[racket] A control-theory question

On Wed, Nov 24, 2010 at 8:44 AM, Anthony Cowley <acowley at seas.upenn.edu> wrote:
> 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. :)
>
> <http://en.wikipedia.org/wiki/PID_controller>
>
> 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.


Thank you so much!  I'll do so.