Dual-EMA Flight Control Linkage for Jam-Tolerant Redundancy
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Solution Overview
Problem
Aircraft flight control systems using electromechanical actuators (EMAs) face reliability issues due to jamming in the driving force transmission path, which complicates the structure and increases weight, while existing solutions require complex redundancy mechanisms.
Innovation Solution
A redundant configuration is implemented with a first actuator attached to the wing main body and a second rotary actuator attached to the control surface, both being EMAs, where the second actuator's output terminal is parallel or coincides with the control surface's fulcrum axis, allowing the control surface to be driven by either actuator, simplifying the mechanism and reducing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single electromechanical actuator is used to drive the control surface, then the structure is simplified and weight is reduced compared to hydraulic systems, but reliability deteriorates due to jamming in the driving force transmission path
Solution Approach 1:
The actuator system is segmented into two independent actuators (first and second actuators) that can operate separately. Each actuator has its own driving force transmission path, so jamming in one path does not affect the other. This segmentation maintains simplicity and light weight while improving reliability through redundancy.
2Reliability
If redundancy is achieved by using multiple electric motors in parallel, then reliability is improved, but device complexity increases extremely
Solution Approach 1:
Instead of connecting multiple actuators in parallel to the control surface (which would create complexity), the patent connects them in series through the horn arm. The first actuator drives the horn arm, which in turn drives the second actuator's input. This inverted series connection simplifies the transmission path while maintaining redundancy, as each actuator can independently drive the control surface through different paths.
3Temperature
If the second actuator is integrated with the control surface with its turning axis parallel to or coinciding with the fulcrum axis, then heat dissipation efficiency is improved through outside airflow, but the attachment complexity increases
Solution Approach 1:
The second actuator is merged with the control surface by aligning its turning axis with the fulcrum axis. This merging allows the actuator to utilize the outside airflow passing through the control surface for heat dissipation. The alignment creates a compact integrated structure that achieves thermal management without adding significant attachment complexity.
Data Source
AI summary
An aircraft flight control system includes a first actuator attached to a wing main body, a horn arm configured to transmit an output of the first actuator to a control surface, and a second actuator that is a rotary actuator and attached to the control surface. At least one of the first actuator and the second actuator is an electromechanical actuator (EMA). A first end of the horn arm is coupled to an output terminal of the first actuator, and a second end of the horn arm is fixed to an output terminal of the second actuator. The second actuator is attached to the control surface such that a turning axis of the output terminal is parallel to or coincides with a fulcrum axis (hinge line) of the control surface.