3 ms·
> You do build a model but its model of observations and actions, not the heater itself. In fact, for vast majority of things we control such as bicycle or fan
by BoiledCabbage 7y ago
> You do build a model but its model of observations and actions, not the heater itself. In fact, for vast majority of things we control such as bicycle or fan or oven, people rarely knows the model of these very complex systems (in terms physical principals and internals).
I think you're mistaking the term model for a replica. You don't need a replica, but you do need a model for your relevant tasks.
If the heater needs 30 mins to warm up before it starts pumping heat, you'll need to model that. If it overheats after running for 3hrs straight you'll need to model that too. You don't need every molecule of the physical item replicated but you do need to model all of the relevant behaviors.
- dTal 7y agoThis sounds a little circular. If a "model" is defined as a representation of a system of sufficient fidelity to control it, then of course all controllers contain models. Deciding which behaviors are "relevant" would appear to be the key issue here.
- mannykannot 7y agoYou have a point, but I think it is useful to have a unifying general principle to use in analyzing the design of regulators, and having a theoretical basis makes it harder to dismiss. I can think of a couple of places where it could have avoided accidents (one tragic and one expensive.) The 1974 DC10 crash in Paris was supposed to be impossible because the airplane could not be pressurized unless the cargo door was properly latched, but the mechanism depended on the position of the handle rather than the latching pins. At Three Mile Island, the operators were trained to use the pressurizer water level as a primary indicator of the state of the system, and turned off the emergency cooling feed as a consequence.