GB1468417A - Wide band angular displacement and velocity sensor - Google Patents

Abstract

1468417 Measuring angular displacement electrically SYSTRONDONNER CORP 6 Aug 1974 34621/74 Heading G1N A transducer assembly for measuring angular displacement over a wide frequency range comprises a solid and a fluid inertia mass each associated with a pick-off to develop a signal voltage which is also fed to individual restoring means to bring the moving members back to their normal position relative to the respective pick-off. The solid inertia mass 10 Figs, 2, 3 constituting the LF transducer is attached to a base 12 by a flexure support 11 and by a taut, spring-loaded wire 41. Angular displacement of the assembly about its central axis is sensed by pick-off 13, e.g. a fixed differential inductance and an armature 16 carried by the inertial mass 10, to produce a proportional current which is fed to moving torquer coil 46 co-operating with fixed magnet 48 to restore the mass 10 to its normal position relative to the base, as sensed by pick-off 13. The HF transducer assembly comprises a moving member carrying a paddle 55, Fig. 5 and an armature 29 in a fluid 53 also contained in flow-path 52, constituting the fluid inertia mass, whereby angular displacement of the assembly about the axis through the pivots 58 is sensed by pick-off 28 to produce a proportional current which is fed to moving torquer coil 59 co-operating with fixed magnet 61. The servo loops for each transducer incorporate electronically the appropriate desired LF and HF characteristics, and, in the case of the LF transducer using the solid inertia mass 10, embodies a positive feedback loop to compensate for mechanical friction. The torque current signals are fed through appropriate band pass filters and summed. The transducer assembly may be used on e.g. a moving TV camera to remove noise due to extraneous angular displacements.