220 results about "Parameter equation" patented technology

The invention pertains to the technical field of machine vision and provides a method for automatically extracting elliptic image features from a complex background image. In the invention, firstly a Canny edge extraction method is utilized to obtain the sub-pixel image coordinates of an image edge, and the adjacent edge pixels are connected to an edge fragment via an edge connection method; arc fragments in the edge fragments which meet constraints of the central distance and the constraints of the radius are fused through using an edge split fusion algorithm based on the arc approximate fit; the arc fragments which pertain to the same ellipse are clustered on the basis of a random sampling consistency robust estimation algorithm; and finally an elliptic parameter equation is obtained by carrying out the least square fitting of the clustered arc fragments in the same category. The proposed elliptic automatic extraction algorithm effectively eliminates the interference of the noise edge in the image, solves the problems of identification and clustering of the elliptic edge of the complex background image, and realizes the automatic extraction of the elliptic image features.

The invention discloses a multi-camera global calibration method based on high-precision auxiliary cameras and ball targets. According to the method, aiming at a multi-camera system which is arranged complicatedly and free of public view field, a global camera coordinate system serves as the world coordinate system, the three-dimensional coordinates, under local coordinate systems, of the sphere centers of a group (at least three) of ball targets are reconfigured by means of cameras to be calibrated and a global camera at the same time, a transfer matrix between two coordinate systems is solved on this basis, and then the transfer matrixes from all camera coordinate systems to the world coordinate system are obtained. When the three-dimensional coordinates of the sphere centers are reconfigured, a single-view method is adopted, a parameter equation is adopted for presenting a spheric projection model, and therefore sphere center reconfiguration precision can be improved greatly. The method has the advantages that operation is easy and flexibility is high. By the adoption of the method, calibration can be achieved conveniently for the multi-camera system which is arranged complicatedly and free of public view field.

The invention discloses a full-automatic calibration method for a structured light hand-eye three-dimensional measuring system. The full-automatic calibration method is designed through deeply analyzing the working principle of a line structured light hand-eye three-dimensional measuring system and is based on three environment feature points and 2 given poses. The calibration method includes that capturing images of three feature points in a scene, and precisely controlling a robot to perform 5 times of translational movement to calibrate intrinsic parameters of a camera and a hand-eye matrix rotating part; giving 2 different poses of the robot, combining with the feature points to form parameter equation information of the plane at different coordinate systems, and calibrating plane equations of a hand-eye matrix translation part and a structured light plane under the coordinate systems of the camera. The calibration method is simple, the feature selection is easy to perform, and the calibration method is important for using the structured light hand-eye three-dimensional measuring system in the actual industrial field.

The invention provides a method for determining a laser peening forming process parameter of a complex curved-surface-shaped workpiece. The method comprises the following steps: according to a curved surface parameter equation of the workpiece, carrying out geometrical characteristic analysis on the curved surface of the workpiece to calculate a main strain direction so as to obtain a laser pulse scanning direction in laser peening forming; establishing a workpiece bending deformation finite element model which takes depth-direction inherent strain distribution as a deformation source, and optimizing an inherent strain field to obtain the inherent strain distribution of different positions of the workpiece along the depth direction, wherein an inherent strain direction is the main strain direction; and according to inherent strain response surface models under different laser peening forming process parameters and the inherent strain of different positions of the workpiece along the depth direction, optimizing the laser peening forming process parameters, and obtaining an optimal laser peening forming process parameter corresponding to different inherent strain fields on the surface of the workpiece. A non-elastic deformation problem can be converted into an elastic deformation problem to improve the efficiency and the precision of finite element simulation.

