602results about How to "Realize high-precision measurement" patented technology

The invention discloses a three-dimensional optimizing route selection method based on an airborne laser radar. The method comprises the following steps of: carrying out flight design according to a feasible route of a line, and acquiring flight field data by the laser radar according to design parameters; carrying out united computation on laser ranging data and POS system positioning data to obtain laser point cloud data through pre-processing the data; post-processing the data to obtain a point cloud classification map, a digital elevation model (DEM), a digital surface model (DSM), a contour line and a digital orthoimage map (DOM); importing into a three-dimensional optimizing route selection system, selecting a line route, checking peripheral landform of a line corridor, and carrying out optimization design on the line; combining with a three-dimensional image and a plane section, carrying out operations of pre-arranging poles and arranging poles in a route selection software, and outputting an image route diagram; and drawing the plane section of the route, and carrying out alignment survey. The method utilizes the section view and the orthoimage in the three-dimensional optimizing route selection system to realize the operations of pre-arranging the poles and arranging the poles, so as to generate a plane section diagram needed by power industry department, and the operation efficiency of route selection is improved.

The invention provides a refrigerant mass and flow measuring method and device and a measuring instrument. The method is used in a refrigerating system and comprises the steps that the evaporation pressure and the condensation pressure are obtained; the air suction temperature and the exhaust temperature of a compressor are obtained, and the compressor shell surface temperature, the environment temperature around the compressor and the compressor consumption power are obtained; the jetting temperature of an intermediate pressure container is obtained, and the oil content of a refrigerant mixture is obtained; a corresponding first enthalpy value, a corresponding second enthalpy value, a corresponding third enthalpy value, a corresponding fourth enthalpy value, a corresponding fifth enthalpy value, an enthalpy value difference and the heat exchange amount of the compressor and the outside environment are obtained through calculation according to the obtained various parameters; and according to the first enthalpy value, the second enthalpy value, the third enthalpy value, the fourth enthalpy value, the fifth enthalpy value, the enthalpy value difference, the heat exchange amount, the consumption power of the compressor and the oil content of the refrigerant mixture, the mass and flow of the refrigerant in the refrigerating system are obtained through calculation. According to the scheme, non-intrusive and high-precision measurement on the mass and flow of the refrigerant is achieved, bad influences brought to the refrigerating system in the measurement process are avoided, and the user experience is improved.

The invention provides a mass and flow measuring method and a device of a refrigerant in a refrigerating system and a measuring instrument. The method comprises the steps of: obtaining an intake temperature of a first compressor, an exhaust temperature of a second compressor, an evaporation pressure, a condensation pressure, shell surface temperatures of the first and second compressors, a surrounding environment temperature, a total consumption power, a spraying temperature, a first supercooling temperature, a second supercooling temperature and an oil content of a refrigerant mixture; calculating corresponding first, second, third, fourth and fifth enthalpy values, enthalpy value differences and total heat exchange quantities of the first and second compressors with external environment according to the obtained data; and calculating the mass and the flow of the refrigerant in the refrigerating system according to the first, second, third, fourth and fifth enthalpy values, the enthalpy value differences, the total consumption power, the total heat exchange quantities and the oil content of the refrigerant mixture. The method realizes non-invasion and high-precision measurement of the mass and the flow of the refrigerant in the refrigerating system, prevents adverse effect on the refrigerating system in the measuring process, and improves the user experience.

The invention discloses a high-accuracy remote absolute displacement measurement system based on optical fiber composite interference, which belongs to the technical field of optical measurement and is composed of a board band light source, an optical fiber isolator, three 3dB couplers, four auto-collimation mirrors, two optical fiber gratings, four reflectors, two detectors, a circulator, a one-dimensional translation platform, piezoelectric ceramics, a feedback control circuit, a signal generator, a signal treatment circuit, an analog to digital (A / D) conversion card, a computer and result output. The high-accuracy remote absolute displacement measurement system uses an optical fiber interferometer to induce displacement and another optical fiber interferometer to demodulate displacement to achieve remote measurement. The optical fiber interferometer for demodulation works in a low coherence interference state and a high coherence interference state, and amplitude of displacement can be determined by low coherence signals to achieve absolute measurement. A value of the displacement can be measured by high coherence signals to feed back and control effects of environment interference on the demodulating optical fiber interferometer, and high-accuracy measurement can be obtained.

