Harbin Institute of Technology

Jiubin Tan

Bo Zhao

Weijia Shi

Lei Wang

Chuanzhi Sun

Yongmeng Liu

Jiwen Cui

JiWen Cui

PengCheng Hu

Pengcheng Hu

Junying Li

Junning Cui

Kunpeng Feng

Jiaxin Li

JianWei Wu

Bingquan Wang

Yang Liu

Hongxing Yang

Ziqi Yin

Jian Shi

Yuanyuan Yang

Yang Yu

ZhongPu Wen

Fazhi Song

Zhengang Lu

Hong Dang

Fan Zhu

Shiyuan Zhao

Jiahao Guo

Xuyang Yu

Yun Zou

Jing Li

Xue Qi

Jianwei Wu

Kaixin Liu

Di Chang

Jingzhi Huang

Wei Gu

Huilin Wu

Shuaiqi Chen

Zhongpu Wen

Pengyu Sun

Aichen Wu

Xu Xing

Xiaofei Diao

Rongwei Wen

Yin Zhang

Fei Wang

An ultrasonic measurement method for plane stress on the basis of a multi-wafer air-coupled transducer relates to the technical field of ultrasonic testing. The method solves problems that a traditional measurement method for plane stress generally computes the plane stress by changing at least 3 different measurement directions and obtaining information such as an acoustic time difference in the 3 measurement directions by using a pair of contact ultrasonic transducers, which is too complicated in operation, and a coupling agent can influence measurement accuracy of the plane stress. The method includes: emitting, by an excitation signal transmission end, an ultrasonic wave passing a wafer of the multi-wafer air-coupled transducer to a member to be measured; receiving, by an excitation signal reception end, an echo returned from the member to be measured through a corresponding wafer of the multi-wafer air-coupled transducer; obtaining an acoustic time difference of lamb waves through data processing according to the ultrasonic wave and the echo; and obtaining first principal stress, second principal stress and an included angle between the first principal stress and a fiber direction of an orthotropic composite material according to the acoustic time difference of the lamb waves. The method is suitable for the field of plane stress testing.

Ultrasonic measurement method for plane stress on the basis of multi-wafer air-coupled transducer

The present disclosure relates to a collaborative phase-shift laser ranging device based on differential modulation and demodulation of coarse and precise measuring wavelength and a ranging method thereof. A collaboration terminal is disposed at a target to be measured of a phase-shift laser ranging system, which can improve the intensity of measurement light and then irradiate the same back to a measuring terminal, thereby resolving the problem of low ranging accuracy caused by the attenuation of light intensity during long-distance ranging. The collaboration terminal detects coarseness gauge signals and modulates a laser source by means of differential modulation; the collaboration terminal detects precision gauge signals by means of difference frequency demodulation, and then the intensity of measurement light is improved by mixing and restoring the precision gauge signals and modulating the collaboration-terminal laser source.

Collaborative phase-shift laser ranging device based on differential modulation and demodulation of coarse and precise measuring wavelength and ranging method thereof

A learning control system includes a movement trajectory generation unit, a learning control unit, a feedback control unit, and an uncertainty compensation unit. The movement trajectory generation unit includes a movement trajectory generator; the movement trajectory generator is configured to generate a reference movement trajectory; a position measured signal is subtracted from the reference movement trajectory to obtain a position error signal which is input to the learning control unit; the learning control unit is configured to generate a feed-forward signal which is added with the position error signal to obtain a corrected error signal; and the corrected error signal is input to the feedback control unit; the feedback control unit includes a feedback controller configured to generate a feedback control quantity which is input to the uncertainty compensation unit; and the uncertainty compensation unit is configured to generate the position measured signal.

