公开(公告)号：US12078472B1

公开(公告)日：2024-09-03

申请号：US18395571

申请日：2023-12-24

Applicant: Harbin Institute of Technology

Inventor： Yisi Dong ,  Chen Zhang ,  Pengcheng Hu

IPC: G01B11/14 ,  G01B9/02001

CPC classification number: G01B11/14 ,  G01B9/02001

Abstract: An interferometric displacement measurement system and method based on phase modulation of polarized light of micro probe are provided. An electro-optic phase modulator is used to perform sinusoidal phase modulation on a light beam emitted by a semiconductor laser to obtain an adjusted light beam. The adjusted light beam is divided by a polarization beam splitter to generate a reference light beam and a measurement light beam. The two light beams are respectively reflected by a built-in reflection surface of a micro probe and a target mirror, and transmitted to a polarization-maintaining fiber circulator. The reference light beam interferes with the measurement light beam at a fiber optic polarization element to generate an interference light signal. A photodetector converts the interference light signal into an interference electrical signal, and the interference electrical signal is demodulated by a signal demodulator to obtain a displacement value of the target mirror.

公开(公告)号：US11802757B2

公开(公告)日：2023-10-31

申请号：US17417925

申请日：2019-04-18

Applicant: HARBIN INSTITUTE OF TECHNOLOGY

Inventor： Pengcheng Hu ,  Di Chang ,  Jiubin Tan

IPC: G01B9/02015 ,  G01B9/02001 ,  G01B9/02003

CPC classification number: G01B9/02007 ,  G01B9/02003 ,  G01B9/02015 ,  G01B9/02027

Abstract: 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 (1), an optical prism (23) and a photoelectric detection and signal processing unit (4). The separately modulated heterodyne laser (1) 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 (233) to produce reference beams (53a, 53b), which are incident to a third beamsplitting surface, and the other part traverses a double-diffraction structure formed by a measured grating (3) and retro-reflectors (234a, 234b) to obtain two measured beams (59a, 59b), 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 (61), and the other part is incident to the third beamsplitting surface and is converged with the corresponding reference beams (53a, 53b) to form second and third interference beams (62, 63). Photoelectric detection and signal processing is performed on the interference signals of the three interference beams (61, 62, 63), so as to calculate horizontal and vertical displacement of the grating (3). The present measurement method and system improve the angular tolerance of tip and tilt of the optical grating (3) while increasing the fold factors.

公开(公告)号：US10145683B2

公开(公告)日：2018-12-04

申请号：US15307300

申请日：2015-03-31

Applicant: HARBIN INSTITUTE OF TECHNOLOGY

Inventor： Pengcheng Hu ,  Jiubin Tan ,  Jiahao Guo

IPC: G01C9/18 ,  G01C9/20 ,  G01C9/00 ,  G01C9/06

Abstract: A method for measuring a dip angle of oppositely crossly placed paired quartered ring-quartered circle nested polar plates. An annular coplanar capacitance measuring head of a sensor unit consists of four quarter round metal plates and four quarter circular-ring-shaped metal plates, the eight metal plates are coplanar and concentric with one another, and a quarter round metal plate and a quarter circular-ring-shaped metal plate corresponding to the same sector angle form a capacitor. Two annular coplanar capacitance measuring heads are arranged on two round insulating substrates, the two round insulating substrates are used as two bottom surfaces of a cylindrical container, the cylindrical container is transversely arranged, and an insulating liquid equal to ½ volume of the cylindrical container is injected into the cylindrical container in a sealing manner. Potential leads extract potentials of the sixteen metal plates and are connected to an input end of a capacitance measuring unit, and the capacitance measuring unit is connected to a dip measuring unit. When the cylindrical container tilts, the relative positions of the two annular coplanar capacitance measuring heads and the insulating liquid are changed, and a dip angle value can be calculated by measuring the change of a capacitance value. Also disclosed is a device for measuring a dip angle of oppositely crossly placed paired quartered ring-quartered circle nested polar plates.

