---- Chris Albertson <albertson.ch...@gmail.com> wrote: > On Thu, Oct 13, 2016 at 9:00 AM, Peter C. Wallace <p...@mesanet.com> wrote: > > On Thu, 13 Oct 2016, dan...@austin.rr.com wrote: > > > > > I just tried a real time Mesa Ethernet config with maxvel = 120000 IPM (2000 > > IPS = 20 MHz step rate at present 10000 steps/In scaling) and maxaccel 20000 > > IPS/S (52 Gs) with a 1 KHz servo thread, and it works fine (Peak following > > errors in the 1-2 mill region) > > The problem to be solved is getting an estimate of the time required > to complete a job. Does the above do this accurately?
Yeah I want to know this. I can run a job for real vs "fast sim" and compare. One prob is the cycle time only goes down to seconds AFAIK. If it's 100x then that's over a minute and a half it could be wrong, but that's still good enough as long as it's not estimating a very short job. I am skeptical that the mechanisms will time themselves the same way, but I don't know enough to say. > The problem is to get the shape of the velocity curves to be the same > in the sim as the real job. In a real 3D wood carving job I thing > the mill never gets to near full speed and is always making think > movements and accelerating. Your sim MIGHT accelerate to quickly and > make some parts of the work run at a constant velocity (your maximum) > > Intuitively (I've not proved it to myself) you need to scale the max > speed and acceleration by the same constant. (But what about third > derivative?) I was told the MAX_JERK parameter- (third deriv) was not actually used, not in the main branch. > > Time estimation seem to be a missing feature. It should not require a > hack I _think_ that a machine tool that has all orthogonal and > linear axis where movement time depends only on delta-X and not on X > (or Y or Z) then you should not require a full simulation to compute > the job time as you can simply sumo the deltas. Note that there ARE > many non-linear machines but mostly these are robots. Time estimation is SUPER important to me. 1. I can tune the machine to trade off one param for another, a lower max speed but higher accel. I need to know if that helps or hurts runtime, and it can actually change from job to job. A large design without sharp features will go faster with high max vel and lower accel. 2. Similarly, I can do changes in design with more raster lines vs less, change size and/or depth, and need to know what the cost of that change is. You'd be surprised, doubling the design's size (quadruple the area) with a ball twice the diameter may actually take LESS time because it's not demanding huge accels in and out of small features. 3. I need to plan my day. A 2 hr carving is a different product than a 6 hr carving. I need to know when it'll be done, do I run this before going out for dinner or will it not be done before I need to leave? And how much to charge before actually doing it. Customers like to be told a price before the work is done. Danny > -- > > Chris Albertson > Redondo Beach, California > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, SlashDot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
