28 results about "Laser doppler velocimeter" patented technology

The invention provides a laser Doppler velocimeter indicating value error calibration device to solve the problems that in the prior art, the structure is complex, the reference speed upper limit is low, and danger exists. The indicating value error calibration device for the laser Doppler velocimeter comprises a single-frequency laser, a first wavelength meter, a second wavelength meter, a 1 * 2 optical fiber beam splitter, a 2 * 1 optical fiber coupler and an optical fiber isolator. The indicating value error calibration device for the laser Doppler velocimeter is simple in structure, low in cost, high in safety coefficient and high in reference speed. In addition, the invention also provides a laser Doppler velocimeter indication error calibration method.

The invention discloses a vehicle-mounted integrated navigation method and device for a laser Doppler velocimeter, and the method comprises the steps: obtaining navigation initial information, carrying out the system initialization and alignment of an inertial sensor based on the navigation initial information, then executing inertial navigation, obtaining the velocimeter data of the laser Doppler velocimeter after an inertial navigation result is obtained, and carrying out the vehicle-mounted integrated navigation of the laser Doppler velocimeter. Combining the inertial navigation result with the tachymeter data to obtain an initial navigation result; and correcting the initial navigation result through a Kalman filtering algorithm to obtain a target navigation result. By comprehensively utilizing the data of the Doppler velocimeter and the IMU, high-precision navigation in a complex environment is realized, and the reliability and robustness of a navigation system are effectively improved. Meanwhile, the corrected attitude, position and speed are output through a Kalman filtering model, the advantages of the two sensors are integrated, the respective errors are reduced, and the method is particularly suitable for navigation in a complex environment, such as the conditions of bumpiness of a road and undulation of the ground.

The invention relates to a thin-film lithium niobate chip for a hybrid integrated laser Doppler velocimeter, a first group of mode field adapters, a 2 * 1 coupler, a polarizer, a phase modulator and a second group of mode field adapters are sequentially cascaded in the chip along an incident light path, and the first group of mode field adapters comprises a first mode field adapter and a second mode field adapter. The first mode field adapter and the second mode field adapter are respectively connected with the input end of the 2 * 1 coupler so as to combine the signal light and the indication light, the output end of the 2 * 1 coupler is connected with the input end of the polarizer, the polarizer is used for filtering the TE0 mode in the signal light, the stray light absorber is used for absorbing the TE0 mode in the signal light, and the stray light absorber is used for absorbing the TE0 mode in the signal light. The output end of the polarizer is connected with the input end of a phase modulator, multiple groups of micro-rings are cascaded in the phase modulator, the output end of the phase modulator is connected with a second group of mode field adapters, and the second group of mode field adapters comprises a third mode field adapter and a fourth mode field adapter which are respectively connected with two output ends of the phase modulator. The chip further comprises a scattered light loop, the scattered light loop comprises a fifth mode field adapter and a vertical coupler which are cascaded, and a III-V group detector is attached to the surface of the vertical coupler.

The invention discloses a device for determining and measuring the braking distance of a freight train, and belongs to the technical field of train braking safety protection, and the device comprises a multi-mode sensing module which integrates the following units: a wheel-rail adhesion monitoring unit which collects the friction coefficient and slip rate of a wheel-rail contact surface in real time based on a laser Doppler velocimeter and a strain gauge sensor; the environment sensing unit is used for detecting rail surface humidity, foreign matter and frost coverage states through a temperature and humidity sensor and an infrared camera; and a train state acquisition unit. According to the invention, through combination of multi-modal sensing and an advanced algorithm, comprehensive monitoring and accurate braking are realized; federal learning breaks a data barrier, and algorithm generalization is enhanced. Adhesion adjustment optimizes braking force distribution and anti-skid control, and stable and safe braking is guaranteed. The carbon emission optimization module promotes green energy conservation, the fault self-healing function, the response time is shortened, the self-healing rate is increased, the requirements of the heavy-load train are met, and the safety, reliability and sustainability of a train braking system are comprehensively improved.

