i posted about my hexapod project “Spider P.I.G” here a while ago. Now it’s completed as in being able to walk. But I am not satisfied, at all (even though everyone around me keeps telling me that it’s perfect and super cool). The legs keep bending and it’s even worse trying to put some weight on it. It can’t even walk in a straight line!
My goal is to be able to put an EEE PC (about 1 kg) on it, acting as the brain. So, I need your help fixing the construction. The problem is that I’m quite limited in tools and materials. I don’t have things like ball bearings or servo brackets nor the money for it. So what i want is some tips on how i could fix things with limited means.
I have already started shortening the legs. Both tibia and femur are 10 cm right now. I’m thinking of shortening them to 5 cm.
What could i do with the femur? I shouldn’t have them only attached to the servo horns, right? I could need a connection on the bottom of each servos. Any ideas how i would construct that with things one commonly have lying around in a workshop?
So what tools and materials do you have? Do you have wood, a saw, glue and such basics? Unless you employ some advanced programming, a significant amount of slippage with the walking surface will probably be required. Looking at the video, I see side legs that appear to be some what collapsed under the body. The flat flexable upper leg part can be braced if it flexes too much. You probably need to be specific as to the mechanical issues that need to be fixed.
I agree on both counts. The material is way too thin. You can see it twisting and bending in the video. You will need to redesign the legs. And they are too long.
It also looks as though the legs are “over-shooting” their target. And then trying to move again before they actually touch the ground. Once your legs are not twisting, you will be able to fine tune the programming better. It looks pretty cool though.
Yeah, but thats just in that video, and for one leg. A servo on that leg broke before the video was recorded so the leg wasn’t right adjusted. It was on a robot club meeting so thats why i didn’t fix it any better before recording.
Anyway, thanks for the tips. I’ve already considered shortening the legs. What do you say about the tibia? Does it need to be shortened? Or is it better leave it longer. I would actually like the femur and tibia and femur the same length, but if it’s better leaving the tibia longer i will do so.
Also, I knew an extra panel for the femur would be needed. It’s just that I don’t have an idea about how to construct it. I really don’t want to have to order anything, so do you guys have any idea how i could make it with some common things in a workshop. What i need is something like a servo hinge and something replacing the ball bearings. I saw that zenta used something called copper bearings on his octapod. Is that some homebrew parts or is it something you buy?