The invention relates to a bidirectional conjugate tooth profile design method for harmonic gear drive. The bidirectional conjugate tooth profile design method for harmonic gear drive comprises the steps of firstly, expressing a flexible wheel top-section convex tooth profile coordinate through a parameter equation, converting to a rigid wheel coordinate system, solving to obtain discrete point coordinates of a theorical conjugate concave tooth profile and a concave tooth profile of a flexible wheel top-section convex tooth profile, determining the working tooth depth of a rigid wheel tooth profile through least square fit, determining a fitted curve section to be a rigid wheel bottom-section concave tooth profile and a rigid wheel top-section concave tooth profile, and calculating to accomplish a tooth profile design of a rigid wheel; and then expressing a rigid wheel top-section convex tooth profile coordinate through a parameter equation, converting to a flexible wheel coordinate system, solving to obtain discrete point coordinates of a theorical concave conjugate tooth profile in a flexible wheel bottom-section range, determining the tooth depth of a flexible wheel through least square fit, determining a fitted curve to be a flexible wheel bottom-section concave tooth profile, and calculating to obtain a flexible wheel working tooth profile. According to the bidirectional conjugate tooth profile design method for harmonic gear drive provided by the invention, the flexible wheel tooth profile and the rigid wheel tooth profile with bi-conjugate and secondary-conjugate phenomena are directly obtained, so that a conjugate contact area and a meshing zone are increased, the tooth surface contact stress is reduced, and the drive accuracy of a harmonic reducer is improved.

The present invention relates to a variable transmission ratio concurrent axis coniflex gear pair geometrical designing method. Based on spherical engagement theory research said method can implement parameter design of given transmission ratio relationship and concurrent axis coniflex gear pair of interaxial included angle. Tooth profile calculation and solid model creation, and utilizes given transmission relationship and interaxial included angle to define parameter equation of a pair of pitch cone faces and utilizes the kinematics relationship of spherical engagement and CAD software to form non-cone gear solid model. Said non-cone gear pair can simplify existent variable transmission ratio transmission mechanism and can be substituted for combination of several pairs of gear pairs, so that it has extensive universality.

The invention discloses an initial alignment method for an MEMS-IMU. Through the initial alignment method, the initial rough alignment time of a strapdown inertial system is further shortened, and the precision of the strapdown inertial system is further improved. The initial alignment method comprises the following steps that 1, sensor data are acquired, wherein the sensor data comprise the data of an MEMS gyroscope and an MEMS accelerometer; 2, initial alignment coordinate systems are established, wherein the initial alignment coordinate systems comprise the solidified carrier coordinate system, the earth coordinate system, the navigation coordinate system and the carrier coordinate system; 3, initial alignment objective functions are established, and an optimal speed reducing method of quick alignment is constructed; 4, a parameter equation of the optimal speed reducing method is determined through the complementary filter principle; 5, a carrier attitude angle is resolved through an quaternion updating algorithm, and calculation of an initial attitude matrix is achieved. According to the initial alignment method for the MEMS-IMU, the calculation precision and efficiency of an initial alignment algorithm are effectively improved, and the application range is wide.

The invention provides a spot facing quality detecting method based on linear laser three-dimensional scanning. The method comprises the following steps: S1, acquiring three-dimensional point cloud data and plane grayscale images of spot facing and an upper surface of the periphery of the spot facing by using a linear laser three-dimensional scanner; S2, processing the acquired three-dimensional point cloud data by using a point cloud database, to obtain a plane parameter equation fitting the upper surface, a vertex coordinate fitting a circular conical surface, a direction vector of an axis,and a taper angle; S3, calculating normal perpendicularity of the spot facing; S4, distinguishing a black part in the plane grayscale image by using a computer vision database, to obtain an inner diameter D of the spot facing; and S5, acquiring a distance H' from a lower circular surface formed by a lower annular edge fitting the circular conical surface to a fitting upper surface. The method is capable of, based on comprehensive application of the linear laser three-dimensional scanner, the point cloud database and the computer vision database, and through the steps S1-S5, rapidly and accurately acquiring related parameters of the spot facing, thereby improving detection efficiency and detection precision.

The invention discloses a distribution type multi-sensing cooperation testing method and a system thereof; the method includes the following steps that: a multi-sensing cooperation testing model is established; area vectors of the area are obtained, and the area vectors of the area are automatically converted to the adjoint vectors; a plurality of systems of partial differential equations are converted to one or a plurality of sequence parameter equations, by the self organization evolution of sequence parameters, a macrostructure is created and a general calculation formula of the uncertain problem decision-making is obtained, wherein a 'cooperation-competition-coordination' process based multi-sensing cooperation testing mechanism model is established, which forms a three-layer reaction type cooperation testing method. The system includes that the data communication is made in the mode of the IPv4/IPv6 based Ethernet, wherein the whole network testing platform comprises a filed test control layer, an enterprise-level monitoring layer and a remote test control layer.

