Re: Angular axes

[Paul <paul.corner-at-tesco.net>]

Hi Tim, John, Chris

Reducing the servo cycle time has a limited effect on improved performance 
and care needs to be taken in setting the value - Too smaller a value will 
result in the entire system locking up. The point at which this happen will 
depend on the CPU speed, PERIOD, and what ever other processes are vying for 
processing time.

I am of the opinion there is a problem in the way UNITS are converted 
internally - Try setting up an ini for a 3 axis metric machine and observe 
the abysmal performance attained. I am sure this is a contributary factor to 
rotary axis problem.
Angular velocities also appear to be implicitly derived - Perhaps a rotary 
feedrate command needs to be added to the interpreter (must look to see how 
other controls handle this).
Coupled with the calculations in the trajectory planner where linear 
velocities take precedence over angular (which Art commented on)..

The interim solution would be to keep feedrates low when doing a coordinated 
linear-rotary move, and also try to keep the moves fairly short.


Regards, Paul.



On Thursday 04 Jul 2002 5:17 am, Tim Goldstein wrote:
> The 4th axis problem is not a new revelation. I mentioned it to Paul
> about 4 months ago and he did some digging into it and has found that
> you can get better performance with it if you reduce the cycle time on
> the angular axis. Even at that it is broke.