I used slow mo footage to improve the walking efficiency of my big dog quadruped robot. The video has clips of a few iterations showing progress. I improved the existing design with steering, more speed and better stability. I hope to get stabilization integrated into the leg geometry in the future.

1 L-Motor

1 Geek servo (Lego compatible) 1 Additional for stabilization

1 Radiolink R6FG RX

1 2 Amp ESC

Sorry for the non Lego radio. It is really good though.

Edited May 2, 20213 yr by MaxBrix

This is even more scary than the real Boston Dynamics one ;-)

Really impressive movement.

Very interesting leg design, and the stability system is simple but effective.  The dangling batteries at 3:55 had me laughing, as I've also temporarily attached batteries to test out mechanisms.  Overall great work, I'm looking forward to the next iteration.

Boston Dynamics Big Dog 4 (Speed Dog). I am trying out a new leg linkage design that has more stable compliance so it can handle non-smooth surfaces. It is also my fastest Big Dog.

 

Amazing build, Bravo!

It seems the balancing is done purely 'mechanically' i.e., without any smart sensors/algorithms.

That reminds me of canons on assault tracked vehicles, where the suspension is such that the canon can retain its aim and shoot while moving, even on uneven terrain, and all that was done purely mechanically.     

I wonder if one can use the part below for the legs. I bought few of them a while back for a similar project (though not as intricate kinematics) ... that never materialized.

The part comes in many variants and colors. The challenge is how to attach it without altering the dynamics too much.

https://www.bricklink.com/v2/catalog/catalogitem.page?P=32133ac01&idColor=9#T=C&C=9

Edited April 12, 20213 yr by DrJB

Big Dog 5 gets lateral hip motion for a 30% speed increase. Progress continues. Still only one L-motor, no brains.

 

 

Great stuff here. Amazing how fluid it moved.

If you want more power for no effort, come over to the dark side.

https://www.custombricks.de/motors-cables-sbrick/cada-power-functions-l-motor.html

These guys have near double the speed of a Lego L motor, and draw somewhere around double the current. It's not just empty revs neither, the torque is also a lot more.

 

Yoo I was happy I read the title first and knew it was called "Big Dog six", otherwise the music might have lead me to understand something very questionable  was that intentional?

Anyways I really enjoy this project thread 

1 hour ago, Gray Gear said:

Yoo I was happy I read the title first and knew it was called "Big Dog six", otherwise the music might have lead me to understand something very questionable  was that intentional?

Anyways I really enjoy this project thread 

Just a happy accident.