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# Questions tagged [control-system]

A system that may be electronic circuits or even software that uses control theory (principally differential equations) to control an output by monitoring various aspects of the system under control and varying inputs all towards meeting a defined goal. Some famous examples are controlling a rockets thrust angle to ensure directional control.

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17 views

### Problem reading control effort frequency response plot

I am trying to plot the frequency response control effort of a control scheme in Matlab, and in particular I want to do this for different values of tau, which is a constant used to add a pole at high ...
57 views

### Switching frequency and controller's crossover frequency in DC-DC converters

In the context of control loop stability of DC-DC Converters, A switch mode power supply is essentially a sampled-data system, therefore the theoretical maximum bandwidth is one half the switching ...
51 views

### Bode Plots and Electrical Circuits - Zeroes and Poles

I would like to understand more electrically with little math (transfer function) involved regarding Poles and Zeroes in a control system (Feedback in DC-DC Buck Converter to be specific). I ...
87 views

### Stability - Driving a Capacitive Load

I know I have been asked not to provide video links and ask questions. But I have no proper guide/mentor or anyone who can provide me better answers other than users in this site. So, please pardon ...
20 views

### Forward path gain

Consider a simple circuit consisting of a pair of wires, where input voltage is equal to output voltage. Here forward path gain is 'G(s) = 1',(fig.1) which gives g(t) = δ(t) {Inverse Laplace ...
38 views

### Relationship between switching frequency and controller's crossover frequency in DC-DC converters

I am reading some answers related to my questions based on control loop stability of SMPS. I came across this question. The accepted answer states: A switch mode power supply is essentially a ...
54 views

### Need help in designing control system

I tried to design the circuit but it doesn't give out the result that I was expecting and hope for and I am not sure why. Any idea on how to fix it? Original Transfer Function ^ Block Diagram ...
32 views

### Problem with performances of a control scheme

I am trying to prove with Matlab that if I have an improper system and I place poles at higher and higher frequencies the performances of the system improves. In particular I am considering the ...
46 views

### Control Loop Stability of DC-DC Converters

I am performing a control loop stability test on my 5V DC-DC Buck Converter with the help of this Keysight App Note I understand that we are injecting a noise signal on the feedback network of this ...
136 views

### Closed Loop System

Why is RC circuit considered closed loop system with negative feedback? Is it because it has a differential equation due to which current 'I' through capacitor 'C' will be C*(dVo/dt) = C*{Vo(t)-Vo(t-h)...
39 views

### Converting transfer function into circuits [on hold]

I am given a transfer function in modern control system and are asked to form a real circuit respect to the transfer function as well as the characteristics such as rise time, etc. The transfer ...
72 views

### Difference between stand alone pid and microcontroller based? Especially in terms of construction and applications?

My confusion is that what is the difference between a standalone pid controller such as the one shown in below link https://akytec.de/en/trm212.html And a microcontroller/microprocessor programming ...
21 views

### hinfsyn function in MATLAB

I am using hinfsyn to get a controller. I am not able to understand the output CL is a transfer function from what to what? Referring to the diagram in the hinfsyn documentation, is it the transfer ...
92 views

### Analog PID vs digital PID? [closed]

What is the difference between hardware/standalone pid controller and that implemented in programming using microcontroller? I have also placed below links of two stand alone pid controllers https:/...
39 views

### Coordination of mechanical and electrical power in electric drives

I want to ask a question to respected specialists in electric drives. It is known that the mechanical power of an electric motor is determined by a simple formula: ${P_{mech}}= M {\omega}$; ...
35 views

### Design of a controller

I am working on a project that requires me to design a controller knowing the following specifications: "The controller performance must be consistent under varying conditions. The rotor must respond ...
50 views

### Bode plot gives negative stability margins for a stable plant

I have a plant whose transfer function has all the poles in the left half of the s-plane (obtained the poles using Wolfram Alpha). However, its bode plot gives negative phase and gain margins; I ...
44 views

### Linear control vs non linear control?

Do linear control come under category of classical control or non classical control? And simliarly what will be category of non linear control? Will it come under category of classical control or non ...
67 views

### Effect of zeroes in stability

I thought earlier that zeros have no direct effect on stability but when I read the below article of Wikipedia where it said under the heading "Effect of poles and zeros " It says that adding zeros ...
17 views

### Digital Steady-State Error for a Ramp input

Since the stead-state error is given by: Hence X(z) = G(z)*U(z) where U(z) = (0.2z^-1)/(1-z^-1)^2 Which is the ramp input in Z-domain at Ts=0.2. This would simplify to xss = lim(z->1)[(z^-1)/(1-z^-1)...
40 views

### How to design this estimator?

I have the following problem to solve: I am really at loss of how to design the estimator for such a system and plot the closed loop step response. This is what I have so far in Matlab: ...
30 views

### Lag compensator vs pi controller?

Although Lag compensator and pi controller have apparently samd function of improving steady state response But how can we decide?which one to use?
14 views

### Lead compensator vs pd controller?

I have already studied that lead compensator is apparently similar to pd controller for both improve transient response But how can we decide?which one to use?
37 views

### Equivalent compensator of pid controller?

As we know that pi controller is equivalent to lag compensator and pd controller is equivalent to lead compensator, so what will be equivalent of lead-lag compensator?
21 views

