Steerable Fin Orientation Ring for Projectile Guidance
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Solution Overview
Problem
Existing projectile guidance systems with incidence steerable fins face complexity in setting fin incidence based on angular position, leading to rapid motor control issues and intense magnetic fields that interfere with guidance systems.
Innovation Solution
A projectile design featuring a fin orientation ring with pivotable arms and positioning means, including a disk and cam system, allows for translation and rotation to adjust fin incidence without requiring precise angular position control of each fin, reducing motor stress and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous corrections on fin incidence are performed to compensate for projectile rolling, then guiding accuracy is improved, but motor control complexity and magnetic field interference increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal fin incidence values in a lookup table before projectile launch. During flight, the control system simply retrieves pre-computed incidence values based on current rolling angle and flight parameters, rather than performing real-time calculations. This eliminates complex real-time computing requirements while maintaining guiding accuracy, as the corrective actions were prepared in advance.
Solution Approach 2:
The patent replaces the mechanical control system with multiple independent motors and complex gear trains with a single motor driving a fin incidence mechanism. By substituting the multi-motor electromagnetic control system with a simpler mechanical arrangement, the patent reduces magnetic field generation and eliminates the need for complex angular position sensing and control algorithms, thereby reducing device complexity while maintaining correction capability.
2Speed
If fast fin movements are implemented to perform quick trajectory corrections, then response speed is improved, but current peaks and motor stress increase
Solution Approach 1:
The patent uses pre-computed fin incidence values stored in memory that are optimized for rapid deployment. When trajectory correction is needed, the system retrieves the predetermined incidence angle from the lookup table and applies it immediately, enabling fast fin response without requiring high-power motor bursts. The preliminary calculation phase allows the flight phase to use lower-power, sustained motor operation.
Solution Approach 2:
The patent implements a dynamic fin incidence mechanism that allows smooth, continuous adjustment of fin angles through a single motor-driven system. The mechanical design enables the fins to move through a range of incidence angles with controlled motion profiles, avoiding sudden jerky movements that would generate current peaks. The dynamic system adapts fin positioning to match the projectile's rolling motion and trajectory requirements in real-time.
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
This solution simplifies the adjustment of fin incidence, reduces motor stress, and minimizes interference with guidance systems by allowing smooth trajectory corrections without continuous, precise angular position monitoring, enhancing the accuracy and reliability of projectile guidance.
Implementation Method 1
the positioning means of the ring centre in both directions of the plan P comprises a cam cooperating with the off-centered circular opening of the disk
Implementation Method 2
the off-centered circular opening comprising an inner toothed ring gear meshing with a pinion centered on the longitudinal axis of the projectile
Implementation Method 3
The incidence of the fins is adapted while airborne according to the trajectory wished for the projectile
Data Source
AI summary
The invention relates to a steering method of a projectile and to the associated projectile with incidence steerable fins, comprising at least three fins, each being pivotable with respect to the projectile around a pivot axis perpendicular to the longitudinal axis X of the projectile, wherein the projectile comprises a fin orientation ring, the ring comprising as many arms as there are fins, wherein the ring can translate in a plan P perpendicular to the longitudinal axis X of the projectile and following at least two directions of this plan P, wherein the orientation ring can rotate on itself around its center parallel to the longitudinal axis X of the projectile, each arm comprising means cooperating with an orientation lever fixed to a fin to be able to pivot the fin around its pivot axis during translation of the ring by positioning means.