Command mixing for roll stabilized guidance kit on gyroscopically stabilized projectile

Abstract

The system and method of mixing pitch and roll commands from a flight control computer to produce fin deflections applied to as few as two fins to simultaneously produce both a rolling moment and a pitching moment. The system may be mechanical or digital where actuators can be linear or rotary, digital or analog. Deflections of the fins are generated which produce pitch and roll moments where addition of pitch and roll commands determines deflection commands to be sent to a first fin and subtraction of pitch and roll commands determines deflection commands to be sent to a second fin.

What is claimed: 
     
         1 . A guidance kit, comprising:
 a first canard and a second canard configured for a projectile, wherein each canard is connected to a respective first and second control horn;   a first actuator acting on the first control horn; and   a second actuator acting on the second control horn;   the first and second actuators are directed by digitally mixed commands from a flight control computer to produce differing canard deflections wherein when the first and second canards deflect in the same direction a pitch moment is generated and when the canards deflect in opposite directions a roll moment is generated.   
     
     
         2 . The guidance kit according to  claim 1 , wherein data from a flight control computer is communicated through a cable or by a wireless interface. 
     
     
         3 . The guidance kit according to  claim 1 , further comprising a position sensor for providing feedback to the flight control computer. 
     
     
         4 . The guidance kit according to  claim 1 , wherein the digitally mixed commands comprises at least one of pitch commands and roll commands generating deflections commands for the first and the second canards which produce the pitch moment and the roll moment. 
     
     
         5 . The guidance kit according to  claim 4 , wherein addition of the pitch commands and roll commands determines the deflection commands to be sent to the first canard and subtraction of the pitch commands and the roll commands determines the deflection commands to be sent to the second canard. 
     
     
         6 . The guidance kit according to  claim 4 , wherein the pitch commands and the roll commands are applied to two fins to simultaneously produce both the roll moment and the pitch moment. 
     
     
         7 . The guidance kit according to  claim 1 , wherein a mixing ratio is varied to accommodate or compensate for different pitch and roll responses. 
     
     
         8 . The guidance kit according to  claim 1 , wherein the projectile is gyroscopically stabilized. 
     
     
         9 . The guidance kit according to  claim 1 , wherein the first actuator or second actuator is a digital servo or an analog servo. 
     
     
         10 . The guidance kit according to  claim 1 , wherein the first actuator or second actuator is a linear servo. 
     
     
         11 . A method for controlling a guidance kit, comprising:
 providing a first and a second canard on a projectile, wherein the first and second canards are acted on by a first and a second actuator, respectively;   receiving mixing commands from a flight control computer on the projectile;   producing differing canard deflections wherein when the first and second canards deflect in the same direction a pitch moment is generated and when the canards deflect in opposite directions a roll moment is generated; and   obtaining a position and a velocity of the projectile for suppling the flight control computer with data for guiding the projectile.   
     
     
         12 . The method for command mixing according to  claim 11 , wherein a mixing ratio is varied to accommodate or compensate for different pitch and roll responses. 
     
     
         13 . The method for command mixing according to  claim 11 , wherein the canards are mechanically controlled. 
     
     
         14 . The method for command mixing according to  claim 11 , wherein the mixing commands comprises at least one of pitch commands and roll commands generating deflections commands for the first and the second canards producing the pitch moment and the roll moment. 
     
     
         15 . The method for command mixing according to  claim 14 , wherein addition of the pitch commands and roll commands determines the deflection commands to be sent to the first canard and subtraction of the pitch commands and the roll commands determines the deflection commands to be sent to the second canard. 
     
     
         16 . The method for command mixing according to  claim 14 , wherein the pitch commands and the roll commands are applied to two fins to simultaneously produce both the roll moment and the pitch moment. 
     
     
         17 . A computer program product including one or more non-transitory machine-readable mediums encoding instructions that when executed by one or more processors cause a process to be carried out for controlling a guidance kit of a projectile, the process comprising:
 providing a first and a second canard on a projectile, wherein the first and second canards are acted on by a first and a second actuator, respectively;   receiving mixing commands from a flight control computer on the projectile;   producing differing canard deflections wherein when the first and second canards deflect in the same direction a pitch moment is generated and when the canards deflect in opposite directions a roll moment is generated; and   guiding the projectile to a target destination.