On 9/3/2012 6:17 AM, Peter wrote:
> Joe, decide on power or torque limiting (these are 2 different things), t=
hen
> implement it. It is a closed loop so you just do Pwmcontrol =3D (limiting=
)?
> Demand: Demand - LimitingSignal; Cycle by cycle current limiting is anoth=
er
> thing, and is actually a good idea, but that requires that you see the
> individual current pulses. It may be, that individual pulse current limit=
ing is
> all you really want, and that is best done in hardware alone imho.
>
Yeah, I'm going to have to tinker with this a bit to get a feel for it. =20
I had to look up the difference between torque and power.  I'm going to=20
have to choose torque, since no work will be done if the motor stalls. =20
I guess I can implement the above logic using a scaling factor k for=20
LimitingSignal.     I can start with k large enough to effectively shut=20
PWM off when limiting.  If that works, I can try decreasing k and=20
observe the effect.
I finally added the wiring for this (and speed and pedal torque input)=20
now it's time to see if it works.
I wish I had put more effort into understanding some physics and=20
whatever math is needed for motor control applications way back when.
Joe W


--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.