STMBL - Finding AC brushless servo parameters RLJ?

yes open loop (the first demonstration in the docs) is fine.
I can see fb_switch0,pos_fb change - it does a 5 point sawtooth for each revolution.
reslimitt0.pos_out doesn't change
what should I be watching to match to?

Chris M

cmorley wrote: yes open loop (the first demonstration in the docs) is fine.
I can see fb_switch0,pos_fb change - it does a 5 point sawtooth for each revolution.
reslimitt0.pos_out doesn't change
what should I be watching to match to?

res0.pos should show the resolver position feedback.

yes it does.
I then I plotted sim0.vel - which seems like the commanded speed.
I now see command with a sawtooth pattern that is twice that of my resolver.
there is more then one offset pin.
Motor offset
fb_switch offset

Neither seemed to make much difference.
res0.poles makes change - it makes the feedback signal flatter.

Could you give a bit more detail of how to make them match?

Chris M

cmorley wrote: I now see command with a sawtooth pattern that is twice that of my resolver.
...
res0.poles makes change - it makes the feedback signal flatter.

That's odd. I would rather expect it to change the sawtooth frequency of the res0.pos.

Is your conf0.polecount correct for the motor?

I am afraid I am stumbling about in the dark even more than you here, I am not anywhere near an STMBL.

andypugh wrote:

cmorley wrote: I now see command with a sawtooth pattern that is twice that of my resolver.
...
res0.poles makes change - it makes the feedback signal flatter.

That's odd. I would rather expect it to change the sawtooth frequency of the res0.pos.

Is your conf0.polecount correct for the motor?

I am afraid I am stumbling about in the dark even more than you here, I am not anywhere near an STMBL.

Hi Andy

I must admit the conversation has left me a little confused too! So far I have been testing the motor with servoterm, running the sine wave input. As I am seeing feedback that matches input, and servoterm seems to error if there is anything wrong with feedback, I had assumed I was running closed loop. Is this the case, or am I running open loop as mentioned by chris?

Hope you have a good time in Stuttgart if you are going!

cmorley wrote: I asked Rene about more docs - he said he would - but like all of us I'm sure he hates docs
When I get something working I will document it somewhere...

Chris M

If you can get the information to me I might be able to help.

JT

Hi Guys

Any chance of a steer on whether the driving with a sinewave section on the STMBL tutorial is open loop or closed loop? I had assumed it was closed:

Connect it rev0.in = sim0.msin

Set amplitude sim0.amp = 1

Set frequency sim0.freq = 0.5

Enable fault0.en = 1

Cheers
Ross

I would guess not - does it fight you if you add load to it?

Chris M

if you connect the sim to hv0.(something) then you would be running open-loop.
I think that connecting to rev0 is simulating a command input, so is closed-loop.

Pity I didn't see this a few hours ago when I was in the same room as Rene.

andypugh wrote:
Pity I didn't see this a few hours ago when I was in the same room as Rene.

Rene from "alo alo" ???