# What is Control systems: Definition + 104 Threads

A control system manages, commands, directs, or regulates the behavior of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large industrial control systems which are used for controlling processes or machines.
For continuously modulated control, a feedback controller is used to automatically control a process or operation. The control system compares the value or status of the process variable (PV) being controlled with the desired value or setpoint (SP), and applies the difference as a control signal to bring the process variable output of the plant to the same value as the setpoint.
For sequential and combinational logic, software logic, such as in a programmable logic controller, is used.

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### Courses How useful is control theory in computational neurosciences?

Hello, I have the opportunity of choosing an elective course on control theory before embarking for my master's program in computational neurosciences and I am weighing the pros and cons. I am looking for advice from PF members who specialized in this field. Since I have chosen enough courses...
2. ### Engineering Advanced control systems, state-space controllers

------------EDIT---------------------------------------------------------------------------- Check comment #7 for neater and faster explanation of the question statement --------------------------------------------------------------------------------------------- The symbols represent: H, water...
3. ### From differential equations to transfer functions

*** MENTOR NOTE: This thread was moved from another forum to this forum hence no homework template. Summary:: Trying to find transfer functions to design a block diagram on simulink with a PID controller and transfer functions for a water tank system. ----EDIT--- The variables and parameters...
4. ### Engineering Why Are Some System States Indistinguishable in Observability Analysis?

https://en.wikipedia.org/wiki/Observability I am studying observability and I try to get some intuition on the topic. Given the observable matrix, we can find the null space. However, the vectors of the null space are states but this differs from the definition of what a state vector of a...
5. ### Engineering How do I use Simulink to create a control system with a 2nd order ODE?

Equation: , where matrix D, C, G and F can be represented by I'm supposed to design a control system that looks like this: I am given that the dynamic model = fcn(D,C,G,dq) where the dq is the same as 𝑞̇ and d2q in the diagram is the same 𝑞̈. The default initial value of [𝑞(0), 𝑞̇(0)] is...
6. ### Engineering Disturbance in a proportional control system

Hello, I found an old thread related to this question but it doesn't look correct to me so was looking for some guidance. I have equated Qo = (Q2+Q1*G) / (1+H*G) I did this by rearranging Qo=Q2+G(Q1-Q0*H) I then went on to the calculations and found before step disturbance: Qo=...
7. ### Engineering Write the differential equation that's equivalent to this transfer function

I have the solution to the problem, and I mechanically, but not theoretically (basically, why do the C(s) and R(s) disappear?), understand how we go from ##(s^5 + 3s^4 + 2s^3 + 4s^2 + 5s + 2) C(s) = (s^4 + 2s^3 + 5s^2 + s + 1) R(s)## to ##c^{(5)}(t) + 3c^{(4)}(t) + 2c^{(3)}(t) + 4c^{(2)}(t) +...
8. ### Getting Started With Control Systems

I am in my 4th year in a Bachelor of Science Electrical Engineering Technology (BSEET) program that leans toward electrical transmission and distribution. I have had two courses in calculus, so have briefly covered differential equations. Unfortunately, my course curriculum does not cover...
9. ### Transfer Function and Control Systems Question

ıs there anyone to solve 8th 9th and 10th problems? It is about transfer function and control systems http://avesis.yildiz.edu.tr/DokumanYetki.aspx?SSNO=33&USER=2813Password= 1234
10. ### Dynamic modeling of a system and transients of the system

Consider, I have a dynamic system model for air compressor. Which means I have modeled the system by including its physics. Does this means I also included the transients of the system? What I think is, when i modeled any system with equations, I think that includes the transients. Is it...
11. ### Viscous drag parallel to the axis of rotation: Control Systems

Homework Statement https://i.imgur.com/WPAKuf4.png seeking G(s) = \frac{\theta_2(s)}{\tau(s)} Homework EquationsThe Attempt at a Solution What does it mean when the viscous drag is parallel to the axis of rotation?[/B] It also turns out that this system needs two equations. I can sort...
12. ### Control systems: Simplifying block diagram

Homework Statement How to show a block diagram can be simplified to a standard first order form for the diagram shown in the image attached and the question is shown in 1.a Homework Equations Standard first order form K/(1+tD) where K gain and t is time constant The Attempt at a Solution...
13. ### Control Systems - How to find dominant poles *without* MATLAB?

Homework Statement Design a lag-lead compensator for the system of Figure 9.37 so that the system will operate with 20% overshoot and a twofold reduction in settling time. Further, the compensated system will exhibit a tenfold improvement in steady-state error for a ramp input. Homework...
14. ### Control systems -- input with non-zero initial conditions

Homework Statement Deriving an s-domain equation for the following inputs a) &b) The Attempt at a Solution I understand how to derive the equation for an input with zero initial conditions (part a) but I'm not sure what to do when there are non-zero initial conditions (part b)
15. ### Can I Simplify a Block Diagram by Making Multiple G5 Blocks?