Learning control system and method for ultra-precision lithographic apparatus based on uncertainty compensation

An air-coupled ultrasonic plane stress detection method for a composite material based on dual-modal sound-time ratios of a Lamb wave includes: S1: assembling a detection device; S2: based on the detection device and the dual-modal sound-time ratios of the Lamb wave in S1, using unidirectionally loaded stress to obtain different stress coefficient relations; S3: based on the stress coefficient relations in S2, solving stress coefficients; S4: based on the stress coefficients in S3, acquiring three sound-time ratios; S5: based on the sound-time ratios in S4, describing a stress state of a detection point; and S6: repeating S4 and S5 till completing detection and scanning. The method improves the accuracy of stress coefficient calibration and air-coupled ultrasonic stress representation of a composite material panel greatly.

Air-coupled ultrasonic plane stress detection method for composite material based on dual-modal sound-time ratios of lamb wave

The disclosure provides a method, system, device and medium for online monitoring of a plane stress field without baseline data based on a piezoelectric transducer array. Since Lamb waves have complex multi-mode characteristics, a suitable excitation frequency needs to be selected according to geometric dimensions of the structure to be measured, and then, only low-order mode Lamb waves are excited inside the measured structure to avoid serious waveform aliasing. For isotropic measured objects, anisotropic characteristics will be generated under the action of pre-stresses, that is, the propagation velocities of ultrasonic waves in all directions are different, but there is a linear relationship between velocity changes in different propagation directions and stresses. Therefore, there is still a linear relationship between the difference of velocity changes in different propagation directions and the stress. According to this characteristic, a characterization method of an absolute stress field without baseline data can be implemented. The method of the disclosure can make full use of the low attenuation characteristics of the Lamb waves to realize online monitoring of the plane stress field with a large coverage area.

Method, system, device and medium for online monitoring of plane stress field without baseline data based on piezoelectric transducer array

A method, system, device, and medium for online stress monitoring without baseline data based on single-mode multi-frequency signal fusion are provided. The method includes: establishing a dispersion curve according to geometric dimensions and material parameters of a measured object; then solving an approximate linear relationship between propagation time of S0 modes with different frequencies and stress at a fixed propagation distance by using a relationship between stress and group velocity, the obtained linear relationship being an acousto-elastic equation required for final measurement; then performing Hilbert transformation on an obtained signal, extracting a signal envelope, and determining arrival time of two excitation frequency signals by means of a peak extraction algorithm and a time domain width of an excitation signal; and calculating a propagation time ratio and substituting the propagation time ratio into a pre-calibrated acousto-elastic equation to solve a stress value of an object to be measured. The disclosure is advantageous in that the multi-frequency data is fused by using dispersion characteristics of a single-mode Lamb wave and an acousto-elastic effect, thereby achieving online stress monitoring without baseline data.

Method, system, device, and medium for online stress monitoring without baseline data based on single-mode multi-frequency signal fusion

Provided is a large high-speed rotary equipment gap stacking assembly apparatus and assembly method based on digital twin, and relates to the technical field of engine assembly measurement. The disclosure solves the problem of unbalanced rotation of the rotary parts caused by large assembly error during multi-stage rotary parts are stacked in a gap way. The disclosure includes the assembly apparatus entity and the assembly method; the assembly apparatus entity is configured to establish data communication with the upper computer through data acquisition apparatus, and upper computer is configured to establish a virtual assembly model; the virtual assembly model and optimal coaxiality of the multi-stage rotary parts in gap stacking can be obtained according to the assembly method, and the assembly process can be controlled by using the virtual assembly model and the optimal coaxiality. The disclosure is suitable for controlling the assembly process of the rotary parts.

Large high-speed rotary device gap stacking assembly apparatus and assembly method based on digital twin

The present disclosure proposes a non-baseline on-line stress monitoring system and monitoring method based on multi-mode Lamb wave data fusion. A Lamb wave dispersion curve is established according to geometric dimensions and material parameters of a measured object, a cut-off frequency of a first-order Lamb wave mode is obtained, an excitation frequency of a Lamb wave signal is determined, and then pure Lamb waves in S0 and A0 modes obtained inside the measured object are obtained; an acoustoelastic equation is established, an elastodynamic equation of the measured object under a prestress condition is solved, and linear relationships between a group velocity and a stress of the Lamb waves in the S0 and A0 modes under the excitation frequency are obtained; data is processed through the on-line monitoring system; a stress gradient in a depth direction is calculated, and finally, a stress state of the measured object is represented. The present disclosure does not require data under a zero stress state as baseline data, does not require designing a wedge block capable of generating a critical refraction longitudinal wave, and combines acoustoelastic effects of Lamb waves in different modes to realize online stress monitoring without the baseline data.

