Circular motion into variable alternating rectilinear motion, by…
Circular motion into variable alternating rectilinear motion, by the wrist or crank-pin on the rotating disk working in the slot of the bell-crank or elbow-lever.
Only the input is driven; every other part of this model moves by physics (MuJoCo), and its ratios are measured. Run it live, change its parameters, or switch the friction off to see the output stop.
- Modelled as
- A disk (the one driven joint, 12 rev/min) carries a crank-pin 3.5 cm from its centre in the slot of one arm of a bell-crank pivoted 9 cm away (the pivot is outside the pin circle, so the bell-crank rocks through 22.9 degrees either way); the bell-crank's other arm, 12 cm long, carries a pin working in a slot across a sliding bar, which is carried 4.7 cm each way: gen156.py.
- Measured
- Bar follows the bell-crank at -0.1196 m per rad (r2 1.000) and the bell-crank follows the disk at 0.2554 per rad over its return swing (expect 0.2535, r2 0.998), two cycles; bell-crank -0.414..0.411 rad, bar -4.91..4.95 cm; the bar's speed varies through the turn. Penetration within the limit.
- Notes
- The pins and the rails of the two slots are two contact classes (the pin of the disk and of arm 2 one, the rails and the bar's cheeks the other); the bell-crank and the bar are free (slot walls only); a plan movement (gravity off).
Film (MP4) · GIF · Still (PNG) · Spec (YAML) · Model (MJCF)
