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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41 views

Transfer function derivation from Op-Amp linear control system

Need to derive transfer functions for blocks B, C and D, unsure on the best method to do so. Any suggestions?
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2answers
176 views

What is the best way to design an emergency button circuit?

I am using an Arduino ATMega as a controller and I have a few methods in mind to operate the emergency button (hardware and software.) utilizing the interrupt button while loop, with a pull down ...
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Why only sine waves?

I have already read a few EE texts where a sine wave is often seen. Why is the sine wave often used as a test function for a circuit or a system? Why don't we use any other signal instead of sine? ...
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42 views

How do I read a step response of the control effort?

I am trying to plot the step response of the control effort of two systems defined with two different controllers, and the plot is: I see that the system which is represented by the red line goes ...
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1answer
54 views

Does the unit step response not affect the transfer function?

I am still confused, this question says that this figure shows three unit step responses and was asked to find the transfer function. Doesn't the input step responses only affect the output? So to ...
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2answers
890 views

Reading a high-speed rotary encoder with a Raspberry Pi

I'm trying to setup a Raspberry Pi to measure the position and speed of 8 DC motors that all have incremental quadrature encoders. At full speed (unloaded), each encoder ticks at 3.3 kHz. I assume ...
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2answers
50 views

Eddy current damping compensation

I have a magnetically permeable element (98% pure iron) vibrating at 3-5Hz between two electromagnets (with iron cores) which is experiencing too much damping, presumably due to eddy current losses. ...
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1answer
30 views

Advice on connecting heater directly to SP2 relay of PID controller?

I have an old Omega CN-9121 PID Controller and a 105Watts 115V Fibre heater mantle with an inbuilt K-type CHromel-Alumel temperature thermocouple also attached into it. I plan to use the PID ...
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1answer
31 views

Interpreting basic contact and switch behaviour in a control system diagram

This might sound a stupid question but in a control system using buttons and contacts I have a bit confusion when it comes to picturing the real device. As an example if we have the following diagram: ...
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44 views

Doubt on singular value decomposition

I am studying control systems and I am studying the topic of Singular Value Decomposition(SVD). I have found a transfer matrix of a systemm, and computed its DC gain. Then I have performed the ...
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1answer
86 views

PI Compensator (for DC-DC Converter Control) transfer function derivation

Here is a PI compensator implemented using a OP-AMP. However, I'm wondering why Gc(s) = - vc/v, instead of vc/v. Not quite sure why there is a negative sign here since Gc(s) is defined as vc/v if I'm ...
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48 views

State-Space-Model from more dimensional Transfer-Function

Im trying to extract the State-Space-Model for an cascaded Buck/Boost-Converter from an set of Transfer-functions \$ G(s)\$ (which I generated with Plecs/Matlab). First of all I want to analyse the ...
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When do the positive sequence negative sequence, and zero sequence apprea?

I have analyzed three phases current in different cases, but I am still confused about some cases. Positive and Negative sequences are appeared but not the zero. Zero sequences is appeared, while ...
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2answers
80 views

Why does a pole at high frequencies attenuates noise?

I am trying to understand the concept of realizability for an improper transfer function, and I am struggling to understand some concepts. I know that if I have an improper transfer function, for ...
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1answer
58 views

What is a non causal system?

I am stydying control systems, and I am trying to understand better the topic of causality. I know that a system is causal if the actual state depends only on the past states and on the present ...
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3answers
492 views

What supplies ATS control circuit when the mains fail?

In a church, I've seen a large generator and ATS panel (automatic transfer switch) so that the generator turns on when there is a failure in the mains. If there is no power in the mains, How does the ...
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1answer
61 views

Why if I add a pole at high frequencies to an improper transfer function it becomes realizable?

Suppose I have an improper transfer function, for example: \$T(s)=\frac{s^2+1}{s+2}\$ I know that this transfer function is unrealizable. Moreover, I have seen that to make it realizable it is ...
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1answer
75 views

RHP zeros in control systems

In the slides of the following link is expressed the concept I am trying to understand : slides I am studying control systems. I have seen that if I have a zero in the RHP, by using decoupling I can ...
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1answer
81 views

How do I get the transfer functions of each channel for a control system?

Consider acontrol system with the following transfer matrix: \$G(s)=\begin{pmatrix} G_{11}(s) & G_{12}(s)\\ 0&G_{22}(s) \end{pmatrix}\$ and suppose I want to get the transfer functions ...
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39 views

op amp stability theory

A little stuck and could use some help. This TI stability App Note on page 15 calculates the Thevenin equivalent circuit of a capacitively loaded op-amp and I can't figure out how they get that form ...
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63 views

Closed-loop system with two cascaded P-controllers produces error increasing with time

The task: I control desired angle \$\theta_{d}\$ with two cascaded \$P\$-controllers, the outer is for desired angular velocity \$\omega_{d}\$ and the inner is for desired angular acceleration \$\dot{...
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27 views

How to find the frequency responses for the below conditions in the eye model?

In the above image it says to calculate the steady state responses for a unit step response. But i need to find calculate the frequency response for the same model.
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3answers
129 views

Transfer function of a classic controller

I want to calculate the transfer function and the gain, zeros and poles of the transfer function, considering that: $$R_1=R_2=R_3$$ $$C_1=C$$ I want to know if this circuit is a P, or PI, or PD, or ...
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142 views

Problem with adding unmodeled dynamics to a system

I am trying to do an analysis similar to : Stability‐and performance‐robustness tradeoffs: MIMO mixed‐µ vs complex‐µ design I have a MIMO system composed by a mass-spring damper system which has a ...
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1answer
98 views

How do I plot the response to a step disturbace of a control system in the time domain?

