# 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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### Confusion in close loop block diagram

I am studying chapter 4 of Dorf title Modern Control systems(11 edition) I am trying to use MATLAB or Labview to implement block diagram for open loop control systems for speed control of an armature ...
15 views

### How can a Memory Controller know when a memory is busy or completed a read/write requisiton? [on hold]

I'm trying to make a memory controller to control a memory model using SystemVerilog. My memory model have a different clock domain than his controller and take different and variable times to do a ...
37 views

### Why does continued fraction expansion work? [migrated]

While checking whether the given polynomial is Hurwitz or not, we perform continued fraction expansion. We were taught how to perform this check(i.e) look at the sign of the coefficients of the ...
62 views

### Disturbance Rejection in a Closed Loop Control System

I was reading an article about disturbance rejection of closed loop control system and I came across the sentence "becomes almost zero, and the effect of the disturbance is suppressed." I have also ...
64 views

### Is a type 2 system is always unstable?

If there are multiple poles at origin, that system is unstable. So a type 2 system will be have s^2 in denominator. So this should be unstable right? Correct me if I am wrong.
51 views

### Difference between four matrices of state space?

I already know that there are two common types of representations used for mathematical modelling. One is transfer function and the other is state space. When dealing with state space representation, ...
44 views

### Confusion regarding step responses of integrator and differentiator?

I am using matlab to study about step response of integrator and also of differentiator using transfer function modelling technique But i have two confusion, one in case of integrator is that step ...
29 views

### Control of a time-variant system

I am working in a control project in which I need to control two variables $x$ and $y$ according to their reference values. Since I don't have an advanced knowledge in modern control theory, I ...
101 views

### How does the second order time constant affect circuit behavior?

I learned that the transfer function of a second order circuit can be expressed in the following standard way: $$\frac{K}{\tau_s^2 s^2 + 2 \zeta \tau_s s + 1}$$ Where: $K$ is the gain $\zeta$ ...
36 views

### Level system of water tank?feedback of close loop? [duplicate]

I have attached a photo from animation from following link https://beta.spiraxsarco.com/learn-about-steam/basic-control-theory/basic-control-theory this photo shows a float in a water tank, it ...
63 views

### How this close loop control systems work? [duplicate]

I have attached photo of a lecture where a slide is showing a close loop control system(theif repulsion system). But i am confused by the electric eye?how it is working?is the robber/theif so mad that ...
629 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 & ...
31 views

### Transient Response and s-plane root location

A second-order system has the closed-loop transfer function T(s)=Y(s)/R(s). The system specifications for a unit step input is as follows: I managed to solve the problem until this step. But I am ...
82 views

### Linearizing hall effect sensors outputs

I'm trying to find a robust solution to linearize four hall effect sensors outout to obtain a signal that I can use in a PID control scheme. The output data is collect via 4 ADC channels on an ...
879 views

### The term Feed-forward and its meaning?

I am trying to understand the technical meaning of the term 'feed-forward', when and where it can be used and where it cannot be used? I have seen this term in various different areas. For example: ...
38 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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### 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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### Control theory in PLC (programmable logic controller)? [closed]

What is the control theory of PLCs (programmable logic controller)? PLCs fall in category of linear control or non linear control?
83 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 ...
74 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 ...
28 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?
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 ...
43 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 ...
39 views

### What is this functions Phase crossover frequency?

OLTF loop gain My approach What I have done wrong?
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### 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 ...
36 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 ...
25 views

### 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 ...
92 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 ...
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 ...
54 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.
79 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 ...
26 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 ...
30 views

### 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^{\...
56 views

### 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 ...
29 views

### 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 ...
71 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 ...
85 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: ...
114 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 ...
32 views

### 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 ...
102 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 ...
40 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....
135 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, ...
46 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 ...
90 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- ...
47 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 ...
90 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) ...
142 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 ...
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{\...