Projectile Control System Coning Maneuver for Roll Authority
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Solution Overview
Problem
Traditional projectiles experience low roll control authority due to opposing roll moments induced by control surface flow fields on tail fins, particularly at low total angles of attack and varying Mach numbers, which current design adjustments fail to adequately address.
Innovation Solution
A method and system that initiate a coning maneuver by bypassing guidance commands and sending modified commands to control surfaces when roll control authority parameters are outside predetermined ranges, using a processor-connected projectile control system to monitor and adjust control surface movements for improved roll control, including asymmetric biasing for steering during the maneuver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If control surfaces are deflected to generate roll control moments, then roll control authority is improved, but opposing roll moments are induced on the tail fins reducing overall control effectiveness
Solution Approach 1:
The patent implements a dynamic control mode selection system that switches between conventional control mode and coning maneuver mode based on real-time assessment of roll control authority. The system monitors flight conditions (Mach number, angle of attack) and dynamically determines when aerodynamic interference occurs, then dynamically switches control strategies to execute coning maneuvers that avoid the interference zone while maintaining roll control effectiveness.
Solution Approach 2:
The patent changes the control parameter strategy by transitioning from small deflection angles in conventional mode to large deflection angles in coning maneuver mode. When aerodynamic interference is detected, the system executes coning maneuvers with control surface deflections exceeding 30 degrees, which generates sufficient roll control moments despite the presence of tail fin interference, thereby overcoming the limitation of low roll control authority in the interference region.
2Force
If physical design changes are made to the projectile structure to address interference, then roll control authority is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces mechanical/structural modifications with a software-based control solution. Instead of physically redesigning the projectile structure (such as changing control surface positions, sizes, or tail fin configurations), the system uses a processor-executed control algorithm that dynamically selects between conventional control mode and coning maneuver mode. This software-based approach eliminates the need for complex structural modifications while achieving the same roll control authority improvement.
3Speed
If coning maneuver is executed to improve roll control, then control response is enhanced, but deviation from guidance trajectory may occur
Solution Approach 1:
The coning maneuver itself is a periodic oscillatory motion where the projectile executes controlled coning movements about its flight path. This periodic action allows the control surfaces to cyclically deflect in a manner that generates average roll control moments while the oscillations naturally average out over time, preventing permanent trajectory deviation. The system executes these periodic coning maneuvers only when interference is detected, and transitions back to conventional mode when interference ceases.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances roll control authority by avoiding interference between control surfaces and tail fins, providing improved controllability and reducing the need for costly physical design changes, while maintaining controlled trajectories.
Implementation Method 1
The control surfaces of the projectile can exhibit low roll control authority when the flow field from the deflected control surfaces induces opposing roll moments on the tail fins
Data Source
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AI summary
A method (200) of controlling a projectile (130) includes initiating an execution mode (204) if a roll control authority parameter is outside of a pre-determined operating range for a projectile (202). The execution mode includes bypassing a guidance command (201) and sending a modified command to execute a coning maneuver (203) to improve control response of the projectile. A projectile control system (100) includes a processor (110) operatively connected to a memory (120). The memory has instructions recorded thereon that, when read by the processor, cause the processor to execute the method operations described above.