Dynamic Process Quality Research Articles

Analytical modelling and design of linear controlled dynamic systems

A generalized canonical mathematical model of multidimensional controlled mining transportation complexes and other technical systems in form by A.M. Letov is considered. A principle of symmetry and an algebraic concept are in the basis of the developed analytical methods of design. A principle of symmetry is realized on a set of indexes of roots of a characteristic equation of the system and on a set of indexes of phase coordinates of the mathematical model. The problem of quality of dynamic processes in time is reduced to an algebraic problem of distribution of roots of a corresponding characteristic equation in a complex plane. An analogy in a procedure of transformation of a characteristic determinant into a polynomial and a structure of elementary symmetrical polynomials of roots is established. A new formulation of an analytical representation of change of phase coordinates in time in a form of ordered determinants with respect to indexes of roots and indexes of phase coordinates is obtained based on residue theorem. An illustration of the developed analytical method of design is performed on a special case of a well-known controlled technical system of the fourth order.

Analytical Modeling of the Dynamic System of the Fourth Order

A canonical mathematical model of a fourth-order dynamical system in the form of A.M. Letov. The analytical modeling methods are based on the algebraic concept and the principle of symmetry. The symmetry principle is realized on the set of four indices of the roots of the characteristic equation and the set of four indices of the phase coordinates of the dynamic system.
 The problem of the quality of dynamic processes in time is reduced to the algebraic problem of distribution of four roots in the complex plane. An analogy is established in the procedure for transforming the characteristic determinant to a polynomial and elementary symmetric polynomials of four roots. On the basis of the theory of residues, a new form of analytical representation of data in time is obtained in the form of ordered determinants with respect to the indices of four roots and indices of four coordinates.
 General provisions are illustrated by a stochastic dynamical system in the form of an asymmetric Markov chain with four states and continuous time, which is described by the fourth-order Kolmogorov equations.

Цифровая коррекция алгоритмов управления асинхронными электроприводами с частотным управлением, применяемых в транспортных механизмах линий непрерывного производства

The article presents proposals on how to adjust the dynamics of asynchronous variable frequency drives used in production equipment. Several papers and patents show that dynamic positive feedback (DPF) on the active current of the motor stator yields significant improvement in static speed accuracy and dynamic process quality. However, analog hardware implementation of this adjustment in drives of production machines is both inefficient and cost-ineffective. This article shows how such adjustment could be implemented in industrial controllers originally designed to work with frequency converters (FC) as process parameter controllers. It further shows that this approach opens up broad opportunities to use standard hardware and software in better asynchronous drive control algorithms.

Optimization of the quality parameters of the transition process in hydraulic pressure regulators

In direct-acting hydraulic regulators, the source of harmful self-oscillations of pressure in hydraulic systems may be their own damping of these regulators. Their elimination is possible by decreasing the valve gain coefficient according to the flow rate, which is determined by the magnitude of the fluid flow increment per unit of displacement of the regulator when the working fluid is throttled in the valve itself.The article discusses the possibility of optimizing the quality parameters of transient processes in pressure regulators with the help of their integral evaluation using the example of optimization of the gain coefficient for the flow rate and the damping coefficient. It is established that the reduction of the gain is most appropriate for its large values. A further decrease in this ratio slightly improves the quality of the transition process, and may worsen the flow characteristic of the steady-state controller due to excessive displacement of the regulator. The tests confirmed the validity of this assessment of the quality of dynamic processes in the transient modes of these regulators.

Parameter Optimization of Coordinated Control System Based on Intelligent Algorithm

This paper studies the issue of modeling and control of large unit coordinated control systems. The system is regarded as a three-input and three-output control object. Based on this, the system model is decoupled and the controller is designed. The controller is designed using an intelligent PID method, which based on genetic algorithm and fuzzy control model. The proposed method can optimize the control effect while ensuring the basic requirements, in order to achieve the goal of improving the dynamic process quality and improving the combustion efficiency.

