Miroslav Rimár

Control of Activity of Aircraft Engines by Analysis of Wear Debris Particles in Terms of Shape and Size

The contribution deals with use of semi-automated method of magnetic separation of particles in order to control mechanical system of aircraft engines. There are three levels of machine wear characterized by means of wear debris particle analysis in the lubrication system of aircraft engines. The shape and size of wear debris particles formed due to machine wear arise immediately in case of wear change thus this method is extremely suitable to control mechanical system washed by lubricant. Analysis of actual samples of lubricating oils containing several types of wear debris at the same time resulted in finding out and characterizing the levels of wear, from standard up to critical one. The contribution describes typical types of aircraft engine lubrication system wear with allocation of the wear level to particular pictures of wear debris particles.

Monitoring of Vibrations in the Technology of AWJ

Vibrations of cutting head act as co-factor causing striation of machined work-piece surface, deteriorating its surface quality. In this paper, measurement and evaluation of vibrations generated during the AWJ machining is performed using specialized diagnostic systems. In conclusion, means to minimize influence of cutting-head vibrations on the machined work-piece surface quality are discussed.

DEPENDENCE OF HARDNESS OF CONTINUES DIE-CASTING PRODUCTS ON FE CONTENT

Nowadays die-casting is one of the best of metal casting system. Die-casting comparing with the other casting methods is cost preferably, the savings may be 20% of the metal needed for the casting and cost savings of foundry production can be around 30%. In this work we have measure hardness of Al-Si alloy respect to its Fe content. In our experiments we have used digital microhardness tester CV 400D respect to the Vickers hardness test. Samples were processed in dentacryl. We have made a conclusion that content of the Fe in the alloy have some influence on the product’s hardness. Even insignificant difference in chemical composition of the casting products will lead to different hardness characteristics of the products.

Technical and Software Equipment for the Real Time Positioning Control System in Mechatronic Systems with Pneumatic Artificial Muscles

This paper explains the design of real-time control system for control of drives containing the artificial muscles. Described is the design of devices hardware and software, as well as design of their involvement in the experimental device. In this paper are referred experimental measurements on the device, aimed at monitoring the change in observed characteristics caused by position changes in artificial muscles during their operation.

The Synergistic Effect of Thermal Collectors Rotation in relation to Their Energy Efficiency and Stagnation Compared with the Static Thermal System in the Conditions of Central Europe

The presented paper deals with the issue of the efficient use of solar energy potential gained from thermal panels via tracking the Sun’s trajectory. Based on long-term measurements of the selected parameters, the efficiency of the installed system in relation to the ecliptic was evaluated in the static regime as well as in a rotary regime. In the comparison of rotary and fixed system of the collectors the presented results show an increase of the effectiveness of rotary one during the period of the day. On closer view the increase is not constant. During the day it varies: the most significant increase is in the afternoon, while the time from 10:30 a.m. to 1:00 p.m. the effectiveness of both systems almost identical. The utilisation of the rotary system as a suitable instrument for the elimination of the system stagnation was also evaluated.

Adaptive Rejection Filter for the Drives Stabilization of Pressure Die Casting Machines

The presented paper deals with the design of a mathematical model of a rejection filter for the drives stabilization applied to pressure die casting processes. The rejection filter allows the stabilization of electrohydraulic servo drives making use of periodically repeated zero transfer functions while taking advantage of the essence of a parallel joint of the proportional unit and a time delay unit. Consequently, the model of the adaptive rejection filter algorithm with a higher form of electrohydraulic servo drives has been mathematically elaborated. The paper comprises the algorithm description for the models implementation in the process of a servo drive control, which to a sufficiently greater extent can respond to the changes in technological parameters of pressure die casting than a conventional drive system. The introduction of a position feedback or a high-speed feedback allows the elimination of excessive porosity formation. By Introducing additional feedbacks, it is possible to affect the speed of a piston movement in the range of a low pressing speed depending on other technological parameters, for example, a melt temperature in the chamber.

Woodchip Combustion Process Quality and the Amount of Combustion Air

The paper deals with woodchip combustion from the point of view of burning control. Control system has to ensure optimal ratio of fuel and air. There are a lot of conditions to satisfy optimization of woodchip burning. The contribution of the paper is concentrated on confirmation of fact that primary/secondary air relation can significantly reduce the among of unburned carbon monoxide.

Equation Model of Stabilization of Low Damped Astatic Systems

The paper deals with the stabilization of low damped astatic systems. They show a low value of a relative damping and consequently a high resonance rise of amplitude frequency response. If astatism occurs in an automatic control system, the situation becomes complicated due to the exhaustion of a phase safety of astatic element. In order to achieve the stabilization, a filter with rejections has been designed. The filter is characterized by rapid rejections of logarithmic frequency characteristics that eliminate resonance rise of a low damped astatic system. A functional model of a discrete filter was created to attest the properties of the filter with a continuous low damped astatic system. Experiments have proved the suitability of the filter application. The method of the filter utilization, the stability of the low damped astatic system as well as the stability assessment by the operator W will be described in the paper.

Analysis of Incremental Measurement of the Arm Position with Actuator

The article contains information about the function and basic properties of the actuator based on pneumatic artificial muscles. The article presents the measurement results of the response of the actuator arm displacement depending on the input pulse. This dependence enables artificial muscles to be better adjusted to the needs of a practical operation, especially in terms of lagging. The article also included calculations of velocity and acceleration of individual time intervals. For the possibility of simulation application, a mathematical model of the approximation curve of the response development is presented.

Simulation Study of Two Alternative Workstations for Pressure Die-Casting Process

The paper introduces two ad-hoc experimental models that emulate the real semi-automated and fully automated workstations of the die-casting production company. The simulation study aims to analyze behavior over time of both models. The intention of the paper is to show that the simulation can be used as a tool to support a decision-making process. It also presents effective approach how to forecast the real system performance.