The utility model discloses a kind of dynamic steel billet laser doppler measuring devices of follow-up, including conveying roller, the inner wall left side of conveying roller is equipped with measuring hole, the left side of conveying roller is fixedly installed with linear displacement rod, the upper movable mounting of linear displacement rod has moving platform, the upper fixed mounting of moving platform has laser doppler velocimeter sensor, first position sensor and second position sensor, the left side of linear displacement rod is fixedly installed with servo motor, the output end fixed mounting of servo motor has adjusting screw rod.The utility model actively adapts to the position change of steel billet, reduces the requirement to the running stability of steel billet, expands the applicable scenario of laser doppler velocimeter sensor, to realize the length measurement of continuous, stable, high-precision to the steel billet that exists swing or bending;It provides accurate length and positioning information for automatic sawing and subsequent process, help to improve product size qualification rate and yield rate.

The present application relates to a kind of continuous elevation measurement method and system based on SINS / LDV combination, belong to geodetic survey field.The system includes strapdown inertial navigation system, laser doppler velocimeter, UPS power supply and navigation computer, wherein, the angular motion and linear motion of sensitive carrier are used to strapdown inertial navigation system;Strapdown inertial navigation system is connected with laser doppler velocimeter and navigation computer respectively;Laser doppler velocimeter is connected with navigation computer, and UPS power supply is connected with strapdown inertial navigation system and laser doppler velocimeter respectively;In order to improve the precision of elevation measurement, the output of laser doppler velocimeter is triggered with the pulse output of strapdown inertial navigation system as benchmark, to prevent the data loss phenomenon caused by the inconsistency of internal crystal oscillator of strapdown inertial navigation system and laser doppler velocimeter.

The application discloses an unmanned mine truck sliding distance laser measuring device and a measuring method, and belongs to the technical field of mine truck detection. The unmanned mine truck sliding distance laser measuring device and the measuring method, which belong to the technical field of mine truck detection, comprise a mine truck with a first mounting hole, and a second clamping plate and a first clamping plate are arranged at the upper and lower ends of the outer side of the first mounting hole, respectively. The application solves the problem that the additional scale plate needs to be laid on a relatively flat position close to the subsequent moving position of the mine truck during detection, and the efficiency is low and the accuracy is poor. After the second clamping plate and the first clamping plate are clamped and fixed, the laser Doppler velocimeter can be unfolded by rotating the second adjusting frame, the unfolded laser Doppler velocimeter can be adjusted in angle by rotating around the connecting roller as the center, the installation position is adapted, and different installation positions and installation heights can be adjusted and adapted during the unfolding process.

This application relates to a thin-film lithium niobate chip for a hybrid integrated laser Doppler velocimeter. Internally, along the incident light path, a first set of mode field adapters, a 2×1 coupler, a polarizer, a phase modulator, and a second set of mode field adapters are cascaded sequentially. The first set of mode field adapters includes mode field adapter one and mode field adapter two, which are respectively connected to the input of the 2×1 coupler to combine the signal light and the indicator light. The output of the 2×1 coupler is connected to the input of the polarizer, which is used to filter out T-waves in the signal light. The E0 mode is used, and the TEO mode in the signal light is absorbed by a stray light absorber. The output of the polarizer is connected to the input of the phase modulator. Multiple micro-rings are cascaded in the phase modulator. The output of the phase modulator is connected to the second set of mode field adapters. The second set of mode field adapters includes mode field adapter three and mode field adapter four, which are respectively connected to the two outputs of the phase modulator. The chip also includes a scattering light circuit. The scattering light circuit includes a cascaded mode field adapter five and a vertical coupler. A III-V group detector is attached to the surface of the vertical coupler.

The utility model discloses a visualized water flow field measuring structure for a hydraulic experiment, which belongs to the technical field of visualized water flow field measuring structures for hydraulic experiments, and is characterized by comprising a circulating assembly, a hollow plate is bolted at the top of the circulating assembly, a detection box is bolted at the top of the hollow plate, and the detection box is provided with a water inlet and a water outlet. A sliding groove is formed in the left side of the detection box, a sliding block is slidably connected to the interior of the sliding groove, a detection assembly is fixedly connected to the left side of the sliding block, and first transparent glass is fixedly connected to the surface of the detection box; the problems that most of existing visual water flow field measuring structures are monitored through laser Doppler velocimeters, most of laser Doppler velocimeter supports are of fixed structures, the positions of the laser Doppler velocimeters cannot be adjusted conveniently through the fixed structures, certain limitation may be generated, and the measurement accuracy is poor can be solved. And the accuracy in the monitoring process is influenced.

