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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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Motor fader PID control

I'm trying to control a motorized fader (linear slide potentiometer) using an Arduino. PID control gives good results for "jumping" to a specific target position, but tracking ramps is a problem, it's ...
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1answer
151 views

Determining Number of states in State Space Modeling

I want to use state space modeling for representing the following circuit system. However, I am unable to decide the number of states. I am able to describe the system with a set of three equations. ...
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205 views

Design of a lead compensator with root locus in matlab

For the transfer function G(s), I tried to design a lead compensator for the function to have a response to the step with the following specifications: Overshoot= 10%; Ts (2%) = 5s. When I simulate ...
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83 views

Guidelines and design considerations for designing a controller for a grid tie inverter?

I'm working on designing a controller for a grid tied inverter. I'm not able to find a suitable reference or book that might help in this case. What I have understood now is: There must 2 loops (...
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62 views

PI or PID vs Manual Controller design using Control theory

Why should we design a controller manually using Bode plots and control theory instead of using PI or PID controllers and tune them? Or more specifically when should I design a controller and when ...
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3answers
176 views

Root Locus, Gain in Feedback Loop. Need help

So this is the system for which I have to draw a root locus if 'K' changes from 0 to infinity. The problem for me is that root locus is drawn for open loop transfer function but 'K' is in the feedback ...
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2answers
85 views

Does the stability of an LTI system depend on the input?

Consider a system \$G(s) = \frac{1}{s}\$. It is marginally stable, as it has its only pole at \$s=0\$. However, if we apply a step input, the output is \$ tu(t) \$, which turns out to be unstable. ...
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1answer
93 views

PI controller - DC voltage regulation

I a voltage source converter, in order to control the DC-Bus voltage a PI controller can be used. The control method is illustrated in the figure below: I would like to ask why the input of the PI ...
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1answer
255 views

Constructing bode plot from experimental data and constructing a transfer function

I've been trying for a few days to convert an experimentally obtained (frequency against magnitude and frequency against phase) graphs to a bode plot and then construct a transfer function from the ...
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1answer
42 views

How do you reduce this simple system diagram for the sake of doing algebraic manipulation?

My guess is that since H(s) is parallel with 1(s) we'd do A(H - 1)? But this is my first ...
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35 views

What are some techniques to troubleshoot a second order sigma delta loop?

I have designed a slightly modified second order (3-bit) multi-bit incremental sigma delta modulator (IDSM) in simulink (system level). The SNR that I get is 45dB, which is not as expected. But ...
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0answers
36 views

Finding the memory polynomial model coefficients

I want to build a memory polynomial model given that I know the corresponding output signals for known input signals. What is the easiest way to find the coefficients of it? And how do we take the ...
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1answer
126 views

How to plot root loci in z plane

How to plot root loci of loop gain G(z)= k/(z-0.5)(z-0.5)(z-0.5) in z plane?
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159 views

How to use the Root Locus design method to improve the transient response of my system?

By closing the loop, I need to design a controller in the feedforward path to minimise the effects of the two pairs of dominant poles of the 5th order transfer function. Use a pole-zero cancellation ...
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1answer
109 views

rlocus() - Not enough input arguments in MATLAB 2018a

I am following this tutorial on root locus methods and when writing: syms s sys = 1/(3*s^2 + 2*s - 1); rlocus(sys) I get: Error using rlocus Not enough ...
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123 views

How do I calculate a PID controller gain for a certain damping coefficient?

I have a third order process and I have to design a PID controller by cancelling out the two most dominant poles of the process. The process transfer function is: The controller is of the form, where ...
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94 views

Steady state error due to disturbance

I was trying to solve a question from the 2004 GATE IN paper, I solved it this way, Now, the book is giving a different solution, I'm pretty sure my way is correct since they pulled the "standard ...
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0answers
31 views

Difference in feedback DAC levels between first and higher order Multibit sigma delta modulators

My objective is to understand the difference between first and higher order Multi-bit sigma delta modulators in terms of DAC feedback signals. I have a setup of 3-bit incremental sigma-delta ...
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0answers
27 views

Designing a CCM Boost PFC rectifier circuit

I am working on designing a CCM Boost PFC rectifier circuit, supplying up to 2.8kW at 400Vdc nominal, while taking 230Vac, 50Hz controlled via negative feedback in the average current control mode. I ...
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0answers
38 views

What is the meaning of the sensivity, of the open loop transfer function, being -1 regarding the non zero pole?

I have to calculate the sensivity of this transfer function regarding the pole s=-10. I used the formula below, and I got the value of -1 but I do not understand its meaning. I replaced (s+10) with p ...
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2answers
92 views

Meaning of transfer function in s evaluated at a complex number

From the pole-zero plot, you can compute the system frequency response by assuming a locus of test points along the \$j\omega\$ axis. Figure from: http://web.mit.edu/2.14/www/Handouts/PoleZero.pdf \...
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2answers
88 views

Nyquist Stability Criteria

Find the stability where: Find the stability: \$ G(s)= \frac{(s+3)(s+5)}{(s-2)(s-4)}; \$ \$ H(s)= 1; \$ I run this code in matlab: ...
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2answers
125 views

Normalization of Pid Output

New to using PIDs. When normalizing a range, we would need to know the maximum and minimum of that range. Since a PID is summing the error in the I portion wouldn't the range be potentially infinite? ...
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68 views

Designing of a PID Controller

First of all, I am new to this Q/A site. If I am doing anything wrong, please forgive me. I am having some trouble solving this problem: Given the system of Figure(1), design a PID controller so that ...
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1answer
96 views

How do integrator circuits serve as memory devices in continuous time system?

