Movable Mass Attitude Control for Rocket Thrust Misalignment
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Solution Overview
Problem
Conventional attitude control systems for rocket-propelled vehicles struggle with thrust misalignment errors, particularly in small vehicles, where existing Thrust Vector Control (TVC) systems are inefficient and not scalable for vehicles with limited mass and size.
Innovation Solution
The implementation of a movable mass system that alters the center-of-mass of the vehicle to generate torque for attitude control, using external or internal masses that can be moved between internal and external locations, and a computing system to calculate and apply the necessary torque to compensate for thrust misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TVC systems (jet vanes, gimbaled nozzle, gimbaled engine) are used for attitude control, then torque can be generated to control pitch and yaw, but the system complexity and mass increase significantly, making them impractical for small rocket-propelled vehicles
Solution Approach 1:
The patent extracts the attitude control function from complex mechanical TVC systems and implements it through a simplified movable mass mechanism. Instead of using jet vanes, gimbaled nozzles, or gimbaled engines, the invention moves a mass within the vehicle to generate the necessary torque for pitch and yaw control, thereby eliminating the need for complex mechanical steering components while maintaining attitude control capability
Solution Approach 2:
The patent changes the control parameter from mechanical actuation (gimbal angles, jet vane deflection) to mass position. By varying the position of the movable mass along the longitudinal axis and laterally, the system generates the required torque to control attitude, transforming the control mechanism from mechanical movement of propulsion components to positional adjustment of a mass
2Measurement precision
If conventional TVC systems are used to compensate for thrust misalignment, then attitude control precision improves, but the mass and size requirements make them unsuitable for small vehicles with limited mass
Solution Approach 1:
The patent uses a movable mass that acts as a counterweight to compensate for thrust misalignment. By positioning this mass laterally and longitudinally, the system generates a counter-torque that offsets the torque caused by thrust misalignment, achieving precise attitude control without requiring heavy mechanical TVC components. The movable mass effectively balances the unwanted torque through its strategic positioning
3Device complexity
If movable mass systems are used for attitude control, then device complexity is reduced and scalability to small vehicles is improved, but the ability to generate sufficient torque for high-performance control is limited
Solution Approach 1:
The patent extends the movable mass system from one-dimensional longitudinal movement to two-dimensional movement by adding lateral positioning capability. This allows the mass to be positioned not only along the longitudinal axis but also laterally, significantly increasing the torque generation capability while maintaining system simplicity. The dual-dimensional movement enables the mass to counteract both pitch and yaw torques effectively
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 effectively controls the pitch, yaw, and roll of small rocket-propelled vehicles by adjusting the center-of-mass, allowing for precise attitude control and compensation for thrust misalignment, even in small vehicles where traditional TVC systems are impractical.
Implementation Method 1
one or more movable masses configured to sufficiently change a center-of-mass of the apparatus so as to effect flight control
Implementation Method 2
a pump configured to pump the one or more movable masses back and forth between the first tank and the second tank
Data Source
AI summary
Attitude of a vehicle may be controlled using movable mass. The movable mass may move inside a vehicle or its outline, outside of the vehicle or its outline, inside-to-outside and/or outside-to-inside of the vehicle or its outline, or any combination thereof. The movable mass may be a solid, liquid, and/or gas. When the center-of-mass of the vehicle is moved relative to the line-of-action of applied forces such as thrust, drag, or lift, a torque can be generated for attitude control or for other purposes as a matter of design choice. In the case of external movable masses that extend from the vehicle or its outline, when operating in endoatmospheric flight, or general travel through a fluid, aerodynamic forces from the atmosphere or general fluid forces may further be leveraged to control the attitude of the vehicle (e.g., aerodynamic flaps).