Dynamic Compensation of Parameters in Servo Drives

In this paper, we studied a servo drive with an unlimited increase in the gain coefficients of the speed con-tour. We demonstrated dynamic compensation of parameters associated with the formation of differential com-ponents based on the coverage of the real coordinates of the control object using static model. It was shown that dynamics of the transient processes is caused by real differentiating links determining the fast and slow components of the transient process. The static velocity error in this case did not depend on the ratio of large and small time constants, as in a single integrating system of subordinate regulation of parameters. Therefore, we considered that parametric disturbances and their compensation occur due to the external astatic circuit. We demonstrated an equivalent transition to the position contour, the speed structure and position generator, corresponding to the organization of the servo drive in the CNC systems. We investigated features of the phase discriminator during the operation of the position sensor in the phase difference mode and carried out model-ing of the servo drive structures and comparative analysis of two and three-circuit systems.

Model Predictive Control Method Based on Deterministic Reference Voltage for Single-Phase Three-Level NPC Converters

When single-phase three-level neutral-point-clamped (NPC) converters operate, there are two main control objectives that need to be met for correct operation. First, the ac source current must be controlled to be sinusoidal. Second, the dc capacitor voltages must be balanced. In original model predictive control (MPC) methods for NPC converters, an optimization process involving an empirical weighting factor design is required to meet both of these objectives simultaneously. This study proposes an MPC approach developed for single-phase three-level NPC converters to meet these objectives using a single reference voltage consisting of a difference-mode term and a common-mode term in each phase. The difference-mode term and the common-mode term are responsible for sinusoidal ac source current synthesis and dc capacitor voltage balancing, respectively. Then, a single cost function compares the adjusted reference voltage with possible voltage candidates to select an optimal switching state, resulting in the smallest cost function value. Different from the conventional MPC method, the proposed approach avoids the selection of weighting factors and the attendance of various control objectives. Thanks to the deterministic approach, the proposed MPC method is straightforward to implement and maintain fast transient performance while guaranteeing the control objectives. Finally, the effectiveness and feasibility of the proposed approach for single-phase three-level NPC are verified through comprehensive experimental results.

Interpretability and variability of metamodel validation statistics in engineering system design optimization: a practical study

Prediction accuracy of a metamodel of an engineering system in comparison to the simulation model it approximates is one fundamental criterion that is used in metamodel validation. Many statistics are used to quantify prediction accuracy of metamodels in deterministic simulations. The most frequently used ones include the root-mean-square error (RMSE) and the R-square metric derived from it, and to a lesser degree the average absolute error (AAE) and its derivates such as the relative average absolute error (RAAE). In this paper, we compare two aspects of these statistics: interpretability of results returned by these statistics and their sample-to-sample variations, putting more emphasis on the latter. We use the difference-mode to common-mode ratio (DMCMR) as a measure of sample-to-sample variations for these statistics. Preliminary results are obtained and discussed via a number of analytic and electronic engineering examples.

FriendlyARM-Based Color to Frequency Representation for Media Packaging Color Detection

This research presents the design and development of a FriendlyARM-based color to frequency representation for media packaging color detection used in small media packaging industrial. The design was based on FriendlyARM Mini 2440 SBC (Single-Board Computer) with 400 MHz Samsung S3C2440 ARM9 processor and the color sensor used in this research was a programmable color light to frequency converter model TCS230 made by Texas Advanced Optoelectronic Solutions (TAOS) company. The frequency information gathered was used to create color to frequency representation. This research study in 4 filter modes: red, blue, green and non filter. Calibrate each CMYK color with standard color checker chart in difference mode. The results of study, the non filter mode can give the results better than red, blue and green mode. The output frequency span between color are 7.432 kHz, 3.5 kHz and 21.31 kHz for Black-Cyan, Cyan-Magenta and Magenta-Yellow frequency spans respectively compared to other filter modes. The advantage of this research are reduce the use of memory for storing the CMYK color data and can speed up the time of restoring and inspecting colors used in media packaging processes.

Nonlinear interaction of wind-driven oblique surface waves and parametric growth of lower frequency modes

Nonlinear interactions between free-surface waves of the same wave speed and wind are studied by extending the linear resonant theory of Miles (J. Fluid Mech., vol. 3, 1957, pp. 185–204). A nonlinear interaction can occur when the steepness of a primary three-dimensional wave, which propagates obliquely to the wind direction, becomes of the order of the cube of the density ratio of air to water. If a secondary wave of smaller amplitude is also an oblique wave, the nonlinear critical-layer interaction between the primary and secondary fluctuations in air generates a difference mode whose wavenumbers are equal to the differences between the primary and secondary values. In addition, the nonlinear interaction in the critical layer between the primary and difference modes induces a parametric-growth effect on the secondary surface wave, if the frequency of the primary wave is higher than that of the secondary wave. The primary wave remains linear during this ‘$2+ 1$ mode critical-layer interaction’ stage between two free-surface waves and a nonlinearly generated mode. The evolution of the secondary-wave amplitude is governed by an integro-differential equation and that of the difference mode is determined by an integral equation. Both inviscid and viscous numerical results show that the nonlinear growth rates become much larger than the linear growth rates. Effect of viscosity is shown to delay the onset of the nonlinear growth. The growth of the secondary and difference modes is more effectively enhanced when the signs of propagation angles of the primary and secondary waves are opposite than when they are equal. The $2+ 1$ mode interaction can occur when wave steepnesses are very small. The nonlinear interaction is entirely confined to a thin critical layer, and the perturbations outside the critical layer are governed by linear equations. It is shown that the initial nonlinear growth of a free-surface wave could be governed by a mode–mode interaction in air.