7 results about "Inverse iteration" patented technology

The application discloses a spacecraft magnetic moment attitude control method based on a non-inverse iteration algorithm, and the method establishes a linear periodic model for a spacecraft attitude control system which only relies on a magnetic moment; on the basis, according to a linear quadratic optimal control theory, an optimal controller design problem is converted into a solution problem of a discrete periodic Riccati equation associated with the optimal controller design problem; on the basis of a gradient descent principle, an error function is constructed, and a non-inverse iteration algorithm based on the gradient descent principle is proposed to solve the discrete periodic Riccati equation, so that a matrix inversion operation in a traditional solution method is avoided, and the calculation efficiency and the numerical stability are effectively improved; the obtained Riccati equation solution is used to obtain an optimal state feedback control law, so that the spacecraft attitude optimal control only using the magnetic moment is realized, and a new solution scheme is provided for an attitude control problem of a limited actuator in a space task.

The invention discloses a method and a device for detecting combustion activation energy of a solid fuel, and relates to the technical field of energy and power engineering. According to the main technical scheme, the method comprises the following steps of: taking burn-out historical experiment data as reference data; and inputting other real experimental data except the real burnout time in the historical experimental data into a preset burnout time calculation model, setting an activation energy initial value input model, and processing the parameter data by using the model so as to output theoretical burnout time, according to the error direction between the theoretical burnout time and the real burnout time, the initial value of the activation energy is adjusted in an inversion iteration mode till under the same fuel characteristic parameters and experimental working condition parameters of the target solid fuel sample, the initial value of the activation energy is adjusted on the basis of an activation energy target value adjusted in the inversion iteration mode; and reducing the error between the new theoretical burnout time output through model processing and the real burnout time to a preset threshold range to obtain an activation energy detection result.

The application relates to the field of hand recognition, in particular to a three-dimensional coordinate construction method and device of hand key points, computer equipment and a storage medium, the method comprising the following steps: acquiring two-dimensional coordinates of hand key points on a two-dimensional image; acquiring an internal parameter matrix and an external parameter matrix of a camera, and calculating a projection matrix according to the internal parameter matrix and the external parameter matrix; the camera is a shooting camera of the two-dimensional image; establishing a projection relationship equation of the two-dimensional coordinates and three-dimensional coordinates of the hand key points according to the projection matrix; eliminating the projection relationship equation to obtain a homogeneous linear equation group of the two-dimensional coordinates and the three-dimensional coordinates; iteratively calculating the homogeneous linear equation group according to a preset inverse iteration algorithm, acquiring an equation solution when an iteration result meets preset requirements, and determining three-dimensional coordinates of the hand key points according to the equation solution. The application can improve the accuracy of conversion of two-dimensional coordinates of hand key points into three-dimensional coordinates.

The invention discloses a method for determining guided wave frequency dispersion characteristics of a liquid-filled steel riser, which is characterized in that three-dimensional guided wave propagation is equivalent to a radial one-dimensional intrinsic problem under an axial symmetry condition, a relation between a complex wave number and frequency dispersion can be obtained only by dispersing the radial direction, and high degree of freedom of three-dimensional modeling is avoided. Internal fluid is not coupled through additional boundary terms, and is merged into the overall system by adopting a section contribution matrix, so that fluid-solid consistent assembly in the same system is realized, and error sources of coupling inconsistency are reduced. An external infinite water area does not use an absorption layer for approximation, and external water is equivalent to a wavenumber-related damping boundary by using radiation impedance meeting an infinite radiation condition; and the self-consistent complex wave number is solved through linearization and inverse iteration, so that the radiation modeling accuracy and solvability are improved.

The invention discloses a solid fuel combustion diffusion coefficient detection method and device, and relates to the technical field of energy and power engineering. According to the main technical scheme, the method comprises the following steps of: taking burn-out historical experiment data as reference data; and inputting other real experimental data except the real burnout time in the historical experimental data into a preset burnout time calculation model, setting a diffusion coefficient initial value input model, and processing the parameter data by using the model so as to output theoretical burnout time. According to the error direction between the theoretical burnout time and the real burnout time, the initial value of the diffusion coefficient is adjusted in an inversion iteration mode till under the same fuel characteristic parameters and experiment working condition parameters of the target solid fuel sample, the target value of the diffusion coefficient is obtained based on the target value of the diffusion coefficient adjusted in the inversion iteration mode. And reducing the error between the new theoretical burnout time output through model processing and the real burnout time to a preset threshold range to obtain a diffusion coefficient detection result.

The invention discloses a spacecraft magnetic moment attitude control method based on a non-inverse iterative algorithm, and the method comprises the steps: building a linearized periodic model for a spacecraft attitude control system which only depends on magnetic moment; on the basis, according to a linear quadratic form optimal control theory, an optimal controller design problem is converted into a solving problem of a discrete period Riccati equation connected with the optimal controller design problem; on the basis of the gradient descent principle, by constructing an error function, a non-inverse iterative algorithm based on the gradient descent principle is provided to solve a discrete period Riccati equation, matrix inversion operation in a traditional solving method is avoided, and calculation efficiency and numerical stability are effectively improved; and an optimal state feedback control law is obtained by using the obtained Riccati equation solution, so that spacecraft attitude optimal control only using the magnetic moment is realized, and a new solution is provided for the attitude control problem of a limited actuator in a space task.

The present application relates to a high-efficiency spectrum sensing implementation method based on the ratio of energy and minimum eigenvalue, and a method for fast calculating sensing decision threshold based on cubic spline interpolation of natural boundary condition: first, sampling M receiving signals of N antennas successively to calculate sampling covariance matrix R x (N); then, calculating the minimum eigenvalue λ of the sampling covariance matrix by using inverse iteration method based on initial value estimation, and calculating sensing decision quantity t=tr(R x (N)) / λ, wherein tr(R x (N)) is the energy of the receiving signal; second, calculating sensing decision threshold γ by using the method of cubic spline interpolation of natural boundary condition; finally, making sensing decision: when t>γ, it is determined that the primary user signal exists, and when t<γ, it is determined that the primary user signal does not exist. The method has the advantages of high efficiency in calculation, easy hardware implementation and reliable sensing result, and is suitable for the primary user signal detection problem with high real-time requirement in cognitive radio system.