Patent ID: 7597041

Claim:
The method of counteracting the gravitational torque acting on a weapon barrel ( 1 ) that is pivotally mounted on a base ( 2 ) at a location spaced from the center of gravity of said barrel ( 1 ), comprising the steps of: providing a spring ( 6 ); positioning said spring ( 6 ) between said barrel ( 1 ) and said base ( 2 ) to exert a force (F) therebetween; providing a force transducer ( 7 ); positioning said force transducer ( 7 ) so as to measure said force (F) and to produce an actual compensation force signal; converting said actual compensation force signal into an actual compensation torque signal ( 8 ); providing a gyroscope ( 13 ); mounting said gyroscope ( 13 ) on said barrel ( 1 ) to determine the elevation angle of said barrel ( 1 ) relative to a horizon and to produce an elevation angle signal ( 14 ); providing a set point generator ( 12 ); causing said set point generator ( 12 ) to generate a needed compensation torque signal ( 11 ) reflective of the torque necessary to counteract said gravitational torque as a function of said elevation angle signal ( 14 ); summing said actual compensation torque signal ( 8 ) with said needed compensation torque signal ( 11 ) to Produce a compensation torque error signal ( 15 ); providing a desired torque drive signal ( 17 ) reflective of a desired torque to be transmitted between said barrel ( 1 ) and said base ( 2 ); summing said desired torque drive signal ( 17 ) with said compensation torque error signal ( 15 ) to generate a compensated drive signal ( 21 ); providing an actuator ( 3 ) between said barrel and base to selectively apply a torque therebetween; operating said actuator ( 3 ) as a function of said compensated drive signal ( 21 ); thereby to counteract said gravitational torque acting on said barrel ( 1 ).