Four-bar linkage
Four sticks joined in a loop: a fixed ground, a crank that turns, a coupler and a rocker. Change their lengths and watch the path drawn by a point on the coupler.
Figure of eight: the path crosses itself
Jansen leg
Theo Jansen's leg, with every length in mm. Change any of them and see how the foot moves: how long its stride is, how high it lifts, and whether the leg jams. The body is held still here, so the foot moves backwards along the ground while the beest walks forwards.
| This leg | Jansen's | |
|---|---|---|
| Stride | ||
| Step height | ||
| Time down | ||
| Closest to jam |
Stride: how far the foot moves while it is down. Step height: how high it lifts. Time down: how much of each turn it is down. Closest to jam: how near the tightest pair of sticks comes to not meeting.
Evolve a beest
A genetic algorithm breeds whole beests. In each generation the beests that score best are the most likely to pass their lengths on to the next. Try hill climbing and random search too, with the same number of evaluations, and compare them on the graph. To score and mutate the beests with your own Python, choose my code.
Arena
A whole beest on the ground, with gravity, friction and the weight of every stick. Its feet can slip and it can fall over, which the scores in Evolve leave out. The crank turns once a second, as a motor would turn it.
| Crank turns | |
|---|---|
| Distance walked | |
| Distance per turn | |
| Still upright | |
| Race |