Let's Make Robots!

The way we walk...

jka's picture
Walks straight ahead
AttachmentSize
FourServoWalker-080617a.zip65.31 KB

This is an attempt to build a walking biped with only 4 servos, since that's what I have left right now. Since I don't have any video recording equipment right now, I'll try to describe how it walks. It start by tilting left to put all the wight on the left foot and lift the right foot. This is done by turning the left foot servo to the left, while turning the right foot to the right to support the robot as far as possible in the tilt, like this:

IMG_8568.jpg

When the left servo turns further to the left, the weight will be on the left foot and the right leg will be lifted:

IMG_8569.jpg

After the leg has been lifted, the robot will use the other two servos to move it forward. At this point, I always reach out for it, because it looks like it's going to fall:

IMG_8574.jpg

 

Next step might be to add a gyro or acceleratometer, so it might adjust itself, if it's going to fall.

The "brain" is an Arduino that is mounted on a perf board. Only port 0-7 are connected because, the Arduino designers have, in their infinite wisdom placed the connector for port 8-13 half a unit from the 0-7 connector, so it won't fit on a standard perf board.

Perf board with connectors

I'll add a video next week, when I get my hands on a camera that can record video (no, there is no camera in my phone and my webcam doesn't work)

 

UPDATE: Video available.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

hi Jesper,

can u send me the modified servo library. the link on the first page seems to be broken.

echorobotics's picture

hey, nice.  that was what my origional design was, but i liked the more humaniod look better, personally.

 

love the autonomy!

Hi, I am new to robotics. I have a Arduino and some servos. Could anyone please explain me in detail that how do you control 4 servos with the Arduino. Please give me diagram, source code etc whatever is possible and you think a new comer like me will need. Thank You.
jka's picture

Pressed "post" twice... Deleted the copy

jka's picture

Hi,

I haven't looked at this for some time and I'm not sure that I have the sourcecode any more. But take a look at the arduino servo library: http://www.arduino.cc/en/Reference/Servo. After version 017, it should be able to control up to 12 servos. I haven't had a chance to test this. Otherwise, look at the servo lib I used: http://www.arduino.cc/playground/ComponentLib/Servo.

Good luck

tried that butto no avail :(
jka's picture
What errors do you get? I must admit it's been a long while since I played with that code and the walker is just lying in a shoebox right now.
the main one is error:'refresh' is not a member of 'servo'
jka's picture
That sentence doesn't make much sense, but if you are having a problem with the servo library, make sure that you use the correct one. I used this one: http://www.arduino.cc/playground/ComponentLib/Servo
crazyraver's picture

i did a little testing and you need the modified servo library

i have hosted it on my site so click here to download

on the regular servo library reshresh is not defined as a function