors installed in the localizer are touched by the ball-head, the spatial relation is calculated between the large aircraft component's ball-head and the localizer's ball-socket. The localizer is driven to achieve a new position by compensation. Relatively, a support revising algorithm is proposed. The localizer's ball-socket approaches the ball-head based on the displacement sensors. According to the points selected from its spherical surface, the coordinates of ball-head spherical center are computed by geometry. Finally, as a typical application, the device is used to conduct a test-fuselage's ball-head into a localizer's ball-socket. Positional deviations of the spherical centers between the ball-head and the ball-socket in the x, y, and z directions are all controlled within ±0.05 mm under various working conditions. The results of the experiments show that the device has the characteristics of high precision, excellent stability, strong operability, and great potential to be applied widely in the modern aircraft industry.展开更多
This paper presents a compact XYZ micro-stage driven by an impact driving mechanism.A moving body is translationally actuated along the X-,Y-,and Z-axes in millimeter-scale range and with nanometer-scale resolution.Cr...This paper presents a compact XYZ micro-stage driven by an impact driving mechanism.A moving body is translationally actuated along the X-,Y-,and Z-axes in millimeter-scale range and with nanometer-scale resolution.Cr-N thin-film strain sensors are integrated into the micro-stage for closed-loop positioning.Closed-loop control is also carried out.The motion errors in six degrees of freedom are also investigated for this micro-stage.It is clarified by analysis of finite element method that rotational motion errors around the driving axis are caused by torques due to tensions from the elastic hinges of microstage.The mechanical structure of XYZ micro-stage to cancel out the torque generated is proposed and the second prototype is fabricated.Although the rotational motion error is successfully suppressed in the second prototype,a rotational motion error of more than 0.1°remains due to remaining torque and assembly error of the elastic hinges.Then,in order to reduce the rotational motion error,the prototype is designed in which the location of elastic hinges is single-layered.By designing a mechanical structure in which torque is suppressed,all rotational motion errors are successfully reduced to less than 0.05°in the prototype with single-layer hinges.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.51775260)the Qinglan Project of Jiangsu Province(2017)of China and the Funds of Nanjing Institute of Technology(Grant No.CKJA201801).
文摘Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an optical fibre displacement sensor(OFBDS)with simple structure and high measurement accuracy,the unified model of the commonly used OFBDS structures was proposed and the feasibility of the intensity⁃modulation of multi⁃structural optical fibre bundles was analysed based on the arrangement characteristics of the fibre bundle end⁃face.The intensity⁃modulation characteristic of different fibre bundles was analysed,and the single coil coaxial fibre bundle was chosen as the fibre probe in this study.The sensor hardware system was designed.Lastly,the calibration experiment,temperature interference experiment,changes of measured plane surface area,and the dynamic experiment were conducted.Results showed that the sensor linear measurement range was about 3 mm,and the sensor system had excellent static and dynamic characteristics.
基金supported by the National Natural Science Foundation of China (Nos. 51875406 and 51805365)
文摘An on-machine measuring(OMM)system with a laser displacement sensor(LDS)is designed for measuring free-form surfaces of hypersonic aircraft’s radomes.To improve the measurement accuracy of the OMM system,a novel Iteratively Automatic machine learning Boosted hand-eye Calibration(IABC)method is proposed.Both the hand-eye relationship and LDS measurement errors can be calibrated in one calibration process without any hardware changes via IABC.Firstly,a new objective function is derived,containing analytical parameters of the handeye relationship and LDS errors.Then,a hybrid calibration model composed of two kernels is proposed to solve the objective function.One kernel is the analytical kernel designed for solving analytical parameters.Another kernel is the automatic machine learning(AutoML)kernel designed to model LDS errors.The two kernels are connected with stepwise iterations to find the best calibration results.Compared with traditional methods,hand-eye experiments show that IABC reduces the calibration RMSE by about 50%.Verification experiments show that IABC reduces the measurement deviations by about 25%-50%and RMSEs within 40%.Even when the training data are obviously less than the test data,IABC performs well.Experiments demonstrate that IABC is more accurate than traditional hand-eye methods.
