Variable-Gain Control Combiner for Rotorcraft Yaw Kick Loads
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Solution Overview
Problem
Aircraft rotorcraft systems face challenges in maintaining structural integrity during extreme maneuvers like 'yaw kick,' where sudden rudder actions cause mechanical stress, requiring either increased mass sizing or limiting control commands to prevent damage.
Innovation Solution
A variable gain combiner is introduced, which combines first and second control orders using an elongated link with a variable lever arm, allowing modulation of the second control order's authority based on a controllable parameter, thereby limiting the impact of sudden movements and preserving structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the aircraft structure is sized for extreme maneuvers like yaw kick, then structural integrity is improved, but aircraft mass increases
Solution Approach 1:
The patent applies a variable gain mechanism that dynamically adjusts the authority of the second control order based on flight conditions. The gain varies as a function of the first control order (collective pitch command), reducing control authority when collective pitch is high and increasing it when collective pitch is low. This dynamic adjustment prevents structural overload during extreme maneuvers without requiring the aircraft structure to be oversized for all possible conditions, thereby resolving the contradiction between structural integrity and aircraft mass.
2Strength
If control commands are limited to prevent structural damage, then structural integrity is improved, but control authority is reduced
Solution Approach 1:
The variable gain mechanism dynamically modulates control authority based on the first control order (collective pitch command). When collective pitch is high, the gain reduces the authority of the second control order (differential pitch/rudder) to prevent structural damage. When collective pitch is low, the gain increases to restore full control authority. This dynamic adaptation resolves the contradiction by providing conditional control limitation rather than permanent restriction.
Solution Approach 2:
The patent changes the parameter of control gain as a function of the first control order. The gain parameter is varied continuously based on the collective pitch command, transforming the control system from a fixed-authority system to a variable-authority system. This parameter change allows the system to adapt control authority to flight conditions, preventing structural damage while maintaining adequate control capability when needed.
3Device complexity
If a fixed gain combiner is used, then device complexity is reduced, but adaptability to different flight conditions is limited
Solution Approach 1:
The patent implements a variable gain mechanism that makes the combiner adaptive to different flight conditions. The gain varies as a function of the first control order, allowing the system to automatically adjust control authority based on the current flight state. This dynamic capability provides adaptability without requiring complex multi-mode control systems or manual interventions, resolving the contradiction between device complexity and adaptability.
Data Source
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AI summary
The present invention relates to a combiner (1) for superimposing a first order (O1) given by a first movement of a first input link and a second order (O2) given by a second movement of a second input link, said combiner (1) comprising an elongated link (5). The combiner (1) includes a linkage (10) articulated to the elongated link (5), the linkage (10) being rotationally movable relative to the elongated link (5) about a linkage axis (AX2), the linkage (10) being provided with an output attachment (11) adapted to be articulated to an output link (53), the combiner (1) comprising a connection system (20) articulated to the linkage (10), the connection system (20) comprising a second attachment (21) adapted to be articulated to the second input link, the connection system (20) comprising a lever arm (25) variable according to a parameter.