Aircraft Sidestick Priority Logic for Dual Input Conflict Resolution
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Solution Overview
Problem
Fly-by-wire aircraft flight control systems face challenges in managing dual input situations where both pilots issue flight control commands simultaneously using independent sidesticks, leading to potentially dangerous conflicts and the need for improved priority management to ensure safe and efficient control.
Innovation Solution
The implementation of a flight control system with momentary and permanent priority switches and visual/aural cues on sidesticks and the glareshield allows pilots to quickly and easily establish and maintain priority, preventing dual input conflicts and ensuring safe operation by designating sole control authority.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If independent sidesticks are used for pilot and co-pilot input, then each pilot can issue control commands independently, but dual input conflicts may occur when both pilots issue commands simultaneously
Solution Approach 1:
The system preemptively detects dual input conditions before they can cause hazardous conflicts. The flight control computer continuously monitors both sidestick inputs and identifies when both pilots are applying force, allowing the system to intervene with priority arbitration before the conflicting inputs can adversely affect aircraft control
Solution Approach 2:
The flight control computer acts as an intermediary between the two independent sidesticks. When dual input is detected, the computer mediates the conflict by algebraically summing the inputs or by assigning priority based on various factors (captain's priority, flight phase, etc.), thus resolving the contradiction between maintaining independent control and preventing harmful conflicts
2Reliability
If priority arbitration logic is implemented to resolve dual input conflicts, then control safety is improved, but system complexity increases
Solution Approach 1:
The flight control computer performs multiple functions: it processes normal flight control inputs, monitors for dual input conditions, arbitrates priority when conflicts occur, and provides annunciations. By consolidating these functions in a single multi-functional system rather than adding separate dedicated hardware for each function, the complexity increase is minimized while achieving reliable priority arbitration
Solution Approach 2:
The system dynamically changes the weighting parameters of pilot inputs based on flight conditions and priority status. During normal operation, both pilots have equal weighting. When dual input is detected, the system adjusts parameters to give priority to the appropriate pilot or algebraically sums the inputs, providing flexible conflict resolution without requiring complex mechanical or electrical switching mechanisms
3Reliability
If algebraic summation of dual inputs is used, then control conflicts are resolved, but the system cannot distinguish between intentional dual input and erroneous simultaneous input
Solution Approach 1:
The system provides annunciations to both pilots when dual input conditions are detected, informing them that their inputs are being combined or that priority arbitration is occurring. This feedback allows pilots to recognize the dual input condition and adjust their actions accordingly, while the flight control computer continues to process the combined inputs to maintain safe aircraft control
Data Source
AI summary
The present invention relates to a fly-by-wire type of aircraft flight control system having a pair of sidesticks for pilot and co-pilot input, respectively, and having logic that controls the priority of input as between the two sidesticks in certain aircraft flight situations. It allows either the pilot or co-pilot to ensure that his/her sidestick is the only one issuing flight control commands at any one moment in time by first pressing a simple latch button located, for example, on the glareshield in the cockpit and then maneuvering the sidestick in the desired manner to effectuate flight control, e.g., pitch and/or roll, of the aircraft.