Aircraft Actuator Control Without a Master Flight Controller
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Solution Overview
Problem
The standard multiply-redundant Fly-By-Wire Flight Control Systems (FCS) architecture lacks redundancy for the master controller, leading to potential catastrophic failures and high costs due to the need for high-integrity FCSs, especially in low-cost unmanned aerial vehicles (UAVs).
Innovation Solution
A masterless flight control methodology where actuator control units distribute flight control responsibilities among multiple FCSs, eliminating the need for a master controller and allowing all FCSs to contribute to decision-making, even if some are deemed unhealthy, by analyzing control signals using means, medians, and modes, and weighting based on age and similarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a master controller is used to manage redundant FCSs, then flight control reliability is improved through centralized monitoring and failover, but a single point of failure is created that could lead to catastrophic system failure
Solution Approach 1:
The patent removes the master controller from the system architecture entirely, extracting the centralized monitoring function and distributing it to individual actuator control units. Each actuator control unit independently monitors control signals from multiple FCSs and determines actuator control signals without requiring a central authority, thereby eliminating the single point of failure while maintaining reliability through distributed decision-making
Solution Approach 2:
The patent segments the centralized master controller function into multiple independent actuator control units, each responsible for specific actuators. This segmentation distributes the monitoring and control decision-making across multiple independent nodes, eliminating the hierarchical structure that created the single point of failure while maintaining comprehensive system monitoring through parallel independent assessments
2Reliability
If high-integrity certified FCSs are used to ensure safety, then flight control reliability is improved, but system cost increases significantly
Solution Approach 1:
The patent employs multiple lower-cost FCSs without requiring high-integrity certification for each individual unit. By using redundant inexpensive FCSs and implementing a masterless architecture where actuator control units independently analyze control signals from multiple FCSs, the system achieves high overall reliability without the prohibitive cost of certified high-integrity FCSs, making the technology economically viable for low-cost UAVs
3Reliability
If multiple stand-by FCSs are provided to increase redundancy, then flight control reliability is improved, but system complexity and cost increase
Solution Approach 1:
The patent merges the monitoring and control functions into the actuator control units themselves, which directly receive and analyze control signals from multiple FCSs. This integration eliminates the need for a separate master controller layer, reducing system complexity while maintaining redundancy. The actuator control units combine multiple control signals through analysis (including statistical methods like mean, median, and mode) to produce actuator control signals, achieving simplified architecture with enhanced redundancy
Data Source
AI summary
Disclosed herein is a method of controlling an aircraft, the aircraft including a plurality of actuators, a plurality of actuator control units, and a plurality of flight control systems for generating control signals. The method comprises, at each of the plurality of actuator control units: (a) from each of the plurality of flight control systems, obtaining a respective control signal for controlling an actuator associated with the actuator control unit, the actuator being one of the plurality of actuators; and (b) providing an actuator control signal to the associated actuator, wherein the actuator control signal is based on an analysis of the obtained control signals.