kmzvokel@bsu-cs.UUCP (Kenneth M. Zvokel) (12/16/88)
I'm currently working on a research project involving path generation for robots. I am trying to teach a robot to draw a number of geometric shapes on any plane (reachable) in the workspace. Does anyone know of any previous research in this area, or is there anyone that has done so themselve thank in advance Ken Zvokel
jbn@glacier.STANFORD.EDU (John B. Nagle) (12/16/88)
How did this get in here? Anyway, assuming that you know where the surfaces are, and just need to do the position control, the problem is straightforward. See "Robot Motion - Planning and Control" for the basics. ISBN 0-262-02182-X. If you only know approximately where the surfaces are, position to a point known to be off the surface and use force feedback to servo the pen onto the surface, with the force feedback operating only perpendicular to the surface. Then write, with the axes parallel to the surface controlled by the writing algorithm and the axis perpendicular to the surface controlled by the force servo loop. If you put some vertical compliance in the pen holder and provide the pen force to the controlling computer, that should be sufficient for servoing, assuming the pen is suitable for constant-force dragging across the paper, and not something exotic like a nibbed pen or a calligraphy brush. No matter what orientation the pen is in, this should work. You do all the writing and servoing computations in coordinates relative to the writing plane, then convert them to absolute coordinates, then compute the inverse kinematics and issue the commands to the robot. John Nagle