Physical features of control of the surface relief of precision products

The quality precision measurements of the product manufacturing or their surface treatment are considered. The importance of high-precision measurements at high speed, which does not require delivering the product to a special control laboratory, is shown. A precision laser measuring system is developed and manufactured, its kinematic diagram is presented and the calibration process is described. The verification of the measuring process results is given on the example of the parts obtained by polishing and grinding the surface. The dependence of the measurement error calculation is given, it is shown that the error of the measuring system is within acceptable limits. The presented measuring system has the capabilities of processing measurement results and constructing 3D images. Thus, the possibility of obtaining the surface topography parameters in accordance with ISO 25178-1, 25178-2 is shown. The methods of the surface treatment and filtering are used to improve the result accuracy of measuring the manufactured part quality, among which the elimination of the average slope, median filtering, and Wiener filter are described. It is shown that the highest accuracy of measurement results in the nanometre range with minimizing distortion losses is possible using the Wiener filter.

Methods of Estimating the Form of the Probability Distribution Density in Tasks of Processing Measurement Results

Issues associated with methods for estimating the shape of the probability distribution density curve are analyzed in order to classify them when processing measurement results. For example, such nonparametric methods as the method of histograms and frequency polygon, as well as the method of classification of distributions, are considered. It is shown that the values of the anticurtosis and entropy coefficient can be taken as independent features of the form of symmetric distributions. For probability distribution densities that have a one-sided character, such as multiplicative noise, a skewness coefficient should be added to the parameters to consider. Recurrent procedures for obtaining current estimates of numerical characteristics of analyzed random processes are given. The results of processing a random process based on recurrent procedures are presented. It is shown that when the number of samples increases, the estimates obtained by using recurrent and non-recurrent procedures converge. The scattering of estimates of probability distribution density parameters, such as variance, relative mean square error, and entropy error, is determined.

Robust Controller Design for Multi-Input Multi-Output Systems Using Coefficient Diagram Method

The coupling between variables in the multi-input multi-output (MIMO) systems brings difficulties to the design of the controller. Aiming at this problem, this paper combines the particle swarm optimization (PSO) with the coefficient diagram method (CDM) and proposes a robust controller design strategy for the MIMO systems. The decoupling problem is transformed into a compensator parameter optimization problem, and PSO optimizes the compensator parameters to reduce the coupling effect in the MIMO systems. For the MIMO system with measurement noise, the effectiveness of CDM in processing measurement noise is analyzed. This paper gives the control design steps of the MIMO systems. Finally, simulation experiments of four typical MIMO systems demonstrate the effectiveness of the proposed method.

How to do Better N400 Studies: Reproducibility, Consistency and Adherence to Research Standards in the Existing Literature

Given the complexity of ERP recording and processing pipeline, the resulting variability of methodological options, and the potential for these decisions to influence study outcomes, it is important to understand how ERP studies are conducted in practice and to what extent researchers are transparent about their data collection and analysis procedures. The review gives an overview of methodology reporting in a sample of 132 ERP papers, published between January 1980 – June 2018 in journals included in two large databases: Web of Science and PubMed. Because ERP methodology partly depends on the study design, we focused on a well-established component (the N400) in the most commonly assessed population (healthy neurotypical adults), in one of its most common modalities (visual images). The review provides insights into 73 properties of study design, data pre-processing, measurement, statistics, visualization of results, and references to supplemental information across studies within the same subfield. For each of the examined methodological decisions, the degree of consistency, clarity of reporting and deviations from the guidelines for best practice were examined. Overall, the results show that each study had a unique approach to ERP data recording, processing and analysis, and that at least some details were missing from all papers. In the review, we highlight the most common reporting omissions and deviations from established recommendations, as well as areas in which there was the least consistency. Additionally, we provide guidance for a priori selection of the N400 measurement window and electrode locations based on the results of previous studies.

Solution of the Problem of Odometric Positioning of a Mining Machine under the Ground by Using a Kalman Filter

