Possible to control robot arm at interactive rate?

ithrak · October 10, 2009, 10:33pm

Hi folks,

originating from computer graphics I’m completely new to the topic of robotics, so I’d be glad to get your support on this: Just to get this right, if I control a, say, AL5A robotic arm via COM port (most likely I would use MS RDS), is it possible to control the arm in realtime? If so, what latency do I have to expect?

Cheers,
ithrak.

robotdude · October 12, 2009, 2:19pm

I don’t know anything about MRS, or MSRDS for that matter. But all you need to do to move the arm is send ascii commands. The SSC-32 manual illustrates these commands.
lynxmotion.com/ViewPage.aspx … ID=70#serv

I’m guessing the latency would not be more than 30mS because PC’s are pretty fast calculating IK math and most people update the SSC-32 every 30mS. Hope this helps…

eddieb · October 12, 2009, 5:26pm

I would say it most certainly is possible. for an example look at this thread and the associated video on youtube.

robotdude · October 12, 2009, 5:36pm

Note, that thread and video illustrate the arm controlled directly from the Bot Board II and Atom Pro 28 processor. No PC was used in this project.

eddieb · October 12, 2009, 5:44pm

Knew there was no PC, guess I didn’t realize there was no SSC-32. Figured you were pumping the servo commands through an SSC-32 from the BAP/BB2. Still shouldn’t be a problem if the update rate is kept in the 30ms range (presumably using 115.2KBaud from a PC).

ithrak · October 12, 2009, 11:44pm

Thanks for the replies, guys! 30ms ought to be fast enough for my intentions.

zoomkat · October 13, 2009, 4:24am

I wrote a simple pc program using another programming language that takes input from a joystick and outputs to a servo controller via the serial port to pan/tilt a two servo pan/tilt cam. Pretty much real time with no noticable control lag.