# US 9,518,807 B2 · Projectile control systems and methods

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- Number: US 9,518,807 B2
- Document ID: US9518807B2
- Status: Granted
- Kind: B2
- Application number: 14/333,088
- Filed: 2014-07-16
- Published: 2016-01-21
- Granted: 2016-12-13
- Earliest claimed: 2014-07-16
- Assignees: Rosemount Aerospace Inc.
- Applicants: Rosemount Aerospace Inc.
- Inventors: Gregory Nash; Gary Willenbring; Robert L. Alford
- Web page: https://patentgrep.com/patent/US9518807B2

## CPC

- F42B 15/01: Arrangements thereon for guidance or control ({steering arrangements F42B10/60}; aircraft flight control B64C; guidance systems other than those installed aboard F41G7/00, F41G9/00; locating by use of radio or other waves G01S; flight control in general G05D1/00; computer aspects G06])
- F42B 10/62: Steering by movement of flight surfaces
- G05D 1/0816: {to ensure stability}
- G05D 1/107: {specially adapted for missiles}
- F42B: EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION (explosive compositions C06B; fuzes F42C; blasting F42D)
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES

## Abstract

A method of controlling a projectile includes initiating an execution mode if a roll control authority parameter is outside of a pre-determined operating range for a projectile. The execution mode includes bypassing a guidance command and sending a modified command to execute a coning maneuver to improve control response of the projectile. A projectile control system includes a processor operatively connected to a memory. The memory has instructions recorded thereon that, when read by the processor, cause the processor to execute the method operations described above.

## Claims

### Claim 1

A method of controlling a projectile, comprising:
initiating an execution mode if a roll control authority parameter is outside of a pre-determined operating range for a projectile, wherein the execution mode includes bypassing a guidance command, and sending a modified command to execute a coning maneuver to improve control response of the projectile, wherein executing the coning maneuver includes moving at least one control surface of the projectile to change a total angle of attack of the projectile.

### Claim 2 (depends on 1)

A method as recited in claim 1, wherein determining if the roll control authority parameter is outside of the pre-determined operating range includes:
monitoring a speed and a total angle of attack of the projectile; and
initiating a monitoring mode if both the speed and the total angle of attack are outside of respective pre-determined ranges, wherein the monitoring mode includes monitoring of a roll-deflection command and determining if the roll-deflection command is outside of a pre-determined roll-deflection command range, wherein if the roll-deflection command is outside of the pre-determined roll-deflection command range then the roll control authority parameter is outside of the pre-determined operating range.

### Claim 3 (depends on 1)

A method as recited in claim 1, wherein the modified command includes a coning acceleration command.

### Claim 4 (depends on 1)

A method as recited in claim 1, wherein the modified command includes an asymmetric biasing command for providing steering capabilities during the coning maneuver.

### Claim 5 (depends on 4)

A method as recited in claim 4, wherein the asymmetric biasing command includes commanding cyclic movement of at least one control surface of the projectile.

### Claim 6 (depends on 1)

A method as recited in claim 1, further comprising:
exiting the execution mode if a pre-determined exit parameter is met, wherein exiting the execution mode includes cancelling the modified command and returning to the guidance command.

### Claim 7 (depends on 6)

A method as recited in claim 6, further comprising determining if at least one of a total angle of attack and a speed is within respective a pre-determined range, if at least one of the total angle of attack and the speed is within its respective pre-determined range then the pre-determined exit parameter is met.

### Claim 8 (depends on 6)

A method as recited in claim 6, further comprising determining if a terminal performance parameter for the projectile is less than or equal to a pre-determined terminal performance parameter threshold, if the terminal performance parameter is less than or equal to the pre-determined terminal performance parameter threshold then the pre-determined exit parameter is met.

### Claim 9

A projectile control system, comprising:
a processor operatively connected to a memory, wherein has instructions recorded thereon that, when read by the processor, cause the processor to:
initiate an execution mode if a roll control authority parameter is outside of a pre-determined operating range, wherein the execution mode includes bypassing a guidance command, and sending a modified command to execute a coning maneuver for improved control response of a projectile; and
a projectile operatively connected to the processor, wherein the projectile includes at least one control surface configured to rotate about its respective control surface axis to generate control forces and moments.

### Claim 10 (depends on 9)

A projectile control system as recited in claim 9, wherein to determine if the roll control authority parameter is outside of the pre-determined operating range, the memory has instructions recorded thereon that, when read by the processor, cause the processor to:
monitor a speed and a total angle of attack of the projectile;
initiate a monitoring mode if both the speed and the total angle of attack are outside of respective pre-determined ranges, wherein the monitoring mode includes monitoring of a roll-deflection command and determining if the roll-deflection command is outside of a pre-determined roll-deflection command range, wherein if the roll-deflection command is outside of the pre-determined roll-deflection command range then the roll control authority parameter is outside of the pre-determined operating range.

### Claim 11 (depends on 9)

A projectile control system as recited in claim 9, wherein the memory has instructions recorded thereon that, when read by the processor, cause the processor to:
determine if a pre-determined exit parameter is met; and
exit the execution mode if the pre-determined exit parameter is met, wherein exiting the execution mode includes cancelling the modified command and returning to the guidance command.

### Claim 12 (depends on 11)

A projectile control system as recited in claim 11, wherein to determine if the pre-determined exit parameter is met, the memory has instructions recorded thereon that, when read by the processor, cause the processor to:
determine if at least one of a total angle of attack and/or a speed is within a respective pre-determined range, if at least one of the total angle of attack and the speed is within its respective pre-determined range then the pre-determined exit parameter is met.

### Claim 13 (depends on 11)

A projectile control system as recited in claim 11, wherein to determine if the pre-determined exit parameter is met, the memory has instructions recorded thereon that, when read by the processor, cause the processor to:
determine if a terminal performance parameter for the projectile is less than or equal to a pre-determined terminal performance parameter threshold, if the terminal performance parameter is less than or equal to the pre-determined terminal performance parameter threshold then the pre-determined exit parameter is met.