New H&P article about feed forwards

http://hydraulicspneumatics.com/200/Issue/Article/False/31840/Issue

It it a light weight article for hydraulic people who don't know much about control. If you have followed what I have said on this forum there will not be anything new. There are still about 500-1000 analog PI controllers that are installed each year in the US that don't have feed forwards.

Good article, Peter. It certainly hits the high points on why you want feed forward.

Keith

Good article Peter. You make it sound easy!

There are still about 500-1000 analog PI controllers that are installed each year in the US that don't have feed forwards.

Click to expand...

Wonder how many of these have at least 6 foot of hose between the valve and cylinder?

Thanks.

Thomas Sullens said:

Good article Peter. You make it sound easy!
Wonder how many of these have at least 6 foot of hose between the valve and cylinder?

Click to expand...

I got a call yesterday from someone that makes marine racing engines for hydroplaces and cigarette boats. He will use this feed forward info to make his dynamometer better. This will allow him to optimize the torque and horse power curves.
Who da thunk it! I talked to him for an hour exchanging information. I learned about dynamometers and he learned about how feed forwards can be applied to dynamometers.

I've been thinking over this article for a while, having been meaning to find out exactly what feed forward is for a while.
So, if I put it in simple terms, Feed Forward is the same as an open loop control scheme, only the output of the Feed Forward is summed with a PID controller.
Feed forward sets the output to close to what is desired, feedback corrects whatever minor errors are there.

Have I got it?

You have got it exactly right!!!

Excellent summary.