822results about How to "Reduce calculation errors" patented technology

The invention relates to a large span rail traffic bridge damage recognition method, including the steps:(1) a sensor is arranged on the bridge which will be examined, the dynamic response signal of a large span rail traffic bridge is measured and is driven by that when a rail vehicle crosses the large span bridge, the signal on the sensor is red by a computer; (2) the benchmark bridge numerical model and the rail vehicle numerical model of the bridge are established; (3) a coupled mechanical analysis system comprising the benchmark bridge numerical model and the rail vehicle numerical model is initialized, an explicit integral method is used to solve the system, the simulated dynamic response signal of the benchmark bridge numerical model on a relative position is red according to the installment position of the sensor; (4) the energy spectrums of the dynamic response signal obtained by monitoring and the simulated dynamic response signal obtained by numerical simulation calculation of the bridge are solved by a multi-scale wavelet packet analysis method, and a damage recognition is carried on by recognizing index. The invention increases the precision of the bridge damage recognition, and the normal use of the bridge structure can not be affected.

The invention relates to a splicing bright-dark line correction method which is applicable to splicing type display screens such as an LED screen. The splicing bright-dark line correction method comprises the steps of determining the size of each display bright block and the size of each display dark block according to the size of splicing units, then controlling and lightening the display screen so as to be provided for shooting to acquire a target image; carrying out image processing on the target image so as to acquire the gray scale center of each of the plurality of bright blocks, and then calculating the display unit spacing and the splicing gap spacing; and finally, calculating a correction coefficient of each marginal display unit, which is adjacent to a splicing gap, of the splicing units by using the display unit spacing and the splicing gap spacing so as to be used for correcting a bright-dark line caused by the splicing gap. According to the invention, people can carry out correction on the bright-dark line accurately by only shooting one image through designing the display unit lightening mode; and furthermore, a problem that the display body uniformity get poor because bright-dark line correction in the prior art is carried out through full-screen analysis can also be avoided.

The invention discloses a time domain bidirectional iteration-based turbine vane flutter stress forecasting method. The method is characterized in that: a set of bidirectional iteration method for a time domain is designed by taking a vane and a surrounding flow field thereof as a three-dimensional fluid solid coupling system, and the flutter stress of the vane is obtained by alternately solving vane deformation and unsteady flow field. The method comprises the following steps of: setting a structural calculation module, a fluid calculation module, a data conversion module, a flutter stress output module, an initial value calculation module and a bidirectional iteration module in a computer; acquiring static vane deformation and steady flow field serving as an initial value by nonlinear iteration; alternately calling the structural calculation module and the fluid calculation module to propel the whole system on time; transmitting fluid solid boundary information through the data conversion module; and outputting the flutter stress on time history. The method realizes integrated calculation of the vane and the flow field, takes the nonlinearity of the coupling system into consideration, and can allow the observation of the whole flutter development process and forecast the flutter stress of the vane.

A method for controlling antenna to automatically track to satellite includes initializing system and fetching effective data of GPS, calculating theoretical angle requiring to be pointed by pitch angle and position angle of current antenna aligning to satellite, fetching compass data to calculate position difference between current pitch angle and position angle of current antenna and said theoretical angle, setting object rotary speed of current motor and driving antenna to make tracking-operation according to said position difference. The device used for realizing said method is also disclosed.

The invention discloses a non-location sensor technology for three-phase electro-magnetic double-salient pole machine starting and low-speed accelerating processes. According to the characteristics of an electro-magnetic double-salient pole machine, exciting current is not applied in a static state, but fixed-cycle low voltage pulse signal judging phase current is applied on armature windings, double-phase series connection self inductance is then calculated, and a rotor position is estimated. During a low-speed accelerating process, the mutual inductance sum of two phases of series connection windings and an excitation winding is calculated according to the armature current gradient when chopped waves are acquired in real time, so that the non-location low-speed accelerating technology for accelerating a motor is carried out. By utilizing the method, the initial rotor position can be accurately positioned, a rotor sector can be identified and fed back in real time during the low-speed accelerating, the maximum inductance is obtained through comparison, and the phase shifting time is determined after time delay. Consequently, the rotor positions can be fed back during the whole starting and accelerating processes, so that the motor cannot be out of step during the starting process and has strong antijamming capability. By utilizing the technology, the three-phase electro-magnetic double-salient pole machine can be enabled to start and accelerate stably and reliably.

