| 摘要 |
<p>982,831. Automatic control. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. May 1, 1961 [April 26, 1960], No. 14636/60. Heading G3R. A hydraulic control system controlling a movable member in response to electrical signals comprises distributing valve 4 which admits a hydraulic fluid from a pump 3 through a pipe D to a ram 1 or exhausts it to a reservoir 2, the valve being operated by a Haust motor comprising a permanent magnet 7 arranged coaxially with the valve spool 8 which has a moving coil 9 attached to it. A device 11 generates feedback signals dependent on the amplitude and phase of displacement of the spool from its mean position. A positional error signal, from the member is applied to an input terminal 20 of a D.C. preamplifier 22 which unbalances a bridge network comprising transistors T1-T4 and power packs, 24, 25 thus supplying a restoring element to coil 9. Feedback signals from the device 11 are applied through an A.C. amplifier 26 and demodulator 27 to a resistor 28 in opposition to the input signal which appears across a resistor 21. An automanual valve 6 blocks the part from pipe D when in the manual position a manual valve 5 then controlling the position of the ram 1. The spool 8 passes through a non resilient diaphragm 10 which offers no restoring force in either direction. The arrangement may be employed to control an arc electrode in response to current and voltage. Specification 982,832 is referred to.</p> |
