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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Calculating discrete-time transfer function
I have a continuous function
\begin{equation}G_p(s) = {1\over s^2} \end{equation}
which I am trying to combine with a zero order hold (with a sampling time of 1 second) to produce a discrete function....
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Why is my zero and pole frequency of this transfer function wrong?
So I have this transfer function:
$$\begin{align}
\dfrac{g_m-sC_{gd}}{s(C_{gs}+C_{gd})}=\dfrac{-C_{gd}\left(s-\dfrac{g_m}{C_{gd}}\right)}{(C_{gd}+C_{gs})\left(s-\dfrac{0}{C_{gd}+C_{gs}}\right)}=-\...
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Why is the closed gain loop -3dB from the open loop gain rather than some other value?
I am reading the book Op Amps for Everyone and in the chapter of feedback loop theory, I have this quote (see picture) where it says in reality the closed loop gain is down by 3dB at the point X as ...
Tony Stewart Sunnyskyguy EE75
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Controllability and Observability of SFG by intuition
For the below block diagram is it possible to conclude controllability by tracing the path from inputs to state variable , similarly to conclude observability by tracing path from state variable to ...
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Nichols plot confusion
The transfer function is \$F(p)=10/(p^2+2p+1).\$
Using Wolfram Alpha, the Nichols plot shows that the argument \$\to -\pi\$ when \$\omega \to +\infty\$.
However, calculating the argument on paper ...
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Determine the maximum value reached by the system output signal
Consider the 2-order system, without zero, whose transfer function is
$$H (s) = \frac{51}{s^2 + 2s + 17}$$
An input signal $$u(t) = 4\varepsilon(t)$$ is applied to this system
Determine the maximum ...
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Cascade vs series?
Is there any difference between cascade combination and series combination in terms of control system? Or they both same?
Since in control system literature,sometimes at some places,we find the word ...
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How to stabilize this system?
I'm trying to understand system stability basics. Let us say I have a system
$$
G(s) = \frac{500}{s^2 - 500}
$$
Since it has two poles in the right half s-plane, it is unstable.
How can I ...
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36 views
PID Control: Is adding a delay before the next loop a good idea?
I am implementing PID control in c++ to make a differential drive robot turn an accurate number of degrees, but I am having many issues.
Exiting control loop early due to fast loop runtime
If the ...
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PID controller for a very wide temperature range (āT=190°C)
I'm designing temperature control system based on Peltier elements. And it's needed to work on a very wide temperature range - from below zero to more than 100Ā°C. So there is two work modes - cooling ...
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Small signal model of a forward converter operating in current mode control
By knowing that I do not know the plant transfer function of the forward converter operating in current mode control, I can be suspicious on the result provided by the following document :
https://...
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Circuit stable in the Bode diagram, unstable in step-response
I am designing a simple current control circuit and trying to simulate it in LT Spice. The circuit is not optimized for some real-world application, it's more a learning method for me to get grip on ...
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Confusions regarding swing up hybrid control?
I am trying to learn about swing up hybrid control and i came across a figure shown in attached snapshot. I have two confusions in this regard:
1)Both "swing up energy control"(u1) and "...
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Supposed to be a trapezoidal BLDC Back-EMF waveform?
INTRO: The project bellow was designed in simulink to drive a BLDC motor. It has a matlab function that basically receives the rotor's angular speed (w) and using N = 6 (N is the number of pole pairs) ...
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Infinite Phase Margin
I have been assigned a control systems problem, where I am supposed to stabilize a system using a controller technique from the frequency domain. When I implemented the system on Matlab and calculated ...
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Finding \$\small K\$ for a given \$\small\zeta\$ value when \$\omega_n\$ (frequency) is not given
Here \$\omega_n\$ (frequency) is not given.
Then upon plotting the Root Locus, how will we find \$\small K\$ at \$\small\zeta = 0.5\$ if we're not using a graph sheet and want to find everything ...
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How loop gain is related to complete transfer function?
I am trying to understand how loop gain of system determines the stability of a complete system.
Loop gain is given by 1+GH where G is forward transfer function (TF) and H is feedback factor.
If we ...
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S domain transfer functions of full bridge inverter
I need to design an inverter circuit as in the schema. It is driven by the unipolar PWM method. I have a problem with the circuit. It would be great if anyone can help me.
I want to get the s domain ...
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Stabilizing plot using root locus method
"Design a PI controller to stabilize the plant \$ G(s)= 1/(s-1)\$ using only root locus method."
Since there are two variables \$K_p\$ and \$K_i\$ ,i.e. one for proportional and one for ...
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140 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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Transfer function of phase change controlled with capacitance
We have an RLC series circuit with sinusoidal voltage source of frequency \$\omega\$. The normal transfer function of current to voltage is:
$$ G(s) = \frac{I(s)}{V(s)} = \frac{1}{R+s L+ \frac{1}{s C}}...
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Help with identifying a transfer function - with neuroscience application
This is a question for you electrical network engineers. The problem has arisen in a neuroscience study I am working on, but I hope to be able to glean some insight from other domains that deal with ...
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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 ...
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What does this switch symbol with a triangle on the contact stand for?
I found this symbol in one of my control circuits. It is a part of a suction valve operated by a motor overload relay.
I have been pulling my hair out trying to find the meaning of this symbol and ...
