Try this one, sorry it moved. http://www.cds.caltech.edu/~murray/books/AM08/pdf/am08-complete_22Feb09.pdf
-- Chris On Tue, May 22, 2018 at 3:04 PM, Gene Heskett <ghesk...@shentel.net> wrote: > On Tuesday 22 May 2018 12:10:47 Chris Albertson wrote: > >> I just got a copy of "Feedback Systems - An Introduction for >> Scientists and Engineers, Karl Johan °Aström and Richard M. Murray" >> >> The book is FREE and pdf format at >> http://www.cds.caltech.edu/∼murray/amwiki >> > I, like others are reporting Chris, am getting a not found error, and I > suspect its the character in the little box in front of the "murray" > string above. Its reproduced as a small "1/4" symbol here in the > browsers (palemoon) font, and I don't think it belongs in a url address. > Swag: caltecs way of establishing copyright? > >> It is an actual set book that seem to be exactly what anyone working >> in this field needs to know. I'd say it is not is mathematically >> oriented as a real university control theory book and certainly well >> above the hobby level. It assume some know age of Calculus but not a >> lot. Pretty much what the title says. But it covers feedback, not >> just motion control. so things like op-amps are covered. But you >> need to know that to if designing control circuits >> >> I'm using stepper motors but already have DRO scales. It seems that >> I should be able to combine open loop counting with closed loop linear >> sensors. >> >> Suggestion above were good, thanks, because they contain a solution I >> had not thought of, drive "I" with different data than "PD" >> >> On Tue, May 22, 2018 at 6:44 AM, John Kasunich <jmkasun...@fastmail.fm> > wrote: >> > On Fri, May 11, 2018, at 11:16 PM, Chris Albertson wrote: >> >> I looked at the unit. It seems like a good idea. It uses inputs >> >> from both the motor's shaft encoders and another encoder on the >> >> object that is being moved, like a linear encoder on the table. >> >> >> >> Question: Let's say I wanted to do this myself. Is there a >> >> method that "everyone" in the machine tool industry uses for >> >> combining the reading of multiple encoders? If not it seems like >> >> the perfect application for a Kalman filter. >> >> >> >> But maybe you don't combine them but use the linear DRO for >> >> position loop and the motor shaft encoders for velocity. >> >> >> >> This is a common problem I think with robot arms. The joint has an >> >> angle sensor but the motor has a shaft encoder. So the control >> >> loops might be nested. >> >> >> >> It reminds my the old saying the "A man with a watch knows what >> >> time it is, a man with two watches is never sure of the time." >> > >> > We did something like this several years ago at Stuart's shop in >> > Wichita, on a big Giddings and Lewis boring mill. >> > >> > We used two PID loops, with their outputs summed. The position >> > command went to both loops. The feedback for one loop came from the >> > motor encoder, and the feedback for the other loop came from the >> > linear scale. >> > >> > The motor loop was tuned as normal, except that the I-gain was kept >> > at zero. The linear scale loop was tuned using ONLY I-gain. So the >> > linear scale loop corrected the fairly small steady-state errors due >> > to things like the lead screw heating up (10 foot long screw, it >> > adds up). It also compensates for backlash in the screw, and if >> > there is much of that it leads to disturbances on direction >> > reversal. Isn't going to fix a clapped out machine, but can improve >> > the accuracy of a tight machine. >> > >> > >> > -- >> > John Kasunich >> > jmkasun...@fastmail.fm >> > >> > -------------------------------------------------------------------- >> >---------- 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 > > > > -- > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > ------------------------------------------------------------------------------ > 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 -- 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
