GB1113993A - Improvements relating to force-feedback servo mechanisms - Google Patents

Abstract

1,113,993. A-D Converters. SPERRY RAND Ltd. 21 Oct., 1965 [1 Oct., 1964; 21 Oct., 1964], Nos. 40085/64 and 42912/64. Heading G4H. An applied input force causes deflection of a beam, this being detected at 18, 31 to produce an analogue signal which in turn causes clock pulses from a source 43 to be applied to the least significant counter 49 of a series 49, 51- 53, 50 or to an intermediate counter 52, depending on the magnitude of the deflection; and the counters operate relays 12 to vary the resistances 56 in circuit with a digital coil 36 until the force exerted by this coil restores the beam to its datum position. The analogue signal from 31 is applied directly to an analogue coil 34 so as to oppose the input force and reduce the deflection which occurs, the current flowing in this coil being reduced substantially to zero when balance is achieved by coil 36. Normally, with small deflections of the beam, only relay 32 operates to energize one of leads 41, 42 controlling, the direction of counting in accordance with the sense of the deflection, but if a large deflection occurs, relay 33 also operates to open gate 80 and close gate 48 whereby the clock pulses are applied to counter 52 so as to increase the rate at which the balancing force is built up. An indication of the magnitude of the input force is given at 54 when the balance condition is reached. Provision is made for preventing over-run at each end of the measuring range.