Quantitative Fault Tolerant Control Design for a Leaking Hydraulic Actuator
Bibliographic record
Abstract
This paper documents the design of a low-order, fixed-gain, controller that can maintain the positioning performance of an electrohydraulic actuator operating under variable load with a leaking piston seal. A set of linear time-invariant equivalent models of the faulty hydraulic actuator is first established, in the frequency domain, by Fourier transformation of acceptable actuator input-output responses. Then, a robust position control law is synthesized by quantitative feedback theory to meet the prescribed design tolerances on closed-loop stability and reference tracking. The designed fault tolerant controller uses only actuator position as feedback, yet it can accommodate nonlinearities in the hydraulic functions, maintain robustness against typical parametric uncertainties, and maintain the closed-loop performance despite a leakage fault that can bypass up to 40% of the rated servovalve flow across the actuator piston. To demonstrate the utility of the fault tolerant control approach in a realistic application, the experimental fault tolerant hydraulic system is operated as a flight surface actuator in the hardware-in-the-loop simulation of a high-performance jet aircraft.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".