Clutch-Decoupled Actuation With Braking for Jammed Actuators
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Solution Overview
Problem
Aircraft actuation systems face issues with jamming, leading to excessive loads on the structure, resulting in weight penalties due to the need for oversized components to withstand these loads, which is undesirable.
Innovation Solution
An actuation system with a clutch and sensors that disconnect the power drive unit from the actuators upon sensing an abnormal load condition, coupled with a brake to prevent uncontrolled movement, thereby mitigating excessive loads without the need for mechanical torque limiters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the structure is sized to resist excessive loading from jammed components, then the system reliability is improved, but the aircraft weight increases
Solution Approach 1:
The patent applies dynamics by making the power transmission system configurable between connected and disconnected states through clutch mechanisms. This allows the system to adapt its structural configuration dynamically - normally connected for synchronous operation, but disconnectable when abnormal loads are detected, thereby avoiding the need for permanently oversized components
Solution Approach 2:
The patent changes the operational parameter of the power transmission line from a fixed connected state to a variable state that can be disconnected. By changing the connection parameter through clutch engagement/disengagement, the system can operate with lighter components while maintaining reliability through dynamic parameter adjustment rather than static oversizing
2Reliability
If mechanical torque limiters are installed to prevent excessive loads, then the system reliability is improved, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical torque limiters with a control system that uses sensors to detect abnormal loads and electronically controls clutch engagement. This substitution of mechanical protection devices with an electronic control-based system achieves the same reliability function while reducing mechanical complexity
Solution Approach 2:
The patent implements feedback by using sensors to continuously monitor the actuation system for abnormal loads and using this information to control clutch engagement. This closed-loop feedback mechanism provides reliable protection without requiring complex mechanical torque limiters, as the system responds intelligently to actual operating conditions
3Productivity
If the power drive unit remains connected to the actuators during abnormal load conditions, then the actuation system maintains full functionality, but excessive loads cause damage to the system
Solution Approach 1:
The patent applies preliminary anti-action by having sensors detect abnormal load conditions before they can cause damage, and by having the clutch control system ready to immediately disconnect the power drive unit. This preemptive approach prevents harmful excessive loads from propagating through the system while maintaining the ability to quickly reconnect and restore full functionality
Data Source
AI summary
An actuation system comprises a plurality of actuators, a common power drive unit for driving the actuators and a transmission line transmitting drive from the common drive unit to the plurality of actuators. A clutch is arranged in the transmission line between the power drive unit and the plurality of actuators for selectively disconnecting the power drive unit from the plurality of actuators. At least one sensor is provided for sensing an abnormal load condition in the actuation system. The at least one sensor is operatively coupled to a clutch control which is configured such that when the at least one sensor senses an abnormal load condition, the clutch control is operative to disengage the clutch so as to disconnect the power drive unit from the plurality of actuators. A brake is operative to brake the actuators upon disengagement of the clutch.