The invention discloses a multi-wire cutting wire speed and wire length high-precision calibration control method, which aims at the problem of wire speed and wire length precision calibration in multi-wire cutting, adopts a laser Doppler velocimeter as reference calibration equipment, records data under different cutting roller diameters and tension states, and further fits corresponding adjustment parameters. And a high-precision line speed and line length calibration target is realized. By means of the method in the scheme, the system can correct and adjust the wire speed and the wire length of the cutting wire, and the wire speed and the wire length can be controlled more accurately; and moreover, the system can perform real-time and accurate compensation control on the wire speed and the wire length under any working condition based on a pre-calibrated high-precision data matrix, so that the process consistency and the control precision of multi-wire cutting are remarkably improved.

The invention provides a laser Doppler velocity measurement device based on a multi-core optical fiber and a vortex light field, and belongs to the technical field of vortex light field velocity measurement. The system comprises a laser, an optical splitter, a phase modulator, a multi-core optical fiber fan-in and fan-out device, a multi-core optical fiber, a gradient refractive index lens, an optical beam splitter, a photoelectric detector, an analog-to-digital converter, an upper computer, a controller and a driving circuit, the optical path design is simplified, direct generation of vortex light is achieved through the multi-core optical fiber, the optical path design is simplified, and the power consumption is reduced. The Doppler probe is formed by the gradient refractive index lens and the multi-core optical fiber, the light beam focusing characteristic is optimized, the quality of a vortex light field is ensured, meanwhile, the flexibility of a system is improved, the advantages of being compact in structure, high in integration level and high in precision are achieved, a stable vortex field can be formed at the position with the short emitting distance, and the requirement for the working environment is lowered. And a more efficient solution is provided for measuring the speed of the compound motion.

The utility model discloses a calibration device for cable meter counting function equipment. The calibration device comprises a fixed bracket, a laser Doppler velocimeter, a plurality of pulleys and a driving assembly, the fixing bracket comprises a laser Doppler velocimeter bracket, a pulley bracket and a driving assembly bracket; the laser Doppler velocimeter bracket is used for fixing the laser Doppler velocimeter; the plurality of pulleys are sequentially arranged and fixed on the pulley bracket; the pulley is used for winding a cable of the measured cable meter counter; the laser Doppler velocimeter is fixedly arranged right above the cable of the pulley in the middle, and one end of the cable is connected with the driving assembly; when the driving assembly runs, the cable is dragged, the measurement result of the laser Doppler velocimeter on the movement distance of the cable is read, an indicating value is read in the device of the detected cable meter counter, data are recorded, and calibration work is completed. According to the utility model, the calibration of the CCTV pipeline detection robot and other cable meter counters with cables can be realized, the automation precision is high, the operation is easy, and the working efficiency and the accuracy of measurement results can be greatly improved.

The present invention discloses a speed measurement method and system applied to a laser Doppler velocimeter. The above method includes: collecting the motion signal of the object to be measured by the laser Doppler velocimeter, and performing parameter setting according to the motion signal; filtering and segmenting the motion signal according to the set parameters, converting the signal of each segment to the frequency domain through fast Fourier transform and performing spectrum analysis to obtain the frequency search range of the signals of each segment; performing wavelet transform on the signals within the segment through the set parameters and frequency search range, and obtaining the instantaneous frequency estimation curve segment of the signal of each segment by extracting the wavelet ridge line; splicing the instantaneous frequency estimation curve segments of each segment, and reconstructing the time-frequency signal to obtain the velocity-time curve of the object to be measured. The present invention uses wavelet transform to process the signal, and combines fast Fourier transform to effectively improve the time resolution and data processing speed of the system.

