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Magnetic Suspension (Amira MA400)
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Brief Description:
Laboratory experiment MA400 Magnetic Suspension
The laboratory setup "MA 400 Magnetic Suspension" embodies the technical implementation of a nonlinear, unstable, single-variable system. It consists of a metal body which hovers freely, an electro-magnet as the actuator and a comprehensive electronic control system.
The nonlinear, unstable controlled member is a freely hovering metal body which is held at the highest point by an electromagnet. The position of the metal body, corresponding to the distance between the body and the magnet, is measured by an inductive distance sensor (LVDT = Linear Variable Differential Transformer) and is passed to the controller as the actual value. The controller passes the actuating signal to the control member which then provides the required change of position. The position setpoint can be varied in the range 0-5mm.
In the standard version the MA401 Laboratory Setup is supplied with a special analog controller. The controller is integrated as an operational amplifier circuit together with the necessary electronics in a 19" housing. Basic control principles can be demonstrated with the standard version. It can be shown that the unstable system can be stabilized by the application of a suitable controller. Furthermore, the effect of the control parameters on the behaviour of the system (disturbance/setpoint step response) can be impressively displayed.
System variables such as the position, external control signal, current (monitored) and analog setpoint are directly accessible at the measurement outputs. In addition by means of a switch the control signal is connectable to an arbitrary external controller like an analog controller or a PC with an A/D-D/A converter-card. The documentation includes sections for assembly and start-up, the theoretical background and the description of the system with the mathematical model of the plant as well as the technical data. The MA401 Laboratory Setup is therefore suitable for teaching and demonstration purposes in all fields of control engineering.
A PC version is available with the option 401-02 alternative to the built-in analog controller. It contains an A/D-D/A converter-card as well as an executable controller program for an IBM-AT compatible PC with ISA slot and the operating system MS-DOS. The controller program provides three different controller versions, a PIDT controller, a fuzzy controller operating with a lookup table as well as a fuzzy controller operating with a knowledge base created using a fuzzy description file. Pull down menus which are activated by a mouse and/or by keyboard (Turbo-Vision desktop of Borland) are used for a comfortable adjustment of controller parameters, the description file, setpoints, measurement acquisition as well as plant identification. The graphic output of recorded data to the screen, to an HP-compatible plotter with a serial interface, to an Epson-compatible printer or to a file using HPGL-format provides the evaluation of the results. In addition the program allows to store the adjusted or measured plant and controller parameters to an ASCII file. Those data can be loaded later on. The included practical course is carried out with analog/digital PID controllers. The influence of the controller parameters on the behavior of the closed control loop is evaluated. The examination of stability is based on the root locus method and on the bode diagram. The documentation is expanded by the sections background of the fuzzy controller and the PIDT controller, the operating instructions for the controller program as well as the guidelines for the practical course with solutions.
The option 401-03 consists of the C++- source code with documentation of the program mentioned under option 401-02 including libraries for the graphic output and the fuzzy operations. Therefore extra software for special control algorithms can be developed by the user. The Borland C++ compiler with the Turbo-Vision library is required to generate an executable program.
Manual of MA400.pdf.
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