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210 results about "Vector angle" patented technology

Angles Between Vectors. Angles between vectors can be found by using the dot product of the two vectors, regardless of the dimensional space of the vectors. For vectors and , the angle θ between them is , where is the dot product of and , and and are the magnitudes of the vectors.

Capacitance current feedforward control method for grid-connected inverter with LCL filter

The invention relates to a capacitance current feedforward control method for a grid-connected inverter with an LCL filter and belongs to the field of electric energy conversion. The capacitance current feedforward control method for the grid-connected inverter with the LCL filter solves the problem of low stability of the grid-connected inverter with the LCL filter in the prior art and the problem of reduced efficiency of a system due to phase difference between grid side voltage and current. The method comprises the following steps of: 1, acquiring three-phase power grid voltage and acquiring a vector angle theta of the power grid voltage; 2, acquiring three-phase output current of the inverter and acquiring direct current components ild and ilq of the inverter side current; 3, acquiring three-phase filter capacitance current and acquiring direct current components icd and icq of the filter capacitance current; 4, setting set values of the inverter output current to perform proportional integral (PI) adjustment on a processed signal, outputting uq, performing PI adjustment on the processed signal, and output ud; and 5, inversely converting the ud and the uq into u(alpha) and u(beta) and performing pulse width modulation on the u(alpha) and the u(beta) to acquire six paths of switching signals which are used for controlling six switching tubes of the three-phase inverter so as to perform capacitance current feedforward control on the grid-connected inverter.
Owner:HARBIN INST OF TECH

Method for cutter-axis vector fairing of complex curved surface five-axis numerical control machining based on kinematical constraints

The invention relates to a method for cutter-axis vector fairing of complex curved surface five-axis numerical control machining based on kinematical constraints, which belongs to the field of precise and efficient processing of complex curved surface five-axis numerical control machining, and particularly relates to a method for cutter-axis vector fairing based on machine tool kinematical constraints in the process of complex curved surface five-axis numerical control machining. The method is characterized by establishing a machining tool swivel feeding shaft angle optimized mathematical model on the basis of determining a cutter-axis fairing adjustment interval on a processing track curve and determining a discrete point according to the cutter step length, carrying out optimization on the corresponding machining tool swivel feeding shaft angle of the discrete point, and determining a corresponding coordination calculation method of a cutter-axis vector; then calculating the rotation angle of the cutter-axis vector opposite to the curved surface normal vector corresponding to the discrete point; and finally, carrying out fitting on the acquired discrete processing track normal vector angle, thereby acquiring a cutter-axis vector function for fairing, and ensuring a rotation axis of a machine tool to be smooth in motion. The method provided by the invention realizes smooth motion of the rotation axis of a five-axis numerical control machine tool, is wide in application range, and effectively improves the processing quality of the complex curved surface.
Owner:DALIAN UNIV OF TECH

Optical flow characteristic vector mode value and angle combination micro expression detection method based on interested area

ActiveCN107358206AImprove the efficiency of micro-expression detectionEasy to identifyCharacter and pattern recognitionOptical flowVector mode
The invention relates to an optical flow characteristic vector mode value and angle combination micro expression detection method based on an interested area. According to the method, firstly, a micro expression video is pre-processed to acquire a micro expression sequence, key face characteristic points are further extracted, and a face interested area having the best effect is found out according to motion characteristics of different expression FACS motion units; optical flow characteristics of the interested area are extracted. The optical flow vector angle information is firstly introduced, an optical flow vector mode value and the angle information are acquired through calculation, through combination of the two, a more comprehensive and more judicious characteristic detection micro expression segment can be acquired; the optical flow mode value and the angle information are combined, the threshold is determined according to magnitude of the optical flow mode value, and a number shape combination method is utilized to vividly and visually acquire the micro expression segment. The method is advantaged in that micro expression detection efficiency is substantially improved, optical flow characteristic vector extraction is carried out only in the key face area, computational complexity is reduced, the consumption time is shortened, and high robustness is realized.
Owner:WUHAN MELIT COMM

Maximum torque per ampere vector control system and control method for position sensor-free internal permanent magnet synchronous motor

The invention discloses a control method of a maximum torque per ampere vector control system for a position sensor-free internal permanent magnet synchronous motor, and belongs to the field of motor control. The problems of complexity of a computing method and low accuracy of an obtained current set value in the conventional maximum torque per ampere control strategy are solved. The control system comprises a permanent magnet synchronous motor, an inverter, a space vector pulse width modulation unit, a three-phase-two-phase coordinate conversion unit, a static-rotational coordinate conversion unit, a Fourier analysis unit, a vector angle regulation unit, a rotating speed regulator, a maximum torque per ampere control unit, a first current regulator, a second current regulator, a rotational-static coordinate conversion unit and a rotor position and rotating speed observer. According to the control method, the magnitude of current amplitude is automatically regulated and compared on the basis of a current vector angle gamma, and an operating point with maximum torque per ampere is automatically searched. The system and the method are applied to maximum torque per ampere vector control over the motor.
Owner:HARBIN INST OF TECH

