10 results about "Great circle" patented technology

This invention relates to a microscopic visual measurement method for machine tool trajectories, and more specifically, a microscopic visual measurement method for machine tool trajectories based on small circle codes scattered within a large circle. The method includes the following steps: S1, a measuring head is fixedly attached to the first moving end of the machine tool, and a measuring target is fixedly attached to the second moving end of the machine tool; the measuring head is connected to a host computer; S2, the field of view of the measuring head is adjusted to the center of the scale range of the measuring target; S3, the image from the host computer is observed to complete the focusing operation, and the coded pattern within the field of view of the measuring head on the measuring target is acquired to determine whether the optical axis of the measuring head is orthogonal to the target plane; S4, the second moving end is moved, with the movement range not exceeding the effective measurement range of the target, to measure the actual movement trajectory of the spindle relative to the worktable. This non-contact microscopic visual measurement method improves the accuracy, efficiency, and safety of positioning.

The application discloses a kind of aircraft off-line trajectory planning methods based on spherical Anya, comprising the following steps: step 1: the mathematical modeling of aircraft flyable area and threat area is carried out, and the Web Mercator coordinate of flyable area and the Web Mercator coordinate of threat area are obtained;Step 2: the mathematical modeling of any two points great circle route, and the mathematical modeling of great circle route and the intersection coordinates of certain meridian or parallel;Step 3: spherical Anya algorithm heuristic value f is designed using great circle route and the intersection coordinates of great circle route and certain meridian or parallel;Step 4: initialize map, input the Web Mercator coordinate of starting point and terminal point, and the Web Mercator coordinate of flyable area and the Web Mercator coordinate of threat area between starting point and terminal point, obtain the optimal path of spherical Anya using spherical Anya algorithm heuristic value f.

The invention discloses a centroid-offset-resistant multi-circle special-shaped target and a binocular vision positioning method thereof, and belongs to the technical field of industrial vision measurement and precise positioning, the target comprises a white background substrate and seven symmetrically distributed black circles, a large circle is arranged in the center, standard perfect circle small circles are arranged right above and right below respectively, and a large circle is arranged in the middle of the black circles. The four corners are respectively provided with special small circles which are designed according to a cylindrical surface nonlinear projection formula. The positioning method comprises the steps that a binocular camera collects a target image, and two-dimensional circle center coordinates are extracted; calculating a three-dimensional point cloud through stereo matching; extracting a cylindrical space axial vector and constructing a normal plane, and orthogonally projecting the three-dimensional feature points to the normal plane for two-dimensional circle fitting; and calculating the reference point coordinates of the internal anchoring column center and the surface highest axis through inverse coordinate transformation. According to the method, positioning errors caused by curvature deformation, space inclination and rotation around the axis of the cylinder are effectively overcome, and positioning robustness and universality under complex working conditions are remarkably improved.

The application discloses a kind of earth magnetic field horizontal component representation methods of removing pole singularity, comprising: based on adolf schmidt semi-normalized spherical harmonic theory, the spherical harmonic representation of geomagnetic field magnetic potential function is obtained by spherical harmonic polynomial expansion calculation method;With south pole or north pole as center, mirror center symmetry extension is carried out to great circle on sphere, so that each point on sphere has a mirror point, so that the mirror extension function of geomagnetic field magnetic potential function is obtained;Two-dimensional Fourier expansion is carried out to mirror extension function using double Fourier series, and double coverage function expansion is obtained;Based on double coverage function expansion, the horizontal component of geomagnetic field is calculated, i.e. the spherical gradient of spherical magnetic potential function is calculated.The realization is based on the existing IGRF model magnetic potential expansion coefficient, the magnetic field tangent vector representation is obtained without being polluted by pole problem, and a new modeling idea and calculation method of spherical tangent vector field are provided.

A cricket ball is disclosed. The cricket ball includes an at least substantially spherical body and multiple spaced apart bumps about a great circle of the spherical body. Each bump has a height in a range of 1.0mm – 3.0mm. A method for making the cricket ball is also disclosed.

