Questions tagged [closed-loop]
The closed-loop tag has no usage guidance.
49
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47 views
Setpoint weighting algorithm for the PI controller
Some time ago I found an interesting modification of the standard PI controller algorithm.
The modification is called the setpoing weighting in the literature and regards the proportional component of ...
0
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1answer
18 views
4 wires encoder to 6 wires Hibrid Servo drive for closed loop stepper motor
I have the HBS860H driver and LPD3806.I wanna know if I can connect this 4 wire encoder, to this 6 wire driver.
HBS860H:
https://hardware-cnc.nl/images/PDF/ACT/HBS86H_English_Manuel.pdf
LPD3806: (i ...
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0answers
42 views
what is the open and closed loop function of this system?
i found this in the text book.
i solved by:
1- found the closed loop function of just the part of B(p) and its "feedback", let's call it B'(p).
2- after that i did H(p) = A(p) / ( 1 + A(p) * ...
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49 views
Interesting driving circuit of a voice coil actuator
I have an interesting circuit to drive the voice coil stage of an old acoustic microscope. I am struggling to understand what the different functions of the opamps in this circuit are.
The circuit ...
1
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1answer
88 views
Determine if the system is stable [closed]
Determine if the system is stable?
How is this done? Is this at one frequency? Is the Loop gain is A x B x C = 0.5
Should phase angles be added together = 173 degrees?
Should I be considering the open ...
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1answer
38 views
Confusion regarding finding closed loop transfer function and damping constant from open-loop transfer function
I have second order transfer function $$ G(s) = \frac{1.247}{s^2+9.76s+23.8}$$ G(s) is in the forward path of a unity feedback system.
How do I find the closed loop transfer function and damping ...
0
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1answer
37 views
Understanding Total Response
QUICK INFO:
I am currently studying about closed and open-loops systems.
BACKGROUND STORY:
Imagine a big antenna is placed on a hill and there is a lot of wind. You want to turn the potentiometer so ...
0
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3answers
128 views
unstable systems with positive phase/gain margin
Open loop Phase/Gain margins provide information on how much margin the closed loop system have until it becomes unstable. In other words, how much you can increase the effective loop gain and or ...
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0answers
42 views
buck small signal modelling
I have a synchronous buck converter and my inductor current looks like this:-
To add voltage-mode closed loop control, I need to do the small signal modelling of the converter. I am a bit confused if ...
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0answers
47 views
Bode plot in Pspice
I want to get the bode plot of the controller part of my Buck converter. For this I looked online and saw a technique that mentioned to add an AC injection source from the voltage output to the top ...
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2answers
117 views
Closed loop system stability with Bode
Stability of the closed loop system (with -1 feedback) can be assessed via Bode plot gain/phase margin analysis of its open loop system.
How can one deduce stability of the closed loop system directly ...
1
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1answer
57 views
Why is the slope of the op amp graph 20 log (AB) in this application note
I am going through the following guide for op amps :
http://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf
On page 87 (screenshot attached) there is a bode plot which has got me slightly ...
0
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1answer
62 views
Open and Closed Loop Amplifier Circuit
For example, say that a system requires an input voltage of 5V, however, you only have a source that can provide 1V. The use of a voltage amplifier is obviously the solution to the problem. However, ...
1
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3answers
96 views
What is the significance of phase margin in an open loop amplifier?
I know the importance of phase margin to ensure stability in closed loop systems, but what about in open loop systems?
I am designing a regulated common based LNA IC that operates in open loop.
Can we ...
1
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1answer
57 views
What is the controlled variable in this particular case?
I have a question, maybe you can help me because I am not sure of the correct definition.
As an example I have a plant with a measured output y in a closed loop system. But as the feedback variable I ...
1
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1answer
64 views
closed loop pole of negative feedback
given w be the pole of open loop what in the pole of the closed lop shown bellow?
i have found axpression for GAIN but for the pole i am not sure.
Thanks.
