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118results about How to "Solve the accuracy is not high" patented technology

Magnetic suspension rotor harmonic current suppression method based on composite friction repetitive controller

The invention discloses a magnetic suspension rotor harmonic current suppression method based on a composite friction repetitive controller. Firstly, a magnetic suspension rotor dynamical model which comprises mass unbalance and sensor harmonic is established. Secondly, the composite friction repetitive controller is designed. The controller is obtained through parallelly connecting a double-mode friction repetitive controller and a phase shift notch filter. The double-mode friction repetitive controller comprises two branches, namely an odd-order harmonic suppression branch and an even-order harmonic suppression branch. The odd-order harmonic and the even-order harmonic can be suppressed in an enhanced manner through distributing the value of a control gain, and dynamic response performance is improved. A friction time delay link is replaced by a friction time delay filter, thereby improving harmonic current suppression precision. Furthermore the phase shift notch filter is introduced for performing additional suppression on fundamental frequency current, thereby reducing current overshoot and improving harmonic convergence speed. The magnetic suspension rotor harmonic current suppression method can realize harmonic current suppression in a fixed rotating speed and is suitable for magnetic suspension rotor harmonic current suppression in which mass unbalance and sensor harmonic exist.
Owner:BEIHANG UNIV

Method for inhibiting radio frequency interference of synthetic aperture radar on basis of neural network

The invention discloses a method for inhibiting radio frequency interference (RFI) of a synthetic aperture radar (SAR) on the basis of a neural network and belongs to the technical field of radar signal processing. Firstly, all global frequency domain characteristic values of an FRI signal are detected from frequency domain data of a SAR original echo; corresponding extended alternating projection neural network (EAPNN network) repository patterns are generated by the frequency domain characteristic values and are memoried into the EAPNN network one by one; then the RFI signal is associated from echo time domain data by utilizing an association function of the EAPNN network; and the echo time domain data is directly subtracted from the associated RFI signal so as to fulfill the aim of inhibiting the RFI. The EAPNN network combines the global characteristics and dynamic tracking characteristics, which are difficult to simultaneously consider in the existing method, and thus, on the premise of ensuring high inhibiting accuracy, a high processing speed can be obtained. The method can be widely used for the fields of the SAR, earth remote sensing and the like and is particularly suitable for places with high requirements on both the inhibiting accuracy and the processing speed and dense RFI.
Owner:中国人民解放军陆军军官学院

Method for acquiring absolute open flow of shale gas layer based on gas productivity index

The invention relates to a method for acquiring absolute open flow of a shale gas layer based on a gas productivity index. The method comprises the following steps of: acquiring shale gas layer parameters of a tested well in a work area, acquiring shale gas layer fracturing parameters of the tested well, and acquiring open flow of the shale gas layer of the tested well by virtue of tested productivity data; sequentially calculating a gas bearing index, a fracturing transformation index and a gas production index of a tested well gas layer by virtue of the acquired parameters, and determining the model coefficient of a model AOFg=A*eB*IPG by virtue of a gas productivity index IPG calculated in a corresponding tested well by utilizing a least square method; and acquiring to-be-predicted well shale gas layer parameters in the work area, acquiring to-be-predicted well shale gas layer fracturing parameters, sequentially calculating a fracturing transformation index, a gas bearing factor and a gas production index of the to-be-predicted well gas layer according to a formula by virtue of the acquired parameters, introducing the gas productivity index into a model AOFg1=A*eB*IPG1, calculating the open flow of the to-be-predicted well shale gas layer, and outputting the calculation result. The method disclosed by the invention is adopted in 30 predicted wells of a certain shale gas field, and the average error does not exceed 20%.
Owner:中石化石油工程技术服务有限公司 +1

Double-vector predicted flux linkage control method for permanent magnet synchronous motor

The invention discloses a double-vector predicted flux linkage control method for a permanent magnet synchronous motor. The method comprises the steps of firstly converting a torque increment into a load angle increment and unifying control objectives as a stator flux linkage vector; calculating and obtaining a reference voltage vector according to a dead-beat idea, selecting a I vector through interval positions of the reference vector and selecting a II vector through subinterval positions of the reference vector; dividing a control period into two parts through optimizing a duty ratio of the voltage vector, making the I vector act on one part of the control period and selecting the II vector or a zero vector in the remaining time; and finally carrying out loop optimization calculation on the selected voltage vectors and the duty ratio to obtain an optimal voltage vector and conveying the optimal voltage vector to the permanent magnet synchronous motor. According to the double-vectorpredicted flux linkage control method for the permanent magnet synchronous motor, torque and flux linkage ripples of a system are reduced while the calculating time of a processor is shortened, and the reliability and the steady-state performance of the system are improved.
Owner:NANTONG UNIVERSITY

