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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
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4answers
10k views

How to use measured step response to tune control system

How does one use a measured step response to tune either a PID or convolution control scheme? Inspired by this answer*, I'm interested a more detailed explanation of how to implement a control system ...
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1answer
2k views

Relationship between switching frequency and controller's crossover frequency in buck SMPS

Context: tuning the control loop of a buck SMPS. I specicifally have a TI TPS40200-based circuit in mind, but I think this applies to SMPS design in general. Quoting from Type 2 compensation network: ...
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6answers
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What is noise gain, really? And how is it determined in the general case?

UPDATE: This question triggered what might fairly be called a research obsession for me. I've gotten pretty close to the bottom of it I think, I've posted my findings as an answer below. There was a ...
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7answers
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Gain margin and Phase Margin Physical Meaning

I have been trying to understand the physical concept of Gain and Phase Margin. What I understand about this is that a relative comparison around the critical point \$(-1,0)\$, which when converted ...
11
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4answers
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Conditional stability

I'm learning about op-amps and feedback and how feedback affects their stability. I've been reading about gain and phase margin and their uses when I came across this: I don't quite understand how ...
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3answers
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over and critically damped systems settling time

I know that for second order systems the settling time(St) equation is: So my question is, should this same formula be used when the system is over or critically damped? Is it right to use it in that ...
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4answers
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Misconceptions about PID Controllers

I'm currently designing an equivalent of the mass-spring-dashpot system, and during the design phase I realized I don't fully understand how PID controllers physically work. Below is an image, the ...
6
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2answers
526 views

What is this RC local feedback configuration?

I'm studying power converter control loops using Christophe Basso's book Designing Control Loops for Linear and Switching Power Supplies. A very common pattern in the compensator circuits is a ...
6
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2answers
3k views

Dimmer to bulb control

I need to control a bulb of 220V, with different intensity light levels. I've an Arduino Uno Board, which receives a variable voltage from a Light-to-voltage converter (TSL12S) (Like a photoresistance)...
5
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1answer
401 views

Effect of zeroes in system stability

Suppose we have two third order systems (a and b), with three poles and two zeroes,poles for both the systems are at the same positions in frequency domain but these systems differ in the placement of ...
4
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3answers
11k views

Detecting dry-running of water pump

What are some reasonably reliable ways of detecting that a water pump (electrical motor based) is "dry running", i.e. no water is passing through the pump either because there is no water available at ...
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1answer
1k views

Mathematical model of the temperature of resistors/heatsinks?

I want to model the transfer function of a resistor mathematically, and am after some resources / tips on if it's possible to do so. For example, if I put 1V into a 1 Ohm resistor, I want to know how ...
0
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1answer
77 views

Control System how to get rid of Steady-State Error For Ramp Input

I am supposed to get rid of the steady-state error for ramp input for this closed loop transfer function Transfer Function of Closed Loop ^ T(s) Closed Loop ^ Since the closed loop is equivilant to ...
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4answers
2k views

How to mount electronics on a vehicle chassis safely

I want to implement a control system I designed for a light electric motorbike. I would like to mount it as professionally as possible on the chassis. It consists of a power system pcb and a SAMC21 ...
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3answers
659 views

Confusion in understanding control system?

I am learning basics of control systems from following link http://instrumentationandcontrollers.blogspot.com/2010/11/types-of-control-systems.html It says that automatic washing machine & ...
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5answers
1k views

System response types

Whenever I am given a system type with a certain transfer function, I am always asked to proceed to find out the 1. impulse response and 2. step response of the system. My question is, what is so ...
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1answer
58 views

How to go about determing the System Type of my setup?

I have a small project where I am PID tuning two servo motors. Something very similar to this: I am interested in finding the system type of the above setup, which includes the PID loop I have tuned. ...
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3answers
311 views

Transistor current control with positive feedback differential amplifier

Hi Folks, I want to analyse the functionality of following OpAmp configuration which seems to be employed as voltage - current conversion. Positive feedback (This is not a Failure and is ...
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5answers
10k views

How to learn PID Control?

I want to learn PID (Proportional–Integral–Derivative) control mainly for temperature. I would like to learn preferably through an easy project to do. Could you please recommend something which ...
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2answers
1k views

System Modeling for Control Systems

After taking classes in control theory as an undergraduate, I ended up not using them at all after I graduated. I've started to fix that by starting a hobby project in controls. My textbooks are ...
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3answers
2k views

How does control theory apply to my real-world processor-controlled boost converter?

