Rotor Yaw Allocation Control for VTOL Fuselage Stability
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Solution Overview
Problem
Existing VTOL aircraft systems face challenges in generating a sufficiently large yaw moment to stabilize the fuselage attitude, particularly when excessive yaw moments are required.
Innovation Solution
An attitude control device that calculates command values for vertical and horizontal rotors to generate yaw moments, allocating the command values between vertical and horizontal rotors based on a threshold, using vertical rotors for steady components and horizontal rotors for non-steady components of the yaw moment command.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If only vertical rotors are used to generate yaw moment, then the structure is simpler, but the yaw moment is insufficient when the required yaw moment is excessive
Solution Approach 1:
The patent combines vertical rotors and horizontal rotors into a unified control system that collaboratively generates yaw moment. The allocation command value calculation unit distributes the yaw moment command between vertical and horizontal rotors based on current flight conditions, enabling the system to achieve sufficient yaw moment by merging the capabilities of both rotor types.
Solution Approach 2:
The patent dynamically adjusts the allocation of yaw moment between vertical and horizontal rotors based on real-time conditions. The allocation command value calculation unit modifies the distribution strategy according to the magnitude of the yaw moment command and threshold values, allowing the system to adapt its control approach to varying operational requirements.
2Force
If horizontal rotors are always used to generate yaw moment, then sufficient yaw moment can be achieved, but energy consumption increases
Solution Approach 1:
The patent applies partial action by using horizontal rotors only when necessary (when yaw moment command exceeds threshold). For smaller yaw moments, only vertical rotors are engaged. This selective activation ensures that horizontal rotors consume energy only when their additional yaw moment capability is truly needed, rather than continuously operating.
Solution Approach 2:
The patent changes the operational parameters of different rotor types based on the magnitude of the yaw moment command. When the command value is below the threshold, vertical rotors operate with higher authority. When it exceeds the threshold, the system transitions to a mixed mode where horizontal rotors are activated to share the yaw moment generation, optimizing energy usage across different operational regimes.
3Use of energy by moving object
If vertical rotors are used for all yaw moment commands, then energy consumption is reduced, but the yaw moment becomes insufficient when the command value is large
Solution Approach 1:
The patent implements dynamic allocation that transitions the system from vertical-rotor-only operation to a combined vertical and horizontal rotor operation when the yaw moment command exceeds the threshold. This dynamic reconfiguration ensures the system maintains energy efficiency for small yaw moments while gaining sufficient yaw moment capability for large commands when needed.
4Use of energy by moving object
If the system uses a threshold-based allocation strategy, then energy efficiency is improved, but the control logic becomes more complex
Solution Approach 1:
The patent segments the yaw moment control into distinct operational regions based on the threshold. The allocation command value calculation unit implements separate control strategies for below-threshold and above-threshold conditions, managing complexity through structured segmentation of the control logic into manageable decision branches.
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
Stabilizes the fuselage attitude in all directions by efficiently utilizing both vertical and horizontal rotors, preventing excessive energy consumption and maintaining stability even under varying conditions.
Implementation Method 1
a plurality of vertical rotors each configured to generate thrust in a vertical direction
Implementation Method 2
a plurality of horizontal rotors each configured to generate thrust in a horizontal direction
Implementation Method 3
calculate a command value of a yaw moment to be applied to the fuselage
Data Source
AI summary
A rotor control device a vertical rotor control unit, a horizontal rotor control unit, and an allocation command value calculation unit. The vertical rotor control unit controls each VTOL rotor based on a first allocation command value. The horizontal rotor control unit controls each cruise rotor based on a second allocation command value. The allocation command value calculation unit sets, as the first allocation command value, a difference between a command value of a yaw moment and the second allocation command value, sets the magnitude of the second allocation command value to 0 when the command value of the yaw moment is less than a threshold, and sets the magnitude of the second allocation command value to a value greater than 0 when the command value of the yaw moment is equal to or greater than the threshold.