let's add acc code!

More
26 Nov 2010 17:23 #5641 by dab77
Replied by dab77 on topic Re:let's add acc code!
thanks john, i can imagine that.. i just signed the dev-mlist, but i have problems with my e-mail..that's why i asked.

Please Log in or Create an account to join the conversation.

More
26 Nov 2010 17:47 - 26 Nov 2010 17:52 #5644 by dab77
Replied by dab77 on topic Re:let's add acc code!
andypugh wrote:

dab77 wrote:

but..correct me please if i'm wrong: in the .ini file now i'm setting the max accel for each axis, but when i move in world mode the acceleration ramp is derivated from the four max accel,is it right? so, what about changing the four max accel on the fly?


That is what you would need to do, but in your case it is somewhat more complicated as your kinematics are distinctly non-linear.

In any case, the INI file is only read at startup, and the accel values then remain constant.

I really do think that you could do exactly what you want with the motion.adaptive-feed pin and a HAL component, though.

i've read something about motion.adaptive-feed, which uses M52 to turn on/off. but it just apply a multiplier on the feed, to override the normal velocity, i don't understand how can i use that. the multiplier goes from 0 to 1. the only way that comes to my mind to use this with accel/decel is connecting the pin with a manual potentiometer to regulate the speed manually, but this is far from what i need!
am i understanding what you mean?

there is lack of a motion.adaptive-max-acceleration pin!
EDIT:
i see in the halui list of exported pins this:
max-velocity
halui.max-velocity.count-enable (default: TRUE)

When TRUE, modify max velocity when counts changes.

halui.max-velocity.counts

counts from an encoder for example to change maximum velocity

halui.max-velocity.decrease

pin for decreasing the maximum velocity (-=scale)

halui.max-velocity.increase

pin for increasing the maximum velocity (+=scale)

halui.max-velocity.scale

pin for setting the scale on changing the maximum velocity

halui.max-velocity.value

Current value for maximum velocity

why don't we think about adding a halui.max-accel.value pin?
Last edit: 26 Nov 2010 17:52 by dab77.

Please Log in or Create an account to join the conversation.

More
26 Nov 2010 18:58 #5646 by andypugh
Replied by andypugh on topic Re:let's add acc code!
dab77 wrote:

I really do think that you could do exactly what you want with the motion.adaptive-feed pin and a HAL component, though.

i've read something about motion.adaptive-feed, which uses M52 to turn on/off. but it just apply a multiplier on the feed, to override the normal velocity, i don't understand how can i use that. the multiplier goes from 0 to 1. the only way that comes to my mind to use this with accel/decel is connecting the pin with a manual potentiometer to regulate the speed manually, but this is far from what i need!
am i understanding what you mean?[/quote]

Almost. I was anticipating using a HAL component to automatically adjust the max velocity pin value in real-time to limit the speed and hence control the acceleration.

However, a drawback with this that just occurred to me is that it only limits the rate of velocity rise, not fall.

With a cartesian kinematics machine you could just pass the position commands through a limit3 hal function, but that probably won't work in this case.
www.linuxcnc.org/docview/html//man/man9/limit3.9.html

Please Log in or Create an account to join the conversation.

Time to create page: 0.125 seconds
Powered by Kunena Forum