| 摘要 |
PROBLEM TO BE SOLVED: To make a positioning device able to give a proper quantization error even when the maximum current value in movable ranges is changed in a positioning device for positioning a driving part whose torque constant is fluctuated by its position. SOLUTION: This device has a position detector 7 for detecting the present position of an object, a control circuit 10 generating a drive commanding value in accordance with the positional error between a command position and the present position, a D/A converter 11 for converting the drive commanding value into an analog voltage, and a voltage and current converting amplifier 12 which has plural gains and which converts an analog voltage into an analog current. Then, the circuit 10 changes over the gain of the amplifier 12 in according with the present position. When the gain the amplifier is made variable and controlled in accordance with the position, it is unnecessary to cover the maximum current range by a commanding value. Thus, a proper quantization error can be obtained and also the maximum current value needed for the position can be obtained in entire mobable range.
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