Hi Shannon,
I think you would need to compute the current speed. I don't think using the DACs would be a good idea because those will have random variations dependent on friction and so forth. Better to use the theoretical trajectory. The axis variable last_vel is the current speed (for the theoretical trajectory) for the axis in counts/sec. So try:
speed =sqrtf(ch0->last_vel * ch0->last_vel + ch1->last_vel * ch1->last_vel);
Regards
TK
| Group: DynoMotion |
Message: 5610 |
From: roa_controls |
Date: 8/27/2012 |
| Subject: Re: detecting decrease in vector speed |
ahhhh last_vel... no doubt it will work fine! I've been testing the dual loop method you suggested a couple of weeks ago and it is working much better that the single loop adc input method that I was using. I'm testing with an ultrasonic sensor tuned to a span that is equal to the plasma arc voltage (001" of travel equals 1 adc unit).
Once again, I thank you Tom.
--- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@...> wrote:
>
> Hi Shannon,
> Â
> I think you would need to compute the current speed.  I don't think using the DACs would be a good idea because those will have random variations dependent on friction and so forth. Better to use the theoretical trajectory. The axis variable last_vel is the current speed (for the theoretical trajectory) for the axis in counts/sec. So try:
> Â
> Â
> Regards
> TK
> Â
> Â
> From: roa_controls <sdavenport.roa@...>
> To: DynoMotion@yahoogroups.com
> Sent: Monday, August 27, 2012 4:34 AM
> Subject: [DynoMotion] detecting decrease in vector speed
>
>
> Â
> Hello,
> Is there a way to determine if the TP is going to, or has decreased the feed rate? I'd like to temporarily turn off height control on my plasma cutter when the speed falls below a percentage of the current set feed rate. If there is no function for this, and I need to calculate it, is it better to do it on encoder counts or can I just read the servo dac's ie speed=sqrt(dac(x)*dac(x)+dac(y)*dac(y))
>
> Thanks, Shannon
>
>
>
>
>
> speed =sqrtf(ch0->last_vel * ch0->last_vel +Â Â ch1->last_vel * ch1->last_vel);
> |
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