48results about How to "Avoid measurement accuracy" patented technology

The invention provides a method and a device for double-star time difference / frequency difference combined positioning. By using the method, the calculation efficiency and the measurement accuracy of the time difference and the frequency difference can be improved. According to the scheme, the method comprises the following steps of: (1) carrying out time difference-frequency difference combined coarse estimate, calculating A(tau, f)=FFT[r(n; tau)], directly measuring the carrier frequency of a composite signal FORMULA for the search of the time difference each time, labeling a frequency spectrum amplitude value and a time difference value and finding out a maximum position, wherein tau is equal to tau1, tau2, FORMULA and tauM; (2) extracting and filtering the composite signal FORMULA, then measuring the carrier frequency, and coarsely estimating the frequency difference; (3) accurately calculating the frequency difference in the adjacent domain FORMULA of an estimated value in the coarsely measured frequency difference and accurately estimating the frequency difference; (4) accurately calculating the time difference in the adjacent domain FORMULA of an estimated value in the coarsely measured time difference and accurately estimating the time difference; and (5) accurately estimating the time difference, estimating the time resolution 1 / Ts of the time difference by using a relevant method and improving the time difference estimate accuracy by using interpolation, wherein Ts is the sampling interval of signals. In the invention, the time difference is calculated by using the signals with a high sampling rate, the frequency difference is calculated by using the signals with a low sampling rate, and the problems of the calculation efficiency and the measurement accuracy of the time difference and the frequency difference are solved by combining the time domain processing with the frequency domain processing.

A shape measuring apparatus includes a point light source including a white light-emitting diode, a collimator lens for forming a parallel beam as a result of causing light emitted from the point light source to be incident upon the collimator lens, a telecentric lens device, including two-side telecentric optics or object-side telecentric optics, for being irradiated with the light that has passed an object to be measured from the collimator lens, and an image sensor for projecting thereon an image of the object produced by the light that has passed through the telecentric lens device.

The invention relates to a method for improving the accuracy of wind tunnel measurements, especially for correcting the influence of a suspension device. According to said method, a model, particularly an aircraft model, is introduced into a wind tunnel on the suspension device that comprises several suspension wires, and at least one sleeve is mounted on one respective suspension wire. The inventive method comprises the following steps: at least two measurements are taken on the same model configuration at least at one respective effective diameter and / or the diameter of the suspension wire in order to determine at least two raw measured values and determine a corrected final measured value for the model from at least two raw measured values. According to a first embodiment of the disclosed method, the effective diameters of the suspension wires are reduced in at least three stages by removing mounted sleeves when detecting raw measured values of the drag coefficient of the model. A final measured value of the drag coefficient, which is corrected by the influence of the suspension device and the interference between the model and the suspension device, can be determined from the raw measured values using interpolation. According to another embodiment, the correction is made by forming the difference between only two raw measured values, one of which is determined from the diameter of the suspension wire without the mounted sleeves. The inventive method is suitable for correcting all aerodynamic parameters that can be measured in wind tunnels. The invention further relates to an apparatus for carrying out said method.

Disclosed herein is a sensor utilizing attenuated total reflection. The sensor includes a first dielectric block; a thin film layer, formed on a first face of the dielectric block, for placing a sample thereon; and a light source for emitting a light beam. The sensor further includes an optical incidence system for collimating the light beam, and making the collimated light beam enter the dielectric block at a predetermined incidence angle so that a condition for total internal reflection is satisfied at an interface between the dielectric block and the thin film layer; a photodetector for detecting the refractive index distribution of the sample obtained within a plane along the interface, by detecting an image carried by the light beam totally reflected at the interface; and an optical compensation system for compensating for image distortion produced by the dielectric block when the predetermined incidence angle of the light beam varies.

A length measuring probe that includes a base body, a guide element and a probe pin having a touch scanning element for touch scanning a measuring object, the probe pin is seated, displaceable in relation to the base body in a measuring direction opposite a spring force F via the guide element. A detection device detects a position of the probe pin with respect to the base body and a first spring element and a second spring element arranged behind the first spring element in the measuring direction so as to prestress the probe pin. The guide element is arranged between the first and second spring elements, on which facing end areas of the first and second spring elements are fixed in place, and wherein the at least one guide element is seated, displaceable in the measuring direction, on the probe pin and on the base body.

