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18 votes
3 answers
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A good textbook for designing signal filters

Since a couple of months ago I started being actively involved in the area of control of dynamical systems. In most cases, designing a controller for a given dynamic system will require the ...
fpe's user avatar
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15 votes
1 answer
2k views

How to deal with a negative pole (unstable) in the pre-filter of a control system?

So while answering how to design a PI controller for a first order time delayed system (Question Here ) Here is the closed loop equation to a control system: $$ G_C(s) = \frac{\frac{K}{T}(1-sT)(s)...
CyberMen's user avatar
  • 831
13 votes
6 answers
6k 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 ...
DSP_CS's user avatar
  • 1,884
12 votes
1 answer
4k views

What is the "waterbed effect" in control system design?

I recently stumbled across some notes on the "Waterbed effect" in some notes by A. Megretski for an MIT course on "multivariate control systems". Here's an excerpt: A common effect, usually ...
nibot's user avatar
  • 3,803
11 votes
2 answers
5k views

How to do prediction using frequency domain data?

Both linear regression and Kalman filtering can be used to estimate and then predict from a time domain sequence of data (given some assumptions about the model behind the data). What methods, if ...
hotpaw2's user avatar
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10 votes
0 answers
197 views

Estimating the input to a system from a system state using EKF [closed]

[ Cross-posted from: https://math.stackexchange.com/questions/164169/estimating-the-input-to-a-system-from-a-system-state ] I have a system for which I have obtained a non-linear time-varying state-...
IainCunningham's user avatar
9 votes
4 answers
16k views

Do we use closed loop or open loop information in Bode plot, Nyquist plot and Root Locus?

When analyzing a control system via Bode, Nyquist and Root-Locus, are we using open or closed loop information? I'm not able to understand when the poles of the open loop are used and when the one of ...
Tendero's user avatar
  • 5,020
7 votes
1 answer
17k views

Why eigen values and poles of a system are equivalent?

In control systems engineering, the stability of a system (modeled in the form of Transfer Function) is determined by the poles of the system in the right or left hand sides. When the model is ...
Robotawi's user avatar
  • 173
7 votes
1 answer
699 views

Kalman Filter: How to Define Inputs and Outputs of a Model

I'm a software engineer with a CS degree working in machine learning. I'm trying to learn about Kalman Filters. In this short YouTube video from Mathworks, there's a discussion on a Kalman Filter with ...
stackoverflowuser2010's user avatar
7 votes
1 answer
994 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 ...
Knut Inge's user avatar
  • 3,462
7 votes
2 answers
320 views

Regarding the choice of cost function in adaptive control - squared error vs absolute error

I did search the question database regarding this question, and although one or two questions came close, they didn't really address my specific question. In adaptive control based on minimizing ...
docscience's user avatar
6 votes
3 answers
914 views

Why is an RC circuit a first order system?

I am going through the following tutorial: Time-Response Identification of a Resistor–Capacitor (RC) Circuit Why do we call the RC circuit a first order system? I understand the order of a system ...
JJT's user avatar
  • 215
6 votes
1 answer
2k views

AutoExposure with nonlinear camera: Non linear proportional PID?

Now I', wondering how to best implement a control algorithm for it. I tried using a PID controler but started with a simple P-control first. The problem is, that when using the equation ...
tim's user avatar
  • 155
6 votes
1 answer
330 views

Is there a strategy for discrete control of a system with dynamics near sample rate?

I'm trying to control a system where the controller sample rate is physically fixed and the plant has significant dynamics on the same order as the sample rate. I understand that one would prefer to ...
tkw954's user avatar
  • 203
5 votes
5 answers
619 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 ...
DSP_CS's user avatar
  • 1,884
5 votes
2 answers
2k views

Which step response matches the system transfer function

A system has the following open loop bode plot: - Which one of the plots below describe the closed loop step response for the entire system? My attempt My initial thought was to look at the static ...
Carl's user avatar
  • 372
5 votes
3 answers
809 views

Discrete State Space Model - Why Are We Calculating $ x \left[ k + 1 \right] $ Instead of $ \dot{\boldsymbol{x}} \left( t \right) $?

