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98results about How to "Avoid imprecision" patented technology

Nonlinear robust controller design method based on back-stepping and sliding mode control technologies and aimed at nonlinear model of quad-rotor unmanned plane

The invention discloses a nonlinear robust controller design method based on back-stepping and sliding mode control technologies and aimed at a nonlinear model of a quad-rotor unmanned plane. A sliding mode controller of a speed-constant reaching law is designed to an attitude angle system of the quad-rotor unmanned plane, and rapid tracking for the attitude angle is ensured. To realize track tracking for the spatial position of the quad-rotor unmanned plane, a sliding mode surface and a virtual control quantity are constructed according to a stepping back control idea to realize nonlinear control law design and system stability design from the kernel to the external layer of a system. After an equation of the related virtual control quantity is obtained, an expected track value of the attitude angle is obtained by solving the equation via arithmetic inverse operation, and a design method of the speed-constant reaching law is used to determine a final input control law of the quad-rotor unmanned plane system. According to the method of the invention, the characteristic that sliding mode control is uncertain for the model and insensitive to external interference is utilized, robust trace tracking for the nonlinear quad-rotor unmanned plane can be controlled under interference.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Structured light visual sensor parameter calibration method for acquiring height information of welded joint

The invention provides a structured light visual sensor parameter calibration method for acquiring height information of a welded joint, relates to the measurement non-specially applied to specific variable, and is a structured light visual system parameter calibration method based on a wedge-shaped target, which processes a two-dimensional image to obtain offset of structured light by calibrating obtained parameters so as to compute and obtain the height information of the welded joint and then to compute three-dimensional coordinate of an intersection point of a laser belt and the welded joint on the target, wherein the structured light visual sensor parameter calibration method specifically comprises the following steps of firstly recognizing horizontal deviation, secondly recognizing vertical deviation, thirdly calibrating structured light visual system parameters by utilizing a camera, and fourthly acquiring the height information of the welded joint. According to the structured light visual sensor parameter calibration method disclosed by the invention, the calibration process doest not involve a large-scale matrix transformation, the computation amount is smaller, a blockage problem of the target doest not exist, and the problem that the misconvergence of globally optimal solution generates in a solving process of a constrained nonlinear equation also does not exist.
Owner:HEBEI UNIV OF TECH

Calibration method for line-structured light sensor based on mechanical movement and device

InactiveCN105043251AAvoid imprecisionAvoid cumbersome matrix transformationsUsing optical meansErbium lasersLaser
The invention relates to a calibration method for a line-structured light sensor based on mechanical movement and a device. The device comprises a camera, a laser, a calibration plane and a movement mechanism. The method comprises the steps that 1) a z-axis of a world coordinate system taking the calibration plane as the ground acts as the vertical direction, an intrinsic parameter A of the camera and an extrinsic parameter of a first checkerboard are acquired by using Zhengyou Zhang checkerboard calibration, and included angle alpha between a z-axis of a camera coordinate system and the vertical direction is acquired by using the extrinsic parameter; 2) the distance between corresponding points on adjacent laser stripes and corresponding image point coordinates are calculated; 3) a normal vector of a structured light plane is solved; and 4) an included angle theta between the structured light plane and the vertical direction is calculated according to the normal vector acquired in the step 3) and the included angle alpha between the z-axis of the camera coordinate system and the vertical direction, and the coordinates of a point on the structured light plane in the camera coordinate system are further acquired so as to complete calibration for a structured light plane equation.
Owner:HEBEI UNIV OF TECH

Plant rhizosphere box and application thereof in micro-domain research of wet land plant rhizosphere

The invention discloses a plant rhizosphere box and the application thereof in the micro-domain research of wet land plant rhizosphere. The plant rhizosphere box comprises a box body, the inside space of the box body is partitioned into a root zone, a near root zone, a far root zone and a non-root zone and other different rhizosphere micro-domain partition zones by a number of rhizosphere partition plugging plates, water distribution units are arranged on the upper part of the box body, and water level regulating units are also arranged on the box body; and a water discharging device is arranged on the bottom of the box body. Through the adjustment of the intervals between the different rhizosphere micro-domain partition zones, the accurate observation and the research of the differentiation changes of different distances from the root system, and/or root zone soil, and/or interval water nutrients, pollutant, and/or microorganism are achieved. Based on the plant rhizosphere box, water flooded habitat of plants grown in wet land can truly be simulated, so that water flow conditions in the substrate can be maintained, and different water pressure retention time and water levels are arranged according to the needs, and the plant rhizosphere box has wide application prospect in plants, especially in the micro-domain research of wet land plant rhizosphere.
Owner:JINAN UNIVERSITY

Method and system for detecting and distinguishing passive synthetic aperture target signal

