[racket] A control-theory question

From: Anthony Cowley (acowley at seas.upenn.edu)
Date: Wed Nov 24 08:44:55 EST 2010

On Wed, Nov 24, 2010 at 4:20 AM, Noel Welsh <noelwelsh at gmail.com> wrote:
> I would adjust the guess by a fraction of the error. This is basically
> a gradient following rule. I.e.:
>  Guess(t+1) = Guess(t) + alpha Error
> where alpha is some parameter that you set via your simulated annealing

As a followup, the rule of thumb I have picked up is that step 1 in
throwing together a controller should pretty much always be, "Why is
PID not appropriate?"

Typically you can't answer this question, and may stop the design
recipe at step 1. :)


Start with a proportional controller (like Noel's suggestion), if it
doesn't *quite* get you to the set point and that steady state error
is an issue, add in the I and D terms.


> On Wed, Nov 24, 2010 at 1:38 AM, Danny Yoo <dyoo at cs.wpi.edu> wrote:
>> Hi everyone,
>> In Moby (my Racket->JS evaluator), I have a parameter that checks the
>> number of steps that the evaluator takes: after a certain threshold,
>> the evaluator temporarily yields control back to the browser, and
>> schedules itself for a restart.  I have a rate at which I want the
>> evaluator to yield --- about five times a second.  However, I don't
>> know how fast my evaluator actually runs per step.
> ...
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