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>> modelling might in fact be a necessary part of regulation. That seems false. PID is used all over, no models. Very simple, very effective.
by amatic 9y ago
>> modelling might in fact be a necessary part of regulation.
That seems false. PID is used all over, no models. Very simple, very effective.
- maxerickson 9y agoOne way to look at a PID controller is that it uses a simple model that is correct in a lot of situations.
- euyyn 9y agoYeah tuning the PID controller is in fact modeling the dynamics of the system. You can't really expect an untuned PID controller to just work.
- sobellian 9y agoThe fact that PID loops work for many systems is a consequence of the dynamics of those systems, for example that the integral of velocity is position and the derivative of velocity is acceleration. A vast array of phenomena can be modeled as 2nd order linear ODEs.
- carlmr 9y agoWhich just means that for many things your brain doesn't need a new model, just to parametrize one of the most common models.
- xaedes 9y agolinear model
- theoh 9y agoI think this Wiki page discusses it: https://en.wikipedia.org/wiki/Internal_model_(motor_control) https://en.wikipedia.org/wiki/Internal_model_(motor_control)
- nabla9 9y agoYes. That sentence is generally untrue if the context is not specified. Either the authors made rudimentary error or they specified the context. If you read forward, they define the problem and discuss error and cause controlled regulation.
- ahartmetz 9y agoAs a bad physicist ("physics is the art of approximation", some prof said during my studies): Indeed, you only have to model the relevant aspect(s) of the system, which may be completely unrecognizable as the system. I guess it's somewhat more true in programming, because if you have only ten lines, can you even call it modeling? That said, I like to say that the best kind of code teaches you something new abou the problem it's solving. Some invariant, widely usable simplification, etc. Still not the same as modeling the system as such, though.
- carlmr 9y ago>because if you have only ten lines, can you even call it modeling? Ten? Do you even Perl?