Actuating drive for a rockets expensive surface

摘要

A control fin actuator (28) for a guided missile (20) includes a pressure actuator (40) having a slidable piston (44) inside a housing (42) . Rolling diaphragm seals (50, 56) of the top piston face (46) and the bottom piston face (48) to the inside wall of the housing (42) divide the interior of the housing (42) into at least two chambers (54, 58). The rolling diaphragm seals (50, 56) eliminate sliding friction as the piston (44) moves within the housing. The two chambers (54, 58) are controllably pressurized to slide the piston (44) within the housing (42), thereby moving a push rod (78) attached to the piston (44) and extending out of the housing (42). The push rod (78) is connected to a missile control fin output shaft (24) by a taut band connector (80) that avoids backlash. A magnet (86) may be positioned adjacent to the push rod (78) to induce eddy currents in the push rod (78), thereby providing a damping force that increases with increasing rate of movement. Pressure in the control chamber (54) is achieved by operating the inlet valve (70) and the exhaust valve (72) in response to feedback information from a rotary position sensor (29), a linear position sensor (88), and/or pressure sensors (90, 92).