The invention relates to a single-tree three-dimensional green quantity measuring method based on mobile two-dimensional laser scanning. The single-tree three-dimensional green quantity measuring method comprises scanning a single tree from several angles by means of a mobile two-dimensional laser scanning system, obtaining complete information of a tree crown, establishing a laser scan line parameter equation by means of information comprising a moving track linear equation and the moving speed, removing the part, of a space to be detected, which is penetrated by laser scan lines based on the principle that the volume of the tree crown is equal to that of the area where scan lines are invisible, reserving the part which is not penetrated by laser scan lines, obtaining a tree crown volume model, and therefore measuring the single-tree three-dimensional green quantity accurately. According to the invention, the single-tree three-dimensional green quantity is measured by means of mobile two-dimensional laser scanning, surface points and internal points of all crown layers are effective utilized, and the accuracy of the volume model is high. According to the invention, manual screening for rejecting the point cloud is not needed, and the computing speed is high.

The invention discloses an SOGI-based single-phase transformer short-circuit parameter on-line real-time identification method. The identification method comprises steps of establishing a T-type equivalent circuit of a single-phase transformer; listing the short-circuit impedance parameter equation and the T-type equivalent circuit equation of the transformer; respectively obtaining the d axis equation and the q axis equation of the T-type equivalent circuit in a dq coordinate system; and using a SOGI-FLL model to extract fundamental wave components and fundamental wave orthogonal components of all input signals, obtaining the d axis component and the q axis component of all input signals in the dq coordinate system, and calculating the short-circuit resistance values Rk and Xk of the single-phase transformer, thereby achieving on-line monitoring of operation states of single-phase transformer windings. When windings of the transformer deforms and break down, the short-circuit impedance of the transformer will change. By measuring voltage and current of the primary side and the secondary side of the transformer, short-circuit parameters of the transformer windings can be identified. Thus, on-line monitoring of the operation states of the transformer windings is achieved; potential risks of the transformer can be found as soon as possible; fault points can be timely removed; operation accidents can be avoided; and service lifetime of the transformer is extended.

The invention discloses an artificial cardiac valve. The thickness of the artificial cardiac valve ranges from 0.4mm to 0.6mm. A modeling equation of the curve face of the artificial cardiac valve is one the following four equations: 1 a round spherical face model parameter equation, 2 a cylindrical face model parameter equation, 3 a rotation paraboloid model parameter equation and 4 an ellipsoid model parameter equation, wherein x, y and z respectively represent a horizontal ordinate, a vertical ordinate and a longitudinal ordinate of a curve space ordinate, and alpha represents a conical inclined angle and is 3 degrees. The invention further discloses a performance analysis method based on ANSYS/LS-DYNA of the artificial cardiac valve and establishes a fluid-solid coupling model of the biological valve prosthesis so as to lay the foundation for fluid-solid coupling of the biological valve prosthesis. The artificial cardiac valve and the performance analysis method based on ANSYS/LS-DYNA of the artificial cardiac valve analyze and compare the four models according to bionics and the principle of the largest opening area and with the combination of bionic theory, the conclusion is obtained: a round spherical face cardiac valve has the best performance, so that powerful basis is provided for the research and optimization of the biological cardiac valves.

The invention discloses a robust adaptive nonsingular terminal sliding-mode control method of automatic train operation. The method comprises that S1) the bearing condition of vertical movement of a train is analyzed, and a train vertical movement power equation including unknown parameters, uncertainty and external interference is established; S2) a nonsingular terminal sliding-mode surface is constructed; S3) an adaptive law of estimated values of the unknown parameters and a parameter equation of parameters of the sliding mode surface are designed; and S4) the nonsingular terminal sliding-mode surface, the adaptive law of estimated values of the unknown parameters and the parameter equation of parameters of the sliding mode surface are substituted into the train vertical movement power equation including the unknown parameters, uncertainty and external interference, a nonsingular terminal sliding-mode closed-loop control equation is obtained, and the nonsingular terminal sliding-mode closed-loop control equation is used to implement robust adaptive nonsingular terminal sliding-mode control of automatic train operation. Thus, position and speed tracking errors of an ATO system can reach the sliding surface within limited time and converged to 0 within limited time.