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1answer
85 views
Can a strong electric field generate an electric current within a closed loop of wire?
I would like to know if an electric current can be generated in a closed loop of wire by using a strong electric field to circulate the free electrons within the closed loop of wire.
Say that you have ...
2
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1answer
52 views
How to deal with controling force by positioning oscillating magnet?
I am trying to code up a closed loop control system on force generated by the paring of strong rare earth magnets. I do not have much experience with PID logic but i have a weak grasp of the basics (...
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0answers
42 views
Closed-loop position control with a stepper motor
Disclaimer: I understand this might not be the optimal setup for this application, but this is what I currently have available.
My controller is connected to:
a stepper motor with a lead screw for ...
2
votes
2answers
78 views
Can an open loop system replace a close loop system
I'm thinking about a mathematical possibility how an open loop system can replace a close loop system so here is my explanation
Let's say I have a plant with transfer function as given in image (1)
...
1
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1answer
56 views
What micro-controllers are suitable for a closed-loop DC Motor? [closed]
I am working on a small experiment on a closed loop DC motor for speed control.
The DC motor is separately excited and fed through a DC chopper.
I would like to know what are the best micro-...
1
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2answers
124 views
Closed Loop Transfer Function - PD Control
For the following control system, I am trying to find the characteristics of the system.
I have firstly found the closed loop transfer functions \$T(s) =\frac{C(s)}{R(s)}\$ , to be:
\$G(s) =K_p(s+9)...
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2answers
188 views
Closed Loop system with a second order dominated response on the verge of instability
I have the forward path transfer function of C(s)G(s) = K/s(s+3)(s+7) and want to find K so that it is second order dominated on the verge of instability.
But i'm not sure how to find it when it is ...
1
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1answer
352 views
Dominant Pole Approximation for loop gain
I have the following loop transfer function for a unity feedback system:
I understand that the \$(s+2)\$ term becomes \$2\$, but what happens to the \$s\$ ?
4
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1answer
704 views
Closed loop vs. open loop system analysis and design
I have found questions similar to mine in the forum but none were quite answered to my full satisfaction. I have two questions:
1) Why is controller design is traditionally done with the open-loop ...
2
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1answer
49 views
PID controller - should terms be completely independant?
I was under the impression that the P, I and D terms of a PID controller should be calculated independently of each other. That is, they would all use the same error information, but none of the three ...
0
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1answer
81 views
Closed loop equation initial value
I am doing math for a closed loop equation. I know the transfer function for a closed loop system is:
(Image copied from "Loop Gain and its Effect on Analog Control Systems" by Gabino ...
0
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1answer
171 views
Improve the performance of Buck Converter Loop Stability
The following are the specifications of my Buck Converter.
Input Voltage Range : 6V to 16V
Output Voltage : 5V
Switching Freq : 2.1MHz
Output Inductor : 22uH
Minimum Load Current : 200mA
Typical ...
0
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0answers
29 views
Drive signal (duty cycle) calculation for PI compensator
I am trying to simulate an inverter with 4 ideal switching devices in LTSpice. I have the compensator working, however I don't the correct equation in terms of calculating the duty cycle.
What I ...
0
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1answer
104 views
Dependent vs. independent current paths
Taking the following circuit:
The path on the left will be on and the same, whereas the path on the right is dependent on what is connected to the base of the transistor (not shown in the above ...
0
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2answers
530 views
Confusion regarding root locus. Open loop or close loop?
Which transfer function ,open loop or close loop do we use/need as a pre req to perform root locus analysis?
I have also attached a snapshot of the relevant webpage of university of Michigan.
I have ...
5
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3answers
377 views
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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6answers
1k views
How does opamp open-loop gain affect closed-loop gain in a circuit?
The gain of an opamp circuit is basically $$A_v=-\frac{R_f}{R_i}$$
But how come the gain of the opamp itself does not appear in the equation? How is the opamp amplifying anything in the circuit? What ...
