Questions tagged [control]
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31
questions
0
votes
1answer
16 views
Measurement delay versus control delay
For a typical control loop (no delay, measurement transfer function is 1) the closed-loop transfer function is
$$ H(s) = \frac{G_{comp}G_{process}}{1+G_{comp}G_{process}} $$
With an actuator delay ...
1
vote
1answer
48 views
What does it mean that a zero is slow?
I am studying control systems, and I have encountered the definizion of slow zero. I am searching on internet and on books, but I don't understand the meaning this. I know that if a zero is too slow, ...
0
votes
0answers
11 views
What is the difference between robust stability and robust performances for a MIMO system subject to uncertainty?
I am studying control systems and I am focusing on the case where uncertainty is present in the system. I have seen that in this case I have to be able to garantee robust stability and robust ...
1
vote
1answer
30 views
Does a RHP zero imposes some limitation in the time domain?
I am studying control systems and I have seen that a non-minimum phase zero imposes limitation in bandwidth , which is that the bandwidth has to be lower than a frequency which is half the frequency ...
1
vote
1answer
46 views
Problem in verifying zero blocking property of a zero of a multiple input multiple output system
I have a multiple input multiple output control system, and in particular a two inputs two outputs system. I want to find the zero state direction and the zero input direction of the system, which has ...
2
votes
1answer
40 views
Is it possible to use a control scheme with a delay as prefilter?
I am studying control systems, and in my studies I have encountered the topic of control scheme of the form
and I have seen thaht this control scheme is really useful since it is possible to add a ...
0
votes
1answer
21 views
Can a pole at the origin be considered a dominant pole?
I am studying control syetems, and I have studied that the dominant poles of a system are the ones closer to the imaginary axis.
Now, consider a system with a pole at the origin. Can this pole at the ...
0
votes
0answers
8 views
How do I design a reference filtering control scheme with a lead compensator?
I am trrying to design a lead compensator for a system. I have the following control scheme:
where $Cr(s)$ is a prefilter which can be a lag or a lead compensator. My obkìjective is to design $Cr(s)$....
0
votes
0answers
11 views
Why does the step response has higher overshoot if the zero is too slow in a lead compensator used as a prefilter?
Consider a control scheme of the following type:
where $C_r(s)$ is used to filter the reference, and it can be a lead compensator of a lag compensator.
One thng I don't understand is why if I ...
2
votes
2answers
40 views
Why does the control effort increase if the bandwidth of the system is higher then the bandwidth of the plant?
I am studying control systems and I am focusing on the control effort.
I have seen that if I place a pole at higher and higher frequencies, if the bandwidth of the system goes above the bandwidth of ...
0
votes
0answers
10 views
Doubt on limitation of the bandwidth of the control sensitivity function
I am studying the mixed sensitivity design for control systems, and I have seen that by introducing weights, which can be for the senstitivity function, complementary senstivity function and the ...
0
votes
1answer
18 views
Understand diagram of a process
I've found this diagram in a slide, but i have no backround to properly understand it. Could you explain to me, in simple terms, how this process behaves and what's the purpose of the blocks $z^{-1}$ ?...
0
votes
1answer
51 views
How do I find transfer functions from a state space representation?
Suppose I have a MIMO system in state space representation, for example:
$A=\begin{bmatrix}
1 &2 &3 \\
4&5 &6 \\
7&8 &9
\end{bmatrix}$
$B=\begin{bmatrix}
2 &3 \\ ...
1
vote
0answers
54 views
Influence of a RHP zero/pole in the frequency response
I am studying loop shaping, and I am looking at loop shaping design with unstable poles and zeros. I have seen that noth unstable poles and zeros introduce limitations in the bandwidth. I have also ...
0
votes
1answer
37 views
Doubt on behaviour of frequency responce of a system
I am doing loop shaping using $H_{\infty }$ approch, and I have a plant with an unstable pole:
G = 10/((s+10)*(s-1));
K1 = 4*(s+1)/s;
where G is the plant, and ...
