walking machine

Walking machines are quite easy to make.
This is a simple walking machine made from bent wire, it runs off a single AA battery.



This is a drawing of the crank/foot mechanism







If large cardboard wheels are substituted for the rockers the action becomes more interesting: make domed covers for the ends of the crank to make it self-righting.



When the wheels meet an obstruction the motor starts driving the crank round, the spinning eccentric weight of the motor & batteries causes the robot to jump up & down and the foot oscillates, this frees the robot from the obstruction.

This one has two offset setscrews instead of a crank


It is much simpler to make and works just as well.



movie
slightly different version on youtube




They are quite aesthetic



This one has a foot, the design of the foot is quite important, paradoxically it seems that if the foot has a freely-rotating wheel (see top of page) it works better.







This is a more sophisticated version, it has 2 AA batteries rather than 2 AAA, they are attached one behind the other so that the batteries & motor are balanced round the axle; an important feature of these machines is minimal moment of inertia (ie keep all the heavy bits as near the middle as possible)



The left-hand wheel is free to rotate around the axle



however the other wheel is tied to the axle by a bit of rubber band, so it can only rotate by about half a turn whereupon it starts to spring back



so it effectively has to rotate with the axle. The foot is loosely hinged through a hole in the the wooden pulley, it is also springloaded with a bit of rubber band



these machines are very responsive to small changes in weight distribution & other minor design changes. Someone ought to make one using an RC motor & Lipo battery, about half the size or even smaller.

flying version




This one works by twiddleing your thumb and forefinger









These things either walk down a gradient or can be pulled along by a bit of thread & a weight



The feet need quite careful adjustment, this one has 'shoes' made from semicircles of card: they should just project below the main cardboard rocker at the 6 o'clock position. Minor differences in adjustment will cause it to deviate from a straight line



similar toys on youtube
latest youtube
They need to be made from heavy photo-quality paper, normal inkjet paper is just a bit too flimsy. It might be strong enough if the toy were made a bit smaller, but then it would be very difficult to adjust the feet



This is a recent design makeover: round rockers with axle 5mm off centre, radius 5mm less than the body. Axle goes through body 5mm below centre.
No end-stops




eLEGS exoskeleton
Buy one: only $20. Looks like it's gear ratio is too low. My ones work because the dynamic forces of the rotating motor/batteries are quite big
link to sodaplay
paper kinetic horse
lego
Littledog robot
steam powered
related ideas
Starfish clip
Halluc II clip
link to toploading washing machine gearbox (similar mechanism)
good site for motors etc
The Lost Thing
Hamster powered walking machine
similar but wind-powered
good site for motors, gearwheels etc
the war of the worlds

the war of the worlds in french



my email is davidvwilliamson@hotmail.com
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and finally...........