What is Control system: Definition and 103 Discussions

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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  1. A

    Use Simulink to check the step response of a control system

    1. I have to use Simulink to check the step response of a state feed-back design (controller) and state estimator (observer). I did the problem and got matrices that I need for the desired poles but I'm not sure how to use Simulink to do them.3. I really don't want to post the exact vales to my...
  2. S

    Derive transfer function of control system with disturbance.

    This is a revision question rather than homework as I have the answer and working. I have attached the block diagram and first part of the answer which explains how to derive the transfer function from first principles. I understand the principles behind this and how the RHS of the equation...
  3. L

    Solving Control System Problems: Natural Frequency and K Linkage Explained

    Homework Statement Since this is a third order system and there will be a zero in its transfer function i am confused that how the natural frequency and K will be linked ? Please do help i really get confused in these type of problems. Homework Equations The Attempt at a Solution...
  4. J

    Satellite Control System With Rate Feedback

    I'm trying to get the transfer function of this rigid control system that uses rate feedback to stabilize it. Using k=1 and kv=0 Attempt at a solution. When kv=0, the rate feedback is removed. In the block diagram, I moved the pickoff point and used the cascade rule to get 1/s^2 and...
  5. N

    Understanding Pole Speed in Digital Control System Design

    When designing a State Observer for a control system the observer poles (eig(A-LC)) should typically be about 10 times faster than the controller poles (eig(A-BK)). But when designing a digital control system what does it mean for the poles to be faster? For the analog case it simply means...
  6. N

    Understanding Digital State Space Control: A Guide to Sensors and Actuators"

    I am trying to implement a digital state space control and am confused about something. The system has the standard state space form: x(k+1) = Ax(k) + Bu(k) y(k) = Cx(k) The vector y(k) comes from the sensors measurements and u(k) is what is sent to the actuator, right?
  7. L

    Control system Transfer Function ( Time constant form)

    Why is time constant form of transfer function in control system better than pole zero form ? If a closed Loop transfer function is given to me how should i find D.C gain ?
  8. Femme_physics

    Control system - Thermistor, thermocouple, PT100

    I'm 95% sure I got it all correct, but I'd appeciate another set of eyes Homework Statement 1) What's a thermistor? What is its principle of action? 2) What's a thermocouple, and what is its principle of action? 3) How does temperature transducer act based on the bimetal principle...
  9. L

    Questions of LMFBR control system

    How to design a LMFBR control system. I mean the whole plnat's operation and reactor control system.
  10. FOIWATER

    S+T=1 sensitivity of a control system

    with s being the sensitivity of a transfer function GC/(1+GC) to the parameter G. (1/(1+GC) I see mathematically how it works out. My question is about the profoundness of the statement. Qualitatively, what does it mean
  11. L

    Control system - open loop transfer function and open loop gain

    control system -- open loop transfer function and open loop gain Is there any difference between open loop transfer function and open loop gain ?
  12. E

    Control system car park system

    Homework Statement A car park has 5 parking slots. When the fifth car enter the car park, a red light notification will turn on indicate the car park is full. When the car park cars decrease from 5 to 4, the red light is distinguished. Homework Equations The Attempt at a Solution I set the...
  13. P

    First Order Control System

    Hi all, got a Control question here, and I'm struggling with what I assume is a simple algebraic step. Thanks in advance! Homework Statement A closed loop control system governs the level of water in a tank (H(s)) to meet a target height (Hi(S)). The flow of water into the tank is controlled...
  14. L

    Adapting touch sensor to mechanical control system

    Hi. I've just started working with the MPR121 capacitive sensor (at the moment I'm working with the MPR121 breakout board sold by sparkfun) for an application that involves detecting a toolhead's distance above a work surface. It's not a problem to ground part of the tool head and some initial...
  15. Z

    Control system with equation C = A*x + B*dx/dt

    Homework Statement This question came up in a computer science / robotics exam and I still don't know the solution for it. I figured out that it's classical mechanics related, so I thought this might be the best place to ask it. Homework Equations C = A*x + B*dx/dtThe Attempt at a Solution I've...
  16. V

    Heating an Oven with Feed-Forward Control

    Homework Statement I am supposed to design a control system with feedback and disturbance feed-forward, with all relevant transfer functions. The system consists of an oven where the temperature T is controlled by an electric heater that dissipates power P_{in}. The temperature outside...
  17. G

    Steady state error of control system on MATLAB

    Given the following system (d(t)=0), I'm supposed to calculate the steady state error for unit step and unit ramp inputs respectively. Basically, the open-loop transfer function of the system is \frac { 3s+0.5 }{ s({ s }^{ 2 }+3s+8) } The closed-loop system is \frac { 3s+0.5 }{ { s }^{ 3...
  18. H

    What do i do if my control system is not observable?

    so i made a state space model of a physical system where A matrix is 4 by 4 and B matrix is 4 by 1. I have 2 inputs in the system and 1 output. I used Matlab to create the A,B,C,D matrices and i used the ctrb (controlability matrix), then the rank function. instead of rank 4 (full rank) i...
  19. G

    What is the effect of a complex pole on control system stability?

