An operative method of abnormal measurement rejection for multidimensional dynamic systems is developed. The method is robust to systematic measurement errors. It does not require information on the value and sign of systematic errors, and also on statistical characteristics of abnormal measurements, and can be used in various technical fields for measurement information processing.
The possibility of applying the sliding mode method to synthesis of an automatic extremum seeking control system for dynamic plants with a static extreme characteristic is discussed. It is recommended to transform preliminary the control plant model by adding a new variable. For the variable it is proposed to use an estimate of the output characteristic gradient. It is shown that this transformation makes it possible to reduce the initial problem of synthesizing the extremum seeking system to a stabilization problem usual for the automatic control theory. The main properties of a closed-loop system are considered and some advises for control algorithm implementation are presented.
The problem of spatial localization of the coherent signal source energy is investigated within the scope of the quadratic and nonquadratic regularization theory on the basis of l2-norms in the conditions of minimal a priori information on the form, frequency-time regions of broadband signal existence, and statistical characteristics of disturbances. A numerical experiment using an antenna array of a nonlinear spatial configuration proved the efficiency of the proposed algorithms for digital reconstruction of the angular energy distribution in the conditions of multipath propagation.
It is shown that for the optimal (by the minimum mean-root-square error) prediction of the moving average process of the q-order the predictability time can exceed the correlation time by a factor of in q the case of a certain combination of the moving average coefficients.
Estimation of intensity of local plastic deformation developing under conditions of fatigue fracture is suggested on the basis of a number of numerical characteristics obtained by analyzing a two-dimensional power spectrum of a series of optical images of the surface. It is shown that the presence of a fatigue crack as a region of low information on the image does not exert any significant effect on the calculated results of energy characteristics of the power spectrum. A comparison of the calculated results with the results of fractal dimension calculations shows qualitative similarity of these approaches, which is based on the multidimensionality of measurements implemented in both of the cases.
An expression is given for a normalized moment (determined in an arbitrary direction) of an energetic spectrum of a gradient image of an arbitrary order. It is shown that the matrix form of this expression makes it possible to obtain analytical expressions for the main moments of the spectrum and the main values for the mean square frequencies of the gradient image and the corresponding directions. It is demonstrated that the estimates of the characteristics can be obtained in the plane of space variables without performing the direct Fourier transform, which is important in solving the problems of image express analysis. Experimental results on a limited amount of test images are presented.
A cellular neural network (CNN) is known as a fine-grain parallel model capable to generate various types of autowaves. This property of CNN allows one to consider it as a new model of autowave processes in distributed active media and determines the necessity of further detailed investigation of the model. A CNN model modification that does not have the neuron bias parameter is described along with its properties. Techniques of using the external inputs for modifying the CNN properties and generating the autowave processes are determined.
Severe requirements are imposed on the geometric parameters of the grid spacers in order to ensure a high reliability of fuel assemblies of nuclear reactors. They specify position of the beam of fuel elements in the transverse and longitudinal directions of the fuel assemblies. This is of extreme importance for preventing their corrosion and maintaining the required heat regime of functioning. A laser measuring machine (LMM) was developed and produced using the multipoint structured illumination method to ensure 100 % 3D inspection of the geometric parameters of grid spacers in Russian VVER-1000 nuclear reactors. A measurement method as well as hardware and software of the LMM are presented. Results of LMM testing in the industrial conditions are presented and discussed. Phase retrieval profilometer for in-process measurement of 3D microstructure surfaces
An optical method for measuring the profile of three-dimensional micro-surface structures is proposed. Spatial spectral information on a surface profile is obtained by measuring its diffraction intensity, from which the surface is reconstructed by using the phase retrieval. A surface with a staircase-like shape having four steps with each step 70 nm high was measured to demonstrate that the method works for arbitrary nonperiodic surface structures. The successfully reconstructed surface is shown. This diffraction method has a potential application in in-process measurements.
Triangulation optical methods for melt level measurement in a crucible during crystal growth are analyzed. Main attention is given to the active method using a laser triangulation sensor. Estimates of the metrological characteristics (systematic measurement errors and effective range) depending on the level of melt, its angular velocity, the distance from the measurement zone to the center of rotation, and the crucible coordinate are presented. The limit value of the melt rotation speed is also estimated. The requirements to the optical system providing the maximal measurement range and also to the algorithms of processing of the optical signal formed as the sensor beam is reflected from the nonstationary mirror surface are formulated. The features of melt level measurement using a passive binocular sensor are discussed.
the case of a certain combination of the moving average coefficients.