The invention discloses an inversion method of micro-pulse differential absorption lidar water vapor spatial and temporal distribution. The inversion method comprises wavelength selection of water vapor detection, calculation and correction of absorption cross sections of water vapor absorption wavelengths and non-absorption wavelengths, and inversion and calibration of water vapor concentrations. An automatic continuous detection device of the micro-pulse differential absorption lidar water vapor spatial and temporal distribution is employed to obtain characteristic backward scattering signals of water vapor absorption in specific spectral lines, the backward scattering signals are subjected to inversion and calibration by a computer utilizing a differential absorption spectrum analysis method, and high-time-resolution, high-spatial-resolution and high-precision water vapor stereo distribution data is obtained.

The invention discloses a detection method of a permanent magnet motor rotor position. The detection method comprises: (1) calculating alpha and beta weight of a stator flux linkage; (2) setting up auxiliary d'-q' coordinate system; (3) figuring out angle from d' axis to d axis, and then obtaining position information of the rotor. By introducing the auxiliary d'-q' coordinate system which has same position angle with the stator flux linkage vector and same revolving speed with a d-q coordinate system, physical quantities in the coordinate system are all direct current when the coordinate system is operated in a steady state, thereby simplifying computation process, and reducing requests to a processor and a sensor. Calculation error is smaller due to the fact that influence of a filter can be basically ignored. Meanwhile calculation can automatically adjust according to the former calculation, and correct an inductance timely, so that final error is lessened.

The invention provides an accurate and convenient method for measuring storage battery residual capacity SOC. The method comprises the steps that a. initial residual capacity SOC<0> of a storage battery is determined; b. working current of the storage battery in the working time is measured in real time; c. residual capacity SOC(t) of the storage battery after continuous working time t is calculated according to the formula 1 (which is expressed in the specification), wherein eta<age> refers to the attenuation coefficient of the storage battery, C<n> refers to the rated capacity of the storage battery, eta<e> refers to the current efficiency coefficient, eta refers to the correction coefficient of the actual capacity of the storage battery, and t refers to continuous working time of the storage battery; and d. after the end of working of the storage battery, eta=1, and the SOC value calculated according to the formula 1 is the SOC value after the end of working of the storage battery of the time, wherein eta<age> refers to the specific value of the actual capacity to the rated capacity of the storage battery after N times of cyclic charge and discharge of the storage battery, C<n> refers to the electric energy which can be discharged by charging to cut-off voltage, eta<e> refers to the specific value of actual current used for electrode reaction to external current in charge and discharge of the storage battery, and eta refers to the specific value of actual capacity which can be charged or discharged by the storage battery to the rated capacity under the actual use state.

The invention discloses a method and device for detecting rain fall through laser. The device comprises a laser light source meeting a certain wavelength and power requirement, a parallel sheet light beam generating system based on a specified generation method, a two-dimensional water particle bidirectional sampling measurement area formed by two parallel sheets perpendicularly intersected in the horizontal direction, a linear array sensor and a rain fall detecting data processing and information feedback system. The device for detecting the rain fall through laser greatly improves the constant and stable property of detecting light and reduces measurement errors caused by light source power fluctuation. A real time humidity/ meteorological parameter sensing critical starting method is adopted. Due to the fact that calibration and correction are conducted before detection, the measurement errors caused by drifting of work points of the system can be reduced to the largest extent, and meanwhile energy consumption of a measurement system is reduced. By means of the device for detecting the rain fall through the laser, the rain fall, raininess and a raindrop spectrum can be accurately and continuously observed and measured in real time. The device for detecting the rain fall through the laser can be applied to the related fields for observing, measuring and forecasting the rain fall including weather, hydrology, high way conditions, airport taking-off and landing and the like.

The invention relates to a cardinal number estimating method and a cardinal number estimating device under a multi-section query condition of big data. The cardinal number estimating method comprises the following steps of dividing the big data into a plurality of sections in advance according to numerical attributes; establishing a tree-shaped index structure, and utilizing each section as a node of the tree-shaped index structure; acquiring a data source to be written in the tree-shaped index structure, and reversely indexing the data source which supports the section query condition; writing the data source which is reversely indexed into the nodes of the tree-shaped index structure, and respectively writing corresponding portions of the data source into data files and a cardinal number estimator; and querying the nodes meeting the section query condition in the tree-shaped index structure according to the section query condition to obtain the cardinal number estimator in the nodes, and logically processing the cardinal number estimator to obtain cardinal number estimated values. The cardinal number counting efficiency is improved by reducing data calculating precision; the query efficiency is high under the optional multi-section query condition; and the online index data updating efficiency is improved by using a big data incremental updating technology.

