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Messages - ART

941
LazyTurn / Re: LazyTurn
« on: August 28, 2009, 10:55:42 AM »
Hi Rich:

  My plan is for first snows... :)

 Im working on a summer project approaching working status ( A next-generation planner) , so once I finish this I'll be back at LT, or on first snow II'll switch back. I needed the break to get fresh again.

Art

942
LazyTurn / Re: LazyTurn
« on: August 28, 2009, 10:28:57 AM »
Hi:

  It has to do with Vista not allowing you to modify a file in certain folders. Try right clicking and selecting "Run as Admin", OR failing that, save the file to your desktop..

Art

943
Well, Preliminary testing shows that version of the tempest test is very smooth, but slower than mach3 by too much in small segment code. THis is because with SCurve planners a lookahead strategy is necessary to see how much speed we can add up to in the stream of gcode.

  This version is Quantum on steroids. It looks ahead and back and precompiles the speed capabilities. On my stress test, which Ill post as well, MAch3 takes 51 seconds on my setup, Tempest takes 56 seconds, not too bad a difference to respect physical motion laws and limit the jerking of the machine, not to mention make the CV blending more controllable by the user.

You only need to unzip this to a mach3 folder to test, and then select "config/set planner type" to turn on the tempest planner , you can swap back and forth between planners as long as your not currently running code. Setting higher Jerk limits will speed up the end result and a number like 12000 or so shoudl work for most of you, lower if your machine is crappy, higher if its a stout solid unit.

 Id be interested in any observations.

Thx
Art
  

944
As attached in MAch3, you have no connection to the 7,8 or 9th axis.
They will be separated to U,V,W in the end. At the moment they are all
simply linear interpolations until such time as kinematics are added.

  Preliminary tests show that Tempest is pretty smooth, does great blending , but
suffers from lower speeds than desired as the segment size gets smaller. Thats whats
currently being worked on, when and if I can speed it up to relative mach3 levels of speed
with small segement concatentation speeds, then Ill be investigating rotational kinemtaics
to make the A,B,C and the U,V,W axis as set rotation vecotr components to the cartesion axis
based on setting tranformational matrix'sfor each rotational axis.

Art

945
Repost.. Sorry, wrong file was attached to original..



Well, interesting results so far. I havent run many small segment files, but numbers so far look pretty good.
Im using a special version of Mach3 that has dual planner capability. One can select Tempest from the config/planner selection menu
and test various files in the two planners ( tempest and mach3's normal planner ) very easily.

 Few notes,

.. config/select planner selects the current planner. If tempest is checked, your using tempest, if not, mach3's traditional planner.
Jerk and CV radius are the only other two entries. Jerk for most will be in the range of 1000 ( very shakey machine ) to 5000, very tight machine to perhaps
1,000,000 ( run close to mach3 levels of jerk allowance ).

  CV is simply the maximum allowed radisl curve blend around corners..

Note:
1)DRO's for FRO are not working in this version.

2) do not use feedhold, its not yet written, you may only stop when using tempest.

3) No reverse or other fancy stuff, this is just a run time test of tempests motion

4) Do not transmit this program to anyone, its all just test code, its likely it will never be released into MAch3, but may appear in some other incarnation of controller.
this is simply my research and how its going.


 I recommend trying a box a few inches on a  side at various speeds, jerks and cv's to compare motion between the two planners.
Please report what you see in terms of motion, but again, dont expect all aspects of MAch3 to work.. ( though an amazing amount do..)
If you try very small segement code, let me know how it does..

   Id prefer no open discussion of this planner, only those permitted on this topic, which I will add to as I wish someone to test it.

Thanks
Art

946
As yet,no. ITs like mach3 in that its either cv or it isnt.. Though that doesnt sound hard to do..

Art

947
Should work on anything..

Art

948
General Mach Discussion / Re: New PlugIn just about done..
« on: July 24, 2009, 03:26:00 PM »
Hi:

  Just to kick in .. You do need VS2003 to compile the plugins, the missing h files are just the Machincludes folder that you need to install. Dont be fooled by compiling under vs2008, while it will sometimes compile the pointers get hosed and it wont work.

  Check Ebay for vs2003, but its about 85.00 these days typically. VC6 can probably do the compile as well.

There is a thread on the forum somewhere where a plugin can be made to work in vs2008, it uses different headers and has a wizard to generate the main core, but youd have to copy the relevent
parts of the plugin to the wizard created shell. Then vs2008 could recompile it. Sorry I dont have time at the moment to get involved in your project myself or Id help out. I suggest you find that VS2008 wizard for plugins if you have vs2008, it works pretty slick and woudl give you the general framework you need to make the shuttle plugin work with whatever compiler you use.