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What is the effect of addition of a compensator(either Lead or Lag) to a system?in terms of addition of poles and zeros?
When we add a compensator(either Lead or Lag) to a plant in series, what is the effect in terms of addition of poles and zeros?
A pole-zero pair is added(meaning one pole and one zero)?
or
a pair of ...
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51 views
Two different expressions for lead compensator?Why?
I am trying to learn about lead compensators from an online resource,but two different articles of same resource mention different expressions of lead compensator, i have also attached snapshots for ...
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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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121 views
Steady error control system sinusoidal disturbance
Consider the control system closed-loop represented such a block diagram below:
Given that: \$G_C(s) = K\$ and \$G(s) = 1/s\$
a) Determine the values of \$ K\$ which the closed-system loop is stable....
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How would the pole and zero frequency expression look like for this transfer function I derived?
This is a practice problem in deriving the transition frequency function for mos and part of the set of questions is to determine the pole and zero frequency expression but this transfer function i ...
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How to calculate wattage required to heat up air inside an enclosure to 50°C?
I've got a polycarbonate enclosure and I'm going to place a heating element inside it to increase the air temperature in it from room to 50Ā°C, plus a fan to maintain temperature. I need to find out ...
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Could somebody clarify the phase angle and gain of this transfer function?
Suppose a circuit with a transfer function of the form \$A(\omega)=\displaystyle\frac{A_0}{1-\frac{j\omega}{\omega_0}}\$ has \$A_0=-10\; V/V\$ and \$\omega_0=100\;rad/sec.\$
We were asked for the gain ...
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178 views
Effect of right half plane zero on bandwidth of control system
It is known that the right half zero and the delay limit the achievable bandwidth of a control system. Can someone please explain the reason, how the right half plane zero limits the achievable ...
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200 views
Stability of a two poles negative feedback amplifier
let's consider this analysis of a two-pole amplifier with negative feedback (Microelectronic Circuits by Sedra Smith 7th edition):
Before showing you my doubts, let's consider this introduction made ...
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Oscillation frequency / criteria from Bode plot, negative feedback system
Got a question, which is very integral to a project that I am writing a report for (which I am to hand in soon, so in a hurry).
Question:
What will my oscillation frequency be?
How will it be ...
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What is meant by “T” and “aT” here?
https://ctms.engin.umich.edu/CTMS/index.php?example=BallBeam§ion=ControlFrequency
I am trying to learn about lead compensator from above link
But i have bit confusion regarding two terms,"...
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1answer
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Singular interval condition for Multi input in Optimal control
The definition of singulr interval is shown in Figure.
I've struggled with this problem.
I think the solution of this prob
is "because if the E_j matrix is not singular, it means the System is ...
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What is the relation between the control voltage and resulting pwm in a voltage-mode control system for DC-DC converters?
I'm currently learning about negative feedback and voltage mode control for various DC-DC converters. I'm very confused about how the control voltage changes the pwm signal, along with how the ...
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Why is frequency not measured in db in bode's plot?
While drawing bode's graph paper where Y axis is gain given in db while the X axis is frequency given in absolute value but scale used is log. I think the reason for log scale on X axis is to increase ...
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2answers
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What's the best starting point for rotor angle estimation for FOC?
I'm driving a BLDC motor with FOC. Right now, I have Space Vector modulation working, where I can give it a magnitude and an angle, and the algorithm will drop the right values into three PWM ...
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88 views
Derivation of Feedforward Gains for current mode control in CCM converter
I recently start to read the dissertation of Dr.Ridley, A New Small-Signal Model for Current-Mode Control and I am stuck on a basic equation.
First we have the function of the inductor current for ...
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648 views
Control System: DC Gain
Mostly, whenever it is asked to find the DC gain of A system; in the solutions provided, they find the steady state error coefficient (corresponding to the Type of the system).
But I figured out that ...
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167 views
What is the mathematical difference between a transfer function and a state transition matrix?
I do know what the difference in meaning is between a transfer function (output over the input) and a state transition matrix $\Phi$ (describes the unforced response of the system). Yet when looking ...
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450 views
Stability of Differentiator Circuit
let's consider a generic differentiator circuit, i.e. a circuit whose transfer function is \$\text{constant}\cdot j\omega\$. For instance, you may consider this circuit with Op-Amp:
I was reading ...
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355 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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211 views
Linearizing hall effect sensors outputs
I'm trying to find a robust solution to linearize four hall effect sensors outout to obtain a signal that I can use in a PID control scheme.
The output data is collect via 4 ADC channels on an ...
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1answer
209 views
doubt on application of stability criteria
I have only seen systems with this transfer function treated in stability criteria with this general form:$$\frac{KG(s)}{1\pm KG(s)}$$ so the $$\lvert H(s)\rvert =1$$
is it possible to apply criteria ...
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81 views
How to generate an impulse to test a system's impulse response
I just started learning some basic control theory to better understand how a transfer function is constructed from a circuit and how a system is characterize by a function. In it I found analyzing a ...
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how to find frequency of oscillations if a order three system given
Frequency of oscillation in rad/sec of a unity feedback system having open loop transfer function G(s)=K/s^3+3s^2+4s+3 is
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Here how can we find steady state error?
Here in the plot shown in attached photo, how can we find steady state error because both blue and orange waves have different amount of error at different time