The invention belongs to the field of wave remote sensing technology, and particularly relates to a method for conducting X wave band navigation radar wave parameter inversion through a band-pass filter based on a novel wave dispersion relation, wherein sea clutter images are obtained through navigation radar so that wave parameter inversion can be conducted. The method comprises the steps that radar image data are collected; radar images are preprocessed; Fourier transform is conducted on an image sequence under a Cartesian coordinate system, so that a three-dimensional wave number frequency image spectrum of the radar images is obtained; wave spectrum information is extracted; wave information inversion is achieved. Influence on the dispersion relation by the ship speed is kept by the filter, the problem that the band pass of a traditional broadband-pass filter is increased along with increase of the movement speed is effectively solved, and therefore filtering can be conducted under the condition that a radar platform is moved along with movement of a ship. In band pass boundary derivation of the novel filter, an approximate value of any quantity is avoided, calculation errors are reduced, influence on the band pass boundary is avoided, band width calculation is more accurate, and wave inversion accuracy is improved.

The utility model discloses an updating method for a moving object based on the road transportation network and GPS, aiming at enabling a central server to trace the former and current position of the moving objects. The utility model is characterized in that the moving object uses GPS to measure the latest running data continuously, through matching with the transportation network, the coordinate of the latitude and the longitude and the direction data are converted into the data format based on the road network, then the current running vector is compared with the running data submitted by the updating on the last position according to the principle of the inertia, and the position updating condition is determined, the current running vector of the moving object is reported to the central server only when the moving object does not keep running as the principle of the inertia. Additionally, the utility model optimizes the updating of the position in the road crossing, only one time position updating of the moving object is performed at most in the road crossing. The utility model has advantages of reducing the communication frequency and improving the data processing efficiency under the premises of securing the processing precision compared with the prior art.

The invention discloses a Lie group filtering-based initial alignment method for strapdown inertial navigation. A strapdown algorithm is described by adopting Lie group and Lie algebra, so that the problem of singular value and a normalized error in a quaternion solving process can be effectively avoided. A new system model is established by integral computation and geographical position information of inertial elements. Recursive estimation is directly performed on an SO(3) group by adopting a Lie group filter, so that the problem of nonlinearity of a quaternion model can be effectively solved, and rapid and accurate initial alignment can be realized. An attitude change of a carrier under swaying interference is reflected in real time, so that the initial alignment can still be rapidly and accurately realized independently of an error model of a system under a swaying condition, and the initial alignment under a swaying pedestal can be finished without fine alignment on the basis of rough alignment. The method is simple in computation and high in adaptability, can be used for a complex random system, and has broad application prospect in practical engineering, the alignment accuracy is ensured, and meanwhile, the alignment speed is increased.

The invention discloses a method for monitoring an operation position of an elevator based on air pressure change. The method is characterized in that the atmospheric pressure at the bottom or the topend of an elevator shaft is used as the reference air pressure, an acceleration threshold value and a speed threshold value of an elevator car are set, the real-time air pressure of the elevator carin the up-down operation process is detected through an air pressure sensor, and an up-down operation height displacement is calculated through the difference between the real-time air pressure and the reference air pressure; and an acceleration sensor is used for detecting an acceleration of the elevator car in the up-down operation process and an acceleration change amount is calculated and a time change amount needed by the acceleration change amount is recorded, and then a real-time driving speed and a real-time acceleration of the elevator car are calculated, and then the acceleration iscompared with the acceleration threshold value and the driving speed is compared with the speed threshold value, and therefore the real-time floor height position and the real-time operation state ofthe elevator car are judged. According to the method, the position where the elevator breaks down can be judged quickly, so that timely and accurate rescue are guaranteed, and the possible operation states of the elevator can be effectively judged.

To reduce calculation errors of remaining battery power so as to take into account capacity diminutions due to cycle degradation and temperature, a remaining power calculation means specifies a temperature correction value for calculation of remaining battery power corresponding to temperature, from among temperature correction values changed every predetermined number of charge/discharge cycles stored in correction value storage means, on the basis of a temperature of a battery cell measured by a temperature measurement means and the number of charge/discharge cycles counted by charge/discharge counting means, and calculates remaining battery power corresponding to the specified temperature correction value. Temperature correction values changed every predetermined number of charge/discharge cycles are used instead of setting different temperature correction values for all charge/discharge cycles, whereby correction of remaining battery power based on cycle degradation and temperature is performed with a small number of parameters.

