by Katie Lilienkamp, (c)2000
You can review this by following the link for
hw3 Notes on the Problem Sets webpage for 2.010.
- Tutorial #3 -- Outline: (This page...)
- PS #2 Review [very brief...]
In general, everyone seemed reasonably clued-in on HW #2, so I'll just put a couple of comments here:
Prob 2.1: For future reference: When modeling motor dynamics and control, note whether you are controlling
CURRENT, in which you can directly indicate the current and
find the resulting torque:
torque = Kt * i.
or
VOLTAGE, which requires a more complicated model that
includes:
back emf
a model of the resistance (and possibly inductance) of the motor.
i(s)/e(s) = 1/([Ls] + R)
Current control is easier to model, but voltage control is typically
much easier to implement in actually BUILDING a real-world motor -- so
expect [in general] to have to deal with this more complicated model.
Prob 2.2: The idea to keep with you here is that a
MEASUREMENT can introduce dynamics of its own into a system (that
can, in fact, affect pole location)... so watch out for cases where
modeling the sensor (as well as the plant) is important in
predicting stability and performance of the total system!
- PS #3 Tips [Some
info here may not be needed for ps #3, but it's all info you'll
eventually need to know...]
Closing a Loop
-- Review (again) of basic algebra and block diagram manipulation.