1
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2answers
149 views
Calculate closed loop gain with Oscilloscope measurements
Using these reading from Agilent MSO-X2012a oscilloscope:
from this circuit:
How do you calculate the close loop gain using these measurements. I already calculated by hand and got Av = 11V.
1
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1answer
417 views
Phase margin is 90 degrees but transient step response shows overshoot
The bode plot of the loop is as shown here
The transient step response looks like this
The block diagram looks something like this -
Basically a single stage opamp(OPAMP in fig) with high gain(...
0
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2answers
283 views
To prove that Close Loop transfer function is sensitive to perturbation in H(s) but not to perturbations in G(s)
The feedback control system with high gain K is shown in figure
-1
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1answer
181 views
how to display an output variable from a speed sensor to a 7 segment display in C. DSPIC33E
I have just started an electrical engineering degree and been set an assignment to create a closed loop motor speed control system in C programming language.
The PIC is a DSPIC33E (BLO032) and the ...
2
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2answers
127 views
Proportional Control Balance Beam
Bit of an unorthodox question I'm sure, but I'm making a balance beam (two rotors on either end of a see saw) with proportional control, and I can't seem to get it to balance at 0.
The proportional ...
3
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1answer
175 views
What is the difference between 'x' and 'plus' symbol in the block diagram
Generally speaking, what is the difference between the 'x' and the 'plus' symbol in a closed loop block diagram?
For example, in
(https://ieeexplore.ieee.org/document/6983570)
, what's the ...
2
votes
1answer
363 views
SG3525 Closed Loop Inverter Waveform Problem
I'm using a sg3525 ic on a full bridge dc-dc converter in closed loop. The system is working fine, I don't have a problem with it. Output is just like what I want.
The problem is inverter part's ...
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1answer
239 views
Sample time of PI controller
I have designed a closed loop current control (PI controller) of a DC-DC converter in continuous time domain and it is working fine. The next task is discreetization of the controller and implement it ...
0
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2answers
874 views
Where does the negative sign come from in this transfer function?
I have a transfer function that was given to me. It's been a really long time since I've done block diagram math, so sorry if this is a newbie question.
Based on the block diagram below (I forgot to ...
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0answers
281 views
Implementing PID in PWM feedback to lower the settling time
I have created the following simple PWM feedback:
The step response is:
I have tried to add PID controller and I ran the following code to test it:
...
0
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1answer
117 views
Why doesn't current flow in the other loop?
I am just now learning about how transistors work, so please let me know if I have a misunderstanding.
I ran a simulation of the circuit drawn below, and the results were that current flowed only in ...
1
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2answers
133 views
Closed current loop control without H-Bridge, PWM
I am trying to find a way how to control the Voice Coil Motor (VCM) or PMSM motor with a closed current loop without the use of an H-Bridge & PWM.
Does anyone know how to make an analog closed ...
4
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2answers
273 views
Cannot predict closed-loop gain of this amplifier
This is the circuit I am currently analyzing: (link to LTSpice file)
I am trying to predict each stage closed loop gain and overall gain (with all loops closed).
First thing I did is calculate DC ...
0
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1answer
125 views
Find optimal gains transfer function
I have the following closed loop transfer function:
$$G(s) = \frac{K(s^2 + 200^2)}{0.05s^3 + (1+K)s^2 + 200{K_v}s + 200K}$$
Where \$K\$ and \$K_v\$ are gains.
My goal is to find the optimal gains ...
0
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2answers
141 views
Closed Loop control of a propeller
Hello I'm trying to control the velocity of the propeller with the pitch angle. I have a diagram from the factor cp over J and phi (see image: Draw.io diagram), but not a analytical formula.
J = v*60/...
2
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5answers
5k views
Understanding of Dominant Pole Compensation
According to Miller Effect, within amplifying devices such as transistors that have inverting voltage gain higher that one, there should be increased input capacitance with increased voltage gain of ...
