Velocity Feedback Element for Position Control

[fuzzycontrolfreak]

velocity feedback

Hi everyone,
I'm working on a project in which i'm trying to control the position of a hydraulic linear actuator. I was told that a velocity signal fedback to the controller helps making a much better response. Not much is stated in the control theory texts i have, and i would like to know more about this, especially that i have a velocity sensor that's built in my system.

I have already tried control without the velocity feedback and have achieved satisfactory results, but i would like to exploit the sensor, and investigate the improvements.

Attached is the control loop for clarification, i would like to know general techniques for tuning the gain 'k' at the velocity feedback loop.

If there is any other more applicable or reliable loop to be used, i'd appreciate the recommendation.
Thanks in advance for all the replies...

 

[kender]

velocity feedback control

Velocity feedback nuance was surprising to me too, when I was learning about it. One would think that the velocity feedback is possible in every system with displacement feedback - just differentiate the displcement. But that's not the case, becasue differentiating displacement inposes a delay. If there's a dedicated velocity sensor (and often it's working on a different pronciples than the displacement sensor), there's no additional dedlay in the velocity feedback branch.

 

[fuzzycontrolfreak]

vlocity feedback

Well yeah, i know that differentiation incorporates delay, and it is not suitable in my situation as the displacement sensor is very noisy. Differentiating the noise will result in a disaster, so i think the only way is to use the velocity sensor i already have, i just wanna know how to set up the loop, and are there any special techniques for tuning this system, or will i have to tune by trial and error...

Thankyou so much for sharing ur opinion..

 

[gonjolz]

control feedback

why after valve , the signal is velocity? that one is the spool valve velocity or what? I also use linear hydraulic actuator in my research. I have used PID and tuning using PSO and some optimization technique.. for initial work, just use trial and error.. it works..