Aircraft Actuator Force-Fight Verification Across Redundant Channels
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Solution Overview
Problem
The increasing complexity of rotorcraft systems has led to tightly coupled flight parameters and controls, making flight characteristics in different regimes significantly different, and existing fly-by-wire systems struggle to decouple these controls effectively, leading to increased pilot workload and potential system failures.
Innovation Solution
A method and system for actuator verification that includes increasing an initiating force in an actuator channel, stopping and holding it at a quiescent value, then increasing to a target value while restraining channels adjust, calculating a force fight test result, and indicating failure if thresholds are exceeded, using redundant flight control computers to ensure accurate force equalization and redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fly-by-wire systems are used to decouple flight controls, then pilot workload is reduced, but system complexity increases
Solution Approach 1:
The flight control system is divided into multiple independent channels (initiating channel and restraining channels), each capable of independent operation. This segmentation allows the system to manage complexity by distributing control functions across separate pathways while maintaining overall system coordination through the force equalization verification process.
Solution Approach 2:
The system implements continuous feedback through force equalization verification, where the initiating channel's force output is monitored and compared against the restraining channels' counter-forces. This feedback mechanism ensures that the complex fly-by-wire system maintains stability and proper force balance, preventing runaway conditions while managing system complexity.
2Reliability
If redundant flight control computers are implemented, then system reliability is improved, but device complexity increases
Solution Approach 1:
Multiple flight control computers are merged into a coordinated system where redundant computers work together through the force equalization verification process. The initiating channel and restraining channels are each controlled by different flight control computers, and their forces are balanced through a unified verification mechanism, achieving reliability through redundancy while managing complexity through integration.
Solution Approach 2:
The system monitors and adjusts force parameters dynamically during verification tests. By changing force levels (increasing initiating force to target values, monitoring restraining forces) and comparing them against thresholds, the system verifies reliability without requiring permanent complex hardware configurations, allowing flexibility in managing redundant system complexity.
3Measurement precision
If force equalization verification is performed with high precision thresholds, then actuator performance accuracy is improved, but measurement precision requirements increase
Solution Approach 1:
The system performs preliminary force equalization verification tests before actual flight operations. By conducting initiating channel force increases and restraining channel response measurements in advance, the system establishes baseline performance characteristics and verifies actuator functionality, ensuring measurement precision is achieved through pre-verification rather than during critical flight operations.
Data Source
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AI summary
In an embodiment, an aircraft such as a rotorcraft (101) includes an actuator (401) and a flight control computer (205) interfaced with the actuator (401). The flight control computer (205) is configured to: increase an initiating force output by an initiating channel (403) of the actuator; stop the increasing of the initiating force in response to observing restraining forces on restraining channels (403) of the actuator; hold the initiating force at a quiescent initiating value while the restraining channels (403) hold the restraining forces at quiescent restraining values; increase the initiating force to a target initiating value while the restraining channels (403) increase the restraining forces to target restraining values; calculate a force fight test result by summing a difference between the target initiating value and the quiescent initiating value with differences between the target restraining values and the quiescent restraining values; and indicate the actuator failed verification in response to the force fight test result being greater than a first predetermined threshold.