Yes, math is required! Just simple trig. Basically, calculate a coordinate on your circle (is it flat on the table, at an angle, or vertical?), then do the IK calculations to move the end effector (pen in the gripper) to that point. Repeat for all points. I think I saw some IK for an arm somewhere on this forum.

Actually, this little task makes the arm sound interesting! I might have to build another arm (an LM arm this time)!

Bane wrote:

thanks, so if i want the head of my robotic arm to do that (simular to this one

http://www.lynxmotion.com/images/jpg/sesa01.jpg) i would need to do some math with the X and Y to have all the servos move the head in a circle movement, right? How do you get a servos variable (a word) proportional to a byte? Also, the atom must sent out every coordinate (with in increments) to the ssc-32; would i just keep adding a constant some variable to get this motion?

Bane

EddieB wrote:

Hmm, while that approach will certainly work it is computationally intense. You might want to google the works of somebody called Bresenham which have a great deal to do with rasterization of functions like lines and arcs and ways to optimize their rendering. Yes I am deliberately sending you guys off on a research project because if you have never done anything with this you will be thrilled at how simply efficient plotting things can be with a few conditionals inside of for..next loops. ;)

I suppose you could use Bresenham's algorithm. I've never found it useful except for on-screen graphics. As I recall, these algorithms tend to calculate points in all four quadrants at the same time. OK for screen, but not so useful for plotter and motion control applications.

I suppose one could calculate a table first (get four table entries at a time), and then go through the table. You could also run BASIC first just to calculate the coordinates needed, and build a table. A small sine table could be used if desired.

Alan KM6VV