L. Fozo

Situational Control, Modeling and Diagnostics of Large Scale Systems

A large scale system in general is a high dimensional high parametric system with complex dynamics. For efficient and optimal function of such systems, it is necessary to propose and implement newest knowledge from the areas of cybernetics and artificial intelligence. Present control systems are often limited to control a complex system only at some given conditions. However in real-world applications these systems find themselves in very different working conditions, what influences parameters of their operation and characteristics of behavior and may lead to errors and critical states. The article deals with overview of methods of situational control and is aimed on implementation of these methods in the area of turbojet propulsion.

Situational modeling and control of a small turbojet engine MPM 20

Small turbojet engines represent a special class of turbine driven engines. They are suitable for scientific purposes and research of certain thermodynamic processes ongoing in turbojet engines. Moreover such engines can be used for research in the area of alternative fuels and new methods of digital control and measurement. Our research, which is also presented in this article, is headed toward these aims. We evaluate and propose a system of digital measurement of a particular small turbojet engine - MPM 20. Such engine can be considered as highly non-linear large scale system. According to obtained data and experiments we propose situational model and situational control algorithms for the engine with use of certain methods of artificial intelligence as new methods of control of large scale systems.

Intelligent Technologies in Modeling and Control of Turbojet Engines

The state of present technologies in technical and also non-technical practice is represented by growing complexity of systems. A turbojet engine as a complex system is multidimensional highly parametric system with complex dynamics and strong non-linear behavior with stochastic properties. Its particular property is operation in a wide spectrum of changes of its operating environment (e.g., temperatures from -60 to +40 °C, different humidity, different pressures, etc.). If we want to secure optimal function of such system, it is necessary to develop models and control systems implementing the newest knowledge from the areas of automation, control technologies preferably with elements of artificial intelligence (AI). The present control systems and dynamic models are often limited to control or modeling of a complex system in its certain (operational) states. However, in practice the turbojet engine finds itself in very different operating conditions that influence its parameters of operation and characteristics. To create progressive control algorithms for a turbojet engine, it is necessary to design models in the whole dynamic spectrum of the modeled system including its erroneous states. Furthermore we need to design a control system that will secure operation converging towards optimality in all eventual states of working environment and also inner states of the system represented by its parameters. This leads to the need of having increased intelligence of control of turbojet engines that reduces workload of a pilot and also increases safety of operation. Safety represents a decisive factor in design of control systems of turbojet engines and is presently bound with increasing authority of them. The present trend designates such control systems as FADEC – Full Authority Digital Engine Control, however in reality such control systems have different levels of authority, intelligence and come in very different implementations. These are often not presented as they are intellectual properties of commercial companies. The article will be aimed on description of some present trends in development of FADEC systems and own proposals of methodologies leading towards design and implementation of a FADEC system with high level of intelligence able to solve all operational situations of a turbojet engine. This is strictly bound with presentation of modern methods of modeling of turbojet engines and the use of advanced methods of mainly sub-symbolic artificial intelligence. The proposed methods are all tested in real-world environment using a small turbojet engine MPM-20 in our laboratory setup. Therefore the article will also deal with approaches in digital real-time measurement of state parameters of this engine and design of control algorithms from engineering standpoint.

Digital Electronic Control of a Small Turbojet Engine - MPM 20

Small turbojet engines represent a special class of turbine driven engines. They are suitable for scientific purposes and research of certain thermodynamic processes ongoing in turbojet engines. Moreover such engines can be used for research in the area of alternative fuels and new methods of digital control and measurement. Our research, which is also presented in this article, is headed toward these aims. We evaluate and propose a system of digital measurement of a particular small turbojet engine - MPM 20. Such engine can be considered as highly non-linear large scale system. According to obtained data and experiments we propose different model models of the engine and design of situational control algorithms for the engine with use of certain methods of artificial intelligence as new methods of control and modeling of large scale systems.

Description of an intelligent small turbo-compressor engine with variable exhaust nozzle

How to use an old turbo-compressor (turboshaft) engine and transfer it into a laboratory system used for design and development of progressive control, diagnostic and modeling algorithms transforming it into an intelligent turbo-compressor engine? The intelligent turbo-compressor engine currently designated as iSTC-21v is a small turbojet engine with a single sided radial compressor, bound combustion chamber, single stage un-cooled turbine and variable exhaust nozzle. The engine is equipped with a real-time measurement and intelligent digital control system using two degrees of freedom (fuel supply and exhaust nozzle diameter). The article describes transformation of an old TS-20/21 engine into such engine, which is suitable for laboratory use, research in different areas of cybernetics with perspective applications in different areas of technical practice like unmanned aerial vehicles, ground auxiliary energetic units, generators, etc. The article is aimed to be inspirative also for hobby engine builders, scale modelers and people who work with small turbo-compressor engines.

FADEC control system for MPM 20 engine

The article deals with full authority digital engine control (FADEC) systems and possibilities of application of concepts and methods of artificial intelligence in such control system. FADEC represents a framework where the most modern methods of artificial intelligence can be applied. This represents a great potential for increase of reliability, efficiency and overall quality of control of turbojet engines. We are trying to design and implement a FADEC control system for our small experimental turbojet engine MPM 20.

Expansion of working envelope of a small turbojet engine MPM-20

Development of aircraft engines is aimed on increase of reliability, efficiency and ecology of operation. The presently still used hydro-mechanic control systems are being replaced by electronic ones characterized by high speed, precision of control and ability to optimize all operating regimes of an engine. One of the aims of research in the Laboratory of intelligent control systems of aircraft engines lies in new possibilities of expansion of working envelope of turbojet engines by implementation of variable exhaust geometry and new approaches in its control strategies and construction solutions. Such expansion can be beneficial for small turbojet engines and increase their possibilities of real-world applications. New control methodologies and approaches can be further expanded to normal sized engines. All these problems are described in the presented article.

Digital start-up control of the small turbojet engine MPM-20

The main thesis of this paper considers the possibilities and difficulties of switching from hydromechanical engine control to FADEC (digital) engine control. Regarding different specifications and elements in system, possible errors, advantages and disadvantages, each method has its specific properties of behavior in specific environments and applications. When considering our controlled system, the MPM-20 small turbojet engine, it is a challenge to propose functional control system with backups and with slight possibility of errors during or before operation. In this paper we propose methods of backups for specific elements, prestart diagnostics and on-line diagnostics.

Thrust vectoring nozzle for small turbojet engine in laboratory conditions

The article deals with description of thermodynamic processes in a class of small turbojet engines with description of experimental and analytic modeling approaches to create a mathematical model. The model will describe a small turbojet engine as a system with one degree of freedom (fast exhaust nozzle), two degrees of freedom controlled by fuel supply and exhaust nozzle diameter. The article then deals with extension of such model with the third degree of freedom in the form of thrust vector. Such system developed for a small turbojet engine can be beneficial in applications with highly maneuverable small unmanned aerial vehicles.

Introduction to advanced modeling and control of turbo-prop engines

The article deals with basic description of turboprop engines as a special class of turbine engines - advanced approaches in its modeling and control. The article will deal with description of analytical and experimental approaches in modeling of individual parts of the engine with description of their thermo-dynamics and states. Such engines are systems with two degrees of freedom and demand advanced control algorithm in case of control with single control lever. The article will deal with design of such control algorithm with perspective use of advanced control methods. Such approaches will increase efficiency, fuel consumption, safety and control comfort for the pilot.