Řada strojní. 2008, roč. 54 / Mechanical Series. 2008, vol. 54

Permanent URI for this collectionhttp://hdl.handle.net/10084/111973

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Now showing 1 - 20 out of 65 results

Usage of process management in the company producing ecological tires with the support of ICT
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Wolf, Jan; Besedová, Hana
High level of competition – so-called hypercompetition – is an issue of increasing importance nowadays. Companies who want to be successful in the global market are forced to use modern methods to be ahead of their competitors. We are concerned with such tools and methods that can simplify apparently complicated matters. Since we find ourselves in a changing and global market environment, only a company who is able to respond to changes very quickly can be successful. The implementing of process management is one of efficient methods. Information and communication technologies can significantly help implement process management. The author of this article describes the usage of process management as an important competitive advantage. The main goal is to design an information system to be used to increase profit and make employees work more efficiently. First of all, main and supporting processes will be identified, based on which the information system will be designed. The system will be created with the aid of MS Access. Thanks to clearly defined individual processes and ICT support, the company will raise its profit.
Sliding mode control and its modification
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Wagnerová, Renata
The paper describes design of sliding mode control. The advantage of this control algorithm is a high robustness, simplicity, and the fact that it does not need knowledge of a mathematical model, only the control system’s order and the ability to measure control disturbances. The disadvantage is a high control activity, which is not useful for all types of control elements. Further there is description of the primary approach to sliding control design, which consists in the extension of nonlinear sliding control of an integration element. For the stabilization task this algorithm will significantly lower the activity of a control variable while maintaining its robustness. In case of following the state trajectory the activity of a control variable will also lower, if the change in the required trajectory is not to fast.
Stability of rigid rotor in journal bearing
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Víteček, Antonín; Tůma, Jiří; Vítečková, Miluše
The article is devoted to active increasing of a stability of a rigid rotor housed in a journal bearing on the supposition that the linear and nonlinear mathematical model is considered.
Suitability of adaptable state feedback for keeping prescribed control quality under changing operation conditions
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Šulc, Bohumil; Lepold, Martin
A state variable feedback technique is usually used when controlled system dynamics is to be changed in a desired way. The results are very good provided that the linear state space representation used in the design is sufficiently valid in the whole operating range. In the paper, we present a case study of a tank cascade with changeable static and dynamic properties. When these changes are so significant that superior PI or PID controllers require resetting, it is advantageous to adapt the proportional state variable feedback. We assessed the impact of the feedback gain changes resulting from changes in the linear state model parameters used in the design of the gains.
Weights initialization methods for MLP neural networks
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Škutová, Jolana
This paper describes the weights initialization methods for two-layer feedforward neural networks. The choice of method influences of a convergence and a minimal final value of cost function for a neural network training process. The neural networks application in different domain to be expected, that their users will be acquired the applicable neural network models. Hence it is important prune away all kinds of an uncertainties while the choice of neural network structure, the learning algorithm in context of other adjustable parameters as well as preparing of suitable learning and testing data set for the neural network learning.
Force and acceleration measurement on mobil parts of car
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Smutný, Lubomír; Tůma, Jiří
The contribution deals with task of combined force and vibration measurement on the difficult mobile objects as the car doors. There are described the examples of instrumentation for these measurement (force hammer, piezoelectric accelerometers, laser sensor of speed displacement). There was used measurement instrumentation set B&K with program support LabPulse. The paper shows testing results of the back car door lock close forces as an example of combined forcevibration task.
Quality assurance approaches in the higher education
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Smutná, Jitka; Farana, Radim
Contribution monitors the situation in the field of quality management improvement in the higher education institutions represented by VSB-Technical University Ostrava, Czech Republic (VSB-TUO) and Queen Mary, University of London, United Kingdom (QMUL). Obtained data are processed and evaluate to identify different quality assurance approaches and structures leading to same aims, thus to create functional quality management system.
