Importance

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Abstract

A reactionless momentum compensated payload positioner adapted to be mounted on a supporting body for providing momentum compensation of an oscillatory and scanning payload and for suppressing reactions in the supporting body to the torques that occur as an aiming angle of the payload is changed. The payload positioner includes a gimbal assembly having at least two axis of rotation including an elevation axis and an azimuth axis. A pair of reactionless drive module are provided for rotating the payload about both axes. Each reactionless drive module includes a housing, a main drive shaft connected to the payload, a DC electric motor for rotating the drive shaft, and a flywheel. The main drive shaft is freely rotatably suspended within the housing by main bearings and the flywheel is freely rotatably mounted to the main drive shaft by bearings. ?In operation, the flywheel counter rotates with respect to the main drive shaft.! The speed of the flywheel is effective to substantially eliminate reaction torques in the supporting body as the aiming angle of the payload is changed. The flywheel is also effective to provide momentum compensation to the payload and thereby substantially eliminate gyroscopic effects that occur due to rotational movement about either one of the two axis of the gimbal assembly. The invention further includes a first position transducer for determining and controlling payload pointing position and speed and a second position transducer for determining and controlling speed of said flywheel. A trim motor is provided for eliminating parasitic drag and for keeping the flywheel in registration with the payload and the payload in registration with the housing. ?The trim motor is also effective to desaturate excessive speed build up of the flywheel due to bias speed errors.!

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First Claim