Sure, I could do it on an ESP32 ... and the two axes of resolver feedback, with the reference generator for the resolvers? and of course I'll need some sort of graphical interface to show the current position, and an interface to an external keypad or somesuch for intial setup and establishing "zero" etc ...
On Sat, 21 Jan 2023 at 18:58, Chris Albertson <albertson.ch...@gmail.com> wrote: > This is a job best done on a $5 microcontroller, like the ESP32. You can > even program the thing in Python to do what is needed. You can generate > the AC as a 3-volt signal to an analog pin and then amplify it. > > Microcontrollers have come a long way. ESP32 is a dual-core 32-bit CPU > with hardware floating point, and yes the entire thing sells for $5 and it > can self-host a python system. All you need to program it is a terminal > window on a PC. > > Yes it is fast enough. On my desk now I an using one to commutate the > coils on a BLDC motor using FOC control. It computes the sinusoidal > voltage that goes the each of the three phases to keep the magnetic field > pointing the right way. Quite a lot of calculations this is not simple > 6-step algorithm. > > Here is an demo-project. An ESP32 is used to compute the voltage on each > of the three phases of a small motor so as to keep the ball on top of the > wheel. There is a second microcontroller with a built-in camera that > tells the ESP32 how far the ball is from the center point. Again a $5 > computer is doing this and if you look there is not 100 lines of code in > the loop. The control is dramatically better then you can do with a Linux > PC and 10x simpler and 100x cheaper. > https://youtu.be/fXxd8guAY7g > > Tracking a green ball is a servo system is a lot like tracing the Moon, > except the Moon is easier to track > > > > > > > > > On Sat, Jan 21, 2023 at 3:26 AM Robin Szemeti via Emc-users < > emc-users@lists.sourceforge.net> wrote: > > > So, in a vaguely CNC related folly I have purchased a 2 axis military > dish > > mount for radio stuff (moonbounce, if you must know) > > > > My plan is to control it from EMC, with a Mesa anything io card and the > > resolver interface, I already have various Mesa cards under EMC, so thats > > not an issue and I have a spare 5i23 PCI card and the isolated IO > duaghter > > card, so with the resolver card I should be able to uses the resolvers, > and > > pick up the limit switches on the IO card. I can just use some Python > > script to work out the moon position and generate "G1 X285.4, Y23.8" or > > whatever MDI motion commands every 15 seconds or so to track the moon, > not > > a problem. > > > > Now, the question is driving the two phase AC servos. Generating vast > > quantities of 50 or 400Hz or whatever AC for the drives is simple > enough, I > > can just use a couple of large Class D amplifiers, no worries. Generating > > the AC low level signals to drive these .... basically, it needs a > constant > > 50Hz signal on one coil of a fixed level, and a variable level sine wave > on > > the other coil, at either +90 or -90 degrees depending on which way it > > needs to go. > > > > Is it possible to use HAL or something to generate the variable level > 50Hz > > servo drive signals and output them from the PWM outputs on the resolver > > card? > > > > -- > > > > Best regards, > > > > Robin Szemeti > > > > Redpoint Consulting Limited > > > > E: ro...@redpoint.org.uk > > T: +44 (0) 1299 405028 > > M: +44 (0) 7971 883371 > > > > CONFIDENTIALITY NOTICE > > The information contained in this e-mail is intended only for the > > confidential use of the above named recipient. If you are not the > > intended recipient or person responsible for delivering it to the > > intended recipient, you have received this communication in error > > and must not distribute or copy it. > > Please accept the sender's apologies, notify the sender immediately > > by return e-mail and delete this communication. > > > > Thank you. > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > -- > > Chris Albertson > Redondo Beach, California > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
