Jim Jackson escreveu:
>On Sun, 20 Mar 2005, noone_1983 wrote:
>
>
>>Hey everyone,
>> I was wondering if anyone had any experience controlling hardware
>>(in this case a servo) with the board that needed to have precision
>>timing. The signal I generate on the output pin has to be a very
>>precisely timed series of pulses, and the nanosleep function just
>>doesn't seem to cut it running on the board. Any ideas?
>>
>>
>This is Linux - Linux is not a realtime OS - so there are limits to what
>it can do which might mean you can't do what you want to do - maybe :-)
>
>You could have a go at changing the number of timer interrupts per sec.
>You could maybe go at 1000/sec instead of 100.
>And do some of your signal generation in the interrupt routine.
>But then again that doesn't guarantee you anything - linux isn't an RT OS.
>
>You need to define what your timing requirements are, what margin of error
>you've got. What happens if, because interrupts are disabled for a longer
>than normal period or something else, the signal you generate is no longer
>accurate - can your hardware cope, can things be corrected?
>
>If no then maybe use a PIC to do some dedicated signal generation and
>timing.
>
>
>
>
Hi.
We're working on a RTAI port to this board so that RT could be achieved,
but it's not trivial and we're not ready yet. Even though, I wouldn´t
believe any servo controller could be directly implemented solely on
software. I'd think some PLD logic could be needed for pulse train
generation or PWM generation. It might be possible using a DtoA
converter to give torque ref to an analog torque controller, but that
doesn't sound good to me given today's standards. Since you're working
with a known hardware setup, it might be possible to have a servo
controller implemented in the kernel (since you know what's connected to
the board and how it's handled, you can have bounded interrupt latency
and jitter).
Ricardo
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|