Ultimate MSXR 3/4DOF

[Riton]

Hi Thanos,
thanks
not easy to solve because the encoder adjustment skips positions.

I will try tomorrow to follow your advice, thank you!
I hard time to set PID.
what would be good is a chart to show the PID tuning.
pluging on a PC to control and adjust the PID is that possible?

I must buy the metallic sheath for shielding cables engines.
cables potentiometers are already shielded.

[Riton]

not perfect...
Cables potentiometers are shielded.
I tried to shield the motor cable with aluminum foil.
There is only too visible difference, but it's still better than no shielding

the drive on the left is a 100%
the potentiometer cable is shielded, but not the motor cable.
I do not have 'the impression that it improves things.

I will order the shielding braid to shield the cables quickly engines.

[tronicgr]

Maybe shield the sensor it self as its placed so close to the motor...

[Riton]

the knob is made ​​of aluminum, I can connect GROUNDED the casing, or add a metallic cover connected to the earth.

[Riton]

Thanos
Is the AMD 64 has a dead zone in the center for potentiometers?
if you look at the display of values, it does not move.

I made a shield to try

I think not having parasites ....

[tronicgr]

Yes, you can add deadzone for the sensors, by increasing the Min Motor Speed on the LCD menu... Set it to 4 -6, or higher to see if things get less bumpy.

See here, you should have this menu setting:
https://www.youtube.com/watch?v=sRZf0N7hLMM


The AMC1280USB allows you to set the PID even smoother than the older AMC644USB... Hope to have it ready soon.


Thanks
Thanos

[Riton]

the best setting is with 5%.

[Riton]

I do not know if the dead zone is a good thing ...
I realize that:
the dead zone is more important
more it oscillates.
may be trying with a dead zone that begins at 0?

for time or there in a dead zone, the engine is in a vacuum, without power supply to maintain.

[Riton]

how to have a proper PID, with a sensor dead zone ?

my axial gearboxes, have no holds without current
it's as if I increase acceleration and décéléation, setting PID is very bad.
for the dead zone, the engine is non-controlling position, the weight of the structure does leave the deadband, then the power again .....

[tronicgr]

Hi,

Yes, is your engine if turning off during dead zone, it will kick back when its in working zone again. The main reason that this is happening to your platform is that the gearbox is not worm drive to block the load backdrive the motor, they seem very easy to backdrive even with no load on the platform.

Did you try to reduce the max frequency (motor RPM) of the inverter? See if you get better results with total output 15RPM max....
I remember I had to reduce the max motor speed on Richard's platform here in san diego, to make the this shaking go away.

Also how do you have your motors wired? Are in Delta or Star wiring? Use Delta if possible. Also there may be a setting for vector control in your inverter, can you check the manual? Or share a link to your VFD manual for me to check? This will make the motor hold better the commanded speed under load...


The only motor I ever seen to hold its position in zero speed is this one here: https://www.youtube.com/watch?v=9CMIPu3t7d0
This amazing motor keeps track of the speed, so if the commanded speed is zero, its doing exactly that... holding its speed to zero!



Thanks
Thanos