Dual-Angle Sensor EMA Sensing Using the Vernier Principle
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Solution Overview
Problem
Aerospace electromechanical actuators require redundant angle sensors for failsafe operation, which increases cost and complexity, and existing solutions do not adequately address redundancy without increasing the number of sensors.
Innovation Solution
An actuator system with two angle sensors having unequal transmission ratios, utilizing the Vernier principle for redundancy, allows determination of rotor angle and output position with only one functional sensor, reducing the number of required sensors to half while ensuring failsafe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two angle sensors are used for redundancy in aerospace EMAs, then failsafe operation is achieved, but device complexity and cost increase
Solution Approach 1:
The patent combines two angle sensors with different transmission ratios into a unified measurement system where both sensors contribute to a single redundant measurement architecture. The sensors are merged through the Vernier principle to achieve failsafe operation while sharing common computational resources for determining rotor angle and output position.
Solution Approach 2:
The angle sensors serve multiple functions: they provide both primary measurement for normal operation and redundant measurement for failsafe operation. The system can determine rotor angle and output position using either sensor individually or in combination, making the sensing system multi-functional and reducing the need for separate dedicated redundant sensors.
2Reliability
If two angle sensors with different transmission ratios are used, then failsafe operation with reduced sensor count is achieved, but measurement precision requirements increase
Solution Approach 1:
The patent employs asymmetric transmission ratios for the two angle sensors, where each sensor has a deliberately different ratio relative to the rotor. This asymmetry is fundamental to the Vernier principle implementation, allowing the system to achieve both redundancy and reduced sensor count while managing precision requirements through the mathematical relationship between the two different ratios.
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 system provides a cost-effective and reliable failsafe operation by determining rotor angle and output position with only two sensors, reducing sensor redundancy and maintaining actuator functionality even if one sensor fails.
Implementation Method 1
two angle sensors with different transmission ratios with respect to the shaft of the high lift system to determine the rotary output position of the EMA. The Vernier principle is used to determine the absolute rotation angle beyond 360° based on the phase difference of the two angle sensors.
Data Source
AI summary
Actuator for aerospace vehicle comprising an actuating element (4), a motor (1) with a rotor (2), a first rotating element (51), a second rotating element (61), a first and second angle sensor (52, 62) for measuring a first and second angle of the first and second rotating element (51, 61) and an actuator control (7) configured to control the motor (1), based on a current output position of the actuating element (4) and based on the current rotor angle, wherein the current output position of the actuating element (4) and the current angle of the rotor (2) of a current control loop are determined based on the first angle, if the second angle sensor fails, and based on the second angle, if the first angle sensor fails.