EMA Torque Limiter Control Near Droop Zone and Mechanical Stops
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electromechanical actuators (EMAs) face challenges in managing torque limits during different operational modes, particularly in the droop zone and near mechanical stops, leading to potential damage from excessive external forces and interference with movable components like spoilers on aircraft wings.
Innovation Solution
A torque limiter device in the EMA that adjusts torque limits based on the actuator's mode and position, disengaging the anti-extension mechanism when excessive torque is applied or near mechanical stops, ensuring safe operation in various modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed torque limit is applied in the anti-extension mechanism, then the actuator is protected from excessive torque in normal operation, but damage can occur in the droop zone and near mechanical stops where lower torque limits are appropriate
Solution Approach 1:
The torque limiter device transitions from a static fixed torque limit to a dynamic adjustable torque limit that adapts to different operational modes. The control system modifies the torque threshold based on real-time detection of operational mode (normal operation, droop zone, near mechanical stops), allowing the anti-extension mechanism to provide appropriate protection levels for each scenario.
Solution Approach 2:
The torque parameter of the anti-extension mechanism is changed based on operational conditions. The control system detects the current operational mode and adjusts the torque threshold parameter accordingly - using a higher threshold during normal operation and a lower threshold in the droop zone and near mechanical stops, preventing damage while maintaining protection.
2Reliability
If the anti-extension mechanism remains engaged during power loss, then the actuator prevents spurious extension, but it interferes with the movement of spoilers and wing flaps in the droop zone
Solution Approach 1:
The engagement state of the anti-extension mechanism is made dynamic rather than static. The control system continuously monitors the operational mode and automatically adjusts the engagement state - keeping it engaged during normal operation to prevent spurious extension, and disengaging it when detecting droop zone operation or mechanical stop proximity to allow smooth movement of spoilers and wing flaps.
Solution Approach 2:
The control system uses feedback from operational mode detection to regulate the anti-extension mechanism. Sensors detect parameters such as actuator position, velocity, and load conditions to determine the current operational mode, and this feedback signal controls the engagement/disengagement of the anti-extension mechanism, ensuring it operates only when appropriate.
3Device complexity
If a fixed torque limit is used, then the system structure is simple, but the actuator cannot adapt to different operational modes requiring different torque thresholds
Solution Approach 1:
The torque limiter evolves from a static mechanical device to a dynamic controlled system. The control system adjusts the torque threshold in real-time based on operational mode detection, enabling the same physical structure to provide different torque limits for different operational scenarios without requiring multiple mechanical components.
Solution Approach 2:
The torque limiter device performs multiple functions through a single integrated system. It provides both high-torque protection during normal operation and low-torque protection in the droop zone and near mechanical stops, while also enabling smooth spoiler and wing flap movement when needed, all through adaptive control rather than multiple separate mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The torque limiter device ensures reliable operation by preventing damage to the actuator and associated components while allowing movement of spoilers and wing flaps even in power loss scenarios, enhancing safety and efficiency.
Implementation Method 1
A torque limiter device in an electromechanical actuator, EMA, adjusts a load setting of the torque limiter depending on an operational mode of the EMA
Data Source
AI summary
An electromechanical actuator assembly operable in a plurality of modes. The EMA assembly includes: an electrical motor having a motor shaft extending along an axis (A) of the EMA, the motor driving the shaft to rotate about the axis; a gear assembly mounted around, and in geared connection with the shaft, to rotate with the shaft; an EMA output connected to the gear assembly such that rotation of the motor shaft causes rotation of the output via the gear assembly, the output rotating at a speed which is a predetermined fraction of the speed of rotation of the motor shaft based on the gear ratio of the gear assembly.