The invention discloses a power grid operation data acquisition system, which is characterized in that an overload detection circuit detects the current flowing through a primary side coil of a current sensor; in case of overload, the harmonic frequency is calculated by a divider IC1; the harmonic impedance is obtained by multiplication of a multiplying unit IC2; one path of the harmonic impedanceis connected to a feedback resistor of an operational amplifier AR1 in parallel; the current of a power grid cable is attenuated and then connected into a primary coil of a current sensor T1 in a windowing regulating circuit; the other path triggers a triode Q1 and a triode Q2 to be conducted; the number of turns of the primary coil of the current sensor T1 is changed; the measurement accuracy isimproved; the current of a secondary coil of the current sensor T1 is converted into voltage and subjected to amplitude limiting amplification through an operational amplifier AR2; the voltage is transmitted to a frequency modulation transmitting circuit under a sampling clock of a switch SW3 to ensure the integrity of signals; the frequency modulation transmitting circuit adopts a frequency modulation circuit taking a triode Q7 as a core to carry out preliminary frequency modulation; and then a controllable frequency multiplication circuit taking a triode Q6 as a core carries out frequency multiplication on the preliminary frequency modulation and add the preliminary frequency modulation to a transmitter, so that the relative frequency offset is increased, and the transmission anti-interference capability is improved.

The invention provides an automatic determination method of a friction mark direction angle of a friction spot image of a four-ball friction test. The method comprises the steps of performing graying processing on the acquired friction mark image without an obvious color, increasing a processing speed of the image, obtaining a plurality of groups of run error peak values by cyclic rotation of a grey friction spot image, and finally obtaining the friction mark direction angle via the obtained maximum run error peak value. The friction mark direction angle can be precisely determined by the quantitative method, and the influence on the measurement precision due to inadequate experience of testing personnel is avoided. And the precise friction mark direction angle can be obtained without contrastive analysis for many times.

The present invention relates to a deaerator 2 including: a liquid flow space; reduced-pressure spaces 25A, 25B, and 25C; gas permeable films 21A, 21B, and 21C that separate these spaces; and a pump for discharging gas from within the reduced-pressure spaces 25A, 25B, and 25C to the outside, and to a liquid chromatograph equipped with the deaerator 2. The deaerator 2 further includes gas partial pressure variation suppression means 23A, 23B, 23C, 25Ab, 25Bb, 25Cb, 29A, 29B, and 29C for suppressing variations in partial pressures of a specific gas in the reduced-pressure spaces 25A, 25B, and 25C.

The invention discloses an ultra-precise displacement measuring system based on an optical neural network. The system comprises a light source, an optical displacement measuring device, an optical neural network, a detector array and a signal processing device. When a target object moves, the system takes a measurement optical signal output by the optical displacement measuring device as a signalinput, the signal is received by the detector array after being processed by the optical neural network, and finally the signal is converted into displacement information of the target object throughthe signal processing device. The invention further discloses an ultra-precise displacement measuring method based on the optical neural network. The optical neural network is used for processing themeasurement optical signal, so that the displacement of the target object can be directly measured; the phase discrimination process of the electronic signal is not needed; the response speed is extremely high; the size can be zoomed; the energy utilization rate is high; and the system is suitable for ultra-precise measurement occasions with high speed and high dynamic performance requirements. According to the system, the multi-degree-of-freedom pose measurement of the target object also can be realized by increasing the number of input measurement optical signals and the number of detector arrays.

The invention discloses a double-circuit parallel transmission line single phase grounding fault point transition resistance value measuring method, which comprises the following steps of calculating zero-sequence current of an II circuit transmission line of a double-circuit parallel transmission line, and accurately calculating a single phase grounding fault point transition resistance value according to the linear relationship between voltage drop and fault distance from a protection installation part of a I circuit transmission line of the double-circuit parallel transmission line to a single phase grounding fault point. The method considers the influences of zero sequence mutual inductance between lines and single phase grounding fault point voltage, overcomes the influences of transition resistance, load current and zero sequence mutual inductance between the lines on single phase grounding fault point transition resistance value measuring accuracy, and has higher measurement accuracy.