Non-baseline on-line stress monitoring system and monitoring method based on multi-mode lamb wave data fusion

A learning control system for a nano-precision motion stage comprises a closed-loop feedback section including a motion trajectory generator, a feedback controller, a motion stage, and a first Fourier transformer; and a feedforward section including a second Fourier transformer, a learning controller, an iteration backward shift operator, and a Fourier inverse transformer. An iteration experiment count j is initialized as j=1, and a j-th frequency domain feedforward signal is initialized to 0; the system is run to collect a frequency domain error signal and a frequency domain position measurement signal; a (j+1)-th frequency domain feedforward signal is updated; and an iteration experiment count j is incremented by 1. The present disclosure can effectively suppress the influence of external noise and disturbances, and improve convergence performance. Moreover, the present disclosure requires less computation, achieves simple determination of learning gains and strong robustness, and is convenient for engineering applications.

Learning control system and method for nano-precision motion stage

The present disclosure provides a multi-frequency hybrid heterodyne laser tracker system based on a single light source. According to the laser tracking system proposed in the present disclosure, multi-frequency laser is obtained by conducting multi-acousto-optic frequency shift on a dual-longitudinal-mode laser unit, and an absolute ranging precision gauge is constructed by using a dual-longitudinal-mode interval of a light source. With the frequency shift difference of a multi-acousto-optic frequency shifter, an absolute ranging roughness gauge is constructed, and the relative displacement measurement of dual-frequency light interference is achieved. Meanwhile, by utilizing the reflection of multiple reflectors and light splitting and combining of polarization prisms, synchronous measurement of multi-wavelength absolute distance, relative displacement and PSD position is achieved, resolving the problem that an existing laser tracker uses multiple light sources, which leads to difference in measurement datum, and consequently to the difficultly in traceback.

Multi-frequency hybrid heterodyne laser tracker system based on single light source

The disclosure belongs to the technical field of precision test and measurement, and provides a two-dimensional photoelectric autocollimation method and device based on wavefront measurement and correction. According to the disclosure, a link of wavefront measurement and correction of a reference light path is added to a traditional autocollimator measuring method. By using wavefront distortion information of the reference light path in the instrument and driving a deformable mirror to compensate for phase distortion of a beam, the link realizes measurement and control on aberration of the optical system of the autocollimator and improves the imaging quality and spot positioning accuracy of the optical system, thereby improving the angle measurement accuracy of the autocollimator. At the same time, by introducing the link, the autocollimator has the ability to resist interference from the external environment, so that the resolution and stability of angle measurement of the autocollimator are further improved. The method makes the traditional autocollimator have a nano-radian order (5×10rad, that is 0.001″) angle resolution and a sub-microradian order (10rad, that is 0.02″) angle measurement accuracy. The disclosure has the technical advantage of realizing angle measurement with high resolution, high accuracy and high stability under the same conditions, and has the abilities to resist environmental disturbances and compensate for errors caused by the disturbances.

Two-dimensional photoelectric autocollimation method and device based on wavefront measurement and correction

The disclosure discloses a stress gradient high-efficiency non-destructive detection system based on frequency domain calculation of broadband swept frequency signals, and a detection method thereof. The detection method includes: step 1: calibrating an LCR wave velocity of an object to be measured; step 2: calculating a starting frequency and a cut-off frequency of broadband swept frequency signals based on the LCR wave velocity of the object to be measured in the step 1 and a stress gradient measuring range in a depth direction of the object to be measured; step 3: converting phase delay to time delay information based on the phase delay of the starting frequency and the cut-off frequency in the step 2; and step 4: determining stresses of depths corresponding to different frequency components based on the time delay information in the step 3 to finally realize layer-by-layer scanning of stresses at different depths of the measured object. The disclosure is used to solve the problem of low stress gradient measuring accuracy, and realize the high-efficiency characterization of the stress gradient in the depth direction.

