Make: Robotic Arms

167Chapter 9: Inverse Kinematics for 3D Movement

First, let’s take care of our top-down view. If

we were to rotate our point of view so we were

looking at our robotic arm from above, it would

look just like the image on the right. If we were

to graph this on a traditional (x, y) graph, it would

look just like a straight line. Even though all three

links are still shown, the result is a single line

with a length determined by the lengths of link 2

and link 3, as well as the angle between the two

links. This length is the variable, shown on our

graph (Figure

9-1

).

Though this first graph does a great job of

showing the rotation of the base of the ...