Rotorcraft Flight Control Prioritization Under Limited Thrust Margin
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Solution Overview
Problem
Unmanned aerial vehicles (UAVs), particularly multi-rotor VTOL aircraft, face challenges in prioritizing attitude control over vertical control during emergency conditions when power is limited, as conventional systems struggle to manage both simultaneously, leading to potential crashes or damage.
Innovation Solution
The implementation of a flight control system that integrates attitude control and electrical power systems to determine thrust margins for each rotor, allowing for the prioritization of attitude control by setting an upper limit on vertical control, ensuring sufficient attitude control capability while maintaining acceptable vertical control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power is allocated to maintain both attitude control and vertical control simultaneously, then both control functions can operate, but the system may crash or suffer damage during emergency conditions with limited power
Solution Approach 1:
The control system segments power allocation into two distinct control functions: attitude control and vertical control. By calculating separate thrust margins for each function based on available power from the first and second power sources, the system can independently manage power distribution to prioritize attitude control while maintaining acceptable vertical control, preventing system failure during emergency conditions.
2Reliability
If attitude control is prioritized over vertical control in low-power conditions, then safe landing is ensured, but vertical control capability is reduced
Solution Approach 1:
The system applies partial action by allocating power such that attitude control receives sufficient thrust margin to ensure safe operation, while vertical control operates with reduced but still acceptable capability. The command generator determines vertical control commands based on the selected thrust margin, providing just enough vertical control to maintain acceptable operation without compromising attitude control safety margins.
3Power
If the system tries to maintain maximum thrust for both rotors, then both rotors can operate at full capacity, but the system cannot prioritize control functions during power limitations
Solution Approach 1:
The system dynamically adjusts thrust margin allocation based on real-time power availability and control priorities. The thrust state determiner continuously monitors the actual thrust state of each rotor and compares it against the maximum thrust capability, dynamically selecting which control function receives priority power allocation. This dynamic adaptation allows the system to transition between different power distribution modes depending on operational conditions.
Data Source
Figure 1A~1B
Figure 2
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AI summary
Methods, apparatus, systems, and articles of manufacture are disclosed for flight control prioritization. An example apparatus includes a thrust state determiner to determine a first thrust margin between a first limit of first available power for first rotors of a rotorcraft and a first thrust state associated with the first rotors, determine a second thrust margin between a second limit of second available power for second rotors of the rotorcraft and a second thrust state associated with the second rotors, and identify the first thrust margin or the second thrust margin as a selected thrust margin based on a vertical control profile of the rotorcraft, and a command generator to determine a first vertical control command based on the selected thrust margin and a second vertical control command, the second vertical control command being executed by the rotorcraft, and control the rotorcraft based on the first vertical control command.