Configuration bifurcations in axisymmetric vector exhaust nozzle (AVEN) and their adverse effects on vector deflection certainty
Bibliographic record
Abstract
An axisymmetric vectoring exhaust nozzle (AVEN) driven by a 3- SPS /3- PRS parallel manipulator is designed to universally vector the exhaust flow of a variable-geometry Laval nozzle (VGLN) surrounded by multiple groups of convergent and divergent flaps suspended by RSRR kinematic chains. The inherent singularities in parallel manipulators cause the 3- SPS /3- PRS parallel manipulator and the RSRR kinematic chains to produce configuration bifurcations, deeply hidden in parallel manipulators and difficult to perceive. They cause the mobile platform not to be controlled by the input parameters at the bifurcation points, leading to disastrous consequences to the flight safety and control reliability of the parallel manipulator applied in the aerospace field. To explore the configuration bifurcation characteristics concealed in the VGLN and RSRR kinematic chains, the joint coordinate variables of the RSRR kinematic chains and the output parameters of the VGLN are employed as bifurcation variables. The configuration bifurcation points corresponding to these bifurcation variables have been marked on their respective configuration curves using the extended equation and the homotopy method. This study reveals, for the first time, the adverse effects of the bifurcation behaviors associated with the RSRR kinematic chains and the VGLN on the gained singular movements and the flight safety of jets equipped with the AVEN. By analyzing the generating mechanisms of singular movements at the kinematic joints in the bifurcation points, several constructive suggestions are proposed to enhance the flight safety and control reliability of the AVEN.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".