| 摘要 |
PURPOSE:To make it possible to control the position of a magnetic body and electromagnetic force, which acts on the magnetic body at a desired value, by controlling the intensity of a current, which is conducted through an electromagnet based on the position of the magnetic body that is detected by a position detector and the value of the desired electromagnetic force. CONSTITUTION:The position signal of a magnetic body 2, which is detected by a linear potentiometer 10, undergoes A/D conversion and the result is outputted. In a current-intensity determining means 8, the position signal of the magnetic body 2 is stored in a memory 14. The current intensity is determined by using relationships among the position of the magnetic body 2, the intensity of a current that is conducted through an electromagnet 1 and an electromagnetic force generated in the magnetic body 2, which are all measured beforehand, based on the preset desired value of the electromagnetic force. The determined current value is converted into an analog voltage value in a D/A converter 16. A PMS waveform is formed by using a comparator 18 based on the said voltage value and a triangular wave outputted from a triangular wave generating circuit 17. Thus a power transistor 19 is driven. The intensity of the current flowing through the electromagnet 1 is detected with a current detecting resistor 20. The signal is fed back through an operation amplifier 21. In this way, the position of the magnetic body 2 and the electromagnetic force acting on the magnetic body are controlled at the desired values.
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