A laser liquid-level measure of floater type consists of screen laser-logging, fixing device of said logging, floater, balance weight and laser distance measurer of reflection type.

The invention relates to a system calibration method for grating stripe projection-based three-dimensional measurement. A calibration object is a system consisting of a projector and a video camera. The method is implemented by the following steps: (1) adjusting the relative positions of the projector and the video camera, so that the projector is parallel with a lens longitudinal axis of the video camera; (2) calculating the absolute phase position of a reference plane by combining a sinusoidal grating phase-shifting algorithm and a Gray code; (3) placing at least two standard blocks, of which the heights are known and different, on the reference plane and calculating the absolute phase position distribution; (4) calibrating a three-dimensional measuring system: establishing projection and imaging models, deducing an object point height-phase position relational expression of an object to be measured, and fitting the coefficients of the height-phase position relational expression by utilizing the standard blocks with known heights and the absolute phase position distribution thereof and through a least square method; (5) calculating the absolute phase position value of the object to be measured and obtaining the height distribution from a calibrated expression so as to realize height measurement of the object. The method has the advantages of high operability and high measuring precision.

The invention discloses an array type parallel laser projection three-dimensional scanning method. The array type parallel laser projection three-dimensional scanning method comprises steps that a laser micro-vibration mirror projection device used for projecting line lasers in different directions and a plurality of array type cameras used for data acquisition are provided; laser cutter separation of each acquired image in different directions is carried out, and the laser cutter centers of the laser cutters in various directions are respectively extracted, and according to a triangle relation among the projection device and the cameras, an object surface three-dimensional coordinate of a line laser position is acquired; the projection device is used to move the line laser on the object surface by one pixel each time, and the above mentioned process of extracting the object three-dimensional coordinate on the laser cutter position is repeated until the three-dimensional coordinate of the whole object surface is acquired by the laser cutter. The laser projection device adopts MEMS scanning vibration mirror laser, and compared with a digital light and physical grating technology, field depth is large, scanning speed is fast, a size is small, and scanning precision is high; and at the same time, the system is used to distribute the cameras in an array, and then the sensitivity to complicated step edge measurement is provided, and then the non-contact, high-speed, and object edge step high precision measurement of the object is realized.

A combined interference device for measurement of aspheric surface includes a laser, a spatial filter, two beam expanding systems, a beam shrinking system, a spectroscope, a convertible lens, three polarizers, two optical plates, four circular optical wedges with small wedge angle, a beam-dividing grating, a 1 / 4 wave plate, a polarizer group and a CCD. In the device, real-time measurement is realized through simultaneous phase-shifting method, and frequency conversion function is realized through rotating two pairs of double optical wedges. The experimental device adopts common optical elements, so the cost is low, and the device can measure aspheric surfaces of different diameters and is suitable for the plane and the sphere. The real-time high precision measurement in conventional environment can be realized, and the invention has frequency conversion function, which is very effective for treating the mirror surface with discontinuous regions.

The invention discloses a comparative measurement method-based multi-parameter vision measurement system of an inner ring of a bearing. The multi-parameter vision measurement system comprises a swing-rod barrier feeding mechanism, an axial parameter measurement apparatus, a radial parameter measurement apparatus, a conveying mechanism, a separation mechanism, a PLC control module, an upper computer control module and a man-machine interaction module. According to the measurement system, with utilization of a standard and high-precision inner ring of a bearing as a reference component as well as a camera as a comparative measurement instrument, a measured outer ring of a bearing is compared with the reference component so as to carry out separation of a qualified product, a reprocessed product and a scraped product based on calculation of a localization error of the outer ring of the bearing. Therefore, not only can automatic comparative measurement of the inner hole diameter of the inner ring of the bearing, the outer diameter, the diameter of a groove, a curvature radius of the groove and the width be realized, but also a bottleneck problem that the system cost is too high due to a requirement of a high resolution ratio of a camera during the high precision detection and large-size detection of the inner ring of the bearing can be solved.