The invention discloses a method for accurately forecasting the five-axis processing milling force of a spiral cutter. The method comprises the following steps: 1) acquiring coordinates of a cutter blade line of the cutter in a cutter rotating coordinate system XrYrZr according to the eccentric state of the cutter; 2) acquiring an instant blade line locus equation containing a cutter eccentric parameter according to an instant cutter tip position and the angular position of a pendulum shaft; 3) building a parameter equation of a straight line l which passes any given cutting point S<*>(i<*>, zc<*> and t<*>) and is perpendicular to the axis of the cutter; 4) acquiring the positions of intersections T of the straight line l and first mi adjacent blade loca according to the instant blade line locus equation containing the cutter eccentric parameter and the parameter equation, and acquiring the cutting layer thickness h(i<*>, zc<*> and t<*>) of the cutting point S<*>(i<*>, zc<*> and t<*>) according to distance h(i<*>, zc<*>, t<*> and mi) between the cutting point S<*>(i<*>, zc<*> and t<*>) and the corresponding intersection T; 5) calibrating the cutter eccentric parameter and a specific cutting force coefficient according to a thin plate milling experiment scheme; 6) acquiring the total cutting force exerted on a workpiece with a basic cutting force mechanical model according to the cutting layer thickness h(i<*>, zc<*> and t<*>)of the cutting point S<*>(i<*>, zc<*> and t<*>), the cutter eccentric parameter and the specific cutting force coefficient. The method can be used for accurately forecasting the total cutting force exerted on the workpiece.

The invention belongs to the five-axis numerical control machine tool machining field, and provides a semi-analysis modeling method of a contact area between a ball-end milling cutter and a guide vane. The semi-analysis modeling method of a contact area between a ball-end milling cutter and a guide vane includes the following steps: performing cutter path programming, and setting numerical control machining parameters; establishing a workpiece coordinate system, and acquiring the parameter equations of the design surface and the machining surface of the vane, and the movement track equation of the ball center of the milling cutter; determining the cutter contact point and the cutter location point during the machining process, taking the cutter contact point and the cutter location point as the origin to respectively establish a three dimensional rectangular coordinate system; converting solving problems of No.1-No.4 boundary curves of the contact area into projection equation solving problems of the curves in an XL-YL two dimensional coordinate system, and respectively solving the projection equations of the No.1-No.4 boundary curves; and obtaining the intersection points of the No.1-No.4 boundary curves, by mutually making a simultaneous system of equations, and obtaining the projection of the contact area. The semi-analysis modeling method of a contact area between a ball-end milling cutter and a guide vane can solve the problem of performing analysis modeling of the contact area during the process of processing a straight-vane-body vane molded in a vane grid by means of a ball-end milling cutter on a five-axis numerical control machine tool.

The invention discloses a mathematical modeling method for multi-scale and multi-field coupling seepage flow of carbon dioxide replacement shale gas, which comprises the following steps: S1, establishing a classification mode of gas flow patterns in multi-scale shale pores and fractures; S2, establishing a multi-scale multi-field coupled seepage mathematical model for carbon dioxide replacement shale gas, specifically include a multi-scale multi-component gas multi-field coupled flow equation of shale, a shale skeleton deformation equation, a shale reservoir energy conservation equation, a physical property parameter equation under that action of a stress field and a fracture medium deformation field, and determining solution conditions; S3, CO2 replacement shale gas multi-scale multi-field coupled seepage mathematical model solution application. The invention has the advantages that: On the basis of the established classification mode of gas flow patterns in multi-scale shale pores and fractures, the invention establishes a shale matrix nanopore, a matrix nanopore and carbon dioxide replacing shale gas multi-component gas system multi-field coupling seepage mathematical model, andestablishes difference numerical models within and among the central grid blocks of the block.