基金supported by the National Natural Science Foundation of China(Grant Nos.52305535,52122512,and 52188102)the Natural Science Foundation of Hubei Province(Grant No.2021CFA075)。
文摘The surface quality of a corrugated plate directly determines the heat transfer property of the thermal power mechanical apparatus.Traditional detection methods are impractical for real-world production,being slow and destructive.In contrast,the point laser displacement sensor,employing the optical triangle method,emerges as a promising device for assessing parts with variable curvature and highly reflective surfaces.Despite its benefits,high-density sampling by an innate frequency introduces challenges such as data redundancy and a poor signal-to-noise ratio,potentially affecting the efficiency and precision of subsequent data processing.To address these challenges,adjustable frequency data sampling has been developed for this sensor,allowing adaptive sampling for corrugated plate digitization.The process begins with surface digitization to extract discrete points,which are transformed into intersection curves using the B-spline fitting technique.Subsequently,dominant points are identified,considering multigeometric constraints for curvature and arch height.Finally,the sampling signal is adjusted based on the distribution information of dominant points.Comparative results indicate that the proposed method effectively minimizes redundant sampling without compromising the accurate capture of essential geometric features.
基金supported by the Northeast Petroleum University Youth Science Foundation(No.2020QNL-13)。
文摘An improved self-mixing grating interferometer based on the Littrow structure has been proposed in this Letter to measure displacement.The grating is integrated inside the interferometer to reduce the impact on the vibration parameters of the object caused by the grating attached to the vibrating object.The+1 st diffracted light returns to the laser cavity after being reflected by the target object,and self-mixing interference occurs.The displacement can be reconstructed by processing the self-mixing signals.The feasibility of the proposed interferometer is demonstrated by experimental measurements,and results show that it can achieve micro displacement measurement with the maximum absolute errors of less than 50 nm.
基金Project supported by the National Natural Science Foundation of China (No. 50905161)the Natural Science Foundation of Zhejiang Province (No. Y1110339)the Fundamental Research Funds for the Central Universities of China (No. 2010QNA4024)
文摘How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel principle and device is developed to solve the problem. Firstly, the working principle of the device is introduced. When three or four displacement sensors installed in the localizer are touched by the ball-head, the spatial relation is calculated between the large aircraft component's ball-head and the localizer's ball-socket. The localizer is driven to achieve a new position by compensation. Relatively, a support revising algorithm is proposed. The localizer's ball-socket approaches the ball-head based on the displacement sensors. According to the points selected from its spherical surface, the coordinates of ball-head spherical center are computed by geometry. Finally, as a typical application, the device is used to conduct a test-fuselage's ball-head into a localizer's ball-socket. Positional deviations of the spherical centers between the ball-head and the ball-socket in the x, y, and z directions are all controlled within ±0.05 mm under various working conditions. The results of the experiments show that the device has the characteristics of high precision, excellent stability, strong operability, and great potential to be applied widely in the modern aircraft industry.
基金supported by JSPS KAKENHI Grant Numbers JP 15H05759 and JP 20H00211。
文摘This paper presents a compact XYZ micro-stage driven by an impact driving mechanism.A moving body is translationally actuated along the X-,Y-,and Z-axes in millimeter-scale range and with nanometer-scale resolution.Cr-N thin-film strain sensors are integrated into the micro-stage for closed-loop positioning.Closed-loop control is also carried out.The motion errors in six degrees of freedom are also investigated for this micro-stage.It is clarified by analysis of finite element method that rotational motion errors around the driving axis are caused by torques due to tensions from the elastic hinges of microstage.The mechanical structure of XYZ micro-stage to cancel out the torque generated is proposed and the second prototype is fabricated.Although the rotational motion error is successfully suppressed in the second prototype,a rotational motion error of more than 0.1°remains due to remaining torque and assembly error of the elastic hinges.Then,in order to reduce the rotational motion error,the prototype is designed in which the location of elastic hinges is single-layered.By designing a mechanical structure in which torque is suppressed,all rotational motion errors are successfully reduced to less than 0.05°in the prototype with single-layer hinges.