The invention mainly aims at precision testing of characteristic parameters such as facial form and surface roughness of a large-scale sphere and an aspheric surface and particularly relates to an outline scanning measuring method and a device of the large-scale sphere and the aspheric surface. The large-scale sphere and the aspheric surface can separate an axial end jump error and a rectilinear motion guide rail error in an X direction in real-time, achieve real-time self-detaching of the axial end jump error of a drive shaft system and an aspheric surface outline measurement value, adopt a reference beam with high direction stability to monitor and compensate a guide rail motion error in real-time and be capable of conduct autonomous detaching and real-time compensation on the high-precision large-scale sphere and the aspheric surface such as the axial end jump error of the drive shaft system and the rectilinear motion guide rail error in the X direction. The outline scanning measuring method and the device of the large-scale sphere and the aspheric surface provides a new method and a new technology for high-accuracy measurement of parameters such as the facial forms of the large-scale sphere or aspheric surface, surface roughness, radius of curvature and the like.

This invention belongs to power measuring technique region, relates to a line frequency parameter measurement and device of electric transmission line. The trait is: measuring electric transmission line by frequency sweeping at intermediate frqquency range of 100 to 2000hz, base on Signal-to-Noise Ratio of measuring signal to set frequency of supply oscillator used for measuring. Base on length of electric transmission line to set voltage of supply oscillator for measuring. picking up fundamental circuit parameter of electric transmission line, then calculate and obtain line frequency equivalent parameter of electric transmission line; line frequency parameter measurement device of electric transmission line includes control system that takes singlechip as controlling center, brainpower numerical control frequency conversion transform power that operated by singlechip, voltage and electric current sensing circuit, digital filter and signal acquisition circuit. Power supply of brainpower numerical controlling, frequency conversion and variable voltage supply signal source to electric transmission line. Electric transmission line detects the signal and then sends to digital filter and signal acquisition circuit. Digital filter and signal acquisition circuit would turn circuit signal to fundamental circuit parameter, and send into singlechip.

The invention relates to the field of rotating moving blade non-contact vibration measurement, and aims at effectively improving the measurement precision of vibration parameters and achieving the high-precision measurement of blade tip gaps. The technical scheme employed in the invention is that a moving blade tip gap and vibration parameter fusion measurement device based on microwave comprises a microwave sensor and a sensor drive module; the sensor drive module comprises a circulator, a phase-locked loop (PLL), a phase shifter, a frequency mixer, a low-pass filter circuit, a high-pass filter circuit, a single-chip microcomputer MCU, a multiplying unit, an adder, an automatic gain control circuit AGC, a comparator, and an A / D analog-digital signal converter; the device also comprise a data collection module which comprises an FPGA (field-programmable gate array), a digital signal processor (DSP), and an upper computer. The device is mainly used for the non-contact vibration measurement of a rotating moving blade.

The invention discloses a comparative measurement method-based multi-parameter automatic measurement system for an outer ring of a rolling bearing. The automatic measurement system comprises a feeding mechanism, a chained transmission mechanism, an axial parameter measurement apparatus, a radial parameter measurement apparatus, a separation mechanism, a PLC control module, an upper computer control module, and a man-machine interaction module. According to the measurement system, with utilization of a standard and high-precision inner ring of a bearing as a reference component as well as a camera and a digital dial gauge as comparative measurement instruments, a measured outer ring of the bearing is compared with the reference component so as to carry out separation of a qualified product, a reprocessed product and a scraped product. According to the invention, automatic comparative measurement of the outer diameter of an outer ring of a bearing and the variation thereof, an inner diameter and the variation thereof as well as the diameter of a groove and the variation thereof can be realized; and moreover, bottleneck problems that the system cost is too high due to a requirement of a high resolution ratio of a camera during the high precision detection and large-size detection of an outer ring of a bearing and the previous multi-parameter detection of an outer ring of a bearing needs to utilize special measurement instruments respectively to carry out measurement can be solved.