I would like to ask why cannot I think G5 in series with G3(G4+G6G7) and then after muliplying them why I cannot think of G5*G3(G4+G6G7) in parallel to G2 so sum G2 and G5*G3(G4+G6G7) ? Thank you.
16. ### Just curious, searching for explanations or research

Outdated Control Systems Engineer with a PhD in Industrial Preventive Maintenance, in training for a double major in Chemistry and Biology. Prefer to work the math, reason and deduct, infer, interpolate and extrapolate, yet a lot is presented to me as to be "simple memorization", so I have to...
17. ### Control theory: block diagram, problem (detailed below)

I´m taking a course on control engineering and I have a test next Tuesday so I need to study the basics which are: Laplace transform, simplification of block diagrams, and analysis of transient and steady state responses. Right now I am dealing with the second one. I know the basic rules of...
18. ### Finding points on root-locus by hand

Homework Statement [/B] I am trying to answer two questions: 1. Solve part (b) in the image above by hand. 2. What are the differences between transfer function (a) and transfer function (b). Homework Equations cos(Im(s) / Re(s)) = ζ The Attempt at a Solution 1. For part one given the...
19. ### Dynamic model of non-linear system

i am finding it difficult to get insight about modelling of non linear system (electrical). my queries are, consider the system is DC DC converter... 1) I read that to study the dynamics of the system we linearise the non-linear system...why do we want to linearise it?... 2)can some one please...
20. ### Which US Graduate Schools are Best for Mechanical Engineering Research?

Hello, My name is Emre and I am a MSc student in mechanical engineering.I am looking for PhD in US.My research interests are mechanical vibrations,rail vehicles,finite element method and control theory.In fact I have 2.68/4 GPA in Undergrad and 3.79/4 GPA in Master.So if anyone has any advice...
21. ### Digital Control Systems Textbook

Hi Guys, I need some material to update, or, better said, to reinforce my skills in Digital Control Systems. In the very beginning I thought on "Digital Control Systems by Benjamin C. Kuo", but, after think about this, I realized that, maybe, this is an oldie for this subject. Do you have any...
22. ### 2nd Order Control system PD controller

Hi, This question on PD control is from a practice quiz. 1. Homework Statement If you can't see it- the question asks to find values for Kp and Kd such that the system achieves 5% OS and has a settling time Ts of 3s. Cs = 3 Cd = 2 m = 5Homework Equations ω_n^2/(s^2 + 2ζw_n + ω_n^2) - 2nd...
23. ### Why Time Response Characteristics Derived from Zero State Equation

QUESTION: 1) Why are Time Response Characteristic's Expressions derived from only from Zero State Equations? NOTE: Nise Control Systems Engineering 6ed uses step inputs to derive Time Response Characteristics for 1st and 2nd order ordinary differential equations...
24. ### Auto track using Kinematic model

Hi, I'm trying to implement an auto track guidance system for ground vehicles (Eg Tractors), I'm using Matlab and Simulink. I'm at a point where I can calculate heading errors. I'm not too sure how to calculate the lateral errors. Also, I need help in designing the controller. I'm using...
25. ### Control Systems of Turbomachinery?

I'm a sophomore of Mechanical Engineering, but I do like delving into more advanced subjects that I haven't seen in undergrad yet, and among those are fluid dynamics. I've made a little bit of research into turbomachinery (while looking for some classes that could interest me hereafter) and...
26. ### Block Diagram Reduction - Control Systems Engineering

Homework Statement Determine the closed loop transfer functions of the systems shown below: Homework Equations Standard block diagram algebra. The Attempt at a Solution I've moved the take off point such that the diagram now looks like: I am having difficulty determining G1(s). The...
27. ### Observable System L Matrix, can a value be negative?

Homework Statement An error matrix is in the form, has a characteristic equation: ## CE: s^2 + 120s + 7200 = 0 ## A state variable feedback system is described by: ## A_F = \begin{bmatrix}0 & 1 \\-616.8 & -40 \end{bmatrix} ## ## B = \begin{bmatrix}0 \\ 1 \end{bmatrix} ## ## C =...
28. ### Design of Experiments Ideas - Control Systems?

Hi everyone, I'm taking a Design of Experiments class which is focused on statistically designed experiments. I'm a bit lost for project ideas and this is my first graduate class. Would anyone have any ideas for an experiment that would have at least controllable factors that might have...
29. ### Understanding Sampling Period 'T' in Digital Control Systems: Tips and Tricks

< Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown > Hi. Please see question no. 1 in the attachment. If i take the inverse Laplace transform or the Z transform, how can i actually get the value of sampling period 'T'. or is there any other way...
30. ### How can you control devices remotely using wireless systems like USRP?

How controlling a device is possible using wireless communications systems like software defined radio?
31. ### How can I control two outputs with a single PID-controller?

