sorry for very newbie questions, I'm very new to all this.
I would like to build a robot which can draw curves with a pen. The size of drawing area would be something like 30 x 40 cm (A3), it would plot just in 2D so X and Y only. And for now, the pen could just either touch the paper or not (i.e. no Z, or pressure) and is just glued to the arm.
I really would like it to be very precise (so it could draw straight lines or circles or Bezier paths, even very small ones, like 6 pt letters). It doesn't have to be very fast and it's ok to have complex software. I also like Arduino, if that limits the choices down a bit. Oh, and cheap is ok, too.
My questions are:
- What "kind" of robot do you recommend? Should I go for "Cartesian" type, like:http://www.garagefab.cc/contraptor
or "Scara" type, like:http://maschinenringraum.blogspot.com/2009/06/articulated-plotting-robot-for-10.html
- What kind of steering should I use? Servos, DC motors, steppers? Isn't it the case with steppers that to draw a curve first it has to be broken up to many tiny lines?
- It is possible to know when a line to draw ends so the robot could gradually slowdown - what kind of motor do I need for this? Is it possible to regulate the speed of simple DC motor, say by this thing "PWM" (pulses)?
- I like that Scara-one very much, however it seems to be very imprecise (~0.5 cm). Is it possible to improve it? I mean, maybe I need to get some servo with say 10 degrees precision, attach it to a gear box with 1000 : 1 ratio and for the size of arm like I want it would more than precise?
- Does it make sense to put all the gears and motors off the arm and to somehow couple its rotations to the joints? Or maybe the servos are so light that this is not needed?
- For lifting and lowering the pen is it ok to use solenoid?
Well, sorry once again for such a basic questions and thanks for any answers!