PID Control and Maxon EPOS 24/5

[bcglaxer]

Hello,

I'm trying to control a Maxon RE-40 motor through a Maxon EPOS 24/5 motor controller. I'd like to use torque control, and eventually stiffness control, but for now I'm just hoping to do something super simple like current control. The attached VI is as simple as they come, but I can't find a set of control gains to make the system stable. I mounted my motor into an MTS Servo-Hydraulic System
and oscilated the motor with a sine wave (1 deg amplitude, 0.5 Hz frequency) and no matter what set point or control gains I use, the PID output exceeds the maximum range I've specified (and I've been very generous with that). Do you have any ideas of what I might be doing wrong?

Please help. I'm desperate 🙂

Thanks,

Brian

[A_Person]

I'm a little confused as to how you have the system setup.  You said that you're oscillating the motor with a sine wave but your VI is using a constant setpoint.  Can you explain your setup a little more and maybe take a screen shot of the graph output you're getting on your front panel?

[bcglaxer]

No worries. I ended up getting it to work. Turns out I just needed ridiculously small gains.

Thanks,

Brian

[mwu23]

Hi,

I am interested in doing torque control, but I think that's equivalent to current control for a DC motor. I can't open the VI you uploaded in your message. It's missing sub VI's that start with "PID." If you're willing to share your code, can you post all the VI's associated with it? I would like to send a particular current profile to the EPOS2 24/5 and have it execute the movement, and then send me back all the associated position data. Do you have this functionality?

Thanks,

Mary

[Andy_C.]

The PID VI is a part of PID & Fuzzy Logic Toolkit. You would have to install the toolkit to use it.