Overview I'm trying to levitate a constrained permanent magnet with 2 electromagnets. I'm having trouble conceptualizing the control system for such an operation. Setup The permanent magnet is fixed onto a horizontal pendulum and is repelled by an electromagnet above and repelled by an...
32. ### Zero order hold -- Discrete control systems

I have some questions related to how a discrete control system is designed. One method is to design the controller in the continuous time domain, arriving at a transfer function (in the s-domain). After that, a transfer function for the ADC system must be taken into consideration. I will suppose...
33. ### Transfer function with Disturbance

Homework Statement Find the steady-state error due to a disturbance Td(s) = 1/s. Set R(s) = 0. if given a system: Homework Equations n/a The Attempt at a Solution I need Y(s)/Td(s). To do this I must find Y(s) in terms of the transfer function Y(s)/R(s) which I have obtained. This gives me...
34. ### Control Systems Engineering - Block Reduction Help

Homework Statement Hello, I'm trying to reduce the following block diagram Homework EquationsThe Attempt at a Solution I appear to be having some issues in doing this. The first thing that I did to reduce this block diagram was to take the forward path that has 2/(s+4) with negative...
35. ### Understanding frequency and dynamics

Can someone please explain intuitively how the terms “frequency” and “dynamics” are related ? I understand the concept of each of these two individually, but I am having some difficulty visualizing what high-frequency dynamics mean. I understand the concept of how time and frequency domains...
36. ### What qualifications do I need for a career in embedded / control systems?

After graduating with a BS in CS, I haven't really found anything in the field very appealing. However, after reading some things, I've found myself very interested in embedded / control systems. My question, is this a field I can pursue with only a BS in CS? Or should I go for a BS or MS in...
37. ### Why the transfer function is represented in S Domain?

Hi all, I would like to know why the Transfre function of the system is represented in S Domain instead of doing all the math in time domain itself. I studied a course on control systems and i wonder why s- domain is taken instead of other domains like Z- domain and others. Please refer belwo...
38. ### Why Is My MATLAB Steady State Error Different from Manual Calculation?

I am trying to calculate the steady state error of the following system but unable to do it. I have used MATLAB and calculated the steady state error to be 0.1128 but don't understand the steps that I need to do to calculate this. Please help. Thanks
39. ### Control systems block diagram reduction

Homework Statement Hi I am having trouble simplifying the attached diagram with respect to the return summing blockHomework EquationsThe Attempt at a Solution there shouldn't be any superposition since there is only one input signal, in the attached file I've simplified A to Be: G3/(G2-G2G3G4)...
40. ### Help in control systems with feedfoward

<< Moderator Note -- thread moved from the EE forum to the HH forums >> Hi I am doing a HW assignment for my control systems and I just need some clarifications on some concepts so i can solve the problem. This is the current problem I am working on. 36) (Homework 4 Problem 2 – Feedforward...
41. ### Bode Plots & Frequency in Control Systems: Demystified

What frequency are they referring to when they plot magnitude versus frequency in a bode plot of a control system? I don't understand where frequency comes from in control systems. I've researched this and I'm still very confused by what is meant by frequency.
42. ### Electrical Engineering - Control Systems - Design Via Frequency Respon

done editing Homework Statement I'm given the following transfer function that represents a physical apparatus G(s) = \frac{X(s)}{F(s)} = \frac{3.333*10^{4}}{s^{2}} I'm asked to design a lead compensator to achieve closed-loop stability. The requirements are that it must have a transient...
43. ### What is the difference between digital controls and digital control systems?

"Digital" Control Systems I recently took a control theory class at my local university and we learned about PID, loopshaping, and state-space methods and implemented them in MATLAB/Simulink and used an Arduino for some projects. However, I was talking with some EEs (I'm an ME) and they were...
44. ### Control systems design software

Are there any software programs for purchase that allow control system modeling and design for individual use under \$1000
45. ### Control Systems - Root Locus with proportional control

Homework Statement Homework Equations See below The Attempt at a Solution Root Locus? Easy Peasy right? Based on provided equation G(s), i solved the coordinates of the root locus diagram using quadratic equation. For the 2nd part of the question, i have to find gain at which rise time...
46. ### Control Systems - stability and settling time

Homework Statement Given G(s) = 1/[(s^2+s+4)(s+6)] and C(s) = k, find the limit of stability of k. Also, what is the range of k such that the settling time is between 10 and 20 seconds. Homework Equations Provided above The Attempt at a Solution I have attempted to set this...
47. ### Thermodynamics : Open and close control systems

Hi all, Q: How do you find out the boundary work using control volume analysis for a tire that is punctured all of a sudden? To proceed, I started off by using the tire as a control volume with one outlet. Using first Law, E(in) - E(out) = dE/dt Final Conditions: P(final) =...
48. ### Electrical Engineering - Control Systems - 2cnd Order System

Homework Statement Given a electrical circuit as one below One can find the transfer function For second order systems this can be written as I know that the damping coefficient can be found using the following formula In the over damped case ζ>1 can easily occur depending on the...
49. ### Control Systems Theory: Determing break frequency mathematically.

Hey there. I have an open loop transfer function TF = K/(t*s^2 + s) where K is known. Given a value for the break frequency (say, w_b = 10 rad/s), I have to determine the value of the time constant, t. I understand how do this with a bode plot, but not entirely sure how to proceed...
50. ### Control Systems Engineering - Signal Flow Graphs

Hi, I seem to be having some issues going from state space representation of a system to signal flow graph representation. My troubles seem to be, if I have something like this \frac{d}{dt}x_{1}(t) = v_{1}(t) In state space representation I list functions to which the derivatives are as...