So my previous post had several significant math errors in it and has been deleted accordingly.

Hopefully this post will have no math errors. If you find any, please point them out.

My idea at some point is to build Bob Wally with a bit of a twist. I'm going back to the DLCJ on the wrist, as well as a DLCJ on each shoulder.

This approach is very one sided, so I have reassigned the variables.

The line between the shoulders is Y=0.

Prime marks designate the far side arm.

A is the arm length.

B is the distance from the shoulder to the wrist joint.

C is the angle between the shoulder line and B.

D is the angle between B and the upper arm.

E is the distance from the elbow to the point(x,0).

F is the angle between the shoulder line and E.

G is the y-height of the elbow.

H is the distance of x (l-x on the far side) plus the x-length of the elbow.

K is the angle between the y axis and the extruder stub arm.

L is the distance between the shoulders.

M is the length of the extruder stub arm.

Xe is the X offset of the extruder.

Ye is the Y offset of the extruder.

derivative, not used

derivative, not used

derivative, not used

derivative, not used

By my count (at 23:00 with work in the morning)

2 square roots, 4 multiplies, 2 addition that we have to do for free to drive the elbows. (B)

4 square roots, 12 multiplies, 2 addition, 2 subtraction (E) also gives us

for later use.

2 square roots, 8 multiplies, 2 division, 2 addition, 2 subtraction (G) remember we have

already.

2 square roots, 4 multiplies, 2 subtraction (H)

1 square roots, 4 multiplies, 2 division, 2 addition (Xe & Ye) I only did H+Hprime and G^2+H+Hprime once each.

The total damage comes to :

11 square roots, 32 multiplies, 4 division, 8 addition, 6 subtraction

Using the figures in this blog:

http://markdow.blogspot.com/2011/06/blink-of-eye-processing-on-arduino.html I calculate that this will take a grand total of 1.12 milliseconds, or 892 operations/second if we use floating point math. Is this fast enough? Or do I need to do all of this in integers to achieve 0.638 milliseconds, or 1,560 operations/second?