Questions tagged [control]
The control tag has no usage guidance.
41
questions
0
votes
1answer
36 views
How to quantify amplitude of oscillations in marginally stable systems?
Transfer function pole on the Imaginary axis indicates that the system is marginally stable which in time domain can be represented as a sinusoidal motion with constant amplitude and frequency of the ...
0
votes
1answer
36 views
Controller in the feedback path?
What happens if the controller of a closed-loop system is placed in the feedback path before the summation point instead of bewtween the summation point and the plant to control?
Is it allowed to do ...
0
votes
1answer
41 views
How does the intuitive notion of causality fit in with control systems?
Edit: By causality, in this question, I do not mean the traditional mathematical definition in the theory o signals and systems; I mean causality as in an intuitive 'what's moving/pushing what notion'....
1
vote
1answer
29 views
Region of root locus not inside the feasible region for a given performance specification
I wanted to plot the root locus for a system, whose plant transfer function is
$$
P(s)= \frac{k}{Ts+1}e^{-ts}.
$$
A PI controller was suggested for this system, and the task is to find $K_p$ and $K_i$...
0
votes
0answers
22 views
Transfer function estimation using System identification
I am posting a control system problem here because of this post reference: https://meta.stackexchange.com/questions/207787/is-there-a-control-theory-site
Question:
I have input and output datasets. ...
0
votes
0answers
24 views
Control of a nonlinear static MIMO System
I am currently writing my master thesis and trying to design a controller for my system. However, the system is somewhat unconventional.
It has a large number of inputs and outputs, is static, non-...
1
vote
0answers
14 views
Controller design with DQ transform
I'm reading this paper on a 3-phase rectifier control. 3-phase rectifiers are usually connected to 50-Hz or 60-Hz grid. One popular control strategy is to transform the 3-phase currents and voltages ...
0
votes
0answers
15 views
Feedforward disturbance signal compensation
The reference Feedforward control concepts through Interactive Tools says, to minimise the effect of the disturbance $d$ on the process output $y$, a compensator $G_{\text{ff}}=P_3/P_1$ shall be used. ...
0
votes
0answers
15 views
How can I correct the settling time when implementing a prefilter?
I have designed a controller for the speed of a motor, I calculated for a settling time 0.1 seconds, it works when i test it without pre filtering, however, i need 0 overshoot, so I implemented a ...
3
votes
1answer
66 views
Stabilizing the inverse transform of a system
Currently I try to understand an unknown mechatronic system. I used white noise as an input signal and measured the output of the system. Then I estimated a 2nd order transfer function (Output/Input) ...
0
votes
1answer
28 views
why if I place the zero of the lead compensator at lower frequencies I have a resonance peak?
I am studying control systems, and I am studying the lead and lag compensator.
I have seen than if I use a lead compensatpr in the following way:
consider a closed loop transfer function:
$T(s)=\...
0
votes
1answer
22 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
56 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
19 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
33 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
62 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
47 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
136 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
29 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
17 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
114 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
20 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
172 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
63 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
40 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
51 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
127 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
155 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 ...
2
votes
2answers
130 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
137 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
333 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
33 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
3k 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
2k 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
77 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
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:
$$G(s)= \frac{w_n^2}{s^2 +2\zeta w_ns +...
0
votes
1answer
57 views
Calculating an in-loop signal as part of a hierarchical control loop
I've got a control system with two feedback paths, with each path going to a different actuator that corrects the error in the system. One feedback path provides feedback at low frequencies, and the ...
1
vote
1answer
65 views
State space equations
I am stuck on this exercise. I don't know how to deal with this squared y in the denominator. What am I supposed to do to obtain state space equations?
ex.1
Simplified dynamic model of the steel ball ...
0
votes
2answers
57 views
Control optimization problem
I am running into a problem where I have a control system $S[t]$ that takes a control $C[t]$, so that
$$S[t+1] = H(C[t,t-1,...], S[t,t-1,...])$$ the response of the system is the history of controls ...
