Torsional Spring Control Actuator for Rolling Missile
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Solution Overview
Problem
Conventional control actuator systems for rolling missiles require high power densities to manage the constant movement of control fins, leading to excessive energy consumption and power requirements, which is a challenge in achieving the desired maneuverability while maintaining feasible power supplies.
Innovation Solution
A control actuator system that incorporates a torsional spring to store energy as the control surface moves, allowing it to oscillate at the natural frequency matching the missile's roll rate, reducing the need for continuous high-power motor operation by using a servo motor to initially rotate the control surface and periodically add energy to maintain desired angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional control actuator systems are used to continuously move control fins at roll frequency, then missile maneuverability is achieved, but power consumption increases linearly with roll rate and deflection angle
Solution Approach 1:
The control fin is made to oscillate periodically at the missile's roll frequency rather than requiring continuous actuation. The torsional spring stores energy during one half of the oscillation cycle and releases it during the other half, enabling the control surface to move back and forth at roll frequency without continuous motor power input.
Solution Approach 2:
The torsional spring serves as an energy storage device that automatically releases stored energy to drive the control surface oscillation. Once the servo motor provides an initial torque to start the oscillation, the spring-mass system sustains itself by converting stored elastic potential energy into kinetic energy, requiring only periodic energy additions from the motor rather than continuous high-power operation.
2Speed
If high gear ratio designs are used to reduce motor speeds, then CAS motor speeds are reduced, but CAS torque requirements increase due to control surface inertia and hinge moments
Solution Approach 1:
The torsional spring is pre-loaded or positioned to provide a restoring torque that opposes the control surface movement in one direction and assists it in the opposite direction. This preliminary energy storage in the spring reduces the peak torque demands on the motor during control surface oscillation, allowing for lower gear ratios and more balanced motor design parameters.
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 approach significantly reduces the overall power requirements for the control actuator system, with the torsional-spring-mass system consuming approximately 20% of the power compared to conventional designs, thereby enhancing the power efficiency and reducing battery demands.
Implementation Method 1
a first mechanism for storing energy as the control surface moves in the first direction and releasing the stored energy to move the control surface in a second direction opposite the first direction. In an illustrative embodiment, the system is adapted to rotate an aerodynamic control surface of a rolling missile, and the first mechanism is a torsional spring arranged such that rotating the control surface in the first direction winds up the spring and releasing the spring causes the control surface to oscillate back and forth
Implementation Method 2
The spring has a spring constant such that the control surface oscillates at a natural frequency mating a roll rate of the missile
Data Source
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AI summary
A control actuator system. The novel system includes a control surface mounted on a body and adapted to move in a first direction relative to the body, and a first mechanism for storing energy as the control surface moves in the first direction and releasing the stored energy to move the control surface in a second direction opposite the first direction. In an illustrative embodiment, the system is adapted to rotate an aerodynamic control surface of a rolling missile, and the first mechanism is a torsional spring arranged such that rotating the control surface in the first direction winds up the spring and releasing the spring causes the control surface to oscillate back and forth, alternating between the first and second directions. In a preferred embodiment, the spring has a spring constant such that the control surface oscillates at a natural frequency matching a roll rate of the missile.