The invention discloses a radius measurement method based on a laser Doppler velocimeter and order spectrum analysis, and the method comprises the steps: determining a measurement region through the laser Doppler velocimeter, collecting a scattered light signal generated in the rotation process of a workpiece, introducing order spectrum analysis, converting the signal from a time domain to an angle domain, and calculating the radius of the workpiece. Therefore, the influence of spindle speed fluctuation on measurement precision is effectively eliminated. Fourier transform and Gaussian fitting are further carried out on the angle domain signals, Doppler orders are extracted, and the workpiece radius is calculated in combination with the interference fringe interval. According to the method, the influence of rotating speed fluctuation on a radius measurement result can be eliminated, the measurement method is not influenced by guide rail thermal drift and structure installation errors, and the measured workpiece is not scratched.

The utility model discloses a connecting mechanism frame of a film drawing machine and a coating machine. The connecting mechanism frame comprises a carrier roller frame, an optical axis, an aluminum guide roller, a heightened belt vertical type seat bearing, a deep groove ball bearing, a shaft fixing ring and a tension controller. The aluminum guide roller is concentrically installed on the optical shaft, the optical shaft is connected with the heightening belt vertical type seat bearing, the heightening belt vertical type seat bearing is installed on the carrier roller frame cross beam, and the tension controller is installed on the carrier roller frame stand column. The deep groove ball bearings are installed on the two sides of the aluminum guide roller, and the shaft fixing rings are installed on the outer sides of the deep groove ball bearings. According to the utility model, the film drawing machine and the coating machine are connected, so that the integration of front and back procedures of product production is realized, the production efficiency can be improved, and the yield can be improved. In addition, two systems of the laser Doppler velocimeter and the tension controller are introduced and can verify each other, and when data are abnormal, an alarm can be given out through the PLC.

FIELD: production of linear products.SUBSTANCE: production of linear products by drawing, rolling, extrusion, twisting, layering, methods and devices for contactless monitoring of surface defects. Claimed device comprises a horseshoe-shaped housing mounted on a telescopic stand with the ability to be folded out of the working area by means of a hinge with light sources, video cameras and a laser Doppler velocimeter installed in it, a switch, a computer, a switch for connecting to a corporate network, a light and sound signaling unit, a connection unit with a process line, a connection unit with peripheral devices in the form of a printer and a marking machine, a mouse, a keyboard, a touch screen and software for collecting, processing and displaying information.EFFECT: increase in the accuracy of defect detection, determination of the geometric dimensions of the body, monitoring of the surface of the working body from all sides in a plane perpendicular to the direction of movement of the working body, creation of the possibility of introducing and removing the control and measuring system from the measurement zone without stopping the technological process and determining the coordinates of the detected defect along the length of the inspected working body.16 cl, 6 dwg

The application belongs to the technical field of integrated navigation and relates to a two-dimensional Doppler velocimeter calibration method and device, computer equipment and medium. The method comprises the following steps: obtaining relevant parameters of a two-dimensional laser Doppler velocimeter to obtain error velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system; converting the error velocity to a carrier coordinate system and then to a navigation coordinate system to obtain error velocity in the navigation coordinate system, and then obtaining an error model of the two-dimensional laser Doppler velocimeter; constructing an error model of a strapdown inertial navigation system; constructing a Kalman filter, taking the global positioning system as a reference, taking the velocity error, position error of the strapdown inertial navigation system and the velocity error of the two-dimensional laser Doppler velocimeter in the navigation coordinate system as observation quantities, estimating the state vector of the integrated navigation system and calibrating it. The method is not limited by the directions of the two beams of the two-dimensional laser Doppler velocimeter.

The application belongs to the technical field of integrated navigation and relates to a loosely coupled land integrated navigation method, device, computer equipment and medium. The method comprises the following steps: acquiring the wavelength of a two-dimensional laser Doppler velocimeter, the Doppler frequency shift of each of a first light beam and a second light beam and the design inclination angle of each of the first light beam and the second light beam, obtaining the error speed of the two-dimensional laser Doppler velocimeter in its own coordinate system; converting the error speed to a carrier coordinate system and then to a navigation coordinate system to obtain the error speed in the navigation coordinate system and then obtain the measurement model of the integrated navigation system; constructing an error model of a strapdown inertial navigation system; constructing a Kalman filter, estimating the state vector of the integrated navigation system and performing navigation. The method can provide the forward speed and the skyward speed of the carrier based on the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system to form a land integrated navigation system.

