Electric Aircraft Thrust Allocation for Minimal Yaw After Faults
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Solution Overview
Problem
In electric drive systems for aircraft, a fault in one subsystem leads to asymmetrical thrust distribution, causing yawing moments that require compensation by the rudder, resulting in increased air resistance and energy consumption.
Innovation Solution
The electric drive system is designed with multiple thrust generators apportioned between subsystems, where each subsystem includes at least two generators, and a control system operates the system to minimize overall yawing moments, ensuring that even in a fault scenario, the remaining motors can operate at an ideal point, potentially eliminating the need for a vertical tail and rudder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the rudder is adjusted to compensate for yawing moment caused by asymmetrical thrust, then straight and level flight is maintained, but air resistance increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-configuring the thrust generators and their apportionment between subsystems before a fault occurs. The control system is designed in advance to detect subsystem failures and automatically redistribute thrust among remaining generators to compensate for yawing moments, eliminating the need for rudder adjustment and reducing air resistance while maintaining straight flight.
2Stability of the object's composition
If the rudder is adjusted to compensate for yawing moment, then flight stability is maintained, but energy consumption increases
Solution Approach 1:
The patent replaces the mechanical aerodynamic compensation system (rudder adjustment) with an electric drive control system. Instead of using aerodynamic forces through rudder deflection to counteract yawing moments, the system electronically controls thrust distribution among multiple electrically-driven thrust generators, substituting mechanical/aerodynamic compensation with electrical control and thrust vectoring.
3Productivity
If thrust generators are distributed symmetrically on wings, then normal operation is efficient, but fault tolerance is reduced
Solution Approach 1:
The patent applies segmentation by dividing the thrust generation system into multiple independent subsystems, each with its own energy supply and control. This segmentation allows individual subsystems to fail without causing complete system failure. The control system can detect which subsystem is faulty and redistribute thrust among remaining functional subsystems, maintaining flight stability even when one subsystem fails.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting thrust parameters of individual generators based on system state. When a subsystem failure is detected, the control system changes the thrust parameters (magnitude and distribution) of remaining generators to compensate for the lost thrust and counteract resulting yawing moments, transitioning from symmetric equal-thrust operation to asymmetric compensated operation.
Data Source
AI summary
The disclosure relates to an electric drive system for an aircraft and to a corresponding operating method. The electric drive system includes a multiplicity of electric thrust generators, wherein each electric thrust generator has an electric motor, and a subsystem group including a multiplicity of subsystems. The thrust generators are apportioned unambiguously between the subsystems so that each subsystem includes two or more of the thrust generators. Furthermore, a control system for operating the drive system is provided, wherein the control system is configured to operate the drive system in such a way that, at least in the event that one of the subsystems of the subsystem group is faulty, an overall yawing moment which is composed of the sum of the yawing moments of the thrust generators of each non-faulty subsystem of the subsystem group essentially disappears.