PMSM rotary transformer zero position initial angle calibration method and calibration system

The invention discloses a PMSM rotary transformer zero position initial angle calibration method and calibration system. The PMSM rotary transformer zero position initial angle calibration method comprises steps of connecting an PMSM, on which a rotary transformer is installed, to a driving motor, enabling a motor stator of the PMSM to perform three-phase short circuit, using the driving motor to drive the PMSM to rotate forward and maintain at a preset rotation speed, using an electronic control unit to perform sampling on three phase current Ia, Ib and I c and a rotary transformer reading phi read at a same moment, using the rotary transformer reading phi read to perform Park conversion on three phase current Ia, Ib and Ic to obtain current vectors Is,p, calculating a vector angle theta p corresponding the current vector Is,p, using the driving motor to drive the PMSM to rotate backwards and maintaining the rotation at a preset rotation speed, using the electronic control unit to record a vector angle theta n corresponding to a current vector Is,n when the motor is rotated backwards, and calculating that a practical electric rotation angle theta 0 corresponding to the rotary transformer reading zero point angle is a zero position initial angle according to a formula theta 0=(thetap+thetan)/2-180 degree.
Owner:GUANGZHOU AUTOMOBILE GROUP CO LTD

Light beam position and polarization angle common light path detection device and method

The invention discloses a light beam position and polarization angle common light path detection device and method based on a photoelectric position sensor. The method comprises the following steps: utilizing a lateral excursion and polarization dispersion prism to shape an incident light beam, outputting orthogonal parallel polarized lights with proportionable light intensities and realizing the contactless space position attitude transfer function; enabling a receiving system to utilize a rotary motor with a coder to drive an analyzer to detect the beacon light polarization through rotation at a constant angular velocity, utilizing the horizontal photoelectric effect of a PSD (Phase-sensitive Detector) to measure the light spot imaging position of beacon light and reversely pushing a beacon light beam position coordinate according to the imaging principle; utilizing light current generated by gathering incident light intensities on the surface of the PSD to detect the incident light intensities, comparing with an angle instantaneously fed back by the rotary motor, obtaining the synchronous polarization angle information of a beacon light beam after the phase sensitive detection, and achieving the function of simultaneously adjusting and detecting the beacon light track and the base vector angle on a same light path and a device. The light beam position and polarization angle common light path detection device has the benefits of simple structure and simple components and is suitable for the multi-dimensional angle measurement demands.
Owner:SHANGHAI INST OF TECHNICAL PHYSICS - CHINESE ACAD OF SCI

High-speed rail heavy rail surface defect detection method based on point cloud method

The invention relates to the technical field of surface defect detection, and provides a high-speed rail heavy rail surface defect detection method based on a point cloud method, which comprises the following steps of firstly, constructing a detection platform, and calibrating a color binocular linear array camera; collecting the initial linear array images of the to-be-detected high-speed rail heavy rail under n visual angles and preprocessing the initial linear array images; mapping the two two-dimensional images under each view angle into a three-dimensional depth image, utilizing a two-dimensional image registration method based on phase correlation to provide the initial registration for two to-be-registered point clouds under adjacent view angles, and performing ICP accurate iteration on each pair of point clouds after registration to obtain the complete surface point clouds; and finally, carrying out defect extraction and segmentation on the complete surface point cloud by utilizing a point cloud region growth algorithm taking the normal vector angle and the curvature change quantity as smooth thresholds to obtain the surface defect distribution of the high-speed rail heavyrail to be detected. According to the present invention, the influence of the image acquisition quality and the detection area range on detection can be reduced, the detection efficiency and the detection rate are improved, and the missed detection rate and the false detection rate are reduced.
Owner:NORTHEASTERN UNIV

High spectroscopic data supervision classifying method based on information quantity dimensionality sequence

A high spectroscopic data supervision classification method based on information quantity dimensionality sequence includes the following steps: reading the high spectrum image data of a certain region; selecting a reference spectrum from the spectrum library or selecting the training sample from images to execute wave band average acquiring reference spectrum; calculating one by one the reference spectrum and all test spectral information quantity dimensionality sequence; executing vector angle matching one by one the test spectrum with all reference spectral information quantity dimensionality sequence, and using minimum distance classification machine to classify; result binarization matching, the matching result of each series of field culture is represented by the binary images, each image only includes a series of field culture. The high spectroscopic data classification method based on information quantity dimensionality sequence introduces the information quantity dimensionality into the spectrum domain analysis, synthetizes the advantages of the all band matching and partial quantization characteristic matching, can obtain higher classification effectiveness and classification accuracy, and has important value in the high spectroscopic data classification and object identification.
Owner:BEIHANG UNIV

Deep foundation pit excavation slope vertical displacement vector angle parameter monitoring and pre-warning method