The invention discloses unmanned mine card slippage distance laser measurement equipment and a measurement method, and belongs to the technical field of mine card detection. According to the unmanned mine truck sliding distance laser measurement equipment and measurement method, a mine truck with a first mounting hole is included, and a second clamping plate and a first clamping plate are arranged at the upper end and the lower end of one side of the exterior of the first mounting hole respectively. According to the mine truck slip measuring device, the problems that in the detection process of existing mine truck slip measuring equipment, the laying position of an additionally-installed scale plate needs to be relatively flat, the scale plate needs to be close to the follow-up moving position of a mine truck, efficiency is low, and precision is poor are solved; the second adjusting frame rotates to unfold the laser Doppler velocimeter, the unfolded laser Doppler velocimeter rotates with the connecting roller as the circle center to adjust the angle and adapt to the installation position, and the laser Doppler velocimeter can be adjusted and adapt to different installation positions and installation heights in the unfolding process.

According to the vehicle-mounted navigation and gravity measurement integrated processing system and method provided by the invention, the single-axis rotation inertial navigation system, the satellite navigation system and the laser Doppler velocimeter are integrated, and the system can intelligently deal with various complex conditions through the environment state detection module and the navigation mode switching module; and a pure inertial navigation calculation result is subjected to feedback compensation through a multi-mode Kalman filter, so that high-precision navigation output is realized. And more pure relative gravity information is obtained based on the compensated carrier navigation information and acceleration information obtained by speed information difference of the carrier under the navigation coordinate system. The relative gravity information is fused with the absolute gravity reference of the navigation starting position, so that the absolute gravity information of the carrier along the way can be solved in real time. According to the method, high-precision multi-mode integrated navigation and dynamic absolute gravity measurement are deeply fused, so that the navigation precision in a complex environment is remarkably improved, and high-precision dynamic absolute gravity measurement is realized.

To provide a laser Doppler velocimeter that has higher accuracy and measures the distance between a focal point that is an intersection of two light beams and a surface of a moving object to correct a speed error.SOLUTION: A differential laser Doppler velocimeter irradiates a moving object with two laser beams separated from a laser source and receives scattered reflected light from the object to measure the velocity of the moving object on the basis of the Doppler effect, and has: a first optical receiving system that receives regular reflected light and scattered reflected light from the moving object; a second optical receiving system that receives the scattered reflected light from the moving object and provides the velocity of the moving object; and a signal processing system that is connected to the first optical receiving system and the second optical receiving system. The signal processing system calculates the distance between the moving object and an intersection of the two beams and the velocity of the moving object from a received signal from the first optical receiving system and a received signal from the second optical receiving system.SELECTED DRAWING: Figure 1

The present invention provides a laser Doppler velocimeter indication error calibration device to address the problems of complex structure, low upper reference speed limit, and danger in the prior art. The device comprises a single-frequency laser, a first wavelength meter, a second wavelength meter, a 1×2 fiber optic beam splitter, a 2×1 fiber optic coupler, and a fiber optic isolator. The device features a simple structure, low cost, a high safety factor, and a high reference speed. Furthermore, the present invention provides a laser Doppler velocimeter indication error calibration method.

The invention discloses a calibration device and method for the dynamic response time of a laser Doppler velocimeter, and belongs to the technical field of velocity measurement, and the calibration device is used in two stages of the calibration method, including the stage of the conduction time of an optical switch, and adopts a single-frequency laser, the optical switch, a photoelectric detector and an oscilloscope; and in the stage of simulating the conduction of the optical switch, the optical switch, the laser Doppler velocimeter and the echo simulation device are adopted. The calibration method comprises the following steps: measuring the conduction time of the light switch, and calibrating the rise time of a step signal during conduction; and simulating the standard signal, switching the optical switch from the off state to the on state, and calculating and determining the dynamic response time of the laser Doppler velocimeter. According to the invention, the speed step signal with fast speed change can be generated without constructing a physical standard speed source, and the speed step signal is used as a standard signal to calibrate the dynamic response time of the laser Doppler velocimeter, so that the dynamic speed measurement capability of the high-speed laser Doppler velocimeter is ensured.

