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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30 views

Nonlinear Observer Question for BLDC

I'm looking at the article posted here, and I'm trying to figure out what it is that they're controlling and how. Specifically, Dave Wilson from TI gave a presentation called "Teaching Old Motors New ...
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38 views

Can my PID controller have negative p value and positive i value for a PID logic

I am building my first PID controller. My process variable and my actuator value are inversly related, meaning if actuator value increases process variable decreases, and vice versa. So I have tried ...
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42 views

Control theory in PLC (programmable logic controller)?

What is the control theory of PLCs (programmable logic controller)? PLCs fall in category of linear control or non linear control?
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55 views

Steady state error

Consider a type 1, first order system, whose open loop transfer function is (K/sT) with unity feedback. To this system if a step input of magnitude A is given, the response will be an exponentially ...
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Which RFID is right for me: range ~0.75m [on hold]

Background: This is a request for an out-of-the box system (or as close as possible). Some minor configuring or programming would be fine, since I'm competent in that realm. I don't know much about ...
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77 views

How to get from theory to a working Industry Control System?

EE Student here who recently finished the classical control theory class. I was wondering the process of how the industry or anyone goes from drawing block diagrams to actually implementing in ...
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71 views

What will be minimum number of states / state variables for these control systems in state-space model?

Consider the systems as LTI and SISO with transfer functions given below: I have read that minimum number of states for an LTI SISO system required to represent in state space analysis for any ...
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23 views

Transfer function using signal flow graph problem

Determine the system transfer function for the following signal-flow diagram of figure I have shown my attempt of solving this problem. Can anyone tell me whether I did this problem properly?
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28 views

Controller and compensator

What is the difference between controllers and compensators While searching for answer the most prominent answer I got was that compensator have magnitude=1 and is used to make sure the system ...
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42 views

How can I prove that for any control system root locus plot starts from poles of OLTF and ends at zeroes of OLTF?

simulate this circuit – Schematic created using CircuitLab G(s)H(s)=N/D T(s)=KN/(D+KN) Proof: ] But For K=0 T=0 For K=infinity T=infinity then how can K=0 {condition where forward path ...
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39 views

What is this functions Phase crossover frequency?

OLTF loop gain My approach What I have done wrong?
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32 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 ...
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35 views

Gain margin using Root locus plot

How can I find Gain margin of any control system given its polar plot In schaum's series I have read that Gain Margin=Ku/Ki but in given figure the system never becomes unstable so shouldn't Gain ...
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How do we determine the roots from a Routh-Hurwitz array?

I know that we can determine the roots on the right-half plane by counting the sign changes in the first column. However, I'm unsure how to find the roots on the left-half plane. Is it the same as the ...
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83 views

How does one position control a voice coil actuator?

I am looking at trying to position control a voice coil actuator (something like these). On the end of the voice coil actuator will be a small load (let's just imagine a 10 oz cube), screwed onto the ...
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25 views

Transfer Function For Electronic Pressure Regulator and a Step input

I was wondering if I could have some help in how to determine the transfer function for a Proportional Pressure Regulator. (VEAB-L-26-D7-Q4-V1-1R1). I have done a basic instrumentation and control ...
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50 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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55 views

Relationship Between Root Locus Pole and Percent Overshoot and Gain in MATLAB

I have a peculiar confusion regarding the relationship between a closed-loop pole on a root locus plot and its gain and percent overshoot. I have found a point on the root locus plot that MATLAB ...
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23 views

Normalizing a nonlinear plant in system identification in control

I have calculated the "active power" and the "the reactive" power of a system in dq axis in nonlinear form and I am doing system identification on this "nonlinear" plant as a MIMO system. The problem ...
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Minimal State-Space-Realization using SVD

A similarity transformation with U produces so following state space model \begin{equation} (A, B, C, D) \stackrel{\tilde{x}=U^{\prime} \cdot x}{\longrightarrow}\left(U^{\prime} \cdot A \cdot U, U^{\...
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Stability and Positive/Negative feedback

I often read that positive feedback is used to get oscillators (since the output of the circuit is summed up to its input signal and so leads to instability), while negative feedback to get amplifiers ...
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Stability of Buck Converter when output capacitance is variable

I am designing a buck converter for an application that has several different loads. Depending on what devices are connected, the capacitance seen at the output of the buck converter can vary ...
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67 views

Why “-1 + 0j” is critical point on Nyquist plot?

I am reading about Nyquist plot from this (http://www.cds.caltech.edu/~murray/books/AM08/pdf/fbs-loopanal_11Nov18.pdf) chapter. On page no. 10-2 its mentioned that "-1 + 0j" is critical point on ...
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78 views

How can I control TRIAC firing angle automatically with a DC voltage?

I have to build an analog proportional controller for a 127 V, 1 kW AC heating resistance. The power delivered to the heating element must be proportional to the difference between a set point ...
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Is it possible to predict the operating state of a power system (using MATLAB) if I have calculated the voltages at all nodes by state estimation?

If I have calculated all the node voltages by state estimation, is it possible to predict which operating state my system is at? By operating state, I mean any of the following: ...
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107 views

Buck-Boost converter without low side switch

Please look at the buck -boost converter below. It is 2 outputs, one buck and one boost output. Would the circuit work as describe in the picture? In what condition the circuit will it work? If so how ...
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Characteristics from transfer function

All! I am trying to figure out characteristics of a second order system The system is (for example) And its characteristics for an unit step input are I want to solve this equation by hand and ...
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86 views

Can a phase margin become bigger than 180° and is this bad?

