GB1260457A - Reduction of oscillation by anti-oscillation means - Google Patents

Abstract

1,260,457. Vibration damping. MESSERSCHMITT BOLKOW - BLOHM G.m.b.H. 7 April, 1970 [14 April, 1969], No. 16331/70. Heading F2S. To reduce or eliminate vibrations of a body, a transducer such as an accelerometer is employed to sense the vibrations and the transducer output is used to control the generation of a force which is made to act directly between the body and an inertia mass, the force being of such magnitude and direction as to nullify the sensed vibrations. Several examples of the application of this principle are disclosed, viz. (a) a coil carried by the body is associated with a magnet which is connected to or constitutes the inertia mass, the coil being energized by the output of a transducer sensing the body's vibrations; (b) a like system in which the coil and magnet are replaced by a suitable magnetostrictive, electrostrictive or fluid-operated, e.g. piston and cylinder device; (c) use of air cushions or air pressure as the force-generating means. In the last-named case, two plates which may be of glass and constitute the panes of a double-glazed window required to be sound-insulated, constitute effectively the body and the inertia mass. The air between them constitutes the means for causing a vibration-eliminating force to act between them. Heater wires are fitted in the air space and the transducer output, by controlling the energization of these wires, determines the temperature and hence the pressure of the air. It is also possible, in the case of moving bodies such as aircraft, to cause the ambient air to function as the inertia mass of the system, the force-generating means being air jets which apply a sucking or blowing action to the surface of the moving body.