The invention relates to the technical field of high-precision laser Doppler linear velocity detection optimization, in particular to a high-precision laser Doppler linear velocity detection method and device, and the method comprises the steps: setting a laser beam of a laser Doppler velocimeter as a vertical beam and an inclined beam, and obtaining an initial Doppler velocimeter; acquiring an optimized Doppler velocimeter based on the initial Doppler velocimeter, performing velocity measurement operation on the first tire by using a vertical light beam and an inclined light beam of the optimized Doppler velocimeter to obtain a first inclined echo light beam and a first vertical echo light beam, and acquiring a reference frequency of a reference light beam, obtaining a first frequency shift based on the reference frequency, the first inclined echo beam and the first vertical echo beam, calculating a first target frequency shift according to a pre-constructed Doppler frequency shift calculation formula, calculating a first speed by using a speed formula, obtaining a first linear speed, and completing the detection of the linear speed by using the first linear speed. The main purpose of the invention is to improve the accuracy of calculating the linear velocity by using the Doppler velocimeter.

The application belongs to the technical field of integrated navigation, and relates to a tightly coupled land integrated navigation method, device, computer equipment and medium. The method comprises the following steps: obtaining related parameters of a two-dimensional laser Doppler velocimeter, and obtaining a conversion matrix of a two-dimensional laser Doppler velocimeter coordinate system and a beam coordinate system; obtaining an output speed of a strapdown inertial navigation system in a navigation coordinate system, and obtaining an output speed of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system; obtaining an output speed of the strapdown inertial navigation system in the beam coordinate system according to the conversion matrix and the output speed of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system; constructing a Kalman filter, taking a difference between the output speed of the strapdown inertial navigation system in the beam coordinate system and a speed of the two-dimensional laser Doppler velocimeter in the beam direction as a filter observation, estimating a state vector of the integrated navigation system, and navigating. The method improves the robustness of the integrated navigation system.

The invention provides an adjustable double-hydrofoil non-uniform incoming flow generating device which is composed of a water tunnel connecting module, a double-hydrofoil incoming flow oscillation generator module, a driving system and a data acquisition system, and a non-uniform flow field with good symmetry can be generated through in-phase flapping of double hydrofoils. And by matching with measuring devices such as a laser Doppler velocimeter, a pressure acquisition system and a high-speed camera, adjustability and controllability of an incoming flow generation process can be maintained while multiple water tunnel tests are carried out, so that powerful support can be provided for research on complex flow mechanisms such as cavitation evolution and underwater vehicle controllability.

This application relates to an online calibration method and apparatus for a laser Doppler velocimeter based on position observation. The method divides the calibration process into two stages: coarse calibration and fine calibration. In the coarse calibration stage, an analytical method is employed. In the fine calibration stage, a robust Kalman filter is first designed to obtain accurate carrier attitude, velocity, and position information. Then, another Kalman filter is designed using the error propagation model of the laser Doppler velocimeter based on position observation to further calibrate the laser Doppler velocimeter. To reduce the impact of non-holonomic constraints being violated during vehicle turning on the calibration results, the output of an astrogyroscope and the output velocity of the laser Doppler velocimeter are used to distinguish whether the vehicle is changing direction, and lateral velocity compensation is performed on the laser Doppler velocimeter's velocity in its own coordinate system when the vehicle changes direction. This method significantly improves the robustness of the laser Doppler velocimeter during the calibration process.

The application discloses a kind of high-precision calibration control methods of wire speed and wire length of multi-wire cutting, for the problem of wire speed and wire length precision calibration in multi-wire cutting, laser doppler velocimeter is used as reference calibration equipment, record the data under different cutting roller diameters and tension state, and then fit the corresponding adjustment parameters, realize the wire speed and wire length calibration target of high precision.Through the method in the scheme, the system can correct and adjust the wire speed and wire length of cutting wire, can more accurately control wire speed and wire length;And, the system can compensate control in real time, accurately to wire speed and wire length under any working condition based on pre-calibrated high-precision data matrix, significantly improve the process consistency and control precision of multi-wire cutting.