A measuring apparatus for measuring surface topography of bearing and other parts comprises a pedestal (1), an absolute encoder (2), a ball screw (3), an X-axis sliding guide track device (4), an X-axis limit switch (5), an X-axis signal collection grating (6), a driving box supporting plate (7), a sensor driving box (8), an upright guide track (9), a Z-axis motor (10), a Z-axis manual adjusting knob (11), an X-axis motor (12), an X-axis belt wheel and cog belt (13), an inductive sensor device (14), a sensor coupling rod (15), a multi-dimensional workbench (16) and an electrical system. The invention can measure more than 100 parameters, including profile, waviness, roughness, peak height, valley deepness, total height, average deviation, gradient, slope, bearing length ratio and others; provides detection reference for users to perform various technical analyses to the workpiece to be measured; and can add certain measurement parameter at any time according to the requirement of users.

The invention discloses a high-precision focus detection device for a long-focus lens, which comprises a laser, a microscope objective, a pin hole, a first Ronchi grating, the long-focus lens to be detected, a second Ronchi grating, ground glass and a CCD (Charge Coupled Device) camera. Light emitted by the laser passes through the microscope objective and the pin hole to form a divergent beam and the divergent beam enters the first Ronchi grating and then passes through the long-focus lens to be detected and the second Ronchi grating; the second Ronchi grating is placed at a certain talbot-order position of the first Ronchi grating, so that Moire fringes can be formed on a talbot image of the first Ronchi grating and the second Ronchi grating; and the fringes are acquired by the CCD camera and the focus of the lens to be detected can be obtained by calculating angles of the fringes. The high-precision focus detection device has a simple structure, is easy to implement, has high precision, can be used for detecting the long-focus lens and accurately measuring the focus in an optical system and particularly can be used for accurately measuring the focus of the large-caliber long-focus lens (the focus is in the range of meters and dozens of meters), so that an error caused by the scanning detection is avoided.

The invention discloses a birefringent crystal temperature compensation based optic fiber pressure sensor and a production method thereof. The sensor comprises a Fabry-Perot pressure sensing head chip, a birefringent crystal, a grin lens, a glass capillary, a quartz glass tube and a multimode optical fiber. Optical signals sequentially pass the birefringent crystal and an optical fiber Fabry-Perot pressure sensing head, then optical path difference is modulated, and double-parameter measurement of pressure and temperature is achieved by detecting variation of the optical path difference of the birefringent crystal and the optical fiber Fabry-Perot pressure sensing head. Comparing with the prior art, the optic fiber pressure sensor has the advantages that high-precision pressure measurement sensing are achieved by introducing temperature measuring result as reference quantity and correcting pressure measurement result, besides, a demodulation instrument achieves synchronous demodulation of temperature and pressure, a demodulation system is simple, data processing is accurate, system cost is low, and practical operation is facilitated.

The invention provides a non-contact measurement method for sizes of forged pieces. According to the non-contact measurement method, feature points are scanned and acquired through cooperation of a linear array CCD and linear structured light, three-dimensional coordinates of the feature points are deduced and three-dimensional modeling are performed on the basis of the optical triangle principle, and thus information such as sizes of the forged pieces is obtained through analysis. Through the measurement device and method, the system resolution is improved, the system measurement range is widened, the problem of target matching in binocular vision is avoided, and large-size three-dimensional high-precision measurement can be achieved.