Противоаварийное управление установками распределенной * генерации

The article presents the results of investigations aimed at elaborating emergency control methods in the power supply systems equipped with distributed generation plants. The control outputs aimed at bringing the operation mode into the stability region were produced by changing the vector of controlled parameters along the specified trajectory and also along a trajectory corresponding to the shortest path from the point of initial mode to the limit hypersurface. The quality of dynamic processes in implementing the control outputs was ensured by coordinated tuning of the automatic excitation controllers (AEC) and automatic rotation frequency controllers (AFRC). It is shown proceeding from computer simulation results that the system can be efficiently brought into the stability region on the basis of limit mode equations by using a startup algorithm that brings the mode to the stability region’s nearest boundary. By using fuzzy technologies to control the tuning of AEC and AFRC it is possible to organize high-quality dynamic transition during unloading of generator in the post-emergency operation mode.

ACCURACY INCREASE OF DYNAMIC OBJECTS STATE ESTIMATION BY A COMPLEX MATLAB-ARDUINO WHEN CYBERPHYSICAL SYSTEMS DESIGNING

The problem of accuracy increase of MATLAB and Arduino interaction when cyber-physical systems designing by making changes into the implementation of the standard protocol of Arduino has been solved. It has been proposed to carry out the analog-digital conversion of all required analog pins with further sequential data transmission to MATLAB when requesting to read data from the first analog pin of Arduino. It allows improving control quality of dynamic processes by reducing the uncertainty range of a high-speed multi-dimensional control system state. In addition, it has been offered to perform the preprocessing of sensors data by means of Arduino that increases the flexibility of cyberphysical systems due to the possibility of the hardware changing without MATLAB software and protocol changing. A formal description of MATLAB and Arduino interaction allows realizing the communications protocol using wireless interfaces as well as microprocessor units and platforms, which are not compatible with Arduino.

Product Lifecycle Oriented Quality Management System for Individualized Customization

To cope with the challenges of traditional quality management system applied in individualized customization, product lifecycle oriented quality management system model for individualized customization, and corresponding functional modules and framework were all put forward. This mode dealt mainly with constructing and running product lifecycle oriented quality management system for individualized customization, furthermore, some of key enabling technologies were studied in detail, including collaborative quality design based on CSCW, dynamic process quality control, quality evaluation oriented to product lifecycle. The corresponding prototype system is developed, which was introduced to demonstrate the rationality and validity of the method as an example of some Heavy Machinery Ltd. It provided an effective method with enterprise implementing individualized customization.

A Study on Dynamic Process Quality Control Method into Supply Chain

To cope with the challenges of monitoring dynamic and variable quality variation into supply chain, diagnosing the abnormal variation at the right moment, is a difficult problem that a enterprise in supply chain faces in process quality control. A dynamic process quality control method, which integrated quality prevention, analysis and diagnosis, was all put forward. This method integrated several enabling technologies such as the theory of similarity manufacturing, Statistical Process Control (SPC), neural network. Furthermore, some key enabling technologies were studied in detail, including process quality analysis on-line based on similarity process and process quality diagnosis based on Elman. It is basis of realizing network, intelligent and automatic process quality control.

Optimal investment and lot-sizing policies for improved productivity and quality

Abstract Productivity and quality are an integrated component of the operational strategy of any firm. An increase in productivity implicitly assumes an improvement in quality. The concept of dynamic process quality control and smaller lot-size production have been employed to eliminate defective items, to reduce the cycle time of a product and to improve quality and productivity. We present a mathematical model to establish the relationship between various parameters of productivity and quality. In addition, the proposed model is used to determine the optimal levels of productivity and quality parameters such as batch sizes, and investment in set-up and process control operations. The basic criterion considered for optimizing the level of such parameters is the minimization of total system cost. The proposed model relates productivity and quality to set-up reduction, queueing of batches, batch sizes, and drift rate reduction. We conclude with an example problem to illustrate the behaviour and application...

Effect of Dynamic Process Quality Control on the Economics of Production

A study of the effect of the dynamic process quality control on the economics of production and the Total System Cost (TSC) is dealt with. A mathematical model is presented for estimating the Economic Investment in Quality (EIQ) and the Economic Production Quantity (EPQ) in a multi‐stage production‐inventory system. The basic criterion considered for the determination of EIQ and EPQ is the minimisation of TSC. The TSC consists of (1) set‐up cost, (2) in‐process inventory carrying cost; this cost is a function of the processing time and the reset‐up time, (3) finished product inventory carrying cost, (4) reset‐up cost, (5) investment in quality control, and (6) scrappage cost. The feature of this research is to consider the aspect of dynamic process quality control, namely, “quality at the source”, by monitoring the quality of the product as the process continues and stopping the process if it goes out of control. A numerical example is given to illustrate the model.