Art

949
Tempest Trajectory Planner / TradeOffs of planning on Scurves
« on: July 21, 2009, 11:18:01 PM »
Hi Guys:

  Now that a test program is released for visualising velocities ( see previous topic ), we can discuss
the limitations or tradeoff's involved in planning strategies.

  When you run the tempest velocity analyser, youll see its preset for a square. Playing with CV , you can see the effect
( on the position screen) of various CV's and motions. Youll note how the velocity in the corners slows or speeds up
dependend on how much cv there is, and the angle of the next line.

  First, lets talk about how Mach3, EMC and most other planners do their job. With the standard preset conditions, ( the square)
select accel and note how the acceleration looks with a jerk of 1000.  This is probablky the smoothest of all planners in this example.
TO see how MAch3 or EMC woudl look, select a jerk limit of 100,000. Note the square waves, thats typical bang-bang acelleration.
The curvy parts are the only difference from Mach3's typical planning. They represent a complex blend and are unaffected by jerk selection.

Tradeoff #1. - Speed.

This example then shows Mach3 with better . more controllable CV blends. Note the time of the 4 moves. ( the last move to 0,0,0,0 is automatic.).
Its about 3.7 seconds. That woudl be close to Mach3's time to do this square. Now set to 1000 jerk and note the time.  Youll see its now
7.4 seconds. SO we can see that SCurves take longer. This figures as it takes longer to drive somewhere if you dont hammer the gas pedal.
With a jerk of 1000, its about 40% longer. Set for 10,000, the time is now 3.94 seconds. Thats probably about where most woudl use such a planner.
Its about 7-10% longer. Thats Tradeoff #1, smoothness takes longer. On the other hand, the corners are better defined, and much more controllable.
Not bad for a 3% loss in iverall velocity. ( in this example anyway..).

Tradeoff #2 - Angular accuracy.

  Change the second waypoint  move ( set back jerk to 1000 for visual clarity ), so it has an A of 50. Notice how the A starts in the middle of the blend from
motion 1 to motion 2. This is because the rotary motion is commaned to match up with motion #2, but #2 is blended with #1. Orientation motion accuracy will depend
on a few things. In this case, the rotary motion WILL start as the motion #2 starts, ( in the middle of the blend) and end as motion #2 stops. However, for accuracy sake
the planner decided not to blend the next motion, but to stop and allow the rotary motion to catch up. The difference in speeds will produce a non-accuracy in the
lineup of the cartesion motion and the rotary motion. How much depends on speed, and time of motion. Changing to a 10,000 jerk will make it line up better.
In terms of accuracy, an Scurve planner will be slightly less acccurate, and speeds must be taken into account.  This is a tradeoff. Speed, smoothness, and complexity combine to
make rotary motion more difficult, but better at not being disjointed. Foir example, you needednt consider slowing the feedrate request for such a motion, they automatically are
fit into the main cartesian motion. Now try changin the waypoint #2 move from 100,100,0,50 to 100, 5, 0, 50. In this case the rotary just cannot fit in the short time it takes to move from
100,0,0 to 100,5,0. Notice what happens, the line is no longer blended to the first, ther eis no time, so the motion is now dead accurate, and the A move will match the Y move to 5, but blending
is prohibbited during this move. Again, this is automatic and done because the math processor decided the motion is so complex that the solution is intractable mathmatically except to
simply do the motion by itself. This is tradeoff #2, the fact that you must consider such impossibel motions, and how they are handled. I call this a CNC singularity, and one should
understand how a planner handles such things. Only real-time experience will tell how how this impacts CNC cutting in a general sense. ( SO far, this is all entirely math based theory. )

 Getting late, more later. This at least has given you something to play with and consider in terms of how a future planner may do its job. And hopefully, has increased your
understanding of motion math, velocity, jerk, acceleration, and rotary blending in moves.

Thanks,
Art




950
Hi All:


 Enclosed with this post is a versionof the analysis program , I post it to further any discussions on the properties of such a planner.
As of now, all 9 axis are responding, and Id liek to post some diiscussion posts on tradeoffs of such planners and how they operate.
This encosed program will facilitate the user understanding the issues discussed as you can try various situtations yourselves.

  Basically, you enter the x,y,z, and a coordinates of any motion group. You should note that the feedrate shown and selected is
in units/second, not units per minute. I defaulted it to 200 so thats ( 200 x 60 ) units per minute.. 12000 inches per minute. Very
high indeed, but using such high values allows one to better disect the operations of such a planner. Try the enclosed program and select
either velocity, acceleration, or position to see the various results of motions, feedrates, CV settings and how they affect accel and velocity.


  Next postings will be on tradeoffs and singularity handling and how they may affect users of such a planner.

Thanks
Art