公开(公告)号：US12287198B1

公开(公告)日：2025-04-29

申请号：US18595318

申请日：2024-03-04

Applicant: HARBIN INSTITUTE OF TECHNOLOGY

Inventor： Haijin Fu ,  Xiaobo Su ,  Liang Yu ,  Pengcheng Hu ,  Xizheng Liu ,  Xin Yang

IPC: G01B9/02 ,  G01B9/02001

Abstract: A heterodyne laser interferometer and a measurement method based on an integrated dual polarization beam-splitting assembly is provided. Technical points: The first polarization beam splitter and the second polarization beam splitter of the integrated dual polarization beam-splitting assembly are arranged in parallel. The first polarization beam splitter is attached with a first polarizer, a third polarizer, and a first quarter-wave plate; The second polarization beam splitter is attached with a second polarizer, a fourth polarizer, and a second quarter-wave plate; The output optical path of the first quarter-wave plate and the second quarter-wave plate is equipped with target mirrors, while the output optical path of the third quarter-wave plate and the fourth quarter-wave plate is equipped with photodetectors. The assembly and adjustment of the present invention is more flexible and reduce the processing difficulty and processing error.

公开(公告)号：US12259240B1

公开(公告)日：2025-03-25

申请号：US18663403

申请日：2024-05-14

Applicant: Harbin Institute of Technology

Inventor： Ruitao Yang ,  Hao Sun ,  Pengcheng Hu

IPC: G01B9/02001 ,  G01B9/02 ,  G01B9/02003 ,  G01B11/02

Abstract: A distance measurement device and method based on secondary mixing of inter-mode self-interference signals of optical frequency combs are provided, which relate to the field of high precision laser distance measurement technologies. A dual-comb light source emits a dual-comb laser into a detection optical module to obtain the inter-mode self-interference signals carrying the to-be-measured distance information. The detection optical module outputs the inter-mode self-interference signals into a generation, acquisition and calculation module of inter-mode self-interference secondary mixing signals to generate the inter-mode self-interference secondary mixing signals, to thereby achieve signal acquisition and obtain a distance measurement result. In this device, coarse and fine distance measurements at different scales are achieved, measurement range and accuracy can be effectively balanced by combing intermediate transition measurement scales and inter-stage transition method, strong real-time property of measurement is achieved, and the light source has low cost and the scale of the system is small.

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：US12253392B2

公开(公告)日：2025-03-18

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：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.