I’ve just noticed that on about three of my legs have significant play in the position of the feet with all the joints static. I’ve had a look at the legs in some detail and it appears that some of the hip parts don’t fit the servos very snugly.
Has anyone else noticed this? Anyone tried to rectify? I’m hoping that I can shim this mounting somehow to reduce the play, thus making the legs’ feet position more repeatable through movements.
I suspect it’s because of the inaccuracy of the cutting of the pieces. Because of the cutting angle on the laser I have some legs with a 10-15 degree rotation along the leg between the foot and the hip. This means the foot is not completely flat when everything is zero.
Even with a shim, I wonder about the accuracy of the servos. It may be very difficult to get exactly the same position each time, given that the slightest difference in angle at the hip causes huge displacement of the foot.
I’ve actually just done a measure of the accuracy of the stock servos (on a sample of one, I accept), which shows around a +/-3 degree absolute error over the range of motion. Critically, the servos would move back to the same positions to within half a degree, so the repeatability is very good.
Might have an opportunity to shim the servo mountings later today.
Some tightly folded kitchen-foil pressed into the hip joint piece which the servos mounts into has really firmed up the legs. Very pleased with this little modification. Also noticed that previously the “set-zero” command encouraged some vibration in the hip joints of the (looser) legs, which has now totally gone away!
try using circuit board stand offs, metal or plastic will do.
The metal ones are obviously stronger.
you can get them at any computer part store.
they have different lengths and have different thread lengths.
You will have to experiment with lengths to get the right ones for your Hexy.
Get matching thread bolts or screws to attach to the body, use washers and a nut on the leg side and nail polish to lock the nut in place.
There may be a small bit of play but you can try different thickness of washer to compensate.