I didn't understand the yellow-marked sentence clearly, and even I did, what does it have to do with the conclusion that follows it? (marked in green). Thanks in advance.. Source: Modern control ...
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59 views

Control issues: Simulation of PMSM in FOC Model

I have been designing a model of an already existing actuator which is run in FOC with an SVPWM inverter and cascade speed-current control. Losses like eddy current or hysteresis, or switching losses ...
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0answers
25 views

Principle and generalization of proportional-resonance controller

simulate this circuit – Schematic created using CircuitLab We can introduce the model of \$u(s)\$ into the controller \$K(s)\$ to realize high accuracy control. \$u(t) = 1\$, i.e. \$u(s) = 1/...
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1answer
52 views

Finding PID parameters .. How?

As in the picture , how can I determine ki , kp , kd I tried (using provided data) by finding ζ and ωn But I end up with third order transfer function could not subsitute my results to find PID ...
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2answers
533 views

What is the relationship between a step input and an integrator?

While trying to understand control engineering from first principles I came across the following which I cannot yet explain intuitively or mathematically. What is the relationship, between a step ...
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1answer
40 views

Replacing Electrical System with a Gain?

I have a system containing both a mechanical and an electrical part, as shown in the block diagram below. I am interested in simplifying this block diagram by eliminating the electrical part and ...
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1answer
68 views

Pole placement to create a full-state feedback controller?

I am learning about control theory by going through Oagata's Modern Control Engineering. As part of a practice exercise I am trying to design a full-state feedback controller that satisfies my ...
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1answer
46 views

Determine the impulse response of the following discrete system

I'm not sure how they got the answer (provided below) for the following discrete system y[n] = x[n]- 2x[n-2]+ x[n-3]- 3x[n-4] the answer is given as .... h[n] = [1 0 -2 1 -3] why is this? any help ...
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1answer
327 views

Reducing the order of transfer function while maintaining same response

Scenario: I have been going through Ogata Modern Control Engineering book and working through several exercises to improve my understanding of basic control principles. I came across the following ...
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0answers
50 views

What is the meaning of the first gain in the block diagram?

I have do design a circuit based on the block diagram below. I know how to design the PID part but I don't understand what the K=2 is. For the PID I have made the following:
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1answer
620 views

Finding the Transfer Function of Spring Mass Damper System

I have been going through Ogata Modern Control Engineering book and working through several exercises to improve my understanding of basic control principles. I came across the following example which ...
0
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1answer
61 views

Dynamic Compensator in Control Loop

Sorry if this has been asked previously, but I couldn't find anything here or elsewhere on Google (but maybe I'm searching the wrong terms). I'm trying to design a Type 2 compensator for a PWM chip I'...
2
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2answers
207 views

Source of poles and zeros in a physical system?

From where does the poles and zeros come into the transfer function of any system? And I am not looking for an answer in terms of mathematics but want to know what is there in any physical system that ...
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1answer
92 views

Calculating the transfer function of this op-amp circuit

The first op-amp is a differential, second one is a follower and third one is a second order low pass filter. I've been struggling with the low pass and the final output of the circuit and I am not ...
1
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1answer
156 views

Gain of an experimental first order step response

I have a pwm driven DC motor control system with magnetic encoder that measures the output shaft speed and outputs the RPM values every 50ms over serial comms to plot a graph of RPM vs Time. The ...
3
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1answer
231 views

Degenerate circuit concept and its theoretical and practical implications

I came across with the term "degenerate circuit" when I was studying solving linear differential equations with Laplace transform. I have learned that a system is called degenerate when the ...
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2answers
250 views

State Space model for three-loop circuit

How do I choose the least number of state variables for the following circuit? I started out by assuming currents $$i_{1}, i_{2}, i_{3}$$ in each of the loops and applied KVL, which fetched me three ...
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1answer
62 views

Control Theorie: Drawing Transition Matrix Trajectories

Given a transition matrix like e.g. $$ \phi(t)=\begin{bmatrix} e^{-3t} & 0 \\ 0 & e^{-3t} \end{bmatrix} $$ What is the analytical way of drawing x(t) for two given starting points? I only ...
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3answers
223 views

why do most sensors have an electrical output, regardless of the physical nature of the variable being measured [closed]

I have been trying to figure out a explanation to this question, can someone explain this ?
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1answer
102 views

Feedback Error Equation

I am currently digging into some amplifier feedback analysis tools papers and literature. I found some "term" right at beginning of this topic that I don't quite understand. That is "Error equation of ...
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1answer
50 views

Method for selecting unique resistor values in all combinations

I do controls, and sometimes I want to monitor more dry contacts than I have digital inputs for. I'm cheap, and don't want to pay for more points, so sometimes I'll put some resistors in parallel ...
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1answer
321 views

Field Oriented Control Feed Forward Term

I implemented a Field Oriented Control (FOC) controller for a synchronous motor, which works already pretty good. Now the I-part of the PI controllers is necessary to achieve a good reference tracking,...
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2answers
83 views

Relationship between eigen values and state feedback

so lets suppose we have a state space model x[k+1] = Ax[k] + Bu[k] y[k] = Cx[k] + Bu[k] and we want to design a state feedback, assuming that the system is ...
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1answer
247 views

Discretizing a PID controller

I am discretizing the PID equation so we have this equation Now if we separate the integral term we get Applying backward euler method Now as we already have a differentiation , by applying ...
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1answer
54 views

Relation between dash pot and spring in forces when extracting a transfer function [closed]

If a spring load some energy and use it for opposing other forces, and a dash pot has a friction, physically the both shouldn't have the same force-displacement equation ? In most of dash pots, we ...
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2answers
773 views

Using mesh analysis to get the transfer function of electrical system

I am studying the book: Control system engineering for Norman S Nise. I left the college few years ago, and I forgot lots of thing about Kirchhof's laws (Voltage and current). I tried to solve the ...