The invention aims to provide a slope stability detection and pre-warning method on the basis of simultaneous monitoring of horizontal displacement and vertical displacement of a slope crest of a foundation pit. The method includes the steps: selection of foundation pit excavation slope displacement monitoring points and datum points; arrangement and installation of displacement monitoring equipment; real-time monitoring of foundation pit excavation slope surface displacement and real-time processing of monitoring data; determination of foundation pit excavation slope vertical displacement vector angle parameters and sequence thereof; determination of pre-warning criterions for stability of the foundation pit excavation slope vertical displacement vector angle parameters; evaluation on dynamic stability of foundation pit excavation slopes and monitoring and pre-warning of instability. By coupling of horizontal displacement and vertical displacement of the foundation pit excavation slopes, an included angle formed by a foundation pit excavation slope surface displacement vector and the horizontal plane is defined as a vertical displacement vector angle, and evaluation and real-time monitoring and predication of dynamic stability of the foundation pit excavation slopes and pre-warning of instability are realized.
Owner:QINGDAO TECHNOLOGICAL UNIVERSITY

Numerical control system-based tool radius compensation vector calculating method

The invention provides a numerical control system-based tool radius compensation vector calculating method which comprises the steps of: judging different switching-over types through analyzing the distribution condition of a vector angle of a tangent line on the switching-over point of a processing segment on a plane coordinate system, and calculating the coordinate point after cutter compensation according to a specific computing method; analyzing the processing segment according to the information of the tool radius, the cutter compensation direction and a workpiece outline coordinate point and the like after collecting and processing the information of a to-be-processed workpiece, calculating vectors of two tangent lines on the switching-over point, and obtaining a switching-over angle of two straight lines according to the vectors of the two tangent lines, drawing the distribution condition of the switching-over angle in the plane coordinate system, and judging the switching-over type of the two straight lines so as to figure out coordinates of the switching-over point by adopting a vector calculating method; and sending information of the coordinates to a numerical control system for next step of interpolation. The numerical control system-based tool radius compensation vector calculating method has the advantages of being simple in calculating method and small in calculating quantity, and being beneficial to the realization of programming especially for the calculation of the switching-over point, thereby increasing the processing efficiency.
Owner:FUJIAN UNIV OF TECH

Method for starting motor without position sensor

The invention discloses a method for starting a motor without a position sensor, which includes: applying a fixed voltage vector to the motor and obtaining Is; subjecting the Is to Clark conversion and obtaining i <alpha> and i <beta>; presetting rotation speed omega r and torque T<e> as 0 by computing to obtain rotor flux-linkage vector angle theta r, subjecting omega r and omega r to PI operation to obtain Te, then subjecting Te and the T3 to PI operation to obtain delta, obtaining theta<s> according to the formula theta <s>=theta <r> +delta, giving Psi* <s> to obtain U<alpha> and U<beta>, subjecting the U<alpha> and the U<beta> to inverse Clark conversion and obtaining U, U and U<c>, acquiring I, I and I<c> through current, subjecting the I, the I and the I<c> to Clark conversion and obtaining I alpha and I beta, obtaining Psi <s> alpha and Psi<s> beta by stator flux linkage operation, obtaining Psi<s> and theta<s> by modular angle operation, obtaining the Te by torque estimate, discretizing the theta<s> to obtain omega<r>, and finishing motor starting process if the omega<r> is equal to the omega*<r>. The method for starting the motor without the position sensor has the following advantages that by combining initial position detection technology with DTC (direct torque control) strategy, loop-locked stable control of the integral control strategy is realized.
Owner:HANGZHOU ZHOUJU ELECTRONICS TECHNOLOGICAL

Electrocardiosignal analysis method of T wave alternans scatter diagram method based on morphology

InactiveCN103006207AReduce the drop in detection accuracyGood test resultDiagnostic recording/measuringSensorsEcg signalT wave
The invention discloses an electrocardiosignal analysis method of a T wave alternans scatter diagram method based on morphology. Aiming at the defects of difficulty in detection of each heart beat T wave alternans amplitude value and complexity in calculation of T wave alternans detection by the spectrum analysis method, the T wave alternans scatter diagram method based on morphology is provided to provide a new effective quantitative index of T wave alternans detection for development of domestic related clinical researches. The method includes: using the T wave window analysis method for sampling T waves of 128 continuous heart beats selected from the American MIT-BIH standard heart beat irregularity database and the European ST-T electrocardio database, making a differential scatter diagram by the aid of the sample points, using vector angle index of the scatter diagram for quantitative analysis of T wave alternans to obtain a vector angle index range for judging whether T wave alternans exists or not, and comparing a T wave alternans detection result obtained by means of the vector angle index of the scatter diagram with the T wave alternans detection result obtained by means of the T wave alternans amplitude of the spectrum analysis method to judge reliability in detection of T wave alternans by the vector angle index.
Owner:SHANDONG NORMAL UNIV
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