SYSTEM FOR SUPPORT THE DESIGN AND OPTIMIZATION OF RECONFIGURABLE MANUFACTURING SYSTEMS

MM (Modern Machinery) Science Journal, March 2015

BRANISLAV MICIETA, VLADIMIRA BINASOVA, MICHAL HALUSKA

University of Zilina, Faculty of Mechanical Engineering, Department of Industrial Engineering,
Zilina, Slovak Republic

e-mail: vladimira.binasova@fstroj.uniza.sk

Abstract  

This paper is an experimental study of the system for support the design and optimization of reconfigurable manufacturing systems (RMS), which contains from the basic components of the proposed solution. Individual parts communicate with each other and exchange information which is necessary for implement required tasks. In addition, this paper also investigates the reconfigurable manufacturing systems, that are designed so that they may allow rapid adaptation of own capacities (market changes, product changes and to unexpected system turbulences). The aim of reconfigurable manufacturing systems is to improve production system response and thereby to provide an alternative to low-cost and high-quality production.

Keywords: reconfigurable manufacturing systems, cladistics, manufacturing configurations, engineering design of production machines
 
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The following papers were presented at 16th International Conference on Mechatronics – Mechatronika 2014, Brno, Czech Republic

ACTIVE VIBRATION CONTROL FOR A FREE PISTON STIRLING ENGINE GENERATOR USING A VOICE COIL ACTUATOR

MM (Modern Machinery) Science Journal, March 2015

ALI HASSAN, ANGEL TORRES-PEREZ, STEFAN KACZMARCZYK, PHIL PICTON

The University of Northampton, Northampton, United Kingdom

e-mail: Ali.hassan@northampton.ac.uk

Abstract  

This work presents the study of active vibration control for a FPSE/LA engine to ensure a reliable engine operation within a broader range of operation frequencies [50 ± 3 Hz] complying with new regulations. An ATMD is discussed as a potential solution for increasing the operational envelope from original frequency requirements of [50 ± 0.5 Hz] to the new range while maintaining vibration amplitudes below 20 μm. A suitable vibration model of the engine setup is discussed and experimentally validated. The active vibration control for the vibration model is achieved by integrating the model of a current controlled Voice coil Motor (VCM). Zero-placement with relative acceleration/position and optimal linear quadratic control with a state observer were studied and compared in the time and frequency domains. The analysis shows that the active control accomplishes damping of vibration even at higher frequencies that coincide with the resonance of the entire system. A set of specifications were obtained based on actuator parameters such as power consumption, actuator strokes and force. The effect of time delays
on the stability with each control strategy was investigated based on the proposed vibration model. Delays were found to affect stability depending on both the control methodology and excitation frequency.

Keywords: β-type stirling engine, active vibration damping, linear quadratic control, feedback-feedforward with zero-placement, voice coil actuator, electrical current control, effect of time delays
 
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ROTOR DESIGN AND OPTIMIZATION OF SYNCHRONOUS RELUCTANCE MACHINE

MM (Modern Machinery) Science Journal, March 2015

JAN BARTA, CESTMIR ONDRUSEK

Brno University of Technology, Faculty of Electrical Engineering and Communication, Department of Power Electrical and Electronic Engineering, Brno, Czech Republic

e-mail: xbarta27@stud.feec.vutbr.cz

Abstract  

The world has a bottomless appetite for electricity. Much of this electricity is used to power electric motors. Thanks to that electric motors represent a huge potential for energy savings. Synchronous reluctance machines are promising electric machines for energy savings. Key to success of synchronous reluctance machines is laying in elimination of rotor losses. This article deals with the design of synchronous reluctance machine of the transverse-laminated type. Rotor design has been made for two different rotor geometries based on general design recommendations. These geometries are studied and compared by using 2D finite element analysis. The geometries are developed by optimization algorithms after that. Optimized design is used for fabrication of synchronous reluctance machine. On fabricated synchronous reluctance machine several measurement and analysis of performance has been made. Finally fabricated synchronous reluctance machine is compared with induction machine with the same frame size.

Keywords: synchronous reluctance machine, transverse-laminate rotor, electromagnetic model, finete element analysis, optimization, torque ripple
 
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TRANSIENT THERMAL ANALYSIS OF SMALL SQUIRREL CAGE MOTOR THROUGH COUPLED FEA

MM (Modern Machinery) Science Journal, March 2015

ROMAN PECHANEK1, VLADIMIR KINDL1, BOHUMIL SKALA2

1Faculty of Electrical Engineering, Regional Innovation Centre for Electrical Engineering, University of West Bohemia, Pilsen, Czech Republic
2Faculty of Electrical Engineering, University of West Bohemia, Pilsen, Czech Republic

e-mail: rpechane@rice.zcu.cz

Abstract  

The thermal analysis is necessary in design process of new electric motor. During motor design process is necessary to know temperatures of induction motor’s (IM’s) construction parts. The calculated temperatures in all motor parts should be lower than critical temperatures. This paper deals with free-dimensional (3D) transient thermal analysis of small squirrel cage motor/induction motor. The design of new IM is based on dimensions of permanent magnet synchronous motor (PMSM). In the initial stage of motor's design the coupled finite element analysis (FEA) method gives enough valuable results of the IM's temperature rise. Coupled thermal analysis is made through computational fluid dynamics (CFD) and finite element method (FEM). The CFD model of IM is used for calculate boundary condition such as heat transfer coefficient. Results of CFD model are implemented in to transient thermal analysis as boundary condition.