The invention relates to an RCS (radar cross section) measurement device based on a single continuous terahertz laser source and belongs to the technical field of terahertz RCS measurement. The RCS measurement device can be used for solving the problem in measuring the RCS of target radars of different sizes in a 2.52THz waveband. The RCS measurement device comprises a CO2 laser pumping continuous terahertz laser, a chopper, a beam splitter, an electrical control variable expansion ratio device, a P3 off-axis parabolic mirror, a P2 off-axis parabolic mirror, a precise movement platform, an M1total reflector, a P1 off-axis parabolic mirror, a scattered signal detector, a first lock-in amplifier module, a computer and a chopper driver. The RCS measurement device is suitable for RCS measurement on the target radars of different sizes.

The invention provides a high-precision measurement system for three-dimensional microdeformation of a mechanical device in a high-low-temperature case, The measurement system comprises a string, a three-dimensional air flotation assembly and three-direction photoelectric displacement sensing devices, wherein each air flotation unit comprises an air flotation shaft and an air flotation sleeve; the three-direction photoelectric displacement sensing devices are respectively installed on an x-direction air flotation unit, a y-direction air flotation unit and a z-direction air flotation unit and are used for measuring the displacements on an x direction, a y direction and a z direction; an x-direction air flotation shaft is installed on a fixed plate; an x-direction air flotation sleeve is installed on the x-direction air flotation shaft in a sliding manner; the x-direction air flotation sleeve is fixedly connected with a y-direction air flotation shaft; a y-direction air flotation sleeve is installed on the y-direction air flotation shaft in a sliding manner; the y-direction air flotation sleeve is fixedly connected with a z-direction air flotation sleeve; a z-direction air flotation shaft is installed on the z-direction air flotation sleeve in a sliding manner; the upper end of the string is connected with a measured piece, and the lower end of the string is connected with the z-direction air flotation shaft of the three-dimensional air flotation assembly. The invention provides the high-precision measurement system, which has high measurement precision and is used for measuring deformation amount of the measured piece in the high-low-temperature case.

The invention relates to an on-line monitoring method of the change of six freedom degrees between the lenses of an astronautical CCD camera with three linear arrays. A laser emitting and receiving device which comprises a laser source, an optical fibre coupler, a laser aligner, a semi-transparent semi-reflecting mirror and a first area array CCD camera is rigidly fixed on a camera lens A, and a laser reflecting and receiving device which comprises a plane mirror, a second area array CCD camera and a third area array CCD camera is rigidly fixed on the a camera lens B. The optical fibre coupler divides lasers emitted from the laser source into three paths, and then, the lasers are respectively aligned by the laser aligner and are output, wherein two paths of the lasers are respectively and directly projected on the two area array CCD cameras of the laser reflecting and receiving device, and the other path of the lasers are reflected on the single area array CCD camera of the laser emitting and receiving device. The change of three rotating freedom degrees and three translational freedom degrees between the lenses of the astronautical camera is solved through the change of facula positions on each area array CCD camera. In the invention, a non-contact measurement method is adopted, the structure of the astronautical camera can not be changed, the processes of installation and adjustment are convenient, the structure is compact, and the on-line operation mode can be achieved.

The invention relates to distributivity long gauge length optical fiber Prague grating strain gage and its manufacturing method. It is formed by many long gauge length optical fiber Prague grating strain gages with series connection. The two ends of the each long gauge length optical fiber Prague grating are respectively connected with mono-mode fiber without coating. Their outer is hitched by annular tube of which two ends are fixed on the mono-mode fiber respectively by optical fiber and annular tube, which two ends are connected with outer mono-mode fiber optical cable by welding point. Composite material packaging layer is covered at the outside of the above structure.

The invention relates to a magnetostrictive displacement sensor with high precision and large measuring range, which mainly comprises a waveguide tube and a sensing electronic head. The waveguide tube is used for generating an echoed signal, receiving an exciting pulse signal, simultaneously generating magnetostrictive effect at the position of a magnetic ring, and generating magnetic torsional wave to be returned to an echo acquisition processing analysis system; the waveguide tube is sleeved with the magnetic ring of a permanent magnet; and the directions of a magnetic field generated by the magnetic ring and a magnetic field generated by the waveguide tube are different, and once the magnetic fields are crossed, the magnetic torsional wave is generated. The sensing electronic head comprises five subsystems, namely a control unit, an exciting signal generating system, a communication system, a power supply circuit and the echo acquisition processing analysis system. The magnetostrictive displacement sensor has the advantages that a stable signal exciting and high-speed data acquisition system is designed, and the anti-jamming design of the signals is enhanced; the application range of the sensor is improved; and the measuring precision is quite high, the measuring range is large, the measuring distance is between 25 and 18,000 millimeters, and simultaneously data measured in long distance can be processed through a Zigbee wireless mode.