InactiveCN103529441AAccurate compensation of motion phase errorsAccurate drag array speedPosition fixationDirection/deviation determination systemsSynthetic aperture sonarTime delays
The present invention provides a method and a system for detecting and distinguishing a passive synthetic aperture target signal, wherein the method comprises the following steps: step 101) constructing a motion doppler receiving model for a target signal under motion of a towed array sonar; step 102) respectively performing cross correlation averaging on target signals which are received by a hydrophone at an overlapping part on spatial position according to a passive synthetic aperture sonar algorithm when the array performs two successive motions in a fixed time interval, and then performing frequency domain wave beam forming treatment on the target signals which are received by array elements at different time periods; step 103) performing energy integration on the output sub-frequency-bands after forming of the frequency domain wave beam for obtaining wave beam output of each time interval; step 104) performing phase estimation on time delay and spatial position movement according to the doppler receiving model, and acquiring a phase correction factor according to the phase estimation; and step 105) compensating the wave beam output through each phase correction factor of time interval, and performing cross combined accumulation on the compensated wave beam output and realizing detection on the target through a time orientation process map.
Owner:INST OF ACOUSTICS CHINESE ACAD OF SCI

Device for improving test accuracy of spectrum absorbance on basis of terahertz optical combs

ActiveCN106442378AAvoid the disadvantages of taking too long to scanAvoid imprecisionColor/spectral properties measurementsPulse beamFrequency standard
The invention relates to a device for improving the test accuracy of spectrum absorbance on the basis of terahertz optical combs. The device is characterized in that one of two ultrafast laser pulse beams with set repeat frequency difference is transmitted through a terahertz wave generating system to generate terahertz waves, terahertz wave signals and the other ultrafast laser pulse beam are respectively focused and are jointly transmitted into a photoconductive detection antenna, the terahertz waves can be quickly scanned by the aid of tiny repeat frequency difference between pump beams and probe beams, a digital converter is controlled by the aid of a cross-correlation instrument and a rubidium atom frequency standard, the signal acquisition time is prolonged to obtain time-domain spectra of continuous terahertz pulse chains, terahertz comb-shaped spectra are obtained by means of Fourier transformation, accurate change of the optical combs is compared before and after sample placement, and accordingly terahertz absorption spectrum lines of samples can be obtained. The device has the advantages that the shortcoming of excessive scanning time consumption of mechanical delay devices can be overcome, the problem of inaccuracy of existing terahertz super-continuous spectra due to laser pulse time jitter can be solved, and the test accuracy of the terahertz spectrum absorbance can be improved.
Owner:UNIV OF SHANGHAI FOR SCI & TECH

Textile fabric cutting device with accurate positioning function

The invention discloses a textile fabric cutting device with an accurate positioning function. The textile fabric cutting device comprises a base. A first slide groove is formed in a side of the outerwall of the top of the base, a first slider is slidably connected with the inner wall of the first slide groove, a support rod which is vertically arranged is welded on the outer wall of the top of the first slider, a transverse beam which is horizontally arranged is welded on the top of the outer wall of a side of the support rod, an electric slide rail is fixed to the outer wall of the bottom of the transverse beam by the aid of screws, a second slider is slidably connected with the inner wall of the electric slide rail, a cylinder is fixed to the outer wall of the bottom of the second slider by the aid of screws, a connecting plate is welded at the bottom of the cylinder, a tailoring device is fixed to the outer wall of the bottom of the connecting plate by the aid of screws, clamp grooves are formed in four corners of the outer wall of the top of the base, and auxiliary magnets are clamped inside the clamp grooves. The textile fabric cutting device has the advantages that the textile fabric cutting device is simple in structure, the problem of inaccuracy due to manual operation cutting can be solved by the aid of the textile fabric cutting device in the integral design, the cutting accuracy can be guaranteed, and excellent cutting effects can be realized.
Owner:盐城融凡纺织制衣有限公司

Apportionment mapping method and apparatus of communication cell and geographical area

ActiveCN108601031AThe area matching relationship is accurateThe matching relationship is accurateNetwork planningLongitudeComputer science
The embodiment of the invention provides an apportionment mapping method and apparatus of a communication cell and a geographical area, and relates to the field of communication geographic data processing. The matching relationship between the communication cell and the geographical area can be determined more accurately. The method comprises the following steps: performing offset processing on the longitude and latitude of a base station according to the geographical data of the communication cell to obtain the longitude and latitude of the communication cell; constructing a Tyson cell corresponding to the communication cell according to the longitude and latitude of the communication cell; dividing a grid into at least one subarea according to boundary data in the geographical data of the Tyson cell and the geographical data of the grid; calculating the area of the subarea and the longitude and latitude of a centroid of the subarea according to the geographical data of the subarea; matching the subarea with the Tyson cell according to the longitude and latitude of the centroid of the subarea and the geographical data of the Tyson cell; calculating the area of the Tyson cell according to the geographical data of the Tyson cell; and calculating a ratio of occupation of the area of each subarea matching the Tyson cell to the area of the Tyson cell.
Owner:CHINA UNITED NETWORK COMM GRP CO LTD +1