Microcontroller based control system for an MR damper in a driver's seat
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Sapiński, Bogdan
This aim of the paper is to present the development of a control system for an MR damper in a driver’s seat which is based on a microcontroller with a fuzzy set processing unit. The paper presents: model of a driver’s seat, control objective, applied control algorithm, development of the control system and experiments.
Laser cutting machine and optimisation of input parameters for fruition required quality of products
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Rovňáková, Sylvia; Líška, Ondrej
The paper depicts the process of cutting sheet metals by the laser machine TRUMATIC L 4030 and indicates the possibilities of machine control based on the roughness measurement. It points out the importance of correct adjustment the input parameters of the laser machine at cutting sheet metals from unalloyed structural steel. The quality of cutting edge depends mainly on its input parameters (the speed of cutting jet, the distance of the jet from the material, power of laser and its pulse frequency or gas pressure). The control system generates suitable parameters by means of technological tables. With respect to various influences (outer, inner, material, technological...) which intervene into the production process, the output quality of the cutting edge cannot be guaranteed. It is possible to raise the quality of production by measurement of the roughness parameters, their estimation, comparison to required values and next intervention - optimisation of input parameters of the machine.
Robust decentralized PID controller : a case study
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Rosinová, Danica
Robust stability is an important aspect in control of real world systems, since uncertainties have to be considered in dynamic system model. This paper studies the robust decentralized controller design for case study: quadruple tank process, [3,4]. Several important aspects of system analysis are shown to choose appropriate pairing and assess stabilizability via decentralized control structure; the main contribution is in decentralized discrete-time controller design. Simulation results illustrate the obtained results and their qualities.
Flow problem in thermal motor analysis
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Poruba, Zdeněk; Szweda, Jan
The paper presents the relations used for CFD simulation of the flow around the body. The procedures for creation of practically usable computer model of bigger mechanical parts and application of its boundary conditions are described, obtained results are presented. The aim of the work was the analysis of temperature field and cooling parameters of current motor geometry with expectation of further optimization to achieve better cooling power and to reduce the mass of the motor.
Relay test for anisochonic models - time domain solution
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Pekař, Libor
Anisochronic models are characteristic for containing state delays. These models have some practical and attractive features; e.g. they enable to fit the dynamics of systems with very high order. This contribution utilizes an idea of anisochronic models identification based on limit cycle information obtained from relay feedback test is investigated. Unlike conventional approaches connected with the frequency analysis of a plant transfer function, the proposed alternative methodology is based on computation with functional differential equation only, i.e. in time domain. Plant parameters to be identified are obtained analytically. In addition, parameter estimation is also improved using autotune variable (ATV+) technique which required an additional delay element. An illustrative example where parameters of a tenth order system are approximated by a first order anisochronic model is presented.
Digitizing of tracking control on a modelling yard
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Pavlas, Roman
The aim of this contribution is focused on digitizing of modelling yard. In introduction is out of print actual state of yard and technology used on that. In next parts is effected analysis accessible technology for digitizing modelling yard and election ones of them. Digital control caused that the locomotives are able to act on a section of the yard independently. This paper was created with support of grants project Nō F1a 2148 - FR VS and Specifical research.
Anisochronous model of the metalurgical RH process
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Morávka, Jan; Michalek, Karel
RH process is a metallurgical process, which serves for vacuum treatment of liquid steel by recirculation method, which enhances quality of steel that was made either in basic oxygen converter (BOF) or in electric arc furnace (EAF). The paper presents a project and verification of appropriate physically adequate cybernetic anisochronous model of this process. This model was obtained on the basis of measured and transformed data of dimensionless concentration of model liquid in the physical model of a pouring ladle with the RH chamber, constructed in the same length (geometric) scale 1:9 to the original objects. Mathematical model will be used for optimisation of RH process under operational conditions.