The invention relates to a magnetic suspension controlled sensitive gyroscope configuration based attitude angle velocity measuring method. According to a dynamical model of a magnetic suspension rotor which moves follows the attitude of a spacecraft, the change of the motion state of a high-speed rotor depends on an external torque exerted on the high-speed rotor, the external torque comprises a magnetic bearing torque and a disturbance torque, and the disturbance torque is associated with the attitude angle velocity of the spacecraft; the magnetic bearing torque can be obtained by detecting the current of a magnetic bearing and the displacement of the rotor, and then through the balancing relationship between the magnetic bearing torque and the disturbance torque, the estimation on the angle velocity of the spacecraft is realized; and by using four magnetic suspension controlled sensitive gyroscopes in pyramid configuration, eight pieces of measuring information about the magnetic torque can be provided, so that the high-precision calculation of the attitude angle velocity and the angular acceleration is realized. According to the method, the attitude control function of the magnetic suspension controlled sensitive gyroscope configuration can be ensured while the estimation on the high-accuracy angle velocity is realized, and the high-precision and high-stability attitude control is realized.

The invention discloses measurement equipment and a measurement method and system for butt joint gaps and jumps of aircraft components. The measurement equipment comprises a positioning device, a measurement device and an upper computer; the positioning device comprises a positioning tool; the measurement device comprises an annular rail, a measurement head, a measurement head driving device and an annular rail driving device. The annular rail and the measurement head are arranged on the positioning tool so that the measurement head driving device can drive the measurement head to move along the annular rail, and the annular rail driving device can drive the annular rail to horizontally move on the positioning tool. Therefore, outline data of whole butt joint areas of the aircraft components to be measured can be measured through motion of the measurement head and the annular rail, and the defect is effectively overcome that since only local characteristic points are measured and measurement data is not comprehensive, the measurement precision is low; accordingly high-precision measurement on the butt joint gaps and jumps of the aircraft components to be measured is achieved.

The invention discloses an SPR phase measurement method for measuring the thickness of a nano-scale double-layer metal film. The method comprises steps: a theoretical curve diagram for a phase change difference between TM polarized waves and TE polarized waves for the metal film layer thickness along with an incident angle change is built; a group of incident angle values with an SPR resonance angle as the center change is set; an interference fringe pattern for a prism-type SPR sensor coating region is acquired; an interference fringe pattern for a prism-type SPR sensor non coating region is acquired; a phase change difference between TM polarized waves and TE polarized waves in a coating region is calculated and obtained; the incident angle is changed sequentially starting from an initial angle, and a measurement curve diagram for the phase change difference along with the incident angle change is obtained; and according to the theoretical curve for the phase change difference along with the incident angle change and the obtained measurement curve, the thickness of the double-layer metal film coating the SPR sensor is determined. The method of the invention has the advantages of simple structure, high measurement precision and convenient operation.

The invention relates to a novel torque optical fiber sensor and belongs to the test technology and optical fiber sensor field. The invention adopts a long-period optical fiber grating or a fused-tapered optical fiber as a measuring element; when the long-period optical fiber grating or the fused-tapered optical fiber is acted by the torque, the period of the long-period optical fiber grating or the optical intensity or the spectrum of the fused-tapered optical fiber can be changed, thereby measuring the torque value. The sensor is formed by a guiding optical fiber, a torsion rod (2), a torsion rod (3), a long-period optical fiber grating or a fused-tapered optical fiber (5), and a spring (4), wherein, two torsion rods (2) and ( 3) are connected by the spring (4) and can relatively be rotated. The long-period optical fiber grating or the fused-tapered optical fiber which are used for sensing are respectively fixed on the torsion rod (2) and the torsion rod (3). In addition, one torsion rod of the torque sensor is provided with a magnet which can form an optical fiber revolution sensor based on the torque measurement with a opposite polarity magnet which is arranged on a rotary mechanism.

