automatica
S. Yordanov, K. Ormandzhiev, G. Mihalev. Some Possibilities for Robust Control of a Double-Operating Water Turbine

Key Words: Robust control; cross-flow water turbine; H∞-norm; system uncertainty; load disturbance.

Abstract. A mathematical model describing the operation of the cross-flow water turbine has been developed in this paper. A robust governor has been synthesized using H∞ techniques to replace the conventional governor of the water turbine . The transient processes in the system are compared to the processes where the classical PID controller is used. The simulations are carried out using MATLAB and the results show that the overall system output performance can be improved using the proposed H∞ robust governor.

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V. Dimitrov, L. Popov. Method of Fully Operational Identification of Slow-Response Objects with Variable Parameters

Key Words: Aperiodic unit; time constant; transmission coefficient; parallel correction.

Abstract. A method for full operational identification of objects or units approximated to an aperiodic unit of the first order where electromagnetic inertia or time-delay are negligible. These are low-power electromechanical systems and small chamber furnaces. The method identifies the time constant T and the transmit coefficient k on the object. Robust control of a first-inertia object is developed – a small electric furnace with forced cooling, for which a predetermined transition process of cooling the material has to be provided. The corresponding parallel correction scheme is implemented, which turns the object into a deinterleaving tracking system.

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automatica
Е. Dimitrovа. GPS Dispatch System for Monitoring and Control in Automobile Transport

Кey Words: Dispatching system; GPS; navigation; transport vehicles.

Abstract. A GPS dispatching system for monitoring and managing of transport vehicles has been developed. It is reliable, easy to use, offers a wide range of features that can be used to optimize financial costs. It increases the productivity and efficiency of work, reduces fuel costs and eliminates abuses. It is available in different variants depending on the investments available. Varied modules can be added and security, navigation and driver monitoring can be ensured.

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V. Hristov, S. Petrov. Solar Tracking System by Microcontroller Arduino

Key Words: DC motor; solar tracking system; Arduino; photoresistor.

Abstract. This article presents the development of a two-axis platform for laboratory-based solar tracking system. The platform has the ability to rotate on the horizontal and vertical surfaces by two direct current motor. The use of an open source Arduino microcontroller makes it convenient to experiment with a variety of platform control algorithms and maximize performance. Its compact size makes it mobile to experiment with in different work environments. An algorithm is used to monitor the illumination of four photo resistors located on a cross.

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automatica
S. Lekova, D. Gocheva. Statistical Analysis of Measurement Data

Key Words: Statistical analysis of data; linear and rank correlation; analysis of variance.

Abstract. Good laboratory practice requires laboratories to ensure the quality of analyzes and assess the extent of human exposure to different chemicals and reagents. The subject of research and analysis are data from measurement of samples between two laboratories, by two different methods, in the processing of ore in the Ellatzite-Med AD Mine Complex. Of particular importance is the reliable measurement of the products (concentrations) from the flotation process (content of copper in the ore, intermediate products, concentrate and waste) as well as the production of molybdenum (feed, concentrate and waste). As a result of the sampling and depending on the characteristic to be determined and the test method, the concentration of the identifiable element is measured differently and with different technical means. The statistical analysis of data of parallel measurements from two or three laboratories involves calculating a linear or rank correlation and analyzing how significant the influence of a laboratory factor is, as well as studying and modeling the relationship between the presence of chemical elements in the ore, waste and concentrate in the process of laboratory control.

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