In the modern mining industry, an urgent technical challenge is the introduction of automatic systems that provide orientation and positioning of mining machines during the development of industrial seams. There are several basic technologies used for positioning combines underground, but their scope is limited by various mining, geological and technological factors. In the conditions of industrial development of VKMKS seams, the vast majority of them are not suitable. Aim. To develop a new approach to the problem of odometric positioning of a mining machine under the ground, as well as to create a simulation model that allows with the required degree of accuracy to determine the current and predicted distance of the miner from the start of production in conditions of noisy measurements. Materials and methods. As a technical solution to the task, the use of BLE (Bluetooth Low Energy) technology is proposed: iBeacon beacons will be dropped in the direction of the combine's movement, and a sensor attached to the rear of the loading bunker will read the distance to the beacon. For simulation modeling of uncertainty during the movement of the combine, the hypothesis of the normal distribution of the speed of movement on sections of random length was considered. When simulating the dropping of the beacon, the hypothesis was used that the scattering value of the beacon upon falling is a two-dimensional normally distributed random variable. Noisy measurements were generated by a stochastic process with increasing scatter boundaries as the sensor moved away from the beacon. The Kalman filter was used as a tool for processing measurement noise. Results. A model has been created that simulates random speeds of the combine's movement on sections of random length, and also a random spread when throwing off Blue¬tooth beacons has been simulated. To generate sensor measurements, an algorithm has been deve¬loped that takes into account the increase in the noise level of the readings when moving away from the nearest dropped beacon. To process the simulated measurements and correctly determine the distance of the beacon-sensor, the Kalman filtering algorithm was used. Conclusion. The proposed approach and the created simulation model make it possible, with a given degree of accuracy, to determine and predict the distance to the withdrawing shearer when mining industrial seams.

Quaternion Method of Calculating Angles while Measuring via Goniometric Precision Instrument System

The article is devoted to the topical problem: increasing accuracy and performance of angle measurements necessary in various branches of science and technology. One of the ways of increasing accuracy and performance of angle measurements is using modern algorithmic methods and mathematic devices for processing measurement information. Thus, in order to increase accuracy and speed of angle measurements on the example of the well-known goniometric precision instrument system (GPIS), it was offered quaternion calculation of angle values while performing goniometric measurements in the work. The efficiency of quaternion calculation is unquestioned as quaternions unlike other traditional methods (in particular matrix with the use of Euler angles, direction cosines) are presented only with four parameters describing angle positions of the objects and have only one connection equation unlike six equations for matrix methods, in particular for direction cosines. The suggested quaternion calculation is used in GPDS as general theoretic and information basis of contactless precision goniometric measurements in preliminary setting navigation sensitive elements (NSE), plane angles, pyramid prisms etc. The usage of the developed quaternion calculation enabled to increase accuracy by 0,25 (in 3 times) and measurement performance in 9 times (up to 6.5 sec.) in comparison with the famous ones. Applying quaternion calculation of angle values implies using a smaller RAM capacity of PC that increases performance of system work. Besides, a smaller amount of mathematic operations performed in quaternion way of calculating angles, except increasing performance, enables to decrease a rounding error in calculation results that is accumulated in multiple measurements and may reach great values. Thus, accuracy and performance of measurements increase.

Comparative analysis of methods for calculating the mode of a stationary random process

The paper considers methods for calculating the mode of a stationary random process when solving the problem of processing measurement results under conditions of a priori uncertainty. The results of the conducted studies allowed us to conclude that the most effective method for calculating the mode for a given sample is the proposed method, which allows to increase the accuracy of its calculation by at least 8 times, compared to methods based on the construction of histograms. It should be noted that the proposed method allows to provide an estimate with an error of at least 5% for samples with a number of measurements of about 5 value.

Comparative analysis of hardware and software of the monitoring method of fun ctioning electromechanical DC converters

THE PURPOSE. The task of analysis and monitoring of the functioning of electromechanical converters in transient and static modes is relevant at the design and operation stages. Software products for recording and processing measurement information, as well as for performing the necessary technical calculations, such as LabView, MatLab Simulink and others, offer great opportunities for solving the task and allow obtaining reliable results. METHODS. The study of electromechanical DC converters with built-in tachogenerators carried out, the measurement and fixing of the output coordinates of which is provided by experimental sets of various configuration with subsequent processing of the results of functional monitoring using application programs. RESULTS. The developed experimental sets differ in the composition and cost of hardware, the need to use one or another software support, the form of presenting the results of monitoring the functioning of research objects and the accuracy of the results. CONCLUSION. The present study aimed at a comparative analysis of two experimental sets. These sets allow obtaining mathematical models of electromechanical DC converters necessary for the implementation of the monitoring method of the function ing. The analysis performed from the point of view of material costs for hardware and software, the processing time of the experimental results and the correspondence of the obtained results to the required accuracy of the formation of mathematical models.

Schedule maintenance and repair system of Locomotive

To increase the efficiency and reliability of locomotives, it is necessary to constantly monitor the operation process. The introduction of modern automatic control and monitoring systems on locomotives is not only a departure from the established state of the equipment, but also an effective and efficient way of processing measurement information that can detect changes in the technical condition of key parts.