Pi Biped Robot walking

[mikerr]

Not another quadcoptor, a proper biped robot!


I had this previously running - walking! - in arduino, but the pi makes more things cheaply possible (like vision, wifi etc)

He's currently still learning to walk under Pi control .

The legs have 6 servos being controlled by servoblaster.

AFAIK servoblaster can only do a maximum of 8 servos, so when arms and head are added I might have to offload servo control to an arduino.

[Ravenous]

So many wires, so little time!

Six servos - can you spell out what they do? I can see the ankle sideways tilt, and maybe a knee/ankle above that. I can't see if the hip has something to twist the leg, or to swing it fore/aft.

The batteries on the head is a good idea - probably helps reduce the sway frequency (if that's the right word).

[mikerr]

Ankle is tilt left/right

Knee is forward/backward

Hip is forward/backward

[simplesi]

What's the basic walk sequence?

Simon

[mikerr]

He just took his first steps without falling over:



http://www.youtube.com/watch?v=lgWbgvLjzlY

[Ravenous]

Awww, that looks so cute

That reminds me, almost time for my next AA meeting . (Only kidding.)

[mikerr]

Hehe, he's already broken part of the top from a drunken fall...

Need to use the knee joints more - then he can walk with less lean, or longer strides.

[Ravenous]

Yeah a bit of knee lift will help, but might also require simultaneous balance from the other leg... Not dared trying any of this myself but planning and programming robot gaits looks very complicated to me...

Still, at least even now he walks better than I dance.

[mikerr]

My nephew Jake (age 8) decided the robot needed dressing and also added cardboard arms and head

Here's the results of his handiwork:


https://www.youtube.com/watch?v=5OQgIfOEktk

As you can see pi-bed also now goes left/right by varying the individual leg's stride length

[mikerr]

Kicking a ball:


https://www.youtube.com/watch?v=noObFbk ... ata_player


This runs the knee/hip servos at full speed, instead of slow smoothly interpolated sweeps like used in walking/ leaning

E.g.

Code: Select all

Servo.hip = 90
Servo.hip= 140 

vs

Code: Select all

For sweep in range (90, 140):
          Servo.hip = sweep
          time.sleep (0.1)

(Not actual code)

Next step is to give it some autonomous behaviour (HC-SR04 ultrasonic sensor and/or camera )

[raygeeknyc]

This looks great! kudos!

I was thinking about how to best spend 2 more servos. I think that an arm with one DOF - up-and-down and a gripper would yield a good ROI. In theory, you can position the bot side to side already and you could mount a small camera on the arm. The only problem remains one of balancing when you actually pick up anything substantial, can your robot "lean back" and still walk?

[mikerr]

Servoblaster is no longer limited to 8 servos - it's just been upgraded to support up to 21 servos now (17 on a Rev1 Pi)
http://www.raspberrypi.org/phpBB3/viewt ... 77#p420177

So using a couple more servos on arms / head /torso isn't a problem - though the weight (distribution) might be.

I've moved the weighty batteries down directly onto the hip now, so there's more torso movement possible without falling over:


and he can now sit down / lie down after a long day


http://www.youtube.com/watch?v=PEIbgrYKP0I

[Inventor_Tommy]

Hi

I am keen to get started on a similar project. Do you have an instructables or have your code available on github or another opensource location? It would be really great if your code was shared It would make robotics 101 available for the novice and robotics learner (myself ).

Regards
Inventor_Tommy

[mikerr]

Yes all my code is shared on github

http://github.com/mikerr/biped

[Inventor_Tommy]

Thank you

[LinuxCircle]

What batteries did you use to power the 6 servos? How many Amps are required in total? Is 3A sufficient for 6 servos?

Wiring scheme would be appriciated

[[avi]]

I was searching for something and landed up on this 2 year old thread.

So...you got any noob level instructions?

[LinuxCircle]

I was searching for something and landed up on this 2 year old thread.

So...you got any noob level instructions?

We built a biped robot and posted Noob Level instruction here: http://www.linuxcircle.com/2015/04/06/l ... -pi-robot/

Let us know or comment on the page if you need further assistance