Integral const. (K_i) isn't working for the stabilizer to work as a PID

pratik

Dear experts,

I seek from you a very urgent assistance regarding as to why the Integral control of the Artiq stabilizer is not working when I am using it as a PID for driving a piezo mirror.

The documentation that I used for the purpose of setting up the same can be found here and more specifically here

The problem in crude words:

Under the condition of using it as a digital feedback loop system, for the purpose of correction of laser pointing jitter or instability along 1D axis, the proportional control (K_p) of the system is working just fine. But when a constant of integral control (K_i) is set to any value except 0 (either +ve or -ve), the error signal blows up way beyond the required set-point. In other words the beam pointing stability no longer hovers around the req. set-point.

I have been trying to solve (with my very limited understanding of the hardware and software of the system) this issue for long, but all my efforts brought me no luck whatsoever. I request you all to help me provide a solution regarding this issue. I shall be ever grateful for this.

P.S Please do not hesitate to request for further info, if any required.

rjo

Please provide more details, quantitative numbers for everything, maybe a sketch of the setup, oscilloscope screenshots, configuration commands, how you have set things up. From the information you provide we can only guess. You don't give a single actual quantitative observation. How would anyone know what +ve and -ve are? Have you talked to someone who knows controller basics?

sp_du

Did you ever figure it out? I actually need configuring the device as a PID. I already finished the setup and MQTT explorer can talk to the broker just fine.