Aircraft Actuator Loading Control via Active Feedback
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Solution Overview
Problem
Aircraft control surface actuators face the challenge of generating excessive loading that can damage the structure they are mounted on, due to their dependency on speed, which existing passive mechanical devices like overpressure valves cannot adequately manage, especially in cases of faults or external interactions.
Innovation Solution
An actuator system with a command unit that receives loading feedback and adjusts the actuation order to limit loading through a limitation unit, reducing control authority and setting a predetermined setpoint value, thereby actively managing and controlling the loading generated by the actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a passive mechanical device (overpressure valve) is used to limit loading, then the structure is protected from excessive loads, but the loading produced or taken up by the actuator becomes dependent on the speed of the actuator, making the device insufficient when loading exceeds structural capacity
Solution Approach 1:
The patent replaces the passive mechanical overpressure valve with an active electronic control system that includes a command unit with a limitation unit. This electronic system receives feedback on the actuator's loading and actively adjusts the actuation order to maintain loading below a predetermined threshold, eliminating the speed-dependency issue inherent in passive mechanical devices.
Solution Approach 2:
The limitation unit within the command unit implements a feedback mechanism that continuously monitors the loading produced or taken up by the actuator and adjusts the actuation order accordingly. This closed-loop control ensures that loading remains within structural capacity limits regardless of actuator speed, resolving the contradiction between structural protection and speed-independent loading control.
2Power
If the actuator generates more loading than necessary for operation, then performance requirements are met, but the structure on which the actuator is mounted is subjected to more sizable loadings than it was dimensioned for
Solution Approach 1:
The limitation unit dynamically adjusts the actuation order based on real-time loading feedback, allowing the actuator to generate the necessary loading for performance requirements while actively preventing excessive loading that could damage the structure. This dynamic control adapts to varying operational conditions to maintain loading within safe limits.
Solution Approach 2:
The system implements preliminary anti-action by proactively limiting the actuation order before excessive loading can occur. The limitation unit anticipates potential overloading conditions and adjusts the control signal in advance to prevent structural damage, rather than reacting after damage has occurred.
3Device complexity
If a passive overpressure valve is used to limit loading, then device complexity is reduced, but the loading limitation is insufficient when loading exceeds structural capacity due to speed dependency
Solution Approach 1:
The command unit with the limitation unit serves multiple functions: it computes the actuation order based on control signals and position feedback, monitors loading through the reception element, and actively limits loading when necessary. This multi-functional approach provides reliable loading limitation without significantly increasing overall system complexity, as the limitation functionality is integrated into the existing command unit.
Data Source
AI summary
An actuator system includes an actuator which is configured to generate a loading on a control surface, as a function of an actuation order received, a command unit of the actuator, which is configured to compute an actuation order of the actuator, a reception element for receiving a current value of the loading generated by the actuator, and a limitation unit configured to reduce the control authority of the command unit as a function of the current value of the loading and to limit the loading of the actuator to a predetermined setpoint value.