Torque Motor Short Circuit Detection via Voltage Thresholding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing servo-valve actuator systems in aircraft turbojets fail to detect differential short circuits in torque motors effectively, leading to late detection of failures that can render the turbojet inoperable or inefficient.
Innovation Solution
A method and device for monitoring servo-valve actuator systems that compare the control current and voltage across torque motors with predetermined thresholds, raising an alarm and signaling failure if the voltage is below a certain threshold, allowing for early detection of differential short circuits without relying on position return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the control current is monitored alone to detect torque motor failures, then the monitoring method is simple, but differential short circuits remain undetectable since the current remains unchanged
Solution Approach 1:
The monitoring method is segmented into multiple conditional steps: first comparing control current with a threshold, then conditionally comparing voltage with a threshold only when current exceeds the threshold. This segmentation allows simple current monitoring to continue while adding voltage monitoring only when necessary, detecting differential short circuits without permanently complicating the system.
Solution Approach 2:
The control current threshold comparison is performed preliminarily before voltage measurement. This preliminary action filters out unnecessary voltage measurements during normal operation, reducing complexity while ensuring voltage monitoring is activated only when a potential failure condition exists.
2Measurement precision
If voltage and current monitoring is continuously performed, then differential short circuits are detected accurately, but the monitoring system becomes more complex
Solution Approach 1:
The monitoring system dynamically adjusts its behavior based on real-time conditions. The voltage monitoring step is conditionally executed only when the control current exceeds the predetermined threshold. This dynamic adaptation maintains high detection accuracy while minimizing system complexity during normal operation.
Solution Approach 2:
The monitoring system uses the control current signal itself to trigger appropriate monitoring actions. When the current exceeds the threshold, the system automatically initiates voltage comparison, making the system self-regulating and reducing the need for external control logic.
3Device complexity
If monitoring is performed only under steady conditions, then the monitoring system is simple, but transient failures are not detected
Solution Approach 1:
The monitoring method is designed to be universal, handling both steady-state and transient conditions through the same conditional logic. The threshold comparisons and alarm generation work effectively regardless of whether the system is in steady state or experiencing transient changes, making the monitoring system multi-functional without requiring separate detection mechanisms.
Data Source
AI summary
A method of monitoring an actuator system including a control device, a torque motor having a voltage Umc across its terminals and actuating a servo-valve, and an actuator controlled by the servo-valve, is provided. The control device is suitable for delivering to the torque motor a control current Icmd as a function of a current setpoint I_c and of a measured current Imes. The monitoring method includes: comparing the voltage Umc measured across the terminals of the torque motor with a predetermined threshold voltage Vthresh; and if the voltage across the terminals of the torque motor is less than or equal to the predetermined threshold voltage, raising an alarm and indicating a failure of the servo-valve. The comparison of the voltage Umc is performed only if the control current Icmd is greater than a predetermined threshold current Iinhib, with a control current less than that inhibiting any signaling of a servo-valve failure.