Actuator Degradation Detection Using Dynamic Displacement Envelopes
Solution Overview
Problem
Existing methods for monitoring actuators are limited in detecting degradation, are complex, and often specific to a particular actuator architecture, failing to effectively detect oscillations, bias, and drift in displacement signals.
Innovation Solution
A system comprising a sensor monitoring unit, trigger unit, parameter and state estimation unit, and isolation unit, which uses a memory unit to store actuator data, computes dynamic envelopes of admissible values, and identifies parameters responsible for displacements outside these envelopes, allowing for the detection, isolation, and estimation of actuator degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art methods are used for monitoring actuators, then the monitoring system is limited to specific actuator architectures, but the method fails to detect degradation of actuator components
Solution Approach 1:
The patent creates a universal monitoring method that can detect degradation across different actuator architectures (electro-hydraulic, electric, pneumatic) by using a common mathematical model and signal processing approach. The method analyzes displacement signals and command signals in a architecture-agnostic manner, enabling the same degradation detection system to work with multiple actuator types without requiring architecture-specific customization.
2Reliability
If prior art methods are used for monitoring actuators, then the system is simple to implement, but it cannot detect oscillations, bias, and drift in displacement signals
Solution Approach 1:
The patent segments the degradation detection process into distinct functional modules: a sensor monitoring unit that detects oscillations and anomalies in displacement signals, a trigger unit that identifies when degradation thresholds are exceeded, and a parameter estimation unit that quantifies degradation parameters. This segmentation allows the system to maintain high detection accuracy while organizing complexity into manageable, modular components that can be implemented systematically.
Solution Approach 2:
The patent introduces mathematical models as intermediaries between the raw sensor signals and the degradation detection logic. These models (including dynamic envelopes and admissible value ranges) serve as mediators that translate complex signal patterns into interpretable degradation indicators, enabling accurate detection of oscillations, bias, and drift without requiring direct complex signal processing in the control logic.
3Measurement precision
If dynamic envelopes of admissible values are computed, then the system can detect displacements outside normal ranges, but additional computational resources are required
Solution Approach 1:
The patent computes dynamic envelopes of admissible values selectively rather than continuously for all operating conditions. The system calculates envelopes based on current operational context and only performs full computational analysis when degradation indicators are detected, using partial computation during normal operation and excessive computation only when needed for accurate threshold detection, thereby balancing precision with energy consumption.
Data Source
AI summary
A method and a system are disclosed for detecting, isolating and estimating a degradation of a corresponding component of an actuator controlled by an actuator command signal, the method comprising obtaining a control signal of the actuator; obtaining a signal indicative of a displacement of the actuator; computing an envelope of admissible values for the displacement of the actuator; determining if the displacement of the actuator is outside the computed envelope and in the case where the displacement of the actuator is outside the computed enveloped computing an estimation of each parameter and state of the actuator; identifying at least one corresponding parameter responsible for causing the actuator displacement to be outside the computer envelope and providing an indication of the at least one corresponding parameter.