Device for automatically blending pesticides and control method

The invention discloses a device for automatically blending pesticides and a control method. The device comprises a water tank, a pesticide mixing tank, a pesticide box and a master controller; a water outlet of the water tank is connected with a water inlet of the pesticide mixing tank through a pump water pipe; a pesticide outlet of the pesticide box is connected with a pesticide inlet of the pesticide mixing tank through a pesticide feeding pipe; a pesticide feeding channel is arranged on the upper end of the pesticide mixing tank; the pesticide outlet of the pesticide mixing tank is connected with a pesticide tank of a spraying device through a pump pesticide pipe; the master controller is used for controlling the volume of pesticides conveyed into the pesticide mixing tank through thepesticide box, the volume of clean water conveyed into the pesticide mixing tank through the water tank, the blending of pesticides in the pesticide mixing tank and the volume of pesticide liquor conveyed to the pesticide tank of the spraying device through the pesticide mixing tank. Pesticide water separation, real-time blending, sufficient mixing and accurate ratio are adopted by the device, sothat the dosage of pesticides and the inflow volume of clean water in the pesticide mixing tank can be effectively controlled and the dilution ratio and the pesticide concentration can be accuratelymeasured.
Owner:SOUTH CHINA AGRI UNIV

Monitoring safety prediction method and system based on model optimization

The invention relates to the field of Internet information processing, and provides a monitoring safety prediction method and system based on a chaotic particle swarm optimization algorithm optimization prediction model, equipment and a medium aiming at the defects of high randomness, large calculation amount, low speed and low efficiency of a parameter adjustment method in an existing data safety monitoring model. A sample data set is divided into a plurality of training subsets and a test set, parameter optimization of a constructed prediction model algorithm is performed by using the plurality of groups of training subsets according to a chaos particle swarm optimization algorithm, and a plurality of groups of optimal parameters are acquired, so that a model with optimized parameters is trained and is utilized to complete prediction of monitoring data. The optimization process is added to the modeling process to achieve parameter optimization, model inaccuracy caused by randomness is avoided, the optimization process is improved in combination with the chaos thought, the parameter optimization effect is improved, the parameter optimization speed is increased to optimize model efficiency, model quality and reliability are guaranteed, and then data safety monitoring accuracy and judgment efficiency are improved.
Owner:北京淇瑀信息科技有限公司

Allocation of channels to radio transceivers

Each base station in a network has an antenna (1) which is connected in the conventional way to a transceiver (2) for handling normal call traffic on one or more radio channels. In addition there is another transmitter (3) which transmits a test signal on each of several test channels, one for each radio channel available for use by the main transceiver (2). The transceiver also has a receiver (4) for detecting the test channels. The system is controlled by a timer (5) which ensures that the transmitter (3) and receiver (4) do not operate at the same time. The receive times may be random, or may be co-ordinated between individual base stations. When the receiver is in operation, it will detect transmissions of the test signals from other base stations. The signal strength is measured (measurement system (6)) and the result is used by a control system (7) to determine a preference value for each channel: the stronger the signal detected, the lower the preference value. The preference value is used to control an amplifier system (8) which controls the signal strength of each channel transmitted by the transmitter (3). It is also used to control the traffic transceiver (2), by selecting which traffic channels are to be used in accordance with the preference values.
Owner:BRITISH TELECOMM PLC

Permanent magnet synchronous motor model modeling method based on data statistics and numerical optimization

The present invention discloses a permanent magnet synchronous motor model modeling method based on data statistics and numerical optimization. According to the method, a testing bench formed by a host machine, a d-axis current estimation model, a q-axis current estimation models and a torque estimation model is built, and the input and output parameters of each estimation model are set respectively; the host machine sets motor automatic operation condition and collects needed data; and for each motor rotation speed point, each scanning point of d-axis voltage and q-axis current has d-axis current, d-axis current estimation second-order model, a q-axis current estimation second-order model and a torque estimation second-order model are established respectively, and the quadratic equation fitting is used to obtain d-axis current, q-axis current and an output torque to be the characteristic parameter of a permanent magnet synchronous motor model to carry out derivation modeling. The experiment testing data is employed, a motor model is established based on statistics and numerical optimization, the inaccurate model problem in formula modeling is solved, thus the accuracy of the motor model is within 5%, and the system level analysis is carried out well.
Owner:SHANGHAI DAJUN TECH

Method for quickly determining action depth positioning resolution of double-end readout detector

The invention discloses a method for quickly determining the action depth positioning resolution of a double-end readout detector. The method comprises the steps: adopting a non-collimation source toirradiate the detector and collecting a certain number of gamma photon events; recording the output of the photoelectric conversion devices at the two ends of the crystal of each gamma photon event; calculating statistical distribution of output signal differences of the photoelectric conversion devices at the two ends; and extracting two boundary positions of the statistical distribution, measuring the energy resolution of the detector module to the corresponding energy ray source by using non-collimation source measurement data, and quickly calculating the action depth positioning resolutionof the detector module by combining the relationship between the action depth positioning resolution and the parameters. Compared with the prior art, the method does not depend on a collimation gammasource, and makes the related factors of the action depth positioning resolution represented by the statistical broadening degree of the output difference of the photoelectric conversion devices at the two ends, and finally, a correlation relationship with the energy resolution of the gamma rays with the corresponding energy is established with the detector module so as to quickly determine the action depth positioning resolution of the double-end readout detector.
Owner:BEIJING INST OF SPACECRAFT ENVIRONMENT ENG
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