Register to reply

Maple seed Personal Transport

by Miey7963
Tags: maple, personal, seed, transport
Share this thread:
Danger
#37
Sep23-10, 02:10 PM
PF Gold
Danger's Avatar
P: 8,964
Quote Quote by boneh3ad View Post
Wow did this thread take a right turn for the obscure
It might well be a "right turn" from the original post, but it seems a necessary tool for determining whether or not the machine in question can work.
boneh3ad
#38
Sep23-10, 02:57 PM
PF Gold
boneh3ad's Avatar
P: 1,486
Quote Quote by Cyrus
I'm talking about replacing states by things like p = p_0 + \delta p and expanding out and dropping terms. Never had to bother with matched asymptotic expansions.
Then you seemingly haven't been introduced to the formal "perturbation techniques" that I am referring to. Sure introducing disturbances and then canceling out nonlinear terms is easy. That represents about 1% of the battle in the techniques that I was referring to that I had to take a class in. They were pretty brutal.

Quote Quote by Danger
It might well be a "right turn" from the original post, but it seems a necessary tool for determining whether or not the machine in question can work.
Well I am sure you could make it technically "work." The real question is not "will it work?" but instead "what's the point?" It doesn't offer any benefit over traditional rotary aircraft.
Cyrus
#39
Sep23-10, 03:26 PM
Cyrus's Avatar
P: 4,780
Quote Quote by boneh3ad View Post
Then you seemingly haven't been introduced to the formal "perturbation techniques" that I am referring to. Sure introducing disturbances and then canceling out nonlinear terms is easy. That represents about 1% of the battle in the techniques that I was referring to that I had to take a class in. They were pretty brutal.
Yeah, for flight dynamics there isn't that much of a need to do anything more than I described. All we want to do is linearize and obtain the A and B matrices. I can imagine if you're trying to look at something more precise like boundary layer flow it gets more involved. If our models are a bit off it's not a huge issue because the controller has some gain and phase margin built into it to account for plant inaccuracies and disturbance rejection.
boneh3ad
#40
Sep23-10, 03:52 PM
PF Gold
boneh3ad's Avatar
P: 1,486
Quote Quote by Cyrus
Yeah, for flight dynamics there isn't that much of a need to do anything more than I described. All we want to do is linearize and obtain the A and B matrices. I can imagine if you're trying to look at something more precise like boundary layer flow it gets more involved. If our models are a bit off it's not a huge issue because the controller has some gain and phase margin built into it to account for plant inaccuracies and disturbance rejection.
Yeah. The point of the ones I have had to use is to take a nonlinear PDE, split it up into n linear PDE's where your accuracy gets better as n increases. That is usually governed by what your small parameter is and the physics of the system. You end up with several equations of increasingly smaller order and you keep as many as you need. Luckily, you don't really need to solve them in my line of work, you just need to extract the information that you need out of it, which is still pretty beastly at times.


Register to reply

Related Discussions
Maple seed (samara) Introductory Physics Homework 6
Srand() seed microsecs? Programming & Computer Science 4
The Winging Seed General Physics 3
Personal transport General Engineering 2
My Seed Theory Cosmology 2