Having a problem with the Toddler

Shaun

Hi everybody -

I am working on getting my Toddler to walk, but I'm have a few difficulties that I can't quite seem to figure out. When my robot attempts to stride, the brass right-angle wires that hold together the stride linkages slip, so that the servo motion isn't being fully transmitted to the legs. I'm sorry, I know I'm probably not describing this properly, without the proper terminology - this is my first robot, so accept my apologies!

Here's a crude diagram of what happens on the first stride. The robot starts centered, then on the first step, the right-angle wires slip, and the robot is leaning backwards on a pretty seroius angle (125 degrees, I would estimate). So the first "image" is the robot at the start (centered), and the second "image" is the position of the robot after one step.

    ----------                   ----------
    |        |                   |        |
    ----------   first step      ----------
    ||     ||      ------>        \\     \\  
    ||     ||                      \\     \\
    ||     ||                       \\     \\
   ----   ----                      ----    ----

After this, the walking motion is severely stunted; for some reason, walking backwards is a bit less problematic. I guess my first question would be, why would these right-angle wires be slipping in the plastic brackets - should they be doing this (in other words, am I chasing a red herring)? It may be worthwhile to note that, if I hold the robot off the ground, the wires do not slip in the brackets - the stride looks pretty smooth, and looks like it should work.

Here is a "diagram" of what I mean by the wires are slipping:

 \|-------------   ------->   |-----\--------
  |\                          |      \
  |                           |

Another question would be, does anybody have any video of a working Toddler that I could examine? I am running the simple programs from chapter 2, if that helps.

Thanks for any tips. I'm having fun, even with the struggles (perhaps partially because of them!).

Shaun

PS - my wife has my video camera right now, but she will be back tomorrow; if a video would help demonstrate my problem, I'll attach one to the post.

hover1

Toddler videos here:

·http://www.parallax.com/Resources/VideoLibrary/ToddlerRobotVideoLibrary/tabid/542/Default.aspx
·

Shaun

Thanks, hover1!

dandreae

Were you able to get it to work properly?

Dave



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Dave Andreae

Parallax Tech Support·

hover1

Are these the "wires" in question? The screws need to be pretty tight. Make sure they are long enough to contact the wire and not have the head of the screw bottom out on the pushrod connector.··

Here is a "diagram" of what I mean by the wires are slipping:

 \|-------------   ------->   |-----\--------
  |\                          |      \
  |                           |

Shaun

hover1 -

That photo is a TREMENDOUS help! I haven't had a chance to look at the robot yet, but I feel like with that closeup of the stride servo, and the videos at the link above, I will be able to diagnose the problem.

Dave -

Thanks for checking in. I probably won't have much time to look at the robot until this weekend, but if I have further troubles I'll let you know. Let me just say that the support from this company is incredible, and from someone in the computer software industry I know how rare that is. I plan to keep coming back to Parallax as I sharpen my robotics skills. Thanks again!

Shaun