5 results about "Least square approximation" patented technology

The invention provides a three-dimensional skin waviness fitting analysis method. The method comprises the following steps: performing boundary analysis on skin point cloud data obtained by laser measurement, performing interpolation sampling from the point cloud data according to a specified area and resolution to obtain point cloud coordinates which can reflect the real condition of the skin and are regularly arranged, performing bicubic spline surface least square approximation based on a sampling point set, and calculating the skin point cloud data according to the bicubic spline surface least square approximation. The method comprises the following steps: acquiring a reference curved surface reflecting the overall distribution trend of an analysis area, calculating distance deviation from a sampling point to the reference curved surface, carrying out filtering smoothing processing, forming a smooth deviation curved surface capable of reflecting the deviation condition of a measurement curved surface, extracting information such as wave crest and wave trough positions, wave amplitude, wavelength and slope in the deviation curved surface, and carrying out skin waviness characteristic analysis. According to the method, the tiny waviness characteristics of the irregular curvature surface of the aircraft can be extracted, the skin waviness distribution condition can be visually displayed, and the method has the advantages of being wide in applicability, small in error, high in reliability, low in time cost and the like.

The application provides a pre-processing method for reducing the peak-to-average ratio of a MIMO-OFDM signal, comprising the following steps: S1, performing constellation point pre-expansion and beamforming on a frequency domain signal X og ; S2, obtaining a time domain signal x m corresponding to the frequency domain signal X m ; S3, obtaining a peak cancellation sequence y m ; S4, calculating a peak cancellation frequency domain signal carried at a reserved subcarrier set according to the peak cancellation sequence y m , performing least square approximation on a time domain signal c m corresponding to the peak cancellation frequency domain signal to obtain an optimal amplification coefficient and obtaining a final time domain signal after peak cancellation; S5, performing one-time clipping processing on the signal, performing Fourier transform to a frequency domain, performing beamforming inverse transform on the frequency domain signal, and performing constellation correction; and S6, inputting the signal into a MIMO system to obtain a transmission signal of each antenna, and determining whether the peak-to-average ratio requirement is met to determine whether to directly transmit or iterate again. The application can greatly reduce the calculation complexity while ensuring the BER performance.

Accumulator thermistor test procedure comprising: charging an accumulator, wherein charging an accumulator comprises applying a controlled charge profile to an accumulator cell in the accumulator, monitoring an increase in mean temperature reported by at least one thermistor on the accumulator over a predetermined time period after the start of charging, preparing at least one thermistor slope by waiting for a time period corresponding to the duration of a final step in the charge profile, and calculating a least-squares approximation of time versus temperature for the at least one thermistor and comparing the at least one thermistor slope with thermistor slope limits defined for the charge profile.

The invention belongs to the technical field of gear transmission systems, and particularly discloses a gear meshing optimization method and system based on random progressive iteration and regularization, and the method comprises the following steps: carrying out the data sampling and preliminary fitting based on a gear tooth surface curve model; aiming at the preliminary fitting, setting an adaptive double-layer optimization framework which comprises a first layer of control point updating strategy optimization and a second layer of parameter distribution optimization, constructing an objective function, and realizing adaptive fusion optimization in the same iterative loop to obtain an optimized involute curve and a curved surface; and for the meshing region, introducing second-order difference smoothing, carrying out multi-objective optimization, and outputting a finally fitted NURBS control point P and an optimized parameter mapping weight w. By adopting the technical scheme, on the basis of least square approximation (LSPIA), the adaptive double-layer optimization technology is integrated, and the fitting precision, the fairness and the convergence speed are remarkably improved by jointly optimizing a control point updating strategy and parameter distribution.

The application discloses a node discrete type strain field analysis method, and steps of the method comprise the following steps: (1) carrying out configuration decomposition on a structure solving domain to obtain extreme values and residual parameters with space coordinates as variables; (2) constructing a virtual definition domain, and realizing smooth analytic continuation based on the extreme values and the residual parameters to obtain an analytic continuation overall smooth virtual configuration; (3) constructing a weight function and a shape function based on the analytic continuation overall smooth virtual configuration and the virtual definition domain to obtain a moving least square approximation of a displacement field; and (4) solving a node discrete type strain field of an original solving domain based on the analytic continuation smooth virtual configuration and the shape function. The application has the beneficial effects that the condition number of the shape function and its derivative is significantly reduced, and the numerical solving stability is effectively improved; and the strain solution of the original problem domain is extracted in combination with the definition domain truncation strategy, and the strain estimation precision of the node discrete type method at the boundary is effectively improved.