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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How should sampling frequency, switching frequency, control loop update frequency, and anti-aliasing filter corner frequency relate?

Suppose one is designing a processor-controlled switching supply. In general, how does one properly select switching frequency vs. control loop update frequency vs. feedback sampling frequency vs. ...
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392 views

Is impulse response always differentiation of unit step response of a system?

I was trying to solve a question in which the transfer function of a system was asked, its unit step response being given: $$ c(t) = 1 - 10^{-t} $$ The method that the book followed was to first ...
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Any open tool for graph plotting for determining PID tuning parameters?

I have gone through several PID implementations and its tuning tutorials, documents and all. The Best tuning tutorial was PID-without-a-PhD.pdf . But has not been of much help. I can say it works some....
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What is a “dry contact input”?

I'm a PC software guy, a newbie to electronics. Recently, I've got a project in which I need to source for a DAQ that can provide dry contact inputs to an interfacing digital output controller. The ...
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Can you control a 12V Solenoid Valve using motor dev kit MCLV-2?

The MCLV-2 is a motor driver development board, of 24 volt and up to 15Amp (in total). Aside driving a motor, I'm also interested in testing to see if these circuitries are suitable to run a 12 volt ...
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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)...
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414 views

PID controller, tuning and creation

I have been having some good success with my first PID controller. It seems it needs just a little bit more work. Below is a picture of a sample run with my controller implemented. Currently I only ...
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Undamped natural frequency

What's the definition of the undamped natural frequency? I've looked and I cannot find it. A second order system has the following transfer function $$ H(s) = \frac{A_o \omega_n^2}{s^2 + 2 \zeta \...
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What are the major advantages of using a closed-loop over an open-loop and vice versa?

I'm trying to gain a better understanding on the pros and cons using closed-loop or open-loop motor control. Also trying to better learn when it's more sensible to apply each one
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Does gain affect stability of a Transfer Function?

I have a control system that we are working on with a forward transfer function of:- \$ \dfrac{K(2s+3)}{s^2(s^4+2s^3+4s^2+2s+7)}\$ So I've set up the routh table for this, I've found there are 2 ...
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The open loop transfer function of a unity feedback control system is given as \$G(s) = \frac{as+1}{s^2}\$

The open loop transfer function of a unity feedback control system is given as \$G(s) = \frac{as+1}{s^2}\$. What value of 'a' will give a phase margin of 45° ? \$G(s) = \frac{as+1}{s^2}\$ \$Transfer\...
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Rise time for second order RC filter?

Can somebody help me in deriving the expression for rise-time for second order RC filter. simulate this circuit – Schematic created using CircuitLab
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695 views

I need help Building A Solid state Electro magnetic Mixer

I'm just getting into electronics, and I would like to build an electromagnetic mixer. See here. Most of the tutorials I have found have magnets stuck to a motor spinning under a non magnetic material ...
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Determining whether a system is LTI given response to a rectangle box input

Given a system, it is possible to determine whether the system is LTI given the response to input to the system, other than the unit impulse? Specifically, my input to the system is $$x(t)=\begin{...
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Definition of a System

A mathematical operator is generaly a mapping between a domain set of functions and a range set of functions.One example is the derivative operator L ( L[f] = f' ) for example. Can i say every ...
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bldc motor torque controller

I have a working custom motor controller for three phase sensorless bldc motors. I've implemented open loop speed control, where the duty cycle is changed to change speed. I've also implemented a ...
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676 views

Designing a PI controller for my power system

I have a power system which is given as: Using MATLAB, I found the system's response to be: As you can see, the system is not stable. So, I need to design a PI controller, so that, the transient ...
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LTI Response Help

A system is known to be LTI. The response of the system to a step function u[n] is δ[n] + δ[n-1]. a.) Find the response of the system to 2u[n] + u[n-1] b.) Find the response to the unit impulse δ[n]....
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884 views

How can I model this linear power system in MATLAB?

For my power system, let us suppose it has the following dynamic model: \$\ x ' = f(x,u)\$. This dynamic model consists of four first order differential equations (see below). Then, I linearized ...
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Can a 110v spa pump curcuit control a 220v spa heater that is on it's own 220v circuit?

I have a 110v spa pump that is itself controlled (on/off) by an air switch. I want to install a spa heater that is 220v, but when I purchased the heater I didn't realize that the heater should only ...
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PID regulator steady state error problem

I'm working with a PI controller that regulates temperature through a pwm duty cycle. It generally controls well. However, the system requires a certain minimum duty cycle to balance the heat loss. ...
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2answers
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What are common control strategies for dosing pumps?

