# Questions tagged [control-theory]

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### Space State on SEP/Ex DC-Motor

I'm currently studying DC motors and I do have some doubts about the dynamics of it. As per explained on [Guru, B.S. and Hiziroglu, H.R., 2001. Electric machinery and transformers (Vol. 726). New York:...
168 views

### How can I calculate gain margin in this transfer function and the constant K?

This is the problem statement: There is a mechanical crane whose Transfer Function is shown. If it is implemented The automatic system shown, closing the loop and adding the G1 block (s), you are ...
100 views

### PWM frequency and control system sampling frequency in dc-dc converters

I am trying to control the output voltage of a simple dc-dc buck converter, which is digitally controlled. The output voltage is sampled, and the control algorithm is run, at every $T_s$ seconds, ...
950 views

### I'm confused a bit on basic control stuff for a PID controller

I'm doing a PID controller demonstration project in which heat is applied to a K type thermocouple and I'm supposed to maintain the temperature read at 50 °C using a PWM signal. I know the basic ...
60 views

### Control system -- closed-loop system problem

Given a closed-loop system as shown below: Suppose that $x(t) = u(t)$ and $d(t)=0.5u(t)$. Determine the output response of $y(t)$ and it's steady state at $t\rightarrow \infty$. I've tried to ...
62 views

### Nichols plot confusion

The transfer function is $F(p)=10/(p^2+2p+1).$ Using Wolfram Alpha, the Nichols plot shows that the argument $\to -\pi$ when $\omega \to +\infty$. However, calculating the argument on paper ...
33 views

### Feedforward from measurable disturbance

Gff is chosen so that it completely cancels the disturbance (Gff = -Gv/P) and Lp < Lv. Is it easier to control if Tp < Tv or Tp > Tv. I am a little bit lost on how to begin here? Should I ...
48 views

### Output of a linear system with discrete feedback

I have this problem here that I had trouble with few years back and I still don't understand https://imgur.com/At2BbWe With a T period discretization on the feedback and a first order hold after it. ...
52 views

### Linearization of nonlinear plant with system identification in Matlab

I hope this question fits in here and there is someone who can maybe help me. I am new to control theory and I have a very complex Simulink model which is nonlinear. I want to have a linear ...
84 views

### Decide P controller gain K so that phase margin is 50 deg

I need help finding the gain $K$ so that the phase margin for the system equals 50 degrees. $$F(s) = K$$ $$G(s) = \dfrac{1}{(s+1)^2}$$ $v$ is a process disturbance sinusoid with amplitude 2.5 and ...
71 views

### From where does State space model equations come from?

I have a good basic understanding on classical control theory. Now I am studying modern control theory.I encountered the following equations as seen below. Online I have only been able to find ...
64 views

### fast analytical technique identifying poles/zeros using degree of freedom

I encounter some engineers who can quickly spot poles and zeros in the circuit by identifying "degree of freedom". For example, a typical technical discussion goes like : "a miller ...
122 views

### Determine range of proportional gain with given overshoot

I have given the open-loop transfer function $$G_{ol} = 1.42 \frac{(s+3)^2+6^2}{(s-1)(s+2)((s+4)^2+4^2)}$$ The task I was given is determining the range of the proportional gain, which makes the ...
203 views

### Tuning PID without transfer function

I'm very new to control theory and I am stuck at PID tuning. I have a given Simulink model but I do not know the transfer function. I want to use a PID to provide new input from the output of the ...
117 views

### Why do I need phase margin if I know the transfer function?

What is the point of examining the phase margin (or gain margin) for a closed-loop system if I can just solve for the transfer function. The transfer function will give any poles and zeros, which can ...
64 views

202 views

### Linear regulator loop dynamics

Given a step change in the input voltage of a standard op-amp based linear regulator, a finite amount of time is needed for the op-amp to sense the voltage difference at its input and do whatever it ...
129 views

### Why is a system description in control theory important?

If you want to control a system (with a loop controller), why actually do you need to know anything about the system itself (its dynamics or the transfer function or impulse response or whatever)? Isn'...
313 views

### Pure transport delay? (Nyquist plot)

How does pure transport delay affect the Nyquist plot, and how is it possible to find the maximum value of the delay, such that the system stays stable even after delay is introduced?