公开(公告)号：US12199407B1

公开(公告)日：2025-01-14

申请号：US18751413

申请日：2024-06-24

Applicant: Harbin Institute of Technology

Inventor： Yisi Dong ,  Wenwen Li ,  Wenrui Luo ,  Chen Zhang ,  Jinran Zhang ,  Pengcheng Hu ,  Ruitao Yang

IPC: H01S5/0687 ,  H01S3/13 ,  H01S5/026 ,  H01S5/06 ,  H01S5/068

Abstract: A frequency stabilization method and system for tunable light sources based on characteristic curve reconstruction are provided, which relate the field of frequency stabilization technologies of modulation absorption spectrum. A set of frequency stabilization control method and system based on internal modulation absorption spectroscopy of light source is constructed, and a high-precision laser frequency stabilization method under large-amplitude and high-bandwidth frequency modulation based on frequency discrimination curve reconstruction is proposed to solve a problem that it is difficult for micro-probe laser interferometry measurement benchmark to balance large-amplitude and high-bandwidth frequency modulation, and high-precision frequency stabilization, resulting in that it is difficult to obtain high relative accuracy measurement under large-range measurement. Under the large-amplitude and high-bandwidth frequency modulation, a distortion model of the frequency discrimination curve and a distortion correction model are constructed, which is used for feedback adjustment of phase compensation and reconstructing the frequency discrimination curve.

公开(公告)号：US12055391B2

公开(公告)日：2024-08-06

申请号：US17706343

申请日：2022-03-28

Applicant: Harbin Institute of Technology

Inventor： Hongxing Yang ,  Ziqi Yin ,  Pengcheng Hu ,  Jiubin Tan

IPC: G01B9/02001 ,  G02B5/30 ,  G02B27/28 ,  G02F1/11

CPC classification number: G01B9/02007 ,  G01B9/02011 ,  G02B5/3083 ,  G02B27/283 ,  G02F1/11

Abstract: 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.

公开(公告)号：US20220290969A1

公开(公告)日：2022-09-15

申请号：US17681148

申请日：2022-02-25

Applicant: Harbin Institute of Technology

Inventor： Liang Yu ,  Pengcheng Hu ,  Xionglei Lin ,  Xiaobo SU

IPC: G01B9/02 ,  G01B11/26 ,  G01B11/00

Abstract: A single-beam three-degree-of-freedom homodyne laser interferometer based on an array detector. A single-frequency laser beam is input to a Michelson interference structure, the measurement beam and the reference beam perform non-coaxial interference and form a single-beam homodyne interference signal by setting the angle of a reference plane mirror, the array detector is selected to effectively receive the single-beam homodyne interference signal, and finally, three-degree-of-freedom signal linear decoupling on the single-beam homodyne interference signal is achieved through a three-degree-of-freedom decoupling method based on Lissajous ellipse fitting. The laser interferometer does is free of angle decoupling nonlinearity, the period nonlinear error is remarkably reduced, compared with other existing three-degree-of-freedom laser interferometers, the laser interferometer has the advantages of being simple in structure, large in angle measurement range and easy to integrate, and the high-precision requirement of the three-degree-of-freedom laser interferometer for displacement and angle measurement is met.

公开(公告)号：US11150077B2

公开(公告)日：2021-10-19

申请号：US17002845

申请日：2020-08-26

Applicant: HARBIN INSTITUTE OF TECHNOLOGY

Inventor： Pengcheng Hu ,  Xiaobo Su ,  Haijin Fu

IPC: G01B9/02 ,  G02B27/12

Abstract: Disclosed is a heterodyne laser interferometer based on an integrated secondary beam splitting component, which belongs to the technical field of laser application; the disclosure inputs two beams that are spatially separated and have different frequencies to the heterodyne laser interferometer based on the integrated secondary beam splitting component, wherein the integrated secondary beam splitting component includes two beam splitting surfaces that are spatially perpendicular to each other; and the two beam splitting surfaces are plated with a polarizing beam splitting film or a non-polarizing beam splitting film, and a measurement beam and a reference beam are the same in travel path length in the integrated secondary beam splitting component. The heterodyne laser interferometer of the disclosure significantly reduces periodic nonlinear errors, has the advantages of simple structure, good thermal stability, large tolerance angle and easy integration and assembly compared with other existing heterodyne laser interferometers with spatially separated optical paths, and meets the high-precision and high-resolution requirements of high-end equipment on heterodyne laser interferometry.