I would like to plot the time response of a step disturbance of a control system, but I am not sure what I have to plot. I have tried to plot the step response of the Sensitivity function, but I am ...
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1answer
68 views

Matlab c2d(1/s) is different than z transform tables

c2d is used to convert a model from continuous to discrete time. The official doc states: sysd = c2d(sysc,Ts) discretizes the continuous-time dynamic system model sysc using zero-order hold on the ...
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1answer
40 views

How do I find specific transfer functions from a plant of a MIMO system?

Suppose I have a physical system, for example a mass-spring-damper system, which has been written in state space. Now, suppose that the matrices describing the system are \$A,B,C,D\$. Moreover, let' ...
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1answer
59 views

What does having complex conjugate zeros implies?

I am studying control systems, and I have found a system which has two complex conjugate zeros. I know that if I had two complex conjugate poles in the system, this implies having some damping in ...
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1answer
62 views

Digital Root Locus in Scilab

I have the following digital plant: \$G(z)=\cfrac{z+1}{(z-0.3)(z-1)}\$ I want to use root locus to design a system with: (1) position error=0; (2) overshoot \$\leq 10\%\$ (3) settling time \$\...
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31 views

What does a peak in the complementary sensitivity function means?

I am studying control systems, and I am focusing on the concept of Sensitivity function and Complementary sensitivity function. I have seen that the sensitivity function is related to disturbance ...
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1answer
45 views

How do I find value of gain that stablizes the system from root locus?

Consider the following root locus: which is obtained by the following code: ...
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1answer
72 views

Design a digital controller for minimize the settling time

I have a system of digital control with unitary feedback, with the following transfer function: $$G(z)=2\frac{(z-0.5)(z-2)}{(z+0.2)(z+1.5)}$$ I need to use a digital controller: $$C(z)=K\frac{z-\...
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162 views

Mixed sensitivity controller design

I am defining a controller using the mixed sensitivity approach, and I have the following specifications: a low frequency attenuation of 60 dB a maximum resonance peak of 2 and I have chosen to use ...
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2answers
57 views

How to predict and compensate for the dynamic and static resistive torque due to losses in a motor

I will have external torques acting upon an axle to which a motor is connected. I want my motor control system to fairly precisely compensate for most of the torque that the motor imposes on the axle ...
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2answers
166 views

Nyquist stability criterion for positive feedback

it is known that the stability of a system with negative feedback may be analized through the Nyquist stability criterion, which is based on observing the number of turns around the point (-1;0) in ...
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2answers
75 views

How is the closed loop transfer function defined for an oscillator?

an electronic oscillator is a device which can generate some signals without input signals. It is an unstable system realized with positive feedback, as shown in the following scheme: Now I have two ...
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2answers
795 views

How to find the critical gain K from the root locus

I am going through Ogata's Discrete-Time Control Systems and working out the following problem found on Page 262. The problem states: Draw root locus diagrams in the \$z\$ plane for the system ...
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1answer
95 views

Root Locus in a feedback loop

I'm trying to draw Root Locus by hand from the following block diagram and confirm the result I got from Routh Hurwitz's table: The table of Routh Hurwitz that I got is the following: And from the ...
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1answer
35 views

Static and dynamic behaviour of a sensor

On a slide, i read that i can model the static behaviour of a sensor as: whereas it's dynamic behaviour as: Is correct to say that the static behaviour is the steady-state behaviour, while the ...
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2answers
74 views

Application of Frequency Response Theorem in Linear Circuits

One of the most important results of control theory for linear systems is the so called "Frequency Response Theorem" (here the references): Briefly, it says that under the hypotesis of stability and ...
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4answers
515 views

Open loop gain and Percent Overshoot Relationship

In the context of control theory, I found a text stating: "Higher the loop gain of the system, larger is the percent overshoot" Can anyone show that analytically? Consider it to be a second order ...
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2answers
245 views

Phase margin and stability

"In control systems, an open loop transfer function having poles in left half plane, should have positive phase margin and positive gain margin to ensure closed loop stability." I was trying to ...
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22 views

Parameter range to ensure stability using Routh Criterion

I have a question regarding Routh Stability for a characteristic equation of the form, $$ 2S^4 + 2S^3 + 4S^2 + (k+1)S + 4 = 0 $$ I need to find the range of K for which the system will be stable. ...
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1answer
70 views

Given desired overshoot graphically find k from the root locus (Scilab)

I want to find \$k_1\$ that leads to the feedbakc system having poles in the 53º line (to have overshoot \$\leq 10\%\$). From the root locus, the poles move along the vertical asymptote centered on -1....
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1answer
741 views

BIBO Stability considerations for Transfer Functions

So I was wondering if you have a system, consider it \$G(s)\$ and it has no initial energy i.e. \$x(0) = 0\$ for the initial condition. If the transfer function exhibits: pole cancellation, would it ...
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1answer
50 views

Obtain the matrix in a control system with tandem/cascade representation

I'm trying to find tandem/cascade and parallel realization for the following transfer function: $$G(s)=\frac{(s+6)^2}{(s+2)^2(s^2+4s+6)}$$ For Tandem/cascade realization, I draw the following block ...
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1answer
72 views

Laplace transform in a block system

I'm trying to understand the resolution of the problem 5.11, but I can't understand how she gets the expression in the rectangle: $$\dot{x}_1=-x_1+2u$$ How can I get the expression in the rectangle?
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678 views

Condition for absolute stability

A necessary condition for absolute stability of a system is Gain cross over frequency < Phase cross over frequency Where Gain cross over frequency is the frequency at which Gain = 1 or 0 dB ...
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3answers
211 views

Buck Converter Feedback Circuitry

Recently I have been studying feedback in switching power converters, and one thing that is still a bit confusing to me is the way the error amplifier is implemented. Here is what the control diagram ...
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3answers
1k 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 ...

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