Dual-Load-Path Actuator Fault Detection via Pivot Mount Imbalance
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Solution Overview
Problem
Existing actuator systems lack redundancy and effective fault detection mechanisms, leading to potential failure in critical applications like aircraft horizontal stabilizer trim actuators.
Innovation Solution
A dual load path actuator assembly with synchronized motors and synchronized drive linkages, incorporating proximity detectors to detect imbalances caused by faults in the drive linkages, ensuring safe operation by stopping the actuator upon detection of a fault.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common ball screw is used in primary and secondary load paths, then device complexity is reduced, but reliability decreases because a single point of failure affects both load paths
Solution Approach 1:
The actuator is divided into two independent sub-actuators (first and second sub-actuators), each with its own motor and drive linkage. This segmentation creates separate load paths that can operate independently, resolving the contradiction by maintaining structural simplicity while achieving reliability through redundancy of independent units rather than shared components.
2Reliability
If fault detection mechanisms are added to the actuator system, then reliability is improved through early fault detection, but device complexity increases
Solution Approach 1:
A proximity detector provides feedback on the position of the pivot mount relative to the driven object. This feedback mechanism enables automatic detection of faults without adding complex diagnostic systems, resolving the contradiction by using a simple sensor that monitors physical position to infer system health and trigger safety responses.
3Reliability
If dual load paths with independent actuators are implemented, then reliability is improved through redundancy, but device complexity and cost increase
Solution Approach 1:
Both sub-actuators connect to a common pivot mount that is offset from the pivot axis, merging the load paths at a critical point. This design allows two independent actuators to work together through a shared mechanical advantage point, achieving reliability through redundancy while reducing overall complexity compared to completely separate actuation systems.
Data Source
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AI summary
An actuator comprising first and second motors, first and second drive linkages, and a pivot mount configured to pivot about a pivot axis, the pivot mount connected to the first and second drive linkages at first and second mount connections offset first and second offset distances from the pivot axis, the motors and first and second drive linkages configured to provide first and second load paths between a drive housing and the pivot mount so that in a first operation state the pivot mount is in a force-balanced orientation about the pivot axis, and a proximity detector positioned to detect when the pivot mount rotates about the pivot axis above a threshold out of the force- balanced orientation, wherein a force imbalance on the pivot mount caused by a fault in one of the first or second drive linkages above a threshold is detected by the proximity detector.