公开(公告)号：US20150043004A1

公开(公告)日：2015-02-12

申请号：US14378880

申请日：2012-11-08

Applicant: HARBIN INSTITUTE OF TECHNOLOGY

Inventor： Jiubin Tan ,  Pengcheng Hu ,  Xiaofei Diao

IPC: G01B9/02 ,  G01B11/14

CPC classification number: G01B9/02007 ,  G01B9/02003 ,  G01B9/02027 ,  G01B9/02045 ,  G01B11/14 ,  G01B2290/70 ,  G01J9/04 ,  G02B27/283

Abstract: A high speed high resolution heterodyne interferometric method and system are provided. The invention uses two spatially separated beams with slightly different frequencies and has two measurement signals with opposite Doppler shift. The switching circuit selects one of the two measurement signals for displacement measurement according to the direction and speed of the target movement. In this invention, the measurement is insensitive to the thermal variation; the periodic nonlinearity is essentially eliminated by using two spatially separated beams; the measurable target speed of the interferometer is no longer limited by the beat frequency of the laser source.

Abstract translation: 提供了高速高分辨率外差干涉法和系统。 本发明使用具有稍微不同频率的两个空间分离的波束，并且具有相反多普勒频移的两个测量信号。 开关电路根据目标运动的方向和速度选择两个测量信号中的一个用于位移测量。 在本发明中，测量对热变化不敏感; 通过使用两个空间分离的光束基本上消除了周期性非线性; 干涉仪的可测量目标速度不再受激光源的拍频的限制。

公开(公告)号：US20250044128A1

公开(公告)日：2025-02-06

申请号：US18744803

申请日：2024-06-17

Applicant: Harbin Institute of Technology

Inventor： Yisi Dong ,  Wenrui Luo ,  Wenwen Li ,  Chen Zhang ,  Jinran Zhang ,  Pengcheng Hu

IPC: G01D5/353

Abstract: A micro-probe laser frequency modulation interferometric ranging method and system, under the premise of not introducing an absolute laser rangefinder to introduce new uncertainties, continuously and slowly changes the modulated laser wavelength, resulting in a continuous periodic phase change in the interference signal obtained by the detector. The laser modulation absorption spectrum shifts from the initial locked absorption peak to another locked peak, and the wavelength changes of the two locked absorption peaks before and after are obtained by checking the table. Meanwhile, calculating the phase difference demodulated by the phase generated carrier (PGC) before and after, and the initial length of optical dead-path is calculated using wavelength scanning technology. Afterwards, utilizing the advantages of high relative distance measurement accuracy of micro-probe fiber optic laser interferometer, real-time measurement of the measured distance is achieved.

公开(公告)号：US20230384090A1

公开(公告)日：2023-11-30

申请号：US17982033

申请日：2022-11-07

Applicant: Harbin Institute of Technology

Inventor： Pengcheng Hu ,  Liang Yu

IPC: G01C9/06 ,  G01C9/08

CPC classification number: G01C9/06 ,  G01C9/08 ,  G01C2009/066

Abstract: A high-precision dual-axis laser inclinometer based on wavefront homodyne interference and a measuring method are disclosed. The method includes: obtaining a laser signal through a laser light source module, transmitting the laser signal to an integrated sensing module, and generating a wavefront interference signal based on the integrated sensing module; and inputting the wavefront interference signal into a signal processing module for performing high-precision decoupling operation to obtain a horizontal inclination angle measurement result. The measurement resolution is high, the measurement result can be directly traced to the laser wavelength, high-precision dual-axis inclination angle measurement can be realized only by using single-beam measurement light, meanwhile, the laser inclinometer has the advantages of being simple in structure, simple in light path, easy to integrate, beneficial to engineering implementation, and high in cost performance, and the requirement of high-end equipment on the ultra-precision inclinometer is met.