I have a limited understanding of control theory. I dealt with poles and zeroes and transfer functions in school. I've implemented several microprocessor-based control schemes for DC/DC converters. ...
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7answers
19k views

Building a temperature-controlled water bath

I want to build an accurate (±2 °C) water heater (sous vide) that heats water somewhere between 30-100 °C according to user input. Although I have an engineering background I have no ...
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5answers
2k views

Laplace transform and the idea of frequency domain analysis

I have studied control theory in depth in my undergrad and still continue to use it on many occasions in my PhD work, but i still don't fully understand why we call Laplace transformation of system a "...
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3answers
2k views

How to tune a PID controller to a nonlinear process

I have a nonlinear thermal process (nonlinear radiation becomes more and more present as temperature goes up) that I would like to tune a PID controller to. I'd like to control the temperature as ...
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1answer
7k views

current control via microcontroller

I have a micro-controller which calculates and decides about the current each minute. Then for one minute the circuit must hold that current constant. Then it should control the current via a buck ...
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1answer
2k views

Type 2 compensation network

I'm working through the excellent text on SMPS design "Switching Power Supplies A to Z", by Sanjaya Maniktala. Right now I'm reading the section on the feedback loop and stabilization. As a first-...
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2answers
3k views

How to switch between two DC power sources powering a motor on an electric vehicle?

Background: For a university final project, my student group is investigating the possiblility of powering a motorcycle with two seperate batteries, each of a different chemistry (Lead-acid and ...
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1answer
78 views

Find the total gain from the following Signal Flow Graph

The signal flow graph for a system is given in the figure. Find resultant gain.
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2answers
4k views

Proportional controller

Sirs, I am not able to understand why Proportional controller introduces offset.Please consider follwing paragraph I found on internet, credit to ** http://blog.opticontrols.com/archives/344 **, ...
2
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1answer
652 views

Derive transfer function from block diagram

I have this block diagram which I already reduced pretty much: Now I want to derive the transfer function from phi_o1 to q. ...
2
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2answers
4k views

How to find the state-variable equations from the signal flow graph of the system?

How to find the state-variable equations, i.e, the state equation & the output equation for the system described by the signal flow graph below?
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1answer
753 views

Transfer Function of Non-Ideal Transformer

What is the mathematical relationship between primary and secondary windings? It can be either in the s-domain, or a time domain expression. This expression must contain all realistic parameters, ...
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2answers
400 views

Finding the transfer function of an non-inverting audio op-amp

I am just doing some independent re-search for myself in audio amplifier (CHIP AMPS) such as the LM1875. I want to learn more about how to compensate for audio chip amps and how their bode plot ...
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2answers
386 views

Mechanical time constant of PMDC Motor in starting and after switching off the supply is same or different?

In my MATLAB/SIMULINK model of the PMDC motor the mechanical time constant has same value in the case starting of motor and after switching off the supply but in experimental setup there is a ...
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1answer
863 views

how to make a system respond to IR laser? [closed]

Lets say i have 2 separate systems called Box A and Box B. Box A has an IR laser beam attached to it. What equipment can i use to make Box A make a certain action ONLY when the IR laser attached to ...
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1answer
97 views

Find the transfer function given responses

We have an open loop system with an input u , a transfer function G(s) and an output y. We apply the following inputs $$u_i(t)=\sin(ω_it), i=1,2,...6 $$ and get the following responses These are of ...
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1answer
107 views

Control System Basics

I am really confused with the difference between steady state error and actuating error. My teacher gave the following notes on this topic and explained using 1 example. He said that there will be 2 ...
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1answer
79 views

Find the largest value of \$K_1\$ and \$K_2\$ for instability of the system

A cascade control system with proportional controller is shown below Theroritically the largest values of the gain K1,and K2 that can be set withot causing instability of the closed loop ...
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2answers
13k views

Make hard drive stepper motor run 7200 rpm

I have an old hard drive (7200 rpm) motor like this: I'm trying to make it run as fast as possible and I start with this code (arduino uno): ...
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2answers
374 views

Switching on and off a LED light if a AC is passing through a wire or not

This is the basic setup of what I'm going to do. Have a wire plugged into the mains that is then connected to a ON/OFF flip switch then goes on to the rest of my project. Want I want to do is to add ...
0
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1answer
116 views

Gain of proportional Controller with distubance \$sin(10t)\$

The diagram below represents the position of ocean oil platform system which use the proportional controller with gain \$k\$. The output \$x(s)\$ is the platform deflection regards the position ...
0
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1answer
74 views

When supply fan VFD starts up it causes communication problems for my energy management controller

We have an energy management system that controls the air handlers for a building. I have one unit that when the supply fan VFD starts up it cause the unit controller to start having communication ...
0
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0answers
102 views

How to find Phase crossover frequency?

I make the imaginary part of \$loop \ gain=0\$ to find phase crossover frequency. But in one video, the person told that this method can only be applied when Polar plot crosses the real axis and ...