Geometric deisgn of planar four-bar mechanisms
Bibliographic record
Abstract
Outstanding issues concerning systematic design procedures for planar four-bar mechanisms, specifically three aspects hitherto not addressed, are treated in this thesis.These include • Advance-retire crank angle ratio for crank-rockers,• Angle ratio for double-rockers and,• Lead-lag angle ratio for double-cranks.This thesis aims to introduce a systematic method to determine parameters of planar four-bar mechanisms which specify a unique mechanism design.The design procedures introduced are based on the geometric properties of mechanisms.The symmetry of these geometric formulations makes it easy to find a unique mechanism design for defined design parameters.Moreover, the relations derived can be conveniently programmed and implemented in "Computer Aided Design (CAD)" algorithms.The equations, which are revealed for the first time in this thesis, can be used to determine a unique planar linkage design for specified design parameters.These design parameters are such characteristics of the mechanisms which are of particular importance to the designer, i.e., link lengths, assembly sequence and choice of fixed link.All design parameters and design formulations are dimensionless, giving this opportunity to the designer to select ratios instead of size.Crank-rocker, slider-crank, double-rocker, and double-crank mechanisms are studied in this thesis.The design parameters are: The ratio of coupler length to crank throw radius to address thanks to my lab-mates, CIM members, and all my good friends specially Payam Rahimi Vahed and Vahid Raissi Dehkordi, who helped greatly in translating the abstract into French.I appreciate the help of Mrs. Joyce Nault in guiding me in the procedure of submitting my thesis.Finally, I am thankful to my parents, who were always at my side during my study
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".