> I want to simulate a robotic arm which has 4 joints.There is an
> example given in the LabVIEW examples section which can be located in
> the Examples>Advanced>Picture control.This example has three joint
> robotic arm simulation. The block diagram given is very complicated
> and is difficult to modify for four joints since I am unable to get
> the basic algorithm behind it. It would be good if some one could
> please explain me the basic algorithm and a way to modify the given vi
> for 4 joints.It would be nice if some one could post some fresh idea
> for simulating a robotic arm. I do not need graphics. In my case a
> straight line having 4 joints will serve the purpose.
Sorry if it is a bit difficult to follow. Screens are much larger today
than they used to be, and the 3D stuff makes is seem more complicated.
The backbone of the example is the Pt On Circle VI. It gives you the
important projected point of each span of the arm. The rest is really
just fluff. Given a point between two spans, the span is drawn, then
the joint over it. Many of the wires are due to colors and the silly
ratio that makes the arm look more realistic.
If I were you, I'd delete each call to DrawJoint and connect the picture
in to the picture out. The DrawJoint VI has no outputs except for the
picture, so no node is dependent on them except for the picture. Remove
bad wires by hitting Ctl-B, and you should be able to run the VI again.
Notice that the joints are still drawn as trapezoids connecting the
points, but no joints are drawn. The color and light direction can be
deleted and when run the trapezoids will now be a greenish color as that
is the default color. Next you can build a simpler Draw span VI and
build a new VI that draws a line between the two points. The circle
info is used to make tangential endpoints, make the two ends of the
spans different sizes, and draw the lines different colors to indicate
the location of the light.
So, after all that you are left with an initial point where joint0 is
based, PtOnCircle takes the angle and length of the span0 and returns
the second point, joint1. Use those points to draw the first span. Use
PtOnCircle with the joint1, angle and length of the next span to find
the next point...
Basically, this is all the VI really does.
Hope this helps.
Greg McKaskle
