Hi John, On Thursday, September 15, 2016 at 3:30:31 PM UTC+1, John Kasunich wrote: > > > You mentioned the LMD18200, and I looked it up. That is a chip, not a > complete driver. It takes a significant amount of electronics knowledge > to make a reliable system, even starting with a chip like that which has > a lot of built-in functionality. Power distribution, ground bounce, > common > mode voltages, choice of switching frequency, electrical noise, thermal > management, circuit board layout, etc, etc, are all non-trivial issues. > > Because you mentioned a naked chip, I assumed that you were > comfortable with all those issues. > > Fair enough - I have used that chip a few times successfully, but perhaps the applications were simple enough to avoid addressing the more complex issues you mention.
> That all depends on your needs. What kind of force/torque fidelity > do you want? > > I honestly don't know yet! I suppose I could try simulating a non-ideal force controller and see if I can still balance my pendulums > In a one-off design, I would NOT use the chip-supplied current > feedback. Many of the hassles of power electronics can be avoided > by isolating the control from the power. I would spend the $10-20 > for an isolated current sensor. For example: > > http://www.digikey.com/product-detail/en/lem-usa-inc/HO-8-NP-0000/398-1141-ND/4331974 > > That seems like a good tip - thanks If the goal is to focus on the control of the pendulum, I would use > a simple hysteresis controller for the current. If you want to get > into the minutia of motor control you could send the output of > that sensor to the controller's A/D converter and do the current > loop in software - although that would require MUCH faster > control loops relative to the pendulum control. > I haven't actually heard of a hysteresis controller before. Is it a bang-bang controller with a deadband? Thanks John. -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.
