Questions tagged [control-systems]
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193
questions
7
votes
1answer
91 views
Fundamental questions about state-space and Kalman filters
I am a dsp guy, I only did a minimum of control theory back in university. While trying to grok state space analysis and (discrete time) regular Kalman filters, I am hitting a few questions that ...
0
votes
1answer
92 views
Model necessary for PID control
As I am not from control theory, I do not understand - after reading the Wiki page about PID control (https://en.wikipedia.org/wiki/PID_controller) and watching some videos - whether a model of the ...
3
votes
1answer
52 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
25 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)=\...
1
vote
3answers
87 views
Whether $y(t) = x(t/3)$ is a memoryless system?
I am a newbie in signal and system, and feeling confused about the memoryless property, it says at the definition, if a system gives output only depends on present input, then its memoryless. So if at ...
0
votes
1answer
18 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
53 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
14 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
31 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
57 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
41 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
32 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
16 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
12 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
43 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
1answer
27 views
Multiply a measured quantity of a control-system in the frequency domain during continious operation
Currently I am working on a feed-forward control system to actively control vibrations. For that purpose I need to measure accelerations on a vibrating structure and use a transfer function in the ...
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 $z^{-1}$ ?...
1
vote
0answers
28 views
How can we do exact simulation for digital systems? [closed]
In digital control system, there are two basic techniques for finding the best digital controller.
First, called the discrete equivalent, we find the continuous compensation and then discretize (best ...
2
votes
2answers
49 views
Where does the error come from in PID control?
Let's say my thermostat is 50 degrees Fahrenheit. I know that 1000 units of kinetic energy are needed to raise the temperature from 80 degrees Fahrenheit. So I calculate how much I need to increase my ...
4
votes
1answer
45 views
Unstable plant transfer function identification
I would like to find the transfer function of an unknown unstable SISO plant.
If it was a stable plant, I would input a sine sweep and measure the frequency response at the output; but I cannot do ...
0
votes
1answer
74 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
55 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
38 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
48 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
38 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:
...
0
votes
1answer
56 views
What real object could be modeled by this transfer function? [closed]
What object from real world could be modeled by this transfer function?
What could parameters b, p1 and p2 stand for?
1
vote
1answer
52 views
Got stack in calculating state-space representation
I got stack in the process of deriving a state-space representation of the following system:
There is an electrical oven described as follows:
control of the power supply $u$,
heating efficiency ...
0
votes
1answer
43 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 ...
4
votes
4answers
146 views
Layman Description of the Kalman Filter
I want to know about Kalman Filter but i tried searching different links including Electrical Engineering StackExchange but the information available there was hardly digestible.
All I am able to ...
0
votes
0answers
24 views
Solving the system response using inverse Laplace transform
I am trying to solve this question but I got stuck when inverting the Laplace transform for this problem. I do not know that whether I do it right or wrong. Moreover, I do not know how to handle the ...
0
votes
0answers
11 views
Optimizing a heating/cooling system for a particular input
Lets say I have a house with 2 rooms. One of them has a window that opens and closes T periodically. So the heat influx behavior of the window is like a square wave. There is an air conditioning unit ...
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 ...
2
votes
1answer
41 views
How to evaluate a close-loop control during transient?
I have implement a close-loop control in order to perform the tracking of the desired signal R.
The basic scenario shall be summarized as follow:
I have to evaluate the performance of my control G ...
1
vote
1answer
498 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
0answers
23 views
Taking transfer function out of real heating system
I have some king of heating system: heater (that I can control current for final power control) and a thermocouple (for measuring the temperature). I also have a device that can record temperatures ...
0
votes
0answers
32 views
Adaptive feedforward cancellation (AFC) and least mean squares (LMS) for periodic disturbance cancellation
I already asked this question on Math Stackexchange and Engineering Stackexchange, but since I did not get an answer yet I want to try it here as well:
I want to implement an adaptive feedforward ...
0
votes
1answer
33 views
Controllability's dependence on B matrix
Assuming the LTI system:
$\dot{x}=Ax+Bu\\$ , where $x\in R^n$
I understand that
the $B$ matrix is usually given, and it is up to us to derive the optimal $u$ given an initial state of the system ...
0
votes
1answer
18 views
External/Internal Description of a System
When an LTI system is NOT completely controllable/observable, does the linear differential equation governing the system give the internal or the external description of a system?
1
vote
2answers
173 views
What is the difference between a controller and a compensator?
I recently revisited some texts on control theory. In some textbooks the term compensator is used, seemingly interchangeably with controller (see e.g. The Control Handbook by Levine, chapter 14 on ...
1
vote
0answers
63 views
Position Kalman Filter fails to track a constant-acceleration path
I'm trying to build a discrete Kalman Filter that fuses accelerometer (acceleration) and GPS (position, velocity) measurements. However, I'm finding that my filter can't properly track a constant-...
3
votes
1answer
45 views
General tips for PID tuning of super low-friction actuator?
I realize this question is not directly related to signal processing, however, it's relevant to system analysis which is relevant to most signal processing engineers. There's also no good alternative ...
0
votes
0answers
31 views
what is the co-variance of system output cooresponding to a non-iid random variable
Consider the following system.$\DeclareMathOperator{\sign}{sign}$
$$
\begin{aligned}
&\dot{e_1}=c_1e_1+c_2e_2+\eta\\
&\dot{e_2}=c_3e_1+c_4e_2-c_5 \sign(e_1)+a \eta
\end{aligned}
$$
which $\eta$...
0
votes
0answers
28 views
How to integrate and differentiate sampled signals?
I am working on a control system which is defined by the equation.
As you can see,the equation is in continuous state.
$T_i$ = integral time and $T_d$ = differential time which are both constants ...
1
vote
1answer
71 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
1answer
41 views
Cascade filter realization equivalence? [closed]
Given
$$H(z) = \frac{11 +4.6z^{-1} -26z^{-2}-3.75z^{-3}}{1-z^{-1}-8.75z^{-2}}$$
I'd like to know whether this realization:
Is equivalent to this one?
In short, is the direct form realization ...
3
votes
1answer
153 views
SRF-PLL discretization problem
So I've been working on how to digitally implement a static reference frame PLL (SRF-PLL), which is a quite popular PLL used for extracting three-phase grid angle.
This PLL works by using the DQ0 ...
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 $...