I have a wrong mental model about phase margin in control theory. I see that a phase of -180° is bad. If my input is a sine wave and I have negative feedback, which has a -180° phase shift, the ...
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33 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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134 views

Why am I getting non-sinusoidal output for sinusoidal input in a mass-spring system?

A mass-spring system is represented by the following transfer function $$ H(s) = \frac{s^{2} + 0.1s + 10}{s^{4} + 0.2s^{3} + 20s^{2}} $$ For a sinusoidal input I am getting a non-sinusoidal output, ...
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40 views

How do I refer the transfer function of a system from its Laplace equivalent?

I have a problem, I know how to analyze circuits in Laplace domain to get the transfer Laplace function. However, I don't know how to translate the answer to "real life" Suppose that I have a ...
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68 views

Why fast inner current loop and slow outer loop of DC-DC converter

Let say we have a DC-DC converter operates with double loop control (inner and outer) , and with switching frequency of Fs= 20000 Hz. Please ,if you could answer the two following questions: 1- ...
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45 views

Controller for RC Filter

My class was asked to implement in MATLAB, a controller for an RC filter configuration with output response: 4/(s+3) The controller should give an output response whose steady state is 1 to unit ...
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1answer
87 views

PID (Arduino) Project - Determining Ki, Kp, Kd

I am working on control system project. I bought a Zumo 32U4. It has built in encoders. The project is divided into three parts: a) Move in a straight line. b) Slows down as obstacle approaches. c) ...
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110 views

Is the transfer function for the given RC network right?

For the question I arrived at the following answer (I have assumed V1 btw) Is my solution right? I just have a big doubt if whether I can use the voltage division rule at point A when there is an RC ...
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72 views

Relation between settling time and natural frequency for a critically damped system

In an article by Wie et al. (1989), for the purpose of calculating the gains of a controller, the equations of motion are approximated by the expression for a damped harmonic oscillation: $$\ddot{\...
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35 views

How to model a Electronic Proportional Control Valve

I am using a VSO LowPro Proportional control Valve (https://www.parker.com/Literature/Precision%20Fluidics/Miniature%20Proportional%20Valves/VSO%20LowPro.pdf) to regulate pressure into a closed ...
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52 views

What is difference between natural response and zero-input response of a system and how to find natural response?

In most books it is said that natural response is another name to zero-input response while in some resources is is mentioned that the classification is based on poles of transfer function and input....
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50 views

System Identification in a closed-loop feedback system [closed]

I have an unstable system that doesn't have a useable output when open-loop excitation is applied. Subsequently I've used a controller to control its output. I want to use the system identification ...
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Nyquist plot of a time delay open-loop transfer function

As shown in the example 6 of here, the Nyquist plot of a open-loop transfer function that has a delay term in the numerator will encircle the origin several times (in fact, infinitely many times). ...
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Obtaining Plant Input data from System Identification (PID)

I'm trying to obtain a mathematical model from a physical plant using MATLAB. Using the system identification tool you need the plant input and output data. I'm struggling to match the theory to my ...
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102 views

Find transfer function and step function for this circuit

Can someone help me to find the transfer function of this circuit (i want to have the tension through the capacitor I think) and the step response in order to get the voltage in the function of the ...
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49 views

Gain deficit and phase margin at crossover

I went through an exercise of the following specifications: A voltage mode buck converter working in CCM mode works with: \$V_{in}\$ min = 10V, \$V_{in}\$ max = 20V \$R_{load}\$ min = 2.5 ohm \$R_{...
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49 views

how to control state space when it is not controllable?

I have the matrix A and B and I computed the controllability matrix and found the rank is lower than n. I know I can't apply pole-placement , how else can I solve the system? n is the order of A
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48 views

Transfer Function [ the transfer function of the feedback stage? (Optical sensor and the lm2917) ]

I have to make a control system that maintains a constant speed of a small car prototype using a DC Gearmotor regardless of external disturbances such as slopes (small slopes). For the development of ...
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39 views

Calculating input voltage required for a series of capacitors to reach a a certain voltage in a certain time

just had a question regarding a system of capacitors. Its from the EE263 Introduction to Linear Dynamical Systems, Stanford University, 2008 Prof Boyd. If I have the step response and eigenvalues of ...
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60 views

What is the purpose of the capacitor in this circuit?

Is the purpose of the capacitor, C1, to filter out any possible DC component that the input signal has?
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48 views

How does force feedback [hardware] work?

Force feedback steering wheels are fairly common, but I don't understand how they work. Specifically, how does a "direct drive"($$$) steering wheel apply a force one way while moving in another ...
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177 views

What is the difference between these two op-amp circuits?

I don't understand why when we design a proportional amplifier, the feedback has to be negative. When I run the simulation in simulink I get the same result for both circuits.
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Power Supply : How to keep SMPS always above the post-regulator that follows it

I'm trying to find a way of building a new power supply for my workshop, in order to keep it small and not so hot I will be using a spare xformer to step down mains to 24v and then a variable buck ...