Stress gradient high-efficiency non-destructive detection system based on frequency domain calculation of broadband swept frequency signals, and detection method thereof

Present disclosure relates to a heterodyne grating interferometric method and system for two-degree-of-freedom with high tolerance. The system comprises a separately modulated heterodyne laser (), an optical prism () and a photoelectric detection and signal processing unit (). The separately modulated heterodyne laser () simultaneously outputs two laser beams at different frequencies, which are incident in parallel to a first beamsplitting surface so as to be split, and then a part thereof is incident to a retro-reflector () to produce reference beams (), which are incident to a third beamsplitting surface, and the other part traverses a double-diffraction structure formed by a measured grating () and retro-reflectors () to obtain two measured beams (), which are incident to a second beamsplitting surface and then are divided into two parts. Wherein one part is converged to form a first interference beam (), and the other part is incident to the third beamsplitting surface and is converged with the corresponding reference beams () to form second and third interference beams (). Photoelectric detection and signal processing is performed on the interference signals of the three interference beams (), so as to calculate horizontal and vertical displacement of the grating (). The present measurement method and system improve the angular tolerance of tip and tilt of the optical grating () while increasing the fold factors.

Heterodyne grating interferometric method and system for two-degree-of-freedom with high alignment tolerance

Disclosed are a linkage device, a transceiver module and a plane stress field measuring device and method capable of achieving synchronous adjustment of distance and angle, and relates to the field of ultrasonic non-destructive testing. The existing technical means for measuring plane stress in the field of ultrasonic testing has the shortcomings that the same testing is only applicable for single materials and the deflection angles of transmitting and receiving transducers are inconsistent. In the application, the linkage device designed by comprising a distance adjusting screw, an angle adjusting screw, a left connecting rod, a right connecting rod, a shaft column and a column lock is adopted, and based on the linkage device, the transceiver module designed by comprising a receiving end wedge, a receiving probe, a transmitting end wedge and a transmitting probe is additionally arranged; based on the transceiver module, the measuring device designed by comprising a pulse transmitting device, an amplifying device and a data acquisition device is additionally arranged, and the stress measuring method applicable for the stress measuring device is provided; and the distance and deflection angle between the receiving probe and the transmitting probe of the detection are adjusted according to a tested part. The application applies to stress measurement in the manufacturing process of mechanical components.

Linkage device, transceiver module and plane stress field measuring device and method capable of achieving synchronous adjustment of distance and angle

Disclosed is a high-stability nano-radian-order angle measuring method and device based on drift value feedback, belonging to the technical field of precision measurement and the field of optical engineering. The device consists of LED light sources, convex lenses, multi-slit diaphragms, beam splitters, deflecting mirrors, steering mirrors, a collimator objective set, linear array CCDs, a four-quadrant position detector and a plane mirror. The method includes: enabling two paths of measuring light beams to carry angle change information of a measured object, respectively forming respective images on two sensors, and calculating a pitch angle and a yaw angle of the measured object relative to an optical axis by using positions of the two images so as to achieve the detection capability on the angle change of the measured object. While a focal distance of the objective is greatly improved by using the collimator objective set, the linear array CCDs are used as sensors to improve a measuring range. Therefore, the technical advantage of nano-radian-order angle limit resolution is achieved under the condition of the same measuring range. The LED light sources, the convex lenses and the multi-slit diaphragms are used, and at the same time, drift value feedback is performed by using the four-quadrant position detector and the steering mirrors, and the system stability is improved to 10 nano-radian order, thus solving the problem of limitation of light beam drift value to limit resolution of an autocollimator. Additionally, a system device designed by the present disclosure has the technical advantages of small structure size, high measurement precision and high measurement frequency response.

High-stability nano-radian-order angle measuring method and device based on drift value feedback

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Heilongjiang, China

Jiubin Tan