### Low pass filter vs lag compensator?

Is there any difference between a low pass filter and a lag compensator?
31 views

### Layman explanation of “dynamics” or “dynamic behaviour”

I often read the term dynamics or dynamic behaviour in electrical engineering especially in control systems course What is meant by it? Is it means that the system whose internal state/properties ...
22 views

### Can I use Mason's gain formula to find ratio of intermediate node variable to input?

In the text book of 'Automatic Control Systems' by Benjamin Kuo, I read like this. Consider the following system. In some books, I saw they are using Mason's formula to find x2/x1 ? Is that allowed? ...
138 views

### How does Laplace transform include the transient response?

When we provide a sinsusoidal input, the evaluation of the solution of the differential equation head-on becomes horrendous. So we give an imaginary, complex exponential input and solve the ...
23 views

Is there any difference between cascade combination and series combination in terms of control system? Or they both same? Since in control system literature,sometimes at some places,we find the word ...
79 views

### Meaning of “Degrees of Freedom” in control system?

I have been searching google for "degrees of freedom," but it shows results relevant to statistics and physics. I am interested in answers in the context of electrical engineering, especially control ...
62 views

### Controller vs compensator?

Both these terms: controller(forexample PID controller) and compensator(Lead compensator) are often encountered in control systems,but what is difference between these two? Brain douglas in this ...
53 views

### PLC Replacement with C++ Embedded System or Application Specific Circuit

I work for a company that uses PLCs in their products, but lately, we have thought about doing away with our PLCs for application-specific circuits, FPGAs, or some other type of system on a chip that ...
127 views

### Kalman filters(in simple words) [closed]

What are Kalman filters and what are their applications? Please give simple explanation. I have tried studying different links but felt hard to digest/understand
33 views

### confusion regarding QNET VTOL(Vertical Take off and Landing)

I was reading a manual about QNET VTOL and i came across a block diagram(shown in attached snapshot) In the explaination of diagram, manual writes that The VTOL device is broken down into two ...
51 views

### How to find phase margin here

Please reference this question: I am not able to find gain cross over frequency to find phase margin. Gain margin is coming infinity here.
47 views

### linear model of a power load at the end of a transmission line

I am working on a controller that will regulate the voltage at the end of a transmission line into a variable load. I am able to ignore the inductive effects of the line at the frequencies of interst, ...
25 views

### state space representation of system with a disturbance

my question is how you can convert the bloc diagram which have a disturbance input to a state space representation and how you can calculate the controllability matrix then if you can give me any ...
40 views

### Confusion understanding transient behaviour?

I am trying to simulate PID controllers in MATLAB Simulink, but I am bit confused by the term "transient behaviour" in how its extreme highlighted forms (aggressive and robust) will affect the system ...
35 views

### Observability matrix different forms

The observability matrix formula is present in two forms in textbooks. My question is about which one to use. the first one: the second one: Now when applying both on the same system, I get ...
2k views

### Confusion in PID loop?for case of zero error?

I am already studying PID control and some how to some extent I have understood it except one main confusion. When the difference between reference input r(t) and current output value y(t) is zero, e(...
15 views

### Possible inconsistencies in solution to second order transfer function step response

I'm trying to use matlab to solve the second order DE for car suspension for a particular oscillation period and overshoot percentage (0.5s and 5%). I thought I had solved it but I've found some ...
20 views

### What is the residue of a response component in Control System Engineering?

I have read Norman S Nice book in Control Systems Engineering, I found in some pages the word residue which get me confused. Could you please help me to understand what does it mean if it says " the ...
97 views

### What does zero transfer function mean?

I am solving a problem where I have to find the transfer function of a system. The system is A = \begin{bmatrix}2&-1&2\\0&1&-2\\0&0&-1\end{bmatrix}, B = \begin{bmatrix}1\\1\\...
63 views

### DC-DC Converter Control Loop Stability

I have asked a similar type of question previously. This one is a little different. Assume, we have the Bode plot of a Control Loop System. In this case, DC-DC Converter. I measure the Gain ...
38 views

### Control Loop Stability - Crossover frequency

I am testing the control loop stability of a DC-DC Converter. One of the Pass-criteria of the DC-DC Converter states, "Cross over frequency should not be higher than 1/8th of switching frequency" ...
44 views

### How to use MATLAB to observe the effect of multiple damping factors?

I want to use MATLAB to observe the effect of changing zeta (damping factor) on system response? Here is a m-file code that plots three responses: underdamped, overdamped and critically damped. <...
242 views

### Confusion in block diagram of open loop and close loop control system?

I am studying Modern Control Systems, 11th edition, by Dorf and Bishop. On page 221 it first shows in fig4.7 open loop control system(the writer names it as open loop) and on page 222 close loop ...
459 views

### Confusion regarding control system of a Mars rover

I am studying Modern Control Systems, 11th edition, by Dorf and Bishop. In its fourth chapter, it discusses design examples and one example is of a Mars rover. In that example, I am confused by the ...
I am reading a book on nonlinear control and disturbance rejection, and in many examples, they distinguish between the "plant model" $G_p(s)$ and the "nominal plant model" $G_p(s)$. They also add ...