IDENTIFYING THE 1-DOF-LOSS VELOCITY-DEGENERATE (SINGULAR) CONFIGURATIONS OF AN 8-JOINT MANIPULATOR
Bibliographic record
Abstract
This work presents the determination of the velocity-degenerate (singular) configurations of the National Aeronautics and Space Administration (NASA) Advanced Research Manipulator Π (ARMII). A previously developed reciprocity-based methodology for identifying the 1-DOF (degree-of-freedom) loss velocity-degenerate configurations of redundant manipulators is successfully applied to the 8-joint ARMII. It is shown that four sets of conditions (one requiring the satisfaction of a single condition, one requiring the satisfaction of two conditions, and two requiring the satisfaction of three conditions), defining families of degenerate configurations resulting in a single motion DOF loss, exist for manipulators having geometries kinematically equivalent to the ARMII. In addition, reciprocal screws characterizing the lost motion are found for each degenerate configuration. The presented degeneracy conditions are complete and they correct erroneous results previously reported in the literature by other researchers. The results also show that partitioning the matrix of unit joint screw-coordinates to identify velocity-degenerate configurations does not work for redundant spherical-wristed manipulators.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".