Dosing pumps means pumps that dose a specific amount with a high accuracy. In many process control scenarios, level gauges or flow meters are used (with low accuracy, at least in some cases), what ...
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Can a DC motor with obstructed movement be damaged?

I am trying to build shades, which should roll up or down, controlled by a DC motor. This motor can only be turned on or off (1/0 to turn it on/off). Also, it should be noted that the microcontroller ...
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661 views

Help finding transfer function for root locus using Matlab

I'd like to pick \$k_d\$ using root locus method, but have problems deriving the necessary transfer function of the system presented below. Assume \$k_p\$ is fixed. The question originates from Randal ...
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Reticulation Controller [closed]

I'm thinking of building my own reticulation controller to drive an automatic watering system. Does anyone out there have a good circuit diagram? A simple 6 or 8 station control with adjustable timer ...
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1answer
197 views

How to Design a State Feedback Controller using an algorithm

I'm studying for an exam and am having a great amount of difficulty wrapping my head around this as I have minimal electrical engineering background, and my notes are confusing. I have read a few ...
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How to implement a self tuning PID-like Controller

I am trying to write a micro-controller program for controlling temperature in a system with the following characteristics: output can only be On or Off, with fixed cycle frequencies (~2-10 per hour) ...
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1answer
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Controling a regular residential 110V/15A circuit switch (or relay) from a PC

I am a software engineer by trade and also a rather skilled and well rounded (residential) builder with a special interest in wiring. I have rewired my entire two-unit house, panels included and seen ...
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1answer
706 views

Using Matlab to draw a step response graph

I've got the next transfer function: $$ \frac{\hat{\alpha}}{\hat{\alpha_{ref}}} =\frac{w_n^2}{s^2+2w_n \xi s+ w_n^2} $$ Now I want to draw a step response input at height of \$\alpha_{ref}\$, where \...
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481 views

Using impulse response to control the system

This post by Olin Lathrop is rather inspiring. The system response is the convolution of the control input with this impulse response, computed every control sample, which is every 500 ms in ...
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Block Diagrams with offset in control theory

I have an equation in the form $$y = mx+b$$. In block diagram form, I could draw this with a proportional gain block and a summer. I was wondering if there are some clever tricks where I can make ...
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1answer
311 views

Controlling temperature of a water bath with induction plate

I am thinking of building a sous-vide cooker using some kind of prebuild heater, controled via an AVR and temperature sensor like the LM35. There are a lot of references around using rice cookers, ...
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1answer
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How to realize these transfer functions as a circuit?

While I am well aware of some of the technique about implementing transfer functions I wanted some input about how can i realize this transfer function with active filters (OpAmps are preferred): 1) $...
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1answer
2k views

Brushless motor controlled via current source math model

I'd like to model a brushless motor's (BLDC) dynamic response using Matlab. I'm controlling the motor by an Elesctonic Speed Controller (ESC). I'd like to derive a transfer function of such a circuit ...
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2answers
2k views

digital PID controller implementation

I am trying to implement a PID controller in the z-domain. What I have done so far is found some values of \$K_p\$, \$K_i\$, and \$K_d\$ that work in the time domain. I have found some information ...
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682 views

Controlling a Motor for test bench

This is my 1st question here and I'm stumped... I spent all my EE classes on programming and ICs. When it comes to AC and motors, I feel worse than ignorant and spent all day trying to research where ...
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2answers
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Measuring tiny voltage variation with Arduino ADC handing the rapid changes in control algo

I'm hoping I can get some advice, I have an industrial laser position sensor from SICK that outputs 0 to 10 volts. I used a voltage divider to scale it down to 0 to 5 volt range, and feeding that into ...
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1answer
771 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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How to implement a closed loop control circuit for slow process?

Given a slow process Vout = Process(Vcontr) which takes a control voltage Vcontr and produces an output voltage Vout but with some lag of the order of one second. ...
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1answer
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RTU card of SCADA systems

In most of electrical SCADA systems, RTU (Remote Terminal Unit) panels are very common in power transmission & distribution companies. There are several cards inside each RTU panel, some are ...
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2answers
397 views

Greenhouse Control Interface

I'm working on a control system for my school's tropical greenhouse based on the Arduino. It'll just do basic logging things, along with allowing someone to selectively water sections of the ...
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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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1answer
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Cruise control implementation

I am doing a project that requires that I implement a cruise control system on an RC car using a GPS for feedback. I have implemented PID controllers before, but this is a little bit new to me ...

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