[Date Index]
[Thread Index]
[Author Index]
Re: Control Function With NDsolve
*To*: mathgroup at smc.vnet.net
*Subject*: [mg19367] Re: [mg19323] Control Function With NDsolve
*From*: "Richard Finley" <rfinley at medicine.umsmed.edu>
*Date*: Fri, 20 Aug 1999 23:09:41 -0400
*Sender*: owner-wri-mathgroup at wolfram.com
Don,
Perhaps what you are asking is obvious to those that work in systems
control theory, but I don't think you have given us enough information to
be able to make a general statement. What are a and b for example? Are
they real and positive?
If so, then since you start out with f = 1 the ODE has the solution:
y[t]==(a/b)(1 - Exp[-b t]
and it tends towards the maximum a/b as t->Infinity which of course it
never actually reaches, so f will never change. On the other hand, if b
is complex, what maximum value of y[t] do you mean...Real, Abs ?? Or
perhaps the solution only has to reach within a certain fraction of ymax
before f changes?
regards,
RF
>>> Don Paddleford <don-paddleford at worldnet.att.net> 08/14/99 09:42PM >>>
In solving a control type dif eq with NDSolve I have the following
question. Suppose the eq is of the following simplified form
y'[t]==a*f[y[t]]-b*y[t]
y[0]==0
How to define f so that it starts at f=1, and changes to f=0 when y
reaches ymax, and then changes back to f=1 when y reaches ymin, and
so
on in oscilatory fashion?
Prev by Date:
**Tricky Symbolizations with the Notation Package**
Next by Date:
**Re: Re: out of memory reading large(?) file (Q:)**
Previous by thread:
**Control Function With NDsolve**
Next by thread:
**Re: Control Function With NDsolve**
| |