Can you help us get our robot unstuck?

[DELurker]

It is an impressive robot. However, as other posters have asked, I'm wondering if it fits in the 54" cylinder with the bumpers mounted.

However, that's not what was asked. To detach the lower arm, your could grab the pyramid leg and give a little push. Alternatively, could you modify your gripper design to add a flange in the vertical direction so that it wraps behind the horizontal poles to take the load?

[Tem1514 Mentor]

I love the design of flipping end over end and will to try and suggest a possible answer that may or may not work is, using the video as a reference.

It may be possible to rotate the robot frame CW around the upper arm and at the same time rotate the lower arm CCW. This will have to done with great care so that as the load is changed from the lower to upper arm you robot doesn't just lose it's grip and fall off

Aside the 54 " possible problem you need to watch out for differences in height from one rung to the next which according to rules may be up to 1/4 inch but I would allow for at least 3 inches either way.

[tsaksa]

Originally Posted by Tem1514 Mentor

I love the design of flipping end over end and will to try and suggest a possible answer that may or may not work is, using the video as a reference.

It may be possible to rotate the robot frame CW around the upper arm and at the same time rotate the lower arm CCW. This will have to done with great care so that as the load is changed from the lower to upper arm you robot doesn't just lose it's grip and fall off

Aside the 54 " possible problem you need to watch out for differences in height from one rung to the next which according to rules may be up to 1/4 inch but I would allow for at least 3 inches either way.

Yes, I agree that this is what probably needs to be done, but if you study the contact points you will see that it may not currently be possible. Trying to rotate the robot frame CW around the upper arm will tend to push the robot frame down. And trying to rotate the lower arm CCW will tend to push the robot frame up. Both are not possible at the same time, and I think this is what ends up jamming the robot in place when it tries to change grips.

The design may need either an additional joint in one of the arms, or some ability to slide one of the pivot points a bit to allow this transfer to proceed smoothly. As it is, there may not be enough degrees of freedom in the system to allow the correct motion that can transfer the weight properly.

[thinker&planner]

It seems like there should be a "sweet spot" where it should release. You jut have to keep testing to find it, but you might consider opening up the grabber/hook part so that it is a little looser. This could be dangerous but might be enough to free it.
An alternative to the piston (If I were on your team, I would rather not add pneumatics for just one thing if you can do it with a motor) would be using a smaller motor (BAG or Bane Bots w/gearbox) and a cam/eccentric wheel to push away from the pyramid corner as you lift the bottom claw/gripper.

Regardless of how you end up doing it, you should definitely program the climb to be autonomous. If you find a sweet spot, it would be completely necessary to automise the climb.