The invention discloses a magnetometer real-time correction device and method. The method comprises the following steps: firstly analyzing magnetometer error interference source features, then analyzing geomagnetic field distribution features and magnetometer measurement principles, subsequently designing the real-time correction device and simultaneously providing the corresponding correction method and process and finally realizing real-time correction and compensation on a course angle of a navigation system in a system level. According to the magnetometer real-time correction device and method, under the situation that the navigation system continuously works, the real-time automatic correction can be realized; meanwhile, the defects of conventional correction and compensation methods (such as an ellipsoid fitting method and the like) are avoided, and the magnetometer error correction can be autonomously, independently and completely realized. The magnetometer real-time correction device and method have the advantages that the course angle of the navigation system is corrected in real time, the error is more completely considered, the correction device is simple, the anti-interference performance is strong, the cost is low, the accuracy is high, and the processing of the calculation process is concise.

The invention discloses a method for judging and positioning bridge cable corrosion. The method comprises the following steps of: arranging a sensor on a cable to be detected, acquiring an actual measured signal by using the sensor and reading the signal into a laptop by using a data acquisition card; establishing a fine numerical model for the cable corrosion judgment by adopting the finite element technology according to geometric dimension, material characteristics and excitation signal conditions of the cable, initializing the numerical model, analyzing and calculating to obtain a simulation response signal, and providing a standard comparison signal for the actual measured signal; using the actual measured signal as a judgment signal of the cable corrosion, and comparing the judgment signal and the standard comparison signal and analyzing the judgment signal by adopting a neural network analysis method, if the damage does not exceed a threshold value, judging that the cable is not corroded, otherwise alarming and positioning the corroded part; generating a recording report and recording a local database. The method for judging and positioning the bridge cable corrosion has the advantages of high resolution, high judging precision and no influence on normal use of the cable.

The invention discloses a method for directly correcting and compensating a course angle of a navigation system and belongs to the technical field of location of navigation systems. The method for directly correcting and compensating the course angle of the navigation system comprises the following steps: firstly expanding an error model of a magnetometer according to the basic principle of circulating the course angle by virtue of the magnetometer; secondarily obtaining a parameter estimation model according to distribution characteristics of an earth magnetic field; finally estimating parameters of the expanded error model of the magnetometer by using a two-step total least square method so as to directly correct the course angle of the navigation system at a system level. The method can be used for correcting and compensating the error of a course angle of an inertial integrated navigation and location system which comprises an inertia measurement unit (IMU) and the magnetometer (or an electronic compass). The method is capable of directly correcting the course angle of the navigation system, strong in robustness, strong in reliability, low in cost, high in accuracy, simple in calculation process, and capable of achieving high-accuracy location and navigation and achieving good effects.

The invention discloses a modeling method for a harmonic model of a three-phase charger of an electric vehicle. The modeling method comprises the following steps: deducing a time-domain expression of an alternating current of the charger of the electric vehicle according to a three-phase uncontrollable bridge type rectification equivalent circuit; creating a three-phase charger harmonic coupling admittance matrix according to obtained charging currents in two work modes; combining the time-domain alternating current with a voltage of the charger, and proposing a model parameter determination method, wherein a coupling effect of the charger-terminal voltage and a harmonic current is considered in the model and matrix elements are not changed along with a harmonic voltage of the charger; creating the harmonic model of the three-phase charger of the electric vehicle in combination with the created coupling admittance matrix according to an admittance matrix parameter calculation method, wherein the harmonic model is used for providing a good theoretical basis for analyzing the characteristics that the harmonic current of a charging station with a plurality of chargers is changed along with the number of the chargers and the charging power. The modeling method can be used for directly and effectively calculating the harmonic current of the three-phase charger of the electric vehicle.

This invention provides an online measurement method for self-cleaning glass contact angle. By using the Actual Conditions closed to the self-cleaning glass coating, the hanging drop test method and thelta/2 Methods, it can measure the self-cleaning glass and its contact angle of related film rapidly and accurately, also more accurately measure the small contact angle compared to other methods.

The invention provides a service life evaluation method for bus electrolytic capacitors of a motor driver. The method comprises the steps: testing the core temperature of each bus electrolytic capacitor of a driver and the working environment temperature by means of a temperature-sensitive technology, selecting the highest core temperature rise [Delta]T among the electrolytic capacitors, and calculating the core temperature T2 of the electrolytic capacitors when the driver is running in a condition with the upper limit environment temperature. The service life of the bus electrolytic capacitors is calculated according to the difference between the highest allowed core temperature and the T2 as well as correction coefficients of bus voltages, so the service life of the driver can be evaluated. According to the method, the influence brought by the difference between an actual temperature upper limit for a driver and a test environment temperature, the influence of bus voltage when the driver is in use and the influence of uneven temperature rises among bus electrolytic capacitors are all taken into consideration. Aspects are comprehensively considered by the method, and an evaluation result is reliable.