The invention discloses a bottleneck quality detection method based on machine vision. The bottleneck quality detection method comprises the following steps: collecting an image of a to-be-detected bottleneck, and converting the image into a grey-scale map; calculating the gradient vector of each pixel point of the grey-scale map, so as to obtain an edge image of the grey-scale map of the to-be-detected bottleneck; cutting edges according to a grey-scale threshold; cutting an inner ring and an outer ring of the to-be-detected bottleneck by taking the area as a character; respectively calculating circle center coordinates and radiuses of the inner ring and the outer ring, averaging the circle center coordinates to obtain the circle center coordinate of the to-be-detected bottleneck, and setting a radius value range according to the radiuses of the inner ring and the outer ring; acquiring a circle parameter equation according to the circle center coordinate and the radius value range of the to-be-detected bottleneck, carrying out circular scanning on a circular ring according to the circle parameter equation, calculating an average gray value, and drawing an average gray value curve; and analyzing the average gray value curve, and determining the annular ring is not damaged when the variation range of the annular ring is in a certain range. According to the bottleneck quality detection method, the detection efficiency of the bottleneck quality is improved.

The invention discloses an optimal attitude maneuver planning method for agile satellite zero-bias drift angle imaging. The method comprises two parts: single planning and iteration optimizing. In the single planning part, the time mapping function is substituted into the axis parameter equation of any target sweep band. Then, two attitude angles are determined by using the tracking constraint, and an attitude angle is determined by orthogonal constraint to further calculate the angular velocity and driving torque sequence. In the iteration optimizing part, the parameter set of the time mapping function is used as the decision vectors, the index function of the single planning result is calculated, the general optimization solver is called to search the optimal solution, and the geometric optics method is used for the horizontal scanning frequency matching of the optimal attitude maneuver. The invention uses the geometrical relation to determine the three-axis attitude maneuver of a satellite to any target sweep band TDI push imaging with the zero-bias angle as the known condition, which avoids the transformation of a series of coordinate systems and the calculation of complex drift angle in a traditional method, and based on this, time mapping optimization is realized, so that the expected maneuver cost in the imaging process becomes the smallest possible.

The invention discloses an accurate modeling and assembling method for an involute worm gear and worm. The accurate modeling and assembling method for the involute worm and gear comprises the following specific steps that: S1: carrying out worm gear modeling; S2: carrying out worm modeling; and S3: assembling the worm gear and the worm. By use of the method, on the basis of a situation that an involute parameter equation is used for constructing a worm spiral line, the three-dimensional entity modeling of the involute worm is realized, so that the established involute worm is used for finishing the three-dimensional entity modeling of the involute worm in cooperation transmission with the established involute worm, and finally, the three-dimensional entity meshing assembling of the involute worm and the involute worm gear is finished.

The invention discloses a planar feature matching-based point cloud crude splicing method. The method comprises the following steps of firstly, selecting one part of data in one plane of all point cloud data as a seed plane, calculating the parameter equation of the seed plane based on the feature value method and starting the growth; secondly, conducting the optimizing process based on the RANSAC algorithm, and effectively reducing the influence of noise points; thirdly, selecting four or more pairs of matched planes and calculating the normal vectors of the planes; finally, according to the normal vectors of the four or more pairs of matched planes, respectively calculating a rotation matrix and a translation amount based on the least-squares method to complete the crude splicing of point clouds.

The invention relates to an ellipse detection method based on Hough conversion and an ellipse detection system based on Hough conversion. The method comprises the following steps of acquiring images; performing edge detection to the acquired images by using an edge detection method, thereby obtaining binary images; performing Hough conversion to the binary images to obtain a candidate ellipse centre; according to coordinates of the candidate ellipse centre and the parameter equation of the ellipse, performing Hough conversion to obtain the parameters of the candidate ellipse; judging whether the candidate ellipse obtained according to the parameters of the candidate ellipse and the candidate ellipse centre is a properly elliptic; if the candidate ellipse is properly elliptic, locating the ellipse. The candidate ellipse can be judged as being properly elliptic and located by the method. The obtained candidate ellipse is judged whether to be true and false by the method, so that the false ellipse is eliminated, the false detection rate is reduced, the detection accuracy of the ellipse is improved and the ellipse can be effectively located.