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 ...
1
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2answers
107 views
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 ...
-3
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0answers
72 views
Characteristic equation of a closed loop system in terms of PI controller [closed]
Just wondering if you could guide me on how to find the characteristic equation of a transfer function \$G(s)\$ in terms of the coefficients in the PI controller?
$$G(s) = \frac{45}{5s + 2}$$
Not ...
-2
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1answer
214 views
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}\$
...
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1answer
117 views
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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3answers
95 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 ...
1
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2answers
49 views
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
...
4
votes
2answers
63 views
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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0answers
41 views
Impulse & Frequency Response Help
Suppose that 2 systems are connected in cascade; i.e., the output of S1 is the input to S2. The 2 systems are specified as follows:
S1: y1[n] = x1[n] + x1[n-1] + x1[n-2]
S2: y2[n] = x2[n] + x2[n-1]
...
2
votes
1answer
120 views
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 ...
1
vote
1answer
57 views
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 ...
-1
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3answers
121 views
Variable liquid flow rate control
I'm not an Engineer by trade, rather a programmer looking to put together a micro controller project that alters the water flow rate of a cooling system to maintain a specific operating temperature ...
0
votes
0answers
81 views
Working of ac servo drive in position control mode and algos for position control
I have started working with a Panasonic AC servo drive of capacity 400W (manual). While trying to understand how a ac servo works in position control mode. After experimenting I have come to the ...
0
votes
1answer
89 views
Control system to minimize a parameter
This is a pretty vague question so please bare with me, I can add further information if required just let me know in the comments. So here is the problem that I want to solve.
There is a system ...
2
votes
1answer
206 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 ...
9
votes
3answers
298 views
PID Control Loops with large and unpredictable anomalies
Short Question
Is there a common way to handle very large anomalies (order of magnitude) within an otherwise uniform control region?
Background
I am working on a control algorithm that drives a ...
1
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1answer
222 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 ...
4
votes
4answers
236 views
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. ...
3
votes
3answers
475 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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votes
1answer
81 views
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 ...
7
votes
3answers
375 views
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 ...
0
votes
0answers
188 views
Settling time and overshoot
I have the next transfer function:
$$H(s)=\frac{P(s)}{1+C(s)P(s)}$$
where $$P(s)=\frac{20}{(s^2-2s+9)(s+100)}$$
$$ C(s)=m(s+40)$$
Now I want to find the settling time and overshoot of \$H(s)\$ as ...
0
votes
1answer
137 views
Closed loop plant-control system
I have the next system, and I want to find the transfer function from d to y.
So I've got the next equations
v = Ce = C(r-y)
e = r - y
u = d + v
y = Pu = Pd + PCr - PCy
Now I know that:
\$e/r ...
1
vote
1answer
89 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 ...
5
votes
5answers
734 views
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 ...
3
votes
1answer
332 views
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 ...
0
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1answer
262 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 ...
7
votes
1answer
117 views
Meaning of an arrow in the control scheme
I cannot understand what the arrow that goes through "internal model" block mean? how can I interpret what does it do? What is the difference from any other "normal" arrow?
Thanks for any clue.
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1answer
94 views
I want to find \$\frac{\hat{\theta}}{\hat{T}}\$
I have the next block diagram, and I want to find the transfer function \$\frac{\hat{\theta}}{\hat{T}}\$. I am not sure how to do this, I've got the rules of connection in a series or parallel, but I ...
5
votes
2answers
687 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 ...
5
votes
1answer
195 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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0answers
79 views
how to specify the output voltage ripple
If I have a power supply design, what is the way to determine the output voltage ripple?
I have read somewhere that you can do something like this, where you set performance specifications ...
4
votes
4answers
221 views
M.S. Math to Engineering Ph.D : Mathematics in Electrical Engineering
I have two Bachelor's degrees. One is electrical engineering and the other one is mathematics. I am studying mathematics (partial differential equations) in the graduate school (Master course) now. ...
1
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2answers
193 views
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 ...
2
votes
1answer
170 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, ...
7
votes
1answer
265 views
Conversion of PID controller components with state feedback into single transfer function and discrete state-space form
I've been wrestling with this problem for about a week now, as a part of a year-long project. We're designing a controller for a specific reactor based on a model. After looking at this for a while, I ...
1
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1answer
171 views
Self Balancing Robot using Computer Vision
I'm planning to implement a Self Balancing Robot which is usually implemented using a gyroscope sensor which gives feedback to the micro-controller to adjust the position with wheels. I'm looking into ...
4
votes
3answers
226 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 ...
2
votes
1answer
362 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 ...
3
votes
3answers
218 views
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 ...
3
votes
2answers
516 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 ...
3
votes
1answer
167 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 ...
6
votes
3answers
270 views
Voltage controlled AC current source
I have been tasked to build a heater for an industrial application. The heater uses resistance to heat the liquid and the application needs very precise control of temperature (+/- 1 degree). Existing ...
2
votes
2answers
1k views
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 ...
3
votes
1answer
526 views
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) ...
3
votes
1answer
320 views
How I can set up a transfer function of y = mx+c?
I have a system governed by the following relationship:
\$V_{OUT} = m * I_{IN} + 5\$
I need to write a transfer function for the equation. Would anyone please give me some suggestion of how to ...
1
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2answers
285 views
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.
...
1
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0answers
153 views
Question about MATLAB Estimate Nonlinear ARX model? (A basic english + engineering question)
First of all, I am a non native speaker. Please help me to understand what exactly MATHWORKS work about NLARX function. My question is what are the difference between nb and nk and how I should write ...
11
votes
4answers
993 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 ...
3
votes
1answer
624 views
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 ...
2
votes
2answers
296 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 ...