    Let's say I have the following transfer function: G(s)=\frac { s-1 }{ { s }^{ 4 }+2{ s }^{ 3 }+{ 3 }s^{ 2 }+{ 4s }+5 } Which is run through MATLAB to obtain the pole-zero format: G(s)=\frac { s-1 }{ ({ s }^{ 2 }+2.576s+2.394)({ s }^{ 2 }-0.5756s+2.088) } Using a quadratic solver...
  20. T

    Where are the PHYSICAL inputs to a control system?

    Hey everyone, I'm brand new here, so please bare with me if my question doesn't come out right. Homework Statement So for my senior design class I am working with a control system that balances an inverted pendulum. Here is my SIMULINK diagram...
  21. E

    Calculating exp(At): Reverse Laplace Transform vs. Matrix Series Method

    Homework Statement I have the following matrix: A=[0 -1; 0 -1] and i need to calculate: exp(At) in several ways, 2 of them are using the reverse Laplace transform and using: I + Ʃ(A^kt^k)/k! i have tried to start the series but i am getting an expression that i can't say which series it...
  22. Z

    Simple autonomous lawn mower control system

    hello friends..i really need some help on my project, i am going to design a control system for a lawn mower..this mower must be able to move by itself using PIC as the brain,can avoid obstacle,move along path created on the field..what details component must i buy aand how to assemble this...
  23. A

    Control System Projects with Computer Interface Ideas

    can someone please give me some ideas of control system projects which have someinterface with computer?
  24. C

    Placement of Reaction Control System on a Spacecraft

    Suppose you have a reaction wheel or a control moment gyroscope on your spacecraft for attitude control. This would be a self contained unit, with 3-axis control. Either device utilizes the conservation of angular momentum, trading angular momentum between the unit and the spaceship frame as...
  25. R

    How to design a nuclear power plant reactor power control system ?

    Can you give me some advice of this topic? Thank you!
  26. T

    Where to start? Modeling a UAV Control System in Simulink

    Hi, I have a small project coming up, based around modeling (and perhaps building) a small Micro UAV system. Its a small device with contra-rotating blades (for stability), and I want to perhaps model the control system using simulink but I really don't know where to start! The aim is for the...
  27. D

    Mathematical modeling of a feedback control system

    My system is a compound pendulum hinged at some distance from one end and have a propeller mounted dc motor at the other end. I wish to position the pendulum with the help of motor propeller system. I tried but i am unable to get a mathematical model for it. I am getting a non linear model...
  28. Z

    Three Tank Control System on Simulink

    I am doing Control on Three Tank System using Simulink and I am newbie in Simulink. I am having a problem in the Simulation of Simulink. I am having the equation as below: az1×Sn×sign(h1-h2)√(2g|h1-h2|) where az1, Sn and g is constant. h1 and h2 is the input of the system. This...
  29. A

    Thermal Control System for Europa Mission

    I am designing the thermal control system for my senior design class. We are designing a lander to go to the surface of Jupiter's Icy moon, Europa. I've been researching about thermal blanketing and coatings for the lander, but other than just the materials that it can be made out of, I haven't...
  30. G

    Control System Help (not an EE)

    Homework Statement (See Attachment for image) Part 1) This system is a model of an actuator with internal springiness, also called a series-elastic actuator.The system naturally decomposes into two subsystems: i) the mass of the actuator m1 with viscous friction b1 due to sliding on the...
  31. D

    Control System Design Exam Prep: Analytical Solutions & MATLAB

    I am studying for an exam coming up and came across a question that i am having a little trouble with. [PLAIN]http://img442.imageshack.us/img442/825/screenshot20101112at110.png I think i could do this in MATLAB, however i will obviously not have MATLAB in this exam. I have a set of equations...
  32. R

    Need Help Understanding Process Control System?

    i have problem to understand the concept of process control system... anyone can help me to find source or link that related?
  33. L

    Building a RC Aircraft with Recovered Control System

    I recently extracted the control system out of a severely damaged RC aircraft (a very simple kit deal). It's got two servos, and a pretty good motor, which works out perfectly for me! I want to build a new aircraft from scratch using the recovered control system. For the fuselage I'm...
  34. K

    Transient response of a control system.