Inter-partition dual-vector model predictive control method for parallel PWM rectifier

The invention discloses an inter-partition dual-vector model predictive control method for a parallel PWM rectifier. The method comprises the steps that voltage vector inter-partition calculation is introduced into model predictive control, and a vector duty cycle modulation method is combined, so that the reduction of zero sequence circulating current and the decrease of processor computation time can be effectively achieved; the influence of different voltage vector combinations on circulating current in a control system is directly analyzed, then 36 voltage vector combinations are divided into 4 partitions, so that the zero sequence circulating current and processor computation burden are reduced; by optimizing effective vector duty cycles of a selected partition, a control cycle is divided into two parts, effective vectors only act on a part of the control cycle, and the remaining time selects zero vectors to further improve the system circulating current suppression precision; andfinally, cyclic optimizing computation is carried out on voltage vectors in the selected partition. The problem of uneven current and waveform distortion caused by the circulating current can be solved without additional hardware devices, and the reliability and efficiency of the system are improved.
Owner:南通莱欧电子科技有限公司

Method for determining wind power curtailment at wind farm based on anemometer data of anemometer tower

ActiveCN105048444AComply with time requirements for calculationsFew parameters involvedWind motor controlMachines/enginesElectricityTerrain
The invention relates to a method for determining wind power curtailment at a wind farm based on anemometer data of an anemometer tower. The method includes the following steps: based on the anemometer data of the anemometer tower, taking factors such as terrains, land forms and wake flow of wind generation sets, into consideration, calculating the wind speeds at the highest positions of the wheel hubs of the wind generation sets, and in accordance with the power curve, obtaining theoretical power of the wind generation sets, calculating the sum of the theoretical power of all wind generation sets at the wind farm and obtaining theoretical power at the wind farm, finally respectively integrating the theoretical power at the wind farm and actual power over time, obtaining a theoretical quantity of electricity and an actual quantity of electricity, and obtaining the wind power curtailment by subtracting the theoretical quantity of electricity from the actual quantity of electricity, thus achieving an accurate calculation of the wind power curtailment at the wind farm. The method is generally applicable to all types of wind farms, and successively addresses the problem of inaccuracy of calculating wind power curtailment by using a template machine method.
Owner:STATE GRID CORP OF CHINA +3

Automatic molding technique for tungsten alloy holding-up hammer and device for realizing technique

The invention relates to a compression molding technique for a tungsten alloy holding-up hammer, and relates to a device for realizing the technique. The innovation points are as follows: the tungsten alloy holding-up hammer provided by the invention is molded through compression by adopting an automatic molding device for the tungsten alloy holding-up hammer; the automatic molding device for the tungsten alloy holding-up hammer comprises a female mold, an upper punch and a lower punch; the technique comprises the following steps: (S1) powder is added; (S2) staging compression is performed for 5 times; the upper punch is used for enabling the female mold to downwards move so as to realize floating compression through the indirect effect of the powder body on the female mold; (S3) after the compression is completed, the pressure maintaining is performed for 56-67 S, and the pressure is relieved; (S4) demolding is carried out. The automatic molding technique and device have the following advantages: as the tungsten alloy holding-up hammer is produced by adopting the powder metallurgy technology, the utilization rate of raw materials is high, and the production cost is low; through the multi-grading compression is combined with the floating compression, the density consistency of products is largely improved, the reject number is decreased, and the processing efficiency is improved.
Owner:NANTONG GUOYI FORGING MACHINE TOOL

Wearable measurement device for blood pressure

A wearable measurement device for blood pressure comprises a watchband, a valve piece, a gas collecting seat, a gas conveying device, an elastic medium and a pressure sensor, wherein the watchband isprovided with an embedding region, the embedding region is provided with a first containing groove, a second containing groove, a gas collecting through hole and a pressure relief through hole, the gas collecting through hole is communicated between the first containing groove and the second containing groove, and the pressure relief through hole is communicated between the first containing grooveand the exterior of the watchband; the valve piece is overlapped in the first containing groove and provided with a valve hole corresponding to the gas collecting through hole; the gas collecting seat is arranged in the first containing groove, overlapped on the valve piece and provided with multiple holes; the gas conveying device is assembled and seals the gas collecting seat; the elastic medium seals the second containing grooves for inflation elastic displacement; the pressure sensor is arranged on the elastic medium. In this way, guided and conveyed gas is transmitted into the elastic medium, and the elastic medium is inflated with gas to expand to push the pressure sensor to abut against the measurement position of a user so that a blood pressure numerical value can be measured.
Owner:MICROJET TECH

Synchronous machining locating clamp and machining method of moving scroll plate and static scroll plate

