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
