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19th EMSS, 2007 |
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19th European Modeling and Simulation Symposium (Simulation in Industry) 4-6 October 2007 Bergeggi (Sv), Italy |
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Session CA-II: Industrial design and Modeling & Simulation I
A ROBUST MOTOR AND SERVO DRIVE MODEL FOR REAL-TIME MACHINE TOOL SIMULATION, Johan Fredin, Johan Wall, Anders Jönsson, Göran Broman
Modern machine tools are complex mechatronic systems. Recently “virtual machines”, incorporating models of relevant parts such as structural components, sensors, actuators and controls, have been proposed as design tools - to aid resource efficient experimentation for better understanding of the complete system and utilization of possible interaction effects. This paper focuses on actuator modelling, as part of the development of a virtual water jet cutting machine. The aim is to develop a robust model of the commonly used permanent magnet synchronous motors and their servo drives. Here, robust includes that the model should be: sufficiently accurate for different motor characteristics without extensive “tuning”, dependent only on commonly available data, and computationally efficient and numerically stable. A novel simple motor and servo drive model is presented and implemented in Simulink. Simulation results for various configurations agree well with corresponding experimental results obtained from a physical test setup. Furthermore, it is shown that the model is capable of producing sufficiently accurate results within the cycle time of the control system of the virtual machine (real-time capability) and it is concluded that numerical instability does not appear for any of the tested configurations even for integration time steps up to this cycle time. The suggested model makes it possible to readily implement any permanent magnet synchronous motor and servo drive in the virtual machine. This enables efficient system simulation to aid well informed design decisions regarding motor selection without expensive and resource consumino trial and error approaches with physical prototypes.
INCREASING PRODUCTIVITY IN CNC MACHINE TOOLS THROUGH ENHANCED SIMULATION SUPPORT – AN INTRODUCTORY STUDY, Johan Wall, Johan Fredin, Anders Jönsson, Göran Broman
One way to increase the productivity of numerically controlled machine tools is to optimise settings such as parameters in the NC-program or in the control system for each specific work piece. Finding optimal parameter settings through trial and error testing is in the general case impractical. The increased productivity potential of optimal parameter settings can however be realised through incorporation of computer simulations and numerical optimisation. The aim of this work is to show the potential of a “virtual machine” as a tool to increase productivity within manufacturing industries through optimisation of CNC machine tool parameter settings. Two test cases with different geometry and geometrical tolerances are manufactured “virtually”. It is show that the ability to adjust CNC machine tool parameter settings to a specific work piece may significantly increase manufacturing productivity. This improvement would most likely not have been possible without advanced simulation support within the same time, cost and general resource frame.
MODELLING AND SIMULATION OF ADVANCED POWER GENERATORS, Jesús Lozano, Amable López, Juan Carlos Sirviente, Antonio Benitez
The model of an electric generator working at variable speed is shown in this communication. This model has been developed starting from the limited information for the different components. After studying the concept of the generator, the critical points and the need of the simulation of the responses to transitory. Next step is the analysis of the real information available of the different elements of the system and the adopted solution for performing the whole model of the system. Finally, the initial results of the simulation of the system are shown.
MODELING OF THE TROPOSPHERIC WATER VAPOR (ON THE EXAMPLE OF TARTU), K.Rannat, P.Miidla, P.Uba
Numerical simulation is a known time- and money efficient way to study different types of processes. This paper tends to give a short report about the preliminary results of modeling a tomographic experiment supported by the real meteorological data in Tartu (Estonia) at a fixed geographical point (58°23'30" N, 26°41'41" E, with antenna height 75,80 m above the reference ellipsoid). Mathematical methods for detection, monitoring and modeling of the tropospheric water vapor are used. The goal of the experiment is to simulate the 3D distribution of tropospheric water according to the local geophysical conditions. The article describes a possibile mathematical approach to construct the virtual ground-based sensors (GPSreceivers) network for a real geographical location and discretization of the troposphere.
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