A continuous state space model is defined as follows. $$ \dot{\boldsymbol{x}}(t) = A \boldsymbol{x}(t)+ B \boldsymbol{u}(t) \\ \boldsymbol{y}(t)= C \boldsymbol{x}(t)+ D \boldsymbol{u}(t) $$ If we ...
MisterFilter's user avatar
5 votes
2 answers
3k views

How to set parameters of the PI controller inside the PLL?

I am going to implement in C++ software the synchronous frame phase locked loop (SFPLL) for estimation of angle and frequency of the three phase grid 220V/50Hz. For the internal PI controller setting ...
Steve's user avatar
  • 397
5 votes
3 answers
1k 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 ...
Ben's user avatar
  • 3,777
5 votes
2 answers
403 views

Stabilizing the inverse transform of a system

Currently I am trying 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 second order SISO transfer function (...
Matthias La's user avatar
5 votes
2 answers
2k views

Does the impulse response of a system have any physical meaning?

In other words, what does the impulse response tell us about the characteristics of the system? For simplicity, let's assume we deconvolve a discrete output and a discrete input to obtain an impulse ...
Xe M's user avatar
  • 53
5 votes
2 answers
4k views

Inverse system in Simulink

I have the following inverse system $$G(s)= s^2 + 2s + 3$$ How do I implement it in Simulink? Note that the transfer function is only accepted if and only if the order of the numerator is less than ...
Kho's user avatar
  • 93
5 votes
1 answer
333 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 ...
Yiftah's user avatar
  • 154
5 votes
1 answer
3k views

Measuring the open loop transfer function in closed loop: what's the better approach?

Considering the closed loop system; $C$,$G$, and $H$ all linear and stable transfer functions, If I chose to excite $\bf r$ and measure $\bf e$, I get the Sensitivity Function, $S$ $$S=\frac{1}{1+CGH}...
docscience's user avatar
4 votes
2 answers
772 views

State space physical meaning

Let $T(s)$ be a transfer function that describes a mechanical system, where the input is force and the output is position. And let $[A,B,C,D]$ be the equivalent state-space representation of $T(s)$, ...
Yiftah's user avatar
  • 154
4 votes
1 answer
1k views

How accurate is the dominant poles approximation in higher order control systems?

From what I have learnt from control systems classes, the dominant poles of a system are those that can be used to analyze a higher order system in terms of the formulas of a 2nd order system. I took ...
First User's user avatar
4 votes
2 answers
10k views

What is the difference between a lag compensation and PI control?

A lag filter or compensator has the Laplace transform transfer function $$G_c(s) = \frac{s+z}{s+p},$$ with $-z < -p < 0$. In practice, the effect of lag compensation in feedback control, is to ...
Max's user avatar
  • 352
4 votes
2 answers
652 views

Why doesn't the convolution of the impulse response match the system's output?

If you define an LTI system sys in scipy, you may conveniently feed an input x to it to get ...
arash's user avatar
  • 183
4 votes
1 answer
2k views

How do I get a faster system response?

I have this model in simulink (the graph is my output): The step input has amplitude 0.5 m/s, and it steps up after 0.1 seconds. The gain $K_p=5$. The saturation block is to keep the voltage between -...
Carl's user avatar
  • 372
4 votes
2 answers
5k 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 ...
snowflake's user avatar
  • 192
4 votes
1 answer
520 views

Effects of delay in a discrete-time controller for a continuous-time plant

I'm trying to understand the effects of sample-to-update delay in digital control of power electronics. I am aware of the issue but not 100% sure how to quantify it. There is an interesting paper by ...
Jason S's user avatar
  • 1,059
4 votes
2 answers
2k views

How to establish transfer function of a speaker?

I'm working on a signal processing project about vocal system, and I'm trying to use controlling theories to solve the problem. I need to get the transfer function, $H(s)$, of a speaker, from ...
Alexander Zhang's user avatar
4 votes
1 answer
1k views

Determining the final value of the output of a discrete system

I'm going through an exam question where I've been told that the samples $f(kT)$ of the following function \begin{equation}{F\left(z\right)=\frac{1}{1-0.819z^{-1}}} \end{equation} are applied to a ...
Ca01an's user avatar
  • 41
4 votes
1 answer
3k views

Find transfer function from root locus and step response diagram?