The present invention provides an interferometer and the like, that is capable of ensuring the speed stability of the movable mirror while achieving the speed up of the reciprocal movement of the moving mirror and suppressing the increment of the maximum instantaneous thrust force required for the turning back as much as possible. The interferometer includes a moving mirror, a movement mechanism for reciprocating the moving mirror, a movement control part for controlling the movement mechanism and allowing the moving mirror to be reciprocated at a constant speed, and a measurement part for measuring a position of the moving mirror. The movement control part is adapted to receive target position data indicating a target position of the moving mirror, and control the movement mechanism to bring the measurement position of the moving mirror measured by the measurement part close to the target position indicated by the target position data.

An optical voltage transformer is connected with an external electric device and includes a primary electrode to which a measured voltage is applied by the external electric device, a first secondary electrode provided oppositely to the primary electrode, an insulation layer provided between the primary and first secondary electrodes and constituting an insulation cylinder integrally formed with the primary and first secondary electrodes, a ground layer provided on an outer circumference of the insulation cylinder and around the first secondary electrode for securing a capacitance by interposing the insulation layer between the ground layer and the first secondary electrode, and an electro-optic element for measuring a voltage between the first secondary electrode and the ground layer. According to the optical voltage transformer, measurement of the measured voltage can be done with high accuracy without affected by its surrounding environment and its downsizing can be achieved by reducing the number of its components.

The invention aims to provide a circuit and a method for measuring resistance of a variable resistor. The circuit comprises single-chip microcomputers, a capacitor, a to-be-tested variable resistor Rx and a standard resistor R1. One end of the capacitor C is connected with the single-chip microcomputer GP0, and the other end of the capacitor C is connected with the ground. One end of the standard resistor R1 is connected with one end of the capacitor C, and the other end of the standard resistor R1 is connected with the single-chip microcomputer GP1. One end of the to-be-tested variable resistor Rx is connected with the single-chip microcomputer GP2, and the other end of the to-be-tested variable resistor Rx is connected with the other end of the standard resistor R1. The other end of the to-be-tested variable resistor Rx is connected with the other end of the standard resistor R1. According to the invention, a charging time T1 of a charge and discharge loop of the standard resistor R1 and the capacitor C and a charging time T2 of a charge and discharge loop between the serially-connected to-be-tested variable resistor Rx and the standard resistor R1 and the capacitor C are measured, and the resistance of the to-be-tested variable resistor Rx is calculated through a mode of Rx=R1*(T2-T1) / T1. The method provided by the invention solves the contradiction between measurement precision and measurement time in the circuit for measuring the resistance of a variable resistor by measuring the charge and discharge time of a capacitor in the prior art, and can obtain a good measurement result for a small variable resistor.

Inverter circuits are connected to a P electrode and an N electrode, and control the U, V and W phases, respectively, of a three-phase motor. The inverter circuits are connected to the three-phase motor through shunt resistors, respectively. The shunt resistors are connected to HVICs, respectively. The HVICs are connected to a counter circuit. The counter circuit is connected to a CPU. The CPU is connected to a clock transmitter and a gate drive circuit.

The invention relates to the communication equipment technology field, relates to an antenna attitude data acquisition apparatus and an antenna adopting the acquisition apparatus and also relates to an antenna attitude data monitoring system adopting the antenna and a method thereof. The antenna attitude data acquisition apparatus comprises a gravitational acceleration device, a magnetic force device, a control unit and an output unit, wherein the gravitational acceleration device is fixedly arranged on the antenna and is used for acquiring mechanical downward inclination angle data of the antenna; the magnetic force device is fixedly arranged on the antenna and is used for acquiring mechanical azimuth data of the antenna; the control unit is electrically connected to the gravitational acceleration device and the magnetic force device respectively and is used for calculating and determining antenna attitude data according to the mechanical downward inclination angle data and the mechanical azimuth data based on a preset calculating rule; and the output unit is electrically connected to the control unit and is used for outputting the antenna attitude data. In the scheme, the antenna attitude data of an antenna body can be detected, and transmission equipment transmits the antenna attitude data to external master control equipment so that real-time monitoring of an antenna body attitude can be realized.

The invention provides a segment assembly measuring and control system and method based on machine vision. The segment assembly measuring and control system comprises an industrial camera, a segment assembly measuring system, a segment assembly control system and a motion control card, wherein the industrial camera is used for collecting images of to-be-assembled segments and an image of an end executor of a segment assembly machine; the segment assembly measuring system is used for measuring the positions and the attitudes of the end executor and the to-be-assembled segments in real time andcalculating the deviation value between the positions and the attitudes of the end executor and the to-be-assembled segments; the segment assembly control system compares the deviation values with a precision value; if the deviation value is less than or equal to the precision value, the segment assembly machine assemblies the segments; if the deviation value is greater than the precision value, the control quantity is calculated and transmitted to the motion control card; and the motion control card is used for converting the control quantity into the analog quantity and outputting the analogquantity to the segment assembly machine so as to adjust the position and the attitude of the end executor. The problem that the efficiency and precision of manual measuring and manual operating of asegment assembly machine system and method are low in the prior art is solved.

