Signal Processing for Aircraft Engine Variable Geometry Mechanism Control
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Solution Overview
Problem
Existing control schemes for variable geometry mechanisms in gas turbine engines rely on speed or torque, leading to excessive wear due to noise-induced continuous adjustments, which affects the engine's response time during rapid power transitions.
Innovation Solution
A signal processing device is implemented to filter and smooth the VGM position request signal using a first-order low-pass filter, rate limiter, and dead band, reducing noise and minor variations, thereby minimizing unnecessary adjustments and wear on mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If control schemes rely on speed or torque values for VGM control, then the engine response time during rapid power transitions is improved, but excessive wear occurs on mechanical components due to noise-induced continuous adjustments
Solution Approach 1:
A signal processing device is introduced as an intermediary between the control system and VGM actuator. This device filters the control signal to remove high-frequency noise while preserving the underlying control intent, thereby reducing unnecessary mechanical adjustments that cause wear, while still maintaining responsive control during rapid power transitions
Solution Approach 2:
The harmful high-frequency noise component is extracted and removed from the control signal using filtering techniques. The filter selectively removes frequency components above a predetermined threshold, separating the useful control signal from the harmful noise that causes excessive mechanical wear
2Reliability
If filtering is applied to reduce noise in control signals, then mechanical wear is reduced, but the response time may be increased due to signal smoothing
Solution Approach 1:
The filter's time constant is carefully selected and optimized to achieve the right balance. By adjusting this parameter, the system filters out noise effectively while maintaining sufficiently fast response characteristics for rapid power transitions, preventing excessive smoothing that would delay response
Data Source
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AI summary
A signal processing device (340) for use in an aircraft engine (10) with a variable geometry mechanism (VGM) (51, 52) comprises a processing unit (512) and a non-transitory computer-readable memory (514) communicatively coupled to the processing unit (512). The memory (514) has stored thereon computer-readable program instructions (516) executable by the processing unit (512) for: obtaining a VGM position request signal; determining whether a variation of the VGM position request signal is within a predetermined range; when the variation of the VGM position request signal is within the predetermined range: filtering the VGM position request signal to reduce a level of noise in the VGM position request signal; and transmitting the filtered VGM position request signal; and when the variation of the VGM position request signal is not within the predetermined range, transmitting a processed signal, based on the VGM position request signal.