    Hi guys. I am a Mechanical Engineering Student but we've a course called Control systems. My question is why does any system(physical like fan,motor or electronic like amplifier) have a TRANSIENT RESPONSE and specially why do electronic components like amplifiers,diode or for that matter any...
  35. M

    Help with deriving transfer function of a second order control system

    Homework Statement Please see attachment for block diagram of the system. Starting with the block diagram given in Figure 2 derive an expression for the overall transfer function of the system, where Gc(s) is in the form given by Eq. (1). Show that the system is a Second Order system...
  36. A

    !Designing a Light-Weight Hovercraft Control System

    Hi everyone, I'm designing a light-weight hovercraft (2 light fans, 4x1.5 V batteries, 30x20cm in size). It needs to travel 6m straight ahead, then make a 90deg turn to the right and travel on for another 2m. The problem is that the craft must make this turn ON ITS OWN, meaning that there...
  37. A

    Aircraft Lateral - Directional Control System help

    Hello, I am in a aircraft dynamics and control class. I am supposed to design a lateral - Directional control system for a UAV in simulink. i.e the plane is starting from North - 0 , East - 0 and 10000ft altitude, and is to go to a way point at some distance N , E and remain at 10,000 alt...
  38. K

    Control System - First order system

    Q: 1) A thermometer requires 1min to indicate 98% of the response to be a step input. Assuming the thermometer to be a first order system, find the time constant. 2)If the thermometer is placed in a bath, the temperature of which is changing linearly at a rate of 10degrees/min, how much...
  39. R

    DC Motor control system question- random reversals

    Hello I have a project in the works that requires a DC motor to turn a somewhat heavy (but with good bearings) gear assembly. The whole thing will be running off of a common computer power supply at 12V. I haven't selected the motor just yet but am leaning toward maybe an old cordless power...
  40. S

    Control System Design for Boost Converter

    Hi guys, I have this problem for my undergrad final year project. I'm trying to design a control system to regulate the voltage output for a boost converter and I am not too familliar with control theory. I've built the control system in MATLAB based on the basic boost equation...
  41. A

    Designing a control system for a heating system

    Homework Statement F = Fahrenheit A particular temperature control system uses electrical heaters, exterior thermal insulation and a thermostat for maintaining the temperature at 170 F +/- 1 F. The thermostat turns the heater on when the temperature drops to 169 F and on at 171 F. Heater...
  42. G

    Solving Control System Problem: Finding Maximum Velocity Error Constant (Kv)

    Homework Statement question: find maximum velocity error constant(Kv) feedback is :1 positive the book says the right answer is:0.75 but every time i calculate E(s) it goes to the wrong answer! please help!
  43. C

    Implementing critically damped in a process control system.

    Doing a Cascade Control lab and I'm stuck on a question. Its asking me how to implement critically damped into a control system. I can't find it any where in my books or the net. thanks.
  44. B

    Transfer Function & Unity Negative Feedback Control System

    Hi there. I'm wondering if anyone can help. I've got a few past papers I'm working on at the moment and there are a few questions I don't even know where to start with. Here's one: a. Write down the transfer function for a time delay and then evaluate its corresponding frequency response...
  45. maverick280857

    Query regarding steady state error in a velocity control system

    Hi I was reading BC Kuo's Automatic Control Systems where I came across a solved problem (page 369 of 7th edition) regarding velocity control. I have a problem understanding how the steady state error has been computed. The original problem and its solution as given in the book are quoted...
  46. E

    What Are the Equations of Motion for the Print Head Control System?

    Homework Statement Please refer to the image attached for problem statement and diagram. There's an inductor somewhere, but I have no idea where and I don't know how to accommodate for it. I can also see that there's another energy storage device, the spring on the right. I have no idea...
  47. D

    Non-Linear Control System and Motor synchronization

    Hello, I am currently trying to design a system that will sychronize two propellor motors, and I must design using the following equation: w'*I + (w^2*r^2*p*S*C_d)/(2) = T_t + T_ss w' = Angular acceleration I = moment of inertia w = angular velocity r = radius of blade p = air density...
  48. wolram

    Two Engines, One Control System: Impossible or Inevitable?

    http://news.uk.msn.com/Article.aspx?cp-documentid=7279188 Surly both engines do not share a single control system.
  49. L

    Airframe dynamics of a model rocket roll control system?

    Hello, I am hoping to build a model rocket with a roll control system for my senior project. Since the idea of building or obtaining a wind tunnel seems infeasible I will need to theoretically calculate how this rocket will behave with various canard fin angles and at various air speeds. I...
  50. L

    I am interested in building a rocket with feedback control system

    I am interested in building a rocket with feedback control system... so I have been interested in model rocketry lately and I was wondering how feasible it would be to design and build a model rocket for my senior project complete with a control system to ensure it flies straight up. I was...
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