The invention discloses an electro-hydraulic servo valve overlap rapid pneumatic measurement gas circuit and a measurement method. The gas circuit is composed of one gas source, one filter, two reducing valves, two solenoid valves, two throttling valves, two flow sensors and a plurality of air pressure sensors; the measurement method comprises the following steps: firstly, acquiring a sample, meeting normal distribution, of an initial position of a valve core of a slide valve pair of an electro-hydraulic servo valve, further obtaining a proper single side confidence interval boundary accordingto the sample and a behavior prediction algorithm, then, before measuring in due form, moving the initial position of the valve core of the slide valve pair to the single side confidence interval boundary firstly, then, starting to control the valve core of the slide valve pair to move left or right, in a process of moving left or right of the valve core, measuring flow rate of a gas circuit through the measurement gas circuit, and feeding back to an industrial personal computer, finally, drawing out full stroke flow rate and displacement curve of the slide valve pair, and obtaining overlap of the slide valve pair through calculation. The gas circuit and the measurement method provided by the invention have the advantages of short measurement process, high test speed, high automation degree, and so on.

Inverter circuits are connected to a P electrode and an N electrode, and control the U, V and W phases, respectively, of a three-phase motor. The inverter circuits are connected to the three-phase motor through shunt resistors, respectively. The shunt resistors are connected to HVICs, respectively. The HVICs are connected to a counter circuit. The counter circuit is connected to a CPU. The CPU is connected to a clock transmitter and a gate drive circuit.

The invention belongs to the technical field of the energy power industry, and particularly relates to a vibration sensing system with a cooling shell. According to the invention, an air-cooled slotted lug and a process gas nozzle for diffusing a flow field of cooling gas are adopted, a cooling gas channel with a special structure and a strand of cooling gas pipe are additionally arranged betweenthe sensor base and the high-temperature casing bracket, and the cooling gas pipe directly jets to the sensor base and flows out along the channel, so that convection cooling is carried out on the whole semi-open chamber; and a cooling air nozzle is arranged on the side surface of the sensor to cool the sensor again. Multiple cooling modes are adopted in parallel to improve the cooling effect, andpractical application verifies that the surface temperature of the sensor can be greatly reduced, and the problem that the measurement precision of the sensor is affected due to too high temperatureis effectively avoided.

The invention relates to a wave load measuring system and a measuring structure thereof. The wave load measuring system comprises a structure used for being placed in water, the structure being provided with a sealing cavity, and an avoiding hole being formed in the cavity wall of the sealing cavity; a measuring module comprising a force measuring sensor arranged in the sealing cavity; one end of the force transducer being rigidly and fixedly connected with the cavity wall of the sealing cavity; a supporting structure, arranged in the avoiding hole in a penetrating manner and being not in rigid contact with the hole wall of the avoiding hole; one end of the supporting structure being rigidly and fixedly connected with the other end of the force transducer, and the other end of the supporting structure being exposed out of the outer side of the hole wall of the sealing cavity to be fixedly connected with an environment fixing structure, so that the force transducer is fixedly connected with the environment fixing structure; and a flexible sealing structure, arranged in the avoiding hole so as to seal a gap between the hole wall of the avoiding hole and the supporting structure. According to the measurement module of the wave load measurement system, the influence of a traditional connecting piece on the measurement precision and stability is avoided, and the measurement precision and stability can be effectively improved.

The invention relates to a sugarcane root system growth dynamic monitoring method, and belongs to the sugarcane root system study technical field; the method comprises the following steps: trenching in a test field at least 6 months before the sugarcane is planted, placing Minirhizotron into the soil at a certain angle, evenly refilling the dug soil layer, and planting the sugarcane on the test field when the tube and the soil are in good contact; using a root system scan system to regularly watch the root system growth conditions and dynamic changes. The sugarcane root system growth dynamic monitoring method mainly comprises a Minirhizotron install method, the install number, the sugarcane plantation, and a sugarcane root system in situ observation method, thus studying the sugarcane rootsystem growth dynamic status, realizing harmless, fast and accurate monitoring and study of the sugarcane root system growth dynamic and form parameters, and providing a harmless, in situ monitoring,efficient and reliable study means for the sugarcane root system study.