The application discloses a multi-class circle special-shaped target resisting heart drift and a binocular vision positioning method thereof, and belongs to the technical field of industrial vision measurement and precision positioning. The target comprises a white background substrate and seven symmetrical black circles, wherein a large circle is arranged at the center, a standard normal small circle is arranged above and below the large circle respectively, and four specially-made class circles are arranged at four corners respectively. The specially-made class circles are designed according to a cylindrical surface nonlinear projection formula. The positioning method comprises the following steps: a binocular camera collects a target image and extracts two-dimensional circle center coordinates; three-dimensional point clouds are solved through stereo matching; a cylindrical space axial vector is extracted and a normal plane is constructed, and three-dimensional feature points are orthogonally projected to the normal plane for two-dimensional circle fitting; and the coordinates of an internal anchor cylinder center and a surface highest axial reference point are solved through coordinate inverse transformation. The application effectively overcomes positioning errors caused by cylindrical curvature deformation, space inclination and rotation around an axis, and significantly improves the positioning robustness and universality under complex working conditions.

The application is a Mercator chart-based great circle route guidance and control method, belonging to the ship track tracking field, comprising the following steps: establishing a ship motion nonlinear mathematical model; designing a great circle route guidance strategy, so that the ship sails along the great circle route according to the expected heading; based on the ship motion nonlinear mathematical model, a third-order closed-loop gain shaping algorithm is used to design a final controller for controlling the ship to track the expected heading; the plan of the great circle route in the ship running process is converted to the Mercator projection chart to obtain the ship sailing trajectory along the great circle route under the Mercator projection. Through simulation verification, the application can effectively control the ship to sail along the great circle arc line, reduce the track error and improve the sailing efficiency.

The invention describes a table tennis ball (2) on the spherical ball surface (6) of which a marking (8) is applied which makes the ball spin detectable with measuring technology. The marking (8) comprises a number of marking points (P i ) which are distributed on the ball surface (6) in such a way that the standard deviation of the lengths (Z i,j ) of the great circle lines (20) between each marking point (P i ) and its three nearest neighbours (14, 16, 18) is at least 12% of the average value (μ) of these lengths (Z i,j ) and the minimum length of the great circle lines (20) between each marking point (P i ) and its three nearest neighbours (14, 16, 18) is at least 40% of the average value (μ) of these lengths (Z i,j ).

The present application provides a calculation method for a Mohorovičić discontinuity (Moho) depth of an extraterrestrial celestial body and a related apparatus. The method includes: obtaining a seismic event with location information from a target extraterrestrial celestial body, and picking up observed travel time differences Tobs of a plurality of seismic phases of seismic body waves relative to a first-arriving P-wave; establishing a plurality of seismological structural models, and calculating a theoretical travel time and a theoretical P-wave first-arrival time for each seismic phase to obtain a theoretical travel time difference Tcal of the seismic phase relative to the first-arriving P-wave; and calculating a travel time residual Tres of each seismological structural model based on the theoretical travel time difference Tcal and the observed travel time differences Tobs so as to determine an average Moho depth of an event-station great circle path of the target extraterrestrial celestial body.

The invention provides a navigation precision assessment data processing method, which comprises the following steps of: 1, determining a transmitting point and a navigation point according to track parameters, and converting from a Chinese geodetic coordinate system to a geocentric large earth coordinate system; 2, according to the basic theorem of a spherical triangle, solving a large circle route between a launching point and a navigation point; 3, according to the sine and cosine theorem of the spherical triangle, the deviation distance between the actual track of the target and the large circle route is determined in the spherical right triangle, and the deviation distance represents the actual navigation precision; and performing navigation precision assessment according to the deviation distance. According to the method, a target navigation precision problem is converted into a target actual track and large circle route distance problem through coordinate conversion by utilizing a large circle route method and a spherical triangle theorem, so that a problem processing thought is simplified, the operation is simple and clear, the result precision is high, and data processing personnel can conveniently carry out processing work.