Keywords: induction motors, machine modelling, thermal analysis, simulation, computational fluid dynamics, finite element analysis
 
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ESTIMATION OF BACK EMF FOR PMSM AT LOW SPEED RANGE

MM (Modern Machinery) Science Journal, March 2015

KONRAD URBANSKI

Poznan University of Technology, Institute of Control and Information Engineering, Poznan, Poland

e-mail: konrad.urbanski@put.poznan.pl

Abstract  

In the paper is presented a comparison of three method of back electromotive force estimation. Presented structures: the observers and the simulator, are utilized to estimate the back electromotive force for speed range below single revolution per second. Theirs instantaneous values are used then to calculate the shaft position of the permanent magnets synchronous motor. Performance of such structures is very important in a case of position estimation at the low speed range. These
methods are based on the following structures for back electromotive force estimation: observer for model of the electrical part of the motor, the observer with modified correction function, and estimation based on the simplified model. Obtained in this way the instantaneous values of the back electromotive force, depending on the method of obtaining them, are characterized by different quality and accuracy of the estimated shaft position. Estimated and measured values are compared and discussed.

Keywords: sensorless control,permanent magnet synchronous motor (PMSM), observer, variable speed drive, vector control, back electromotive force (back EMF)
 
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MODEL-BASED SYSTEM ASSESSMENT OF THERMOELECTRIC ENERGY HARVESTING FROM THE EXHAUST GAS PIPE OF OIL-FIRED HEATINGS

MM (Modern Machinery) Science Journal, March 2015

MARCO NESARAJAH, FELIX FELGNER, AND GEORG FREY

Saarland University, Dept. of Mechatronics Engineering, Chair of Automation and Energy Systems, Saarbrücken, Germany

e-mail: Marco.Nesarajah@aut.uni-saarland.de

Abstract  

We present a methodology to assess the design of ther-moelectric Energy Harvesting Systems (EHS) from exhaust gas pipes. In this application, thermoelectric generators (TEGs) are used to generate electricity using a temperature difference, based on the Seebeck Effect. The hot side temperature is given bythe waste heat in theexhaust gasof an oil-fired heating system and, at the cold TEG side, two different cooling options are considered, forced air and liquid cooling. The assessment is based on a comprehensive modular model, which includes, besides a detailed TEG model, the heat transfer conditions as well as an adaptive control strategy.The model, build up in the modeling and simulation environment Modelica®/Dymola®, serves to design such an EHS in an optimal way, meaning that a reasonable number of TEGs for the system and a suitable cooling method are chosen.Moreover, for each cooling method, an individual control strategy is defined to maximize the power output of the EHS.

Keywords: thermoelectric generator,oil-fired heating, energy harvesting, system assessment, Modelica®
 
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MODIFIED HAMILTONIAN ALGORITHM FOR OPTIMAL LANE CHANGE WITH APPLICATION TO COLLISION AVOIDANCE

MM (Modern Machinery) Science Journal, March 2015

YANGYAN GAO1, MATHIAS LIDBERG2, TIMOTHY GORDON1

1University of Lincoln, Brayford Pool, Lincoln, United Kingdom
2Chalmers University of Technology, Gothenburg, Sweden

e-mail: yagao@lincoln.ac.uk, mathias.lidberg@chalmers.se, tgordon@lincoln.ac.uk

Abstract  

This paper deals with collision avoidance for road vehicles when operating at the limits of available friction. For collision avoidance, a typical control approach is to: (a) define a reference geometric path that avoids collision; (b) apply low-level control to perform path following. However, there are a number of limitations in this approach, which are addressed in the current paper. First, it is typically unknown whether a pre-defined reference path is feasible or over-conservative. Secondly, the control scheme is not well suited to avoiding a moving object, e.g. another vehicle. Further: incorrect choice of reference path may degrade performance, fast adaptation to friction change is not easy to implement and the associated low-level control allocation may be computationally intensive.In this paper we use the general nonlinear optimal control formulation, include some simplifying assumptions and base optimal control on the minimization of an underlying Hamiltonian function. A particle model is used to define an initial reference in the form of a desired global mass-center acceleration vector. Beyond that, yaw moment is taken into account for the purpose of enhancing the stability of the vehicle. The Hamiltonian function is adapted as a linear function of tyre forces and can be minimized
locally for individual wheels; this significantly reduces computational workload compared to the conventional approach of forcemoment allocation. Several combinations of actuators are studied to show the general applicability of the control algorithm based on a linear Hamiltonian function. The method has the potential to be used in future vehicle control systems across a wide range of safety applications and hence improve overall vehicle agility and improve safety.