PendingCN110539190AReduction of secondary clamping position accuracySolve the accuracy is not highPositioning apparatusMetal-working holdersEngineeringAnnular array
The invention discloses a synchronous machining locating clamp and a machining method of a moving scroll plate and a static scroll plate. The clamp comprises a bottom plate, the static plate and themoving plate, wherein the static plate and the moving disc are located on the bottom plate. An annular static plate locating seat and an annular moving plate locating seat are arranged on the bottom plate. At least three press cylinders are arranged at the position, in the circumferential direction of each of the static plate locating seat and the moving plate locating seat, of the bottom plate inan annular array manner. Press blocks used for pressing the corresponding scroll plates are arranged on pistons of the press cylinders. The two ends of the bottom plate are rotationally connected with a fixed seat and a drive seat used for driving the bottom plate to turn over. Avoiding holes are formed in the bottom plate, the static plate locating seat and the moving plate locating seat in thevertical direction in a penetrating manner. In the machining method, two cutters are adopted for achieving synchronous machining with completely-communicating parameters. According to the synchronousmachining and locating clamp and the machining method, clamping efficiency is improved, operation is simple and convenient, manpower is saved, secondary clamping is avoided, machining efficiency and position precision are improved, procedures are reduced, and products keep consistent through synchronous machining.
Owner:昆山金力达机械科技有限公司

Method for restricting rotation of rotary machinery rotor

The invention discloses a method for restricting rotation of a rotary machinery rotor. The method comprises the following steps: firstly determining the maximum rotation position of a rotor in a small rotary machinery rotor system; subsequently fixing a magneto-rheological elastomer dynamic vibration absorber on the rotor system so as to perform the operation for restricting the vibration, wherein the magneto-rheological elastomer dynamic vibration absorber is used according to the following steps: fixing the magneto-rheological elastomer dynamic vibration absorber at the maximum rotation position of the rotor, and starting the system of the magneto-rheological elastomer dynamic vibration absorber to reduce vibration amplitude of the rotor and restrict the vibration, wherein the value of rigidity ka of the magneto-rheological elastomer dynamic vibration absorber is regulated by specifically utilizing the characteristic that the rigidity of a magneto-rheological elastomer is controllable, so that the inherent frequency is nearly equal to the vibration frequency of the rotary machinery rotor system. According to the method disclosed by the invention, the equipment is good in controllability and low in fault rate; the system is good in operation stability; the method can be used for restricting the vibration of the rotary machinery rotor system.
Owner:NORTHEASTERN UNIV

K clustering intelligent selection microwave signal multipath interference suppression method

The invention discloses a K clustering intelligent selection microwave signal multipath interference suppression method, and relates to an interference suppression method. The method comprises the following steps: 1) establishing and training a multipath interference suppression model; 2) setting test conditions of the antenna in the anechoic chamber; 3) adding reflection plate interference sources of different materials or shapes to establish an interference model; 4) dividing the difficulty condition of the interference degree; and 5) correspondingly and respectively selecting proper algorithms according to interference degree classification to complete K-clustering intelligently-selected microwave signal multipath interference suppression. When the multipath interference mode is simple,a polynomial regression algorithm is used, a gradient descent method is used to train the model until the error converges, the current optimal multipath interference suppression model is stored, theoperation is simple, and the precision is improved. And when the multipath interference mode is medium, multipath interference suppression under the condition of three interference paths is realized by adopting a random forest. When the multipath interference mode is difficult, the neural network is adopted to realize multipath interference suppression under the condition of five interference paths, and finally, the optimization efficiency of the antenna is improved.
Owner:XIAMEN UNIV

Unmanned aerial vehicle examination evaluation method and system

InactiveCN110060187AKeep abreast of the learning situationEasy to formulateData processing applicationsSimulationEvaluation system
The invention relates to the field of unmanned aerial vehicle examinations, and provides an unmanned aerial vehicle examination evaluation method and system for the problem of poor teaching effect ofan unmanned aerial vehicle, and the method comprises the steps: receiving a practical operation evaluation instruction, calling practical operation evaluation information according to the practical operation evaluation instruction, and sending the practical operation evaluation information to a first user side for practical operation flight evaluation; receiving assessment flight state informationof the first user side practical operation flight assessment, generating practical operation assessment result information according to the assessment flight state information, and sending the practical operation assessment result information to a second user side for display, wherein the practical operation evaluation instruction comprises a simulated practical operation evaluation instruction and a field practical operation evaluation instruction, when a simulated practical operation evaluation instruction is received, simulated practical operation evaluation information is called, and whenan on-site practical operation evaluation instruction is received, on-site practical operation evaluation information is called. The problem that the teaching effect of offline education of the unmanned aerial vehicle is poor can be solved. The invention also discloses an unmanned aerial vehicle examination evaluation system.
Owner:BEIFANG TT AVIATION TECH DEV BEIJING CO LTD
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