Thingiverse
Chebyshev Lambda walker by ekowi
by Thingiverse
Last crawled date: 4 years, 5 months ago
Print this set, mount on a base platform, add batteries, connect with your favourite controller, and go!
This is an implementation of the Chebyshev's Lambda mechanism for converting rotary motion into walking motion, which is very flat compared to others like Klann linkage or Theo Jansen linkage. The walking "point" or locus is located above the mechanism so the foot must be extended down from that point. Rather than making another lambda linkage for the rear support point ("hind legs"), I duplicate the movement with parallelogram linkage so the front and back "legs" are connected together with a "foot".
In this design, two feet are connected together with 180 degree phase shift with a crank. The rotary motion source is the planetary gearbox (https://www.thingiverse.com/thing:2733387). Two sets of this will support a vehicle with differential drive.
I put 2x 18650 lithium batteries (~8 volt) for those poor 3 volt motors, and with 20% duty cycle it already runs on the floor! Already broke the crank with too much power. The motor and controller gets hot too. Servo motors are just too expensive.
Video: https://youtu.be/kv6pAXbO2gc
One set consists of:
1x base
1x crank1, crank2, crank3
4x barA
2x barB
2x barB2
2x barC
2x foot
1x planetary gearbox without the wheel
There are holes which need to be tapped for 3mm screw while others are for free rotation of the screw as axle.
The tapped holes are:
horizontal holes on the base
3 side holes on crank1
hole on the end of barB
hole on the large end of barB2
holes on barC
The screws joining the bars are not tightly set but allow for free movement, then a nut is put to hold the screw to the tapped hole end.
Update 25/12/2018:
Second version: https://www.thingiverse.com/thing:3312413
This is an implementation of the Chebyshev's Lambda mechanism for converting rotary motion into walking motion, which is very flat compared to others like Klann linkage or Theo Jansen linkage. The walking "point" or locus is located above the mechanism so the foot must be extended down from that point. Rather than making another lambda linkage for the rear support point ("hind legs"), I duplicate the movement with parallelogram linkage so the front and back "legs" are connected together with a "foot".
In this design, two feet are connected together with 180 degree phase shift with a crank. The rotary motion source is the planetary gearbox (https://www.thingiverse.com/thing:2733387). Two sets of this will support a vehicle with differential drive.
I put 2x 18650 lithium batteries (~8 volt) for those poor 3 volt motors, and with 20% duty cycle it already runs on the floor! Already broke the crank with too much power. The motor and controller gets hot too. Servo motors are just too expensive.
Video: https://youtu.be/kv6pAXbO2gc
One set consists of:
1x base
1x crank1, crank2, crank3
4x barA
2x barB
2x barB2
2x barC
2x foot
1x planetary gearbox without the wheel
There are holes which need to be tapped for 3mm screw while others are for free rotation of the screw as axle.
The tapped holes are:
horizontal holes on the base
3 side holes on crank1
hole on the end of barB
hole on the large end of barB2
holes on barC
The screws joining the bars are not tightly set but allow for free movement, then a nut is put to hold the screw to the tapped hole end.
Update 25/12/2018:
Second version: https://www.thingiverse.com/thing:3312413