Keywords: collision avoidance, vehicle control, active safety, vehicle dynamics, intelligent vehicle, optimal control
 
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EXPERIMENTAL INVESTIGATION ON THE EFFECT OF INJECTING WATER TO THE AIR TO FUEL MIXTURE IN A SPARK IGNITION ENGINE

MM (Modern Machinery) Science Journal, March 2015

DANIEL BUSUTTIL, MARIO FARRUGIA

University of Malta, Msida, Malta

e-mail: mario.a.farrugia@um.edu.mt

Abstract  

Water injection is a means of internal cooling of the engine. During combustion, excess temperatures generated are absorbed by water as latent heat. Optimum water injection quantities were found to be about 0.015 ml to 0.031 ml of water per cycle on a 592 cc SI engine. The experiments were carried out by tapping the fuel injector signal and designing a circuit to inject water at the instant petrol is injected. Fuel injection duration was tuned by using a Wide Band Lambda sensor. The engine was supercharged as well by means of compressed air supply and regulated by hysteresis control. Water injection was investigated while varying spark advance to find the Maximum Brake Torque (MBT). Maximum obtained torque improvement with water injection was 16 %. This was achieved at a manifold absolute pressure of 120 kPa, with air temperature at ambient. The same load condition, 120 kPa, with air heated to the temperature that would be obtained from isentropic compression, resulted in a torque improvement of 7 %.

Keywords: thermal engineering, ignition internal combustion engines, mechatronics, automotive applications, water injection
 
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The following papers will be presented at 9th International Conference for Young Researchers and PhD Students ERIN 2015,
Moninec, Czech Republic

EVALUATION OF HARDNESS CURVES OF MULTILAYER WELDS OF CREEP RESISTANT STEEL 1.6946 USING SAW METHOD TO THE “ULTRA” NARROW GAP

MM (Modern Machinery) Science Journal, March 2015

LUKAS HOLUB1, JIRI DUNOVSKY2, JAN SUCHANEK1

1CTU in Prague, Faculty of Mechanical Engineering, Department of Manufacturing Technology, Prague, Czech Republic
2CTU in Prague, Faculty of Transportation Sciences, Department of Vehicle Technology, Prague, Czech Republic

e-mail: holub@ll-c.cz

Abstract  

The paper deals with partial verification of mechanical properties (through waveform measurements hardness HV10) obtained after SAW multi-pass welding in "ultra" narrow gap. Simulated homogenous welds of high pressure (HP) turbine rotors (30CrMoNiV5-11) formed with various types of filler materials (TOPCORE 838 B Thermanit MTS 616) using the same temperature cycle and subsequent heat treatment were tested. The detailed evaluation of hardness measurements HV10 was performed on the prepared metallographic test specimens. The test specimen made by Thermanit MTS 616 shows higer hardness values then the specimen made by TOPCORE 838 B.

Keywords: submerge arc welding, narrow gap, low alloysteel, hardness HV10, turbine, ro
 
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RESISTANCE SPOT WELDING OF MAGNESIUM ALLOY AZ61

MM (Modern Machinery) Science Journal, March 2015

T. KRAMAR1, P. VONDROUS1, M. KOLARIKOVA1, K. KOVANDA1, L. KOLARIK1, M. ONDRUSKA2

1Czech Technical University in Prague, Faculty of Mechanical Engineering in Prague, Prague, Czech Republic
2Slovak University of Technology in Bratislava, Faculty of Materials Science & Technology in Trnava, Trnava, Slovak Republic

e-mail: tomas.kramar@fs.cvut.cz

Abstract  

Resistance spot welding (RSW) was used to weld Mg alloy AZ61A. To research weldability of this alloy many welding parameters, e.g. current, time, pressure, have been tried in wide range on the welding source DALEX PMS 11 – 4. Visual check was followed with metallography, tensile test etc. Some defects as solidification, liquation cracks, porosity were found. The creation of imperfections was found to be dependent on parameters, so finally optimized parameters were found. The best influence on weld integrity, i.e. weld w/o cracks, was to set cooling time directly after welding. For sheet metal of 1 mm optimum welding parameters were 8 kA, 100 ms, 9 kN and long cooling time. Another problem found, was limited lifetime of Cu electrodes, when in contact with Mg melt. This contamination damagedsurface quality of electrodes, further influencing weld quality. High enough electrode pressure can diminish this problem.

Keywords: resistance spot welding, RSW,  Mg alloy, AZ61, solidification cracking
 
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