Aircraft Actuator Force-Fight Mitigation via Offset Correction
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Solution Overview
Problem
In systems with multiple actuators controlling the same aircraft or vehicle part, force fighting occurs due to differences in mounting structures, thermal variations, and aging, leading to undesirable operation and loss of symmetry.
Innovation Solution
A force-fighting mitigation system that determines and stores offset corrections for each actuator at multiple desired positions, using a three-point rigging system to synchronize their movements and correct for errors, ensuring harmonization between desired and actual positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple actuators are used to control the same aircraft part for redundancy and balance, then reliability and strength are improved, but force fighting occurs due to positioning differences leading to loss of symmetry
Solution Approach 1:
The system changes the control parameters by introducing individual offset corrections for each actuator. The control system determines the actual position of each actuator and calculates offset values that compensate for positioning differences, thereby eliminating force fighting while maintaining the redundancy provided by multiple actuators
Solution Approach 2:
The system implements feedback by continuously monitoring the actual position of each actuator and comparing it with the desired position. Based on this feedback, the control system adjusts the offset corrections dynamically to ensure all actuators reach their target positions simultaneously, preventing force fighting and maintaining symmetry
2Manufacturing precision
If actuators are designed to be identical in all respects, then consistency is improved, but force fighting still occurs due to mounting structures, thermal differences, and aging
Solution Approach 1:
The system applies preliminary anti-action by pre-calculating and storing offset corrections for each actuator based on their individual characteristics. These offset values are applied in advance to counteract the effects of different mounting structures, thermal variations, and aging, preventing force fighting before it occurs
Solution Approach 2:
The system applies local quality by treating each actuator individually with its own specific offset correction rather than using a uniform control approach. This allows the system to compensate for local differences in mounting structures, thermal characteristics, and aging patterns specific to each actuator
Data Source
AI summary
A force fight mitigation system comprising: control means configured to provide a position command to each of two or more actuators arranged to position a surface, the position command indicative of a desired position of the actuator relative to the surface; means to detect the actual position of the actuator relative to the surface in response to the position command; and means to determine an offset between the desired position and the actual position and to store a rigging correction based on the offset; wherein, for each actuator, an offset is determined for each of three or more desired positions.