I am given the response of a step of magnitude of 3 and the root locus and I have to find the transfer function of the system. The function I find gives me the step response(magnitude of 3 again) of ...
John Katsantas's user avatar
4 votes
1 answer
151 views

Understanding an adaptative single neuron PID controller

I only know the "vanilla" use of a Kalman filter and I am currently trying to understand an article available here (the algorithm is presented in the 6 first pages) : Adaptive Single Neuron ...
NokiYola's user avatar
  • 507
4 votes
1 answer
60 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 ...
Mattia S.'s user avatar
4 votes
1 answer
1k views

Developing Lead Compensator to Decrease Settle Time

This is a follow up to this question. I've approximated the transfer function for a system to be H = zpk([0.012 -1.05 18],[-0.22 -0.22 -45 -1000],10000);. My goal ...
cicey60307's user avatar
4 votes
0 answers
253 views

Digital control: Exercise solution

Can you help me (show me how) to solve the following exercise? For the process with transfer function $G(s)=e^{-2s}/(s+1)$ design a digital controller with sampling time $T_{s} = 1$ that meets the ...
Backo's user avatar
  • 141
3 votes
3 answers
11k views

Why oscillations in PI control?

When integral control is added to proportional controller (i.e. PI control), why steady state error becomes 0 and why oscillations appear , how actually the integrator works ?
Talha Yousuf's user avatar
3 votes
1 answer
2k views

In the context of transfer functions, what is the relationship between the terms "proper", "causal", and "realizable"?

I am thinking about these terms in the context of linear control. A transfer function is proper if the degree of the numerator is not greater than the degree of the denominator. I've read often that ...
Max's user avatar
  • 352
3 votes
1 answer
926 views

How can a system be unstable if $L(j\omega)$ is never exactly $-1$?

Say we have a linear system with unity feedback, with loop transfer function $L(j\omega)$. The closed-loop transfer function from reference to output is $T(j\omega) = \frac{Y(j\omega)}{R(\omega)}=\...
Max's user avatar
  • 352
3 votes
1 answer
512 views

How do you design using bode plots?

[Control Systems Engineering by Nise] Hey, I have some confusion regarding bode plots and how they can be used to display both open loop and closed loop information. This also partially relates to my ...
AlfroJang80's user avatar
3 votes
2 answers
1k 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 ...
J.D.'s user avatar
  • 183
3 votes
2 answers
3k views

Is this system time invariant?

I've been working at this problem for a while now, and can't seem to come to a solid conclusion - is this system time invariant? $y(t) = \int_{-\infty}^{t} e^{-9(t-\tau)} x(\tau)d\tau $ My reasoning ...
Jeff Isaacs's user avatar
3 votes
2 answers
4k views

What is the Reference in Control Theory?

I've started studying Control and I've come across some concepts that I'm finding a bit difficult to understand. For example, in the system showed here, there is a signal called "reference" as well ...
Tendero's user avatar
  • 5,020
3 votes
2 answers
3k views

Kalman Filter with Accelerometer with DC Offset

Goal: For a particle moving uniaxially, to estimate position ($d$) and velocity ($v$) from noisy acceleration ($a$) and very noisy position (GPS) measurements using a Kalman filter. Catch: The ...
Diego's user avatar
  • 51
3 votes
1 answer
194 views

Designing a Transfer Function with given requirements

While reading about the root locus method, I thought of a question and couldn't seem to answer it. Suppose for a negative feedback system, all the open-loop poles and zeroes and the centroid $\big(\...
LM2357's user avatar
  • 103
3 votes
2 answers
2k views

Control design: under what conditions can closed-loop poles be placed arbitrarily?

Say we have a single-input linear system $\dot{\mathbf{x}} = A\mathbf{x}+Bu$. With full-state feedback ($u=-G\mathbf{x}$), it is straightforward to arbitrarily place the $n$ closed-loop poles (i.e., ...
Max's user avatar
  • 352
3 votes
2 answers
1k views

How do we determine the required sampling rate of a closed loop control system?

Consider the controlled dynamical system $\dot{x}_t = f(x_t, u(t-\tau_{sd}))$, where $0<\tau_{sd}$ denotes the time delay caused by sampling. It is intuitively clear that the time delay caused by ...
kbakshi314's user avatar
3 votes
1 answer
343 views

What does it mean that a zero is slow?

I am studying control systems, and have encountered the definition of a slow zero. I am searching on internet and in books, but I don't understand the meaning this. I know that if a zero is too slow, ...
J.D.'s user avatar
  • 183

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