The invention provides a method and a device for double-star time difference / frequency difference combined positioning. By using the method, the calculation efficiency and the measurement accuracy of the time difference and the frequency difference can be improved. According to the scheme, the method comprises the following steps of: (1) carrying out time difference-frequency difference combined coarse estimate, calculating A(tau, f)=FFT[r(n; tau)], directly measuring the carrier frequency of a composite signal FORMULA for the search of the time difference each time, labeling a frequency spectrum amplitude value and a time difference value and finding out a maximum position, wherein tau is equal to tau1, tau2, FORMULA and tauM; (2) extracting and filtering the composite signal FORMULA, then measuring the carrier frequency, and coarsely estimating the frequency difference; (3) accurately calculating the frequency difference in the adjacent domain FORMULA of an estimated value in the coarsely measured frequency difference and accurately estimating the frequency difference; (4) accurately calculating the time difference in the adjacent domain FORMULA of an estimated value in the coarsely measured time difference and accurately estimating the time difference; and (5) accurately estimating the time difference, estimating the time resolution 1 / Ts of the time difference by using a relevant method and improving the time difference estimate accuracy by using interpolation, wherein Ts is the sampling interval of signals. In the invention, the time difference is calculated by using the signals with a high sampling rate, the frequency difference is calculated by using the signals with a low sampling rate, and the problems of the calculation efficiency and the measurement accuracy of the time difference and the frequency difference are solved by combining the time domain processing with the frequency domain processing.

A current sensor is provided on a bus bar via which a reactor is connected to a power module. The reactor is separated from the current sensor by a partition made of metal having a magnetic shielding effect. An output terminal of the reactor is provided on either one of a surface of the reactor on a first side and a surface of the reactor on a second side, the first side being farther from a mounting surface of a power converter across a plane passing through the center of the reactor, the second side being closer to the mounting surface from the plane.

The invention discloses an equivalent period fitting measurement method for a low-voltage electric appliance product short circuit tolerance intensity test power factor. According to a principle thati(t) consists of a periodic component Imsin([omega]t+[phi]u-[phi]) and an exponential decay component Imsin([phi]u-[phi]).e<-R / L.t>, the periodic component is a constant value on equal period intervalmoment on an i(t) curve, the Imsin( [phi]u-[phi]) is a constant value after a test loop is closed and therefore the i(t) can be equivalent to i(t)=A+B.e<-t / T> (wherein A, B and T are all constants),multiple groups of equal period current values i(t) are subjected to the curve fitting of a specific exponential decay function i(t)=A+B.e<-t / T>, and a great quantity of power factor measurement calculation values are obtained; then, a linear fitting method is used, a power factor numerical value with highest occurrence frequency is selected from the power factor calculation values to serve as a final test loop power factor; and therefore, an influence brought by unstable current measurement accuracy and frequency is avoided. The measurement method is simple, and measurement accuracy is high.

To minimize a measurement range when a near field measurement is performed on the directivity of a massive-MIMO antenna, and prevent the accuracy of measurement from deteriorating. Beam direction detection means 33 causes a probe antenna 12 to perform a rough scanning in a state where an electromagnetic wave radiation plane 1a of a test antenna 1 is directed toward a reference direction directly facing a measurement plane P, and detects the direction of a beam radiated by the test antenna 1 on the basis of a received signal thereof. Antenna direction change means 34 changes the direction of the test antenna 1 so that the detected direction of a beam is directed toward the center of the measurement plane P.

The present invention provides an interferometer and the like, that is capable of ensuring the speed stability of the movable mirror while achieving the speed up of the reciprocal movement of the moving mirror and suppressing the increment of the maximum instantaneous thrust force required for the turning back as much as possible. The interferometer includes a moving mirror, a movement mechanism for reciprocating the moving mirror, a movement control part for controlling the movement mechanism and allowing the moving mirror to be reciprocated at a constant speed, and a measurement part for measuring a position of the moving mirror. The movement control part is adapted to receive target position data indicating a target position of the moving mirror, and control the movement mechanism to bring the measurement position of the moving mirror measured by the measurement part close to the target position indicated by the target position data.