servo system and transfer function etc.

[MrAl]

Hello again Steve,


Oh ok, no problem. But since you brought it up i thought it would be helpful to compare too.
I do appreciate your feedback and contribution in any case too, so it was not a waste of your time by my own viewpoint. As you can note before we started this conversation i had overlooked a couple things myself and it's only after discussing that i started to remember things of old again So it wasnt a waste for me either. I was able to refresh some ideas myself which i like to do too.
But now i feel a little bad that maybe i stressed my view too strongly.

 

[steveB]

Hi MrAl,

No problems, and no need to feel bad. You've seen that I'll stress my view strongly in some cases too. The goal here in this thread is to help PG. If I thought it would help him, I would stress my view more strongly now. But, as long as at least one view helps him, we are doing well.

 

[steveB]

That's now how it would be abbreviated; it would be m-N.

I had meant to respond to this before, but then forgot. It's almost not worth pointing this out since it's obvious to all of us from everyday experience, but since we are in a student's thread, it doesn't hurt to point out something here that might stick in PG's mind in years to come. The usual convention I've seen conforms to the reference below. Typically in papers, or when writing by hand, it's good practice to use a raised dot, and not a dash. I agree, if one does this diligently, then there is no problem. Personally, I always use dots in anything I do by computer. This applies to variables in equation and for units too. I try to do this in hand-written derivations also, but it's very hard to be diligent and consistent when working fast, so I often don't do it and just try to be careful. Ideally, one should always use raised dots to avoid ambiguity. For example, how do you know f(t-τ) is not f times t-τ, instead of the function f(t-τ), unless one uses dots. Often, people use spaces, so f(t-τ) and f (t-τ) are different, and mN and m N are different.

http://www.poynton.com/notes/units/

The problem is that (especially in hand written derivations) people either get lazy or get absent-minded, and forget to put the dot or don't leave enough space. Then, the author or another reader might misinterpret. Often context clarifies any ambiguity, but it's good to have a system that minimized possible ambiguities. For this reason, I would prefer N m over m N (or even m-N) for torque units.