In a detection and ranging apparatus that performs direction-of-arrival estimation using a sensor array and that enlarges an effective aperture using a plurality of transmitting sensors, adverse effects associated with time division switching are eliminated, achieving high-accuracy measurement. A transmitter wave is spread in modulators by using mutually orthogonal codes, and the resulting transmitter waves are radiated from two transmitting sensors. Signals received by receiving sensors are each split by a splitter into two parts, which are then respectively despread in a demodulator by using the same codes as those used in the transmitter.

The invention discloses a non-contact type overvoltage sensor based on the electro-optic effect. The non-contact type overvoltage sensor comprises a non-contact sensing unit and an electro-optic sensing unit, wherein the non-contact sensing unit comprises an induction metal plate and a low-voltage arm module, the induction metal plate is used for being arranged below an aerial power transmission line, the low-voltage arm module is arranged between the induction metal plate and the ground, the low-voltage arm module is composed of a capacitor C2 and a peripheral circuit of the capacitor C2, one end of the capacitor C2 of the low-voltage arm module is electrically connected with the induction metal plate, the other end of the capacitor C2 is grounded, and a voltage signal output end between the capacitor C2 and the induction metal plate is electrically connected with a signal input end of the electro-optic sensing unit. The non-contact type overvoltage sensor based on the electro-optic effect is simple in structure, small in size, high in stability, and convenient to install, popularize and apply, and facilitates remote control; mutual conversion between optical signals and electrical signals is achieved through the electro-optic effect, long-distance signal transmission is achieved through optical fibers, and compared with a traditional photoelectric sensor, the non-contact type overvoltage sensor based on the electro-optic effect has the advantages that the size is smaller, the response efficiency is higher, and the sensor is not influenced by an electromagnetic field.

The invention relates to an FPGA-based high precision time interval measurement method. The method comprises the following steps: performing rough measurement on the time intervals between two pulsesby adopting a pulse filling counting method to obtain a rough measurement result of the time interval; based on an FPGA tap delay chain, performing fine measurement on a phase difference less than a clock cycle to obtain a fine measurement result of the time interval; and determining a final measurement result of the time interval according to the rough measurement result and the fine measurementresult. According to the method, a wide range of time intervals can be measured by combining the rough measurement and the fine measurement and utilizing the high precision time delay interval of tensof picoseconds of an FPGA delay unit. The invention also discloses an FPGA-based high precision time interval measurement system.

The invention relates to a three-dimensional deformation measuring device for a measured piece in a high-temperature and low-temperature box. The measuring device comprises a string, a three-dimensional air floating assembly and signal acquisition modules with encoders in three directions. Each air floating unit comprises an air floating shaft and an air floating sleeve. The signal acquisition modules with the encoders in the three directions are respectively installed on an x-direction air floating unit, a y-direction air floating unit and a z-direction air floating unit. An x-direction air floating shaft is installed on a fixed plate. An x-direction air floating sleeve is slideably installed on the x-direction air floating shaft. The x-direction air floating sleeve is fixedly connected with a y-direction air floating shaft. A y-direction air floating sleeve is slideably installed on the y-direction air floating shaft. The y-direction air floating sleeve is fixedly connected with a z-direction air floating sleeve. A z-direction air floating shaft is slideably installed on the z-direction air floating sleeve. The upper end of the string is connected with the measured piece and the lower end of the string is connected with the z-direction air floating shaft of the three-dimensional air floating assembly. The three-dimensional deformation measuring device for the measured piece in the high-temperature and low-temperature box provided by the invention has the advantage of high measurement precision.