Gianina Gabor

Interpolative control algorithm applied on a 3D-mechatronic system

The study presented in the paper aims to investigate the control performances of an interpolative control algorithm applied on a complex nonlinear system. In the specified context, the study was made based on results obtained through simulations on a 3D-Crane. The results were compared with data obtained from a classical PID system that also incorporates the 3D-Crane.

TEMPERATURE CONTROL SOLUTION USING INTERPOLATION FOR A GEOTHERMAL POWER PLANT

Abstract The practical control problems are hard to solve using analytical approaches. The solutions frequently obtained, based on a theoretical concept, are quasi-empirical and they are reflecting the expert knowledge regarding the controlled process of the technologist and the control engineer knowledge regarding the system behaviour. These knowledge are available only on a punctual manner and refers to a low number of functional/working regimes that can be synthesized into bases of rules that suites to interpolative methods. The paper presents in this context the temperature control of the CO 2 after the vaporizers, part of a geothermal power plant. A solution that uses as controller a three points relay with feedback loop is proposed. The dynamic of the controller is adapted using interpolative manners based on the variations of the major measurable disturbances acting on the vaporizers. The proposed solution, designed quasi-empiric, brings better dynamic and stationary performances compared to the actual control version. There are presented: the structure of the controller, the model of vaporizers block used in the design, the design steps of controller parameters and the dynamic performances of the control systems obtained by simulations.

Redundancy method used in PLC related applications

PLC related applications are more complex as far as more components are involved. If some error occurs, diagnosis can take some time, but a logical procedure will shorten the time needed to locate the fault. The probability of failure of different parts of typical PLC systems shows [1] that 95% of PLC systems are external faults and occur on plant items such as: sensors, actuators, transducers, limit switchers, and others. The possibility of determining the validity of the data gathered from all transducers of the control system assures a way of short time fault detection. Consequently, a fault-tolerant control system must be implemented using redundant structures, representing an alternative for malfunctioning element detection. This paper presents a method used to design and implement a control system based on redundant structures. A case study for the geothermal power plant at the University of Oradea was developed. The redundant structure considered was simulated using MathLab/Simulink and analyzed using different scenarios. Finally, a possible implementation of resulting control system structure is done using a programmable logical controller (PLC).

The circulation of current components, an analyse about efficiency of electrical power consumption

This paper describe methods of analysis concerning efficiency in electrical power consumption (efficiency in electrical power transfer from the electrical generator to the electrical consumers). In the presence of unbalanced or/and non-linear consumers, the analysis gets more complicated; in those situations, the described analysis points upon the importance of electrical current flow computation (more precise, about flow of sequence negative component of electrical current or harmonic components).

Numerical algorithms for Lyapunov stability analysis of interpolative control structures

The complexity and specificity of stability analysis applied to interpolative-type control structures makes the study of such property a difficult, almost impossible task - at least in the analytical manner. Therefore, a better solution could be represented by the numerical approach. In this context, this paper starts with developing some methods and techniques with applicability for analysis of the interpolative-type controllers, based on Lyapunov method perspective. These methodological aspects are gathered together into a specific procedural algorithm. Based on this algorithm, a set of MATLAB-SIMULINK programs able to offer, in a flexible and user-interactive way, a possible solution to Lyapunov-stability analysis for a class of interpolative-type control systems with linear or non-linear processes of 2nd and 3rd order are developed. The solution based on the implemented software packages was finally validated through some practical examples.

A Tool for Modeling and Simulation of Real-Time Systems Behaviour

In several real-time applications, tasks are not only subjected to complete their deadlines, but more control of the scheduling process is required. In such situations, quality of service is interpreted in many ways (jitters, response times, etc.). In other real-time environments the objective is to optimize a performance measure while respecting release times and deadlines; other environments permit modifications of release times, but not of the deadline times, in a controlled manner. This paper focus on additional issues related on precedence constrains and variable execution times that could be considered during scheduling. In this idea, the paper presents a way of possible integration of such issues into a tool used for modelling and simulation of real-time systems behaviour.