1
vote
1answer
46 views
Doubt on the relationship between the sensitivity and the complementary sensitivity function
I am doing loop shaping with the following transfer functions:
G = 10/((s+10)*(s+1));
K1 = 0.5/s;
where G is the process and K1 is the controller, and If I ...
0
votes
1answer
33 views
How can a stable system have a RHP pole?
I am working with a control system which has an unstable pole in the process. So I have the following transfer functions for the controller and for the process:
...
3
votes
3answers
76 views
Frequency warping when integrators are replaced with backward-euler and forward-euler integration
Resonant controllers are used in the power industry. The transfer function
is
$G_{res}(s) = \frac{K_i*s}{s^2 +2*\omega_c*s+ \omega_o^2}$
The "textbook" discrete implementation is depicted in the ...
1
vote
1answer
52 views
Understanding Matlab's Automatic Gain Control function
I am trying to understand the automatic gain control block provided by the communications toolbox. The documentation is here: Documentation
My questions are in regards to two of the configurable ...
0
votes
1answer
31 views
Discretizing a Controller with the Backward Difference Method
In the book "Modern Control Engineering" by Paraskevopoulos it's proved how to discretize a generic controller in the form:
$G(s)=\frac{Y(s)}{U(s)}=\frac{a}{s+a}$
where $a$ is a constant. Done this, ...
0
votes
0answers
34 views
Doubt on inversion of the dynamics
I am studying control system and I have encountered the topic of the inversion of the dynamics. So I have seen that the ideal situation would be
$C(s)=P(s)^{-1}$
but there are some problem with ...
2
votes
1answer
62 views
Lead compensator vs lag compensator?
I already know that lag compensator acts like PI controller and improves steady state and lead compensator acts like PD controller improves transient state but how they achieve their goal? Despite ...
0
votes
1answer
26 views
confusion about poles and zeros of Lead compensator?
I was reading about lead compensator from a website but i am not able to understand how they have extracted zero and pole from transfer function of lead compensator as shown in attached photo?
or ...
13
votes
6answers
2k views
Relation between signal processing and control systems engineering?
Control systems engineering and Digital signal processing are both important courses/subjects of electrical engineering But how these two subjects/courses are related to each other??
Also please ...
1
vote
1answer
381 views
Effect of origin poles on stability?
What will be stability if we have only one single pole at origin in s domain??
and what will be the case for multiple poles at origin in s domain?
1
vote
1answer
70 views
Is a good practice to use one PID in rise time and another PID for steady time in order to eliminate oscillations during steady time?
I'm trying to control temperature with PID(Kp,Ki, Kd). During the rise time the system use one PID and when target is reached the system switch to another PID with other parameter in order to ...
0
votes
0answers
17 views
Finding gain on root-locus
I have to design a compensator using root locus for the system $G(s) = \frac{1}{s\cdot(s-4)}$ that follow the following criteria:
$op\% \le 5\%$
$t_{2\%} \le 4s$
So I started computing $\zeta$ and $...
0
votes
0answers
38 views
On $H_\infty$ norm for transfer function
For a given scenario in the context of control system, I'm trying to investigate how the $H_\infty$ norm can be calculated for a transfer function as follows:
$$G(s)= \frac{w_n^2}{s^2 +2\zeta w_ns +...
0
votes
1answer
48 views
Calculating an in-loop signal as part of a hierarchical control loop
I've got a control system with two feedback paths, with each path going to a different actuator that corrects the error in the system. One feedback path provides feedback at low frequencies, and the ...
1
vote
1answer
62 views
State space equations
I am stuck on this exercise. I don't know how to deal with this squared y in the denominator. What am I supposed to do to obtain state space equations?
ex.1
Simplified dynamic model of the steel ball ...
0
votes
2answers
56 views
Control optimization problem
I am running into a problem where I have a control system $S[t]$ that takes a control $C[t]$, so that
$$S[t+1] = H(C[t,t-1,...], S[t,t-1,...])$$ the response of the system is the history of controls ...
