Slope-Based Event Detection for Turbine Engine Actuating Systems
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Solution Overview
Problem
Current methods for detecting latent failures in actuating systems of gas turbine engines, such as broken or inoperable linkages between actuators and components, are either unreliable or require additional hardware, leading to inefficiencies and increased costs.
Innovation Solution
A method involving controllers that determine slopes of engine operating characteristics before and after an actuation command, generate a delta slope, and compare it to a threshold to detect failure events, allowing for timely control actions to resolve issues without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional hardware components (e.g., pressure sensor) are added to detect latent failures, then detection capability is improved, but weight and cost increase
Solution Approach 1:
The patent replaces the mechanical/hardware-based detection system (pressure sensor) with a signal-processing-based system. The controller uses existing sensor signals to generate lagged signals and calculate slope differences, substituting physical hardware with computational methods to detect linkage failures without adding weight.
Solution Approach 2:
The patent creates a virtual copy of the expected system behavior through lagged signals. By generating a lagged version of the actuator command signal and comparing its slope with the actual sensor signal slope, the system creates a reference model that copies normal operation patterns, allowing failure detection without additional hardware.
2Reliability
If additional hardware components (e.g., pressure sensor) are added to detect latent failures, then detection capability is improved, but cost increases
Solution Approach 1:
The patent replaces expensive additional hardware (pressure sensor, linkage position sensor) with software-based signal processing using the existing controller. This substitution eliminates the need for costly additional components while maintaining failure detection capability.
Solution Approach 2:
The existing controller serves dual purposes: it continues to control the actuator while simultaneously performing failure detection functions. The controller uses its existing computational resources to process signals and detect failures, making the system self-sufficient without requiring additional dedicated detection hardware.
3Device complexity
If lag signals are used to detect valve movement, then detection method is simplified, but false positives increase when engine operating characteristics trend upward or downward
Solution Approach 1:
The patent takes the lagged signal concept further by not just comparing levels but comparing rates of change (slopes). By calculating the slope of both the lagged signal and the sensor signal, and then finding the difference, the system captures the dynamic behavior pattern, which is more robust to trending conditions than simple level comparison.
Solution Approach 2:
The patent transitions from static comparison (lagged signal levels) to dynamic comparison (slopes of signals). By focusing on the rate of change rather than absolute values, the system adapts to trending operating conditions and detects the dynamic pattern of actual valve movement versus commanded movement, reducing false positives.
Data Source
AI summary
Methods for detecting events, e.g., failures, in actuating systems for turbine engines are provided. In one exemplary aspect, a first slope and a second slope are determined. The first slope is determined by calculating the slope of an engine operating characteristic as a function of time prior to an actuation command. The second slope is determined by calculating the slope of the engine operating characteristic as a function of time after the actuation command. Thereafter, a delta slope is generated based at least in part on the difference between the first slope and the second slope. The delta slope is then compared to a predetermined threshold to determine whether a failure in the actuating system has occurred. Turbine engines configured to detect such events are also provided.