Application of CAN bus with dSPACE simulator usage
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Mahdal, Miroslav; Klečka, Radim
In recent years we can see the increasing of electronic control systems in cars. The reason of this increasing is to ensure better safety, comfort, requirements of users and to bear up against the competitive pressure etc., last but not least the pressure of single governments on all the time reducing of consumption sources and the tendency to lower the emitting of emissions to the atmosphere too. These require to implement new systems to the car. The growing of control systems has the influence on quantity of interconnecting wires, which brings the problems (failure rate, unreliability of connection, disturbance, energy losses, etc.). The right coordination of individual control units have to be ensured e.g. the co-operation of engine, ABS/ASR and automatic gearbox. These systems come through different tests for the ensuring of correct functions. For these purposes the serial communication protocol (Controller Area Network - CAN) by BOSCH company was created. The protocol is designed especially for using in the cars. CAN is used for connection of different device types (drivers, sensors, actuators etc.) through the serial data bus. This protocol is used in different industrial applications too. The reason is above all the lower price, easy access point, reliability, high data rate and easy extensibility.
Ball bar test for machine tools
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Loebl, Tomáš; Onderová, Iveta
This paper deals with a problematic of machine tools and their precision. It is talking about Ball bar test of the machine tools. Paper deals with one measurement made in company Microstep on their machine tools. In this part are also presented results of the test and at the end is made conclusion from this result. In second part is describing measurement system from company Renishow for ball bar test. It is Measurement system QC10. It also describes the way of testing by this measuring system. In third part it describes different mistakes in kinematics and geometrics of machine tools. It also describe the way how the look at the graphical result of the test.
Nowadays industrial control systems
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Loebl, Tomáš; Kureková, Eva
This paper is dealing with nowadays possibilities of machine controlling and steering. In paper is talking about impact of design of control system itself on the process of creating of control software for the system. On the other hand is also talked about symbiosis of machine design and control system design. Paper compares different approach in machine controlling systems .It talks about advantages and disadvantages of different control system. In some cases it talks also about possible application of the system. The result of the paper is overview of nowadays controlling possibilities, their power and possible field of applications. At the end of the paper is described one real application of control system in PCB vertical line.
Design of discrete-time compensator for reference tracking with disturbance rejection
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Kozáková, Alena
The paper deals with the design of a discrete-time state space compensator to track a reference command when the plant is subject to a measurable disturbance signal. The approach called Command Generator Tracker [3] covers a broad class of reference and disturbance signals describable by linear differential equations with constant coefficients. The design technique is LQ based and its principle consists in augmenting the plant model so that the resulting compensator includes modes of both the reference and disturbance signals. In such a case, proper reference tracking and disturbance rejection are guaranteed. Standard LQ problem solution applied for the extended system yields both the feedback and the feedforward gains of the CGT compensator.
Investigation of transient states of the hydraulic power unit cooperating with the servovalve
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Korzeniowski, Roman; Pluta, Janusz
Authors present results of laboratory researches carried out on electrohydraulic servodrive which is working under intensive occurring of dynamic states of operation. Carried out laboratory researches aimed to characterise mutual interaction between a servo-drive and a hydraulic power supply. In the paper authors take note of pressure time diagrams in output port of the hydraulic power unit and input port of the servodrive both connected together with hydraulic hose. Authors are studding influence of working parameters settings of the hydraulic power supply into pressure course in the feeding line. We also investigated how real courses of measured pressures are different from the pressure value established for the relief valve.
Two valves control of hydraulic drive by way of inverted flow characteristic
(Vysoká škola báňská - Technická univerzita Ostrava, 2008) Koňařík, Petr
Paper deals with control of hydraulic drive by the help of inverted flow characteristics of hydraulic valves. One edge valves or two edges valves, theirs combinations and 3/3-way valves are able to control each chamber of cylinder separately as independent control action members. The case of two three-position three way valves can realize the same functions as a classical three position four-way valve to control hydraulic cylinder, but with an additional control degree of freedom, which could be in several cases profitable. Especially when user can use required criteria in form of required pressures ratio or flows ratio inside of cylinder chambers. In paper the control concept of inverted three-dimensional valves characteristic and inversed dynamic valve behaviour are described. Intended control concept allows transferring classical hydraulic circuit course and its unsymmetrical static characteristics of circuit realization with single piston rod of cylinder to a course of hydraulic circuit with double piston rod of cylinder.

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