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RAČUNALNIŠKO PROGRAMIRANJE IN MODELIRANJE DELOVNEGA STROJA
Klemen Gajšek, 2010, bachelor thesis/paper

Abstract: Za diplomsko nalogo sem si izbral temo na področju računalniškega modeliranja in programiranja. Kot praktični primer sem uporabil delovni stroj-cepilec polen, ki služi za cepljenje polen in uporabniku omogoča lažje delo z manj fizičnega napora. V nalogi sem se opredelil predvsem na konstruiranje samega stroja in na posamezne komponente, kako jih izdelati ter preračune, ki jih zajema takšen delovni stroj. V diplomski nalogi bom natančneje prikazal in opisal, s katerimi računalniškimi programi sem si pomagal pri modeliranju celotnega stroja in NC programiranju določene komponente stroja. Naredil sem tudi simulacijo delovanja stroja ter simulacijo poti orodja.
Keywords: Computer Aided Design, Constuctive Solid Geometry (CSG), volumetrično modeliranje, NC (numerical control), programiranje numerično krmiljenih strojev.
Published: 11.10.2010; Views: 1481; Downloads: 202
.pdf Full text (2,96 MB)

4.
Electrohydraulic pressure control by a self-adjusting proportional derivative controller
Darko Lovrec, Friedrich Faber, 2006, original scientific article

Abstract: The main characteristic of an electrohydraulic pump control system is the presence of an electrical signal path. It requires at least one sensor for the controlled value (in this case pressure), delivering feedback to be compared with the electrical or numerical reference in the controller. The additonal expense penalty for the sensor and the valve is offset by the advantage of flexibility in the structure and parameters of the controller in comparison to hydraulic - mechanical concepts. Thus, the transfer response can be adapted to demands, even in the operational state. Sophisticated control structures can be implemented easily in the form of computer or microcontroller programs. The layout of electrohydraulic pressure control discussed in this study includes the presented loading unit. The variable pump is designed to act together with a proportional valve having two metering edges. It is less expensive compared to the design with a synchronizing cylinder and four metering edges. However, only inferior static and dynamic performance can be expected. Hydraulic energy is supplied to the control valve directly from the output port of the pump - with the advantage of simple assembly, as there are no additional components required - but with the drawback that there is influence on the control loop`s properties at every change in the disturbance value or reference. The aim of the study presented in this paper is a more efficient and simple concept compared to other known methods for pressure control of the above mentioned pump including the dynamics of the distribution network, and also the characteristics of the hydraulic load with special focus on improvements in steady state and dynamic behaviour.
Keywords: automatic control engineering, electrohydraulic systems, pressure control, self-adjusting proportional controller
Published: 31.05.2012; Views: 1020; Downloads: 24
URL Link to full text

5.
Remote lab experiment RC oscillator for learning of control
Suzana Uran, Darko Hercog, Karel Jezernik, 2006, original scientific article

Abstract: In the paper a remote lab experiment RC oscillator used to support Web based learning, to support learning by doing, to learn control design and to minimize the gap between theory and practice is presented. The experiment was designed with a special care for visualisation of important control design parameters in Bode plot and Root-Locus diagram. The experiment is based on MATLAB, LABview and DSP2 learning module. Using RC oscillator experiment RC circuit step response based or sinusoidal response based analysis, P controller design using Bode plot or Root-locus, relations between control design parameters and control performance and discrepancy between theory and practice could be covered. A homework based on RC oscillator experiment is presented and obtained experiences are discussed.
Keywords: control learning, RC oscillator, remote lab
Published: 31.05.2012; Views: 1064; Downloads: 28
.pdf Full text (2,40 MB)
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6.
Adaptive self-learning controller design for feedrate maximization of machining process
Franc Čuš, Uroš Župerl, 2007, original scientific article

Abstract: An adaptive control system is built which controlling the cutting force and maintaining constant roughness of the surface being milled by digital adaptation of cutting parameters. The paper discusses the use of combining the methods of neural networks, fuzzy logic and PSO evolutionary strategy (Particle Swarm Optimization) in modeling and adaptively controlling the process of end milling. An overall approach of hybrid modeling of cutting process (ANfis-system), used for working out the CNC milling simulator has been prepared. The basic control design is based on the control scheme (UNKS) consisting of two neural identificators of the process dynamics and primary regulator. Experiments have confirmed efficiency of the adaptive control system, which is reflected in improved surface quality and decreased tool wear.
Keywords: end milling, adaptive force control, artificial intelligence, optimisation, adaptive control systems
Published: 31.05.2012; Views: 870; Downloads: 17
URL Link to full text

7.
Pressure control in hydraulic systems with variable or constant pumps?
Darko Lovrec, Samo Ulaga, 2007, original scientific article

Abstract: The paper deals with electrohydraulic supply systems with variable (adjustable( supply pressures. Two control concepts are used in practice: the pressure control concept using a variable pump and constant speed of the driving electric motor as the commonly used concept, and the pressure control concept with a constant pump and a speed-controlled electric motor as the alternative concept. The typical features and the applicability of both conceps, as well as their dynamic responses are studied in this work.
Keywords: automatic control engineering, hydraulic systems, pressure control, constant pumps
Published: 31.05.2012; Views: 994; Downloads: 0

8.
Fuzzy logic based quality monitoring in short-circuit gas metal arc welding
Marjan Golob, Arpad Köveš, 2007, original scientific article

Abstract: Conventional methods, e.g. destructive and non-destructive testing methods, are expensive and time-consuming; therefore, possibilities of online and automated quality control of a welding process during welding as such are investigated. The paper deals with the possibilities of application of fuzzy logic to the analysis of weld quality, particularly assessment of the weld surface condition by means of measurable electric signals emitted during welding. A simple fuzzy inference system was realised which could relatively efficiently assess the weld quality on the basis of time variations of the welding voltage and short-circuit time in a certain time window.
Keywords: fuzzy systems, fuzzy logic, gas metal arc welding, GMAW, quality monitoring, statistical analysis, quality control, weld quality
Published: 31.05.2012; Views: 940; Downloads: 43
URL Link to full text

9.
Software and equipment for remote testing of sensors
Barbara Brezovec, Vojko Matko, 2007, original scientific article

Abstract: An improved approach for remote testing of elements and systems is presented in this article. To ensure high reliability of products, tests must be done in the production phase to detect possible errors in working mode. Because environmental testing involves long-term processes the possibility of remote observation and remote controlling of tests is very useful solution. The concept is to connect the testing chamber with a personal computer, create a reliable driver and control it remotely over the local network or Internet from other client. It is designed for performing tests on wide area of sensors and sensor based systems.
Keywords: sensors reliability, testing methods, remote control, virtual instruments
Published: 31.05.2012; Views: 1039; Downloads: 104
.pdf Full text (243,72 KB)
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10.
SMC with disturbance observer for a linear belt drive
Aleš Hace, Karel Jezernik, Asif Šabanović, 2007, original scientific article

Abstract: Accurate position tracking control of a linear belt-driven servomechanism can cause vibrations in the drive response due to compliance and elasticity introduced by force transmission through the belt. This paper proposes a new control algorithm that has been designed by Sliding Mode Control theory. Though it has been proved to assure robust and vibration-free operation, position error peaks still appear at velocity reversals due to nonlinear friction phenomenon. Thus, the control scheme has been extended by asymptotic disturbance observer. The experiments presented in the paper show improved position tracking error response while maintaining vibration suppression.
Keywords: motion control, disturbance observer, sliding mode control, timing-belt drive, vibration suppression
Published: 31.05.2012; Views: 1080; Downloads: 45
URL Link to full text

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