Questions tagged [pid-controller]

A PID controller is a (closed) control loop feedback mechanism. It is used in industral control for proportional, integral and derivative feedback.

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32 views

Confusion understanding transient behaviour?

I am trying to simulate PID controllers in MATLAB Simulink, but I am bit confused by the term "transient behaviour" in how its extreme highlighted forms (aggressive and robust) will affect the system ...
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Common types of control logics/schemes? [on hold]

What are the different schemes/logics for controllers? Only these 3 Pid controller , on-off controller and fuzzy controller ? Or there are also schemes/logics other than these above 3?
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Confusion in PID loop?

I am already studying PID control and some how to some extent I have understood it except one main confusion. When the difference between reference input r(t) and current output value y(t) is zero, e(...
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2answers
108 views

Why use PI controller for speed, instead of full PID?

I am building a two-wheels self-balancing robot and using PID controller to control its speed. The measured value is the encoder signals from the Hall sensors on the back of the DC geared motors. But ...
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1answer
25 views

Read Data from Temperature Controller using MATLAB, Need Help

I am trying to read data from a temperature controller called ATR-401 using MATLAB's tool box called Instrument Control Toolbox but every time i try to read data from it i get an error "A timeout ...
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3answers
1k views

How stable are PID loops really?

This is not a question about tuning PID loops for stability. I am assuming the output looks stable. The question is: Do PID loops ever achieve absolute stability, or is there inevitably a periodic ...
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38 views

Control and code in LTSpice

I'm starting to use LTSpice, after having used MATLAB/SIMULINK/PLECS for a long time. I would like to do some simple feedback control (PI), without analog components (OPamps, comperators, etc). Just ...
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32 views

Using PID relay to drive multiple contactors

I am a physicist by training but have been tasked with designing a heating controller box for a custom application that will be used in an industrial setting. I would like to make sure that I am ...
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2answers
90 views

How can I decide relay on-off periods depending on the PID output [closed]

In my PID project, I am using discrete time PID formula as follows. u(k)=u(k-1)+Kc * [(e(k) – e(k-1)) + (Ts*e(k))/Ti + Td/Ts * (e(k) – 2*e(k-1) + e(k-2)) As you know PID output increases over time ...
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1answer
48 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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1answer
55 views

µC control of a force testing machine

At work we have a machine that is used for testing and calibrating force sensors. It basically consists of a huge lever that is actuated by an electric motor with a gear reduction and a calibrated ...
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1answer
85 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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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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1answer
112 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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1answer
98 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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88 views

Why SSRs for heaters?

In the context of building PID controllers for very large heater systems (ovens, kilns, etc.) nearly all the designs I encounter use an SSR to switch the load, a choice I don't understand. The power ...
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1answer
38 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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1answer
51 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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1answer
84 views

Heating rods control using PWM

I'm not an electrical expert and lately, I ran into a problem using PWM for steady control of a heating rod. Let's assume there is a set value (Temp in C) for the heating rod. I'm currently using a ...
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3answers
53 views

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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1answer
117 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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1answer
165 views

When to use analog PID

So I am building a rather simple constant current load to test power supplies. I am using an INA138 for high-side current measurement with only 5V power (and I have reasons for that, unfortunately) ...
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3answers
92 views

How to make sense of speed vs Torque curves in speed control mode

I am operating my motor in closed loop speed control mode using motor controller. Toque vs speed curves gives us a relation between them which is one-one correspondence. But in a closed loop speed ...
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Ripple in output voltage

I am working on an Active Clamp Forward converter. Schematic is given here: Specs: Output voltage-5V Input voltage 26..42V frequency=500KHz Output power=10W It is working fine in open loop, but in ...
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1answer
50 views

PID: how to deal with delay between controller and a process?

In designing a digital pll, I'm facing a problema with a communication delay between the loop filter output and the frequency synthesizer (via SPI). If I dont consider the communication delay the ...
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1answer
87 views

How to implement low pass filter in the differential part of PID in time domain

I programmed PID in MATLAB: ...
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Values got from programmed PID are different from ones simulated in Simulink

Please also read Update I created a PID simulation in Simulink: where the Step block is set with parameters: ...
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How to stabilize the magnetic levitation system? [duplicate]

I have asked similar question before also but want to try again - Not able to levitate magnet for magnetic levitation project I followed everything from this project but still, the magnet is not ...
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1answer
120 views

Not able to levitate magnet for magnetic levitation project

I am following a hackster project on magnetic levitation here - https://www.hackster.io/jsirgado/magnet-levitation-with-arduino-eeeee4 However, I have followed everything but still, it's not working. ...
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Design PI a controller for a “kind of” non-linear system

I have to design a controller for a plant ("Base"). My problem is related to the input term B*T0: in this case I have one output and two input. I think that I can split the "Base" model in two parts "...
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A peculiar issue in an atomic force microscope [closed]

I'm not sure where else to turn for this issue. Hopefully you all can offer some insight. Sorry the title is so vague, I don't know how to explain this concisely. I am a teaching assistant for an ...
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2answers
185 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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2answers
120 views

Proportional Control Balance Beam

Bit of an unorthodox question I'm sure, but I'm making a balance beam (two rotors on either end of a see saw) with proportional control, and I can't seem to get it to balance at 0. The proportional ...
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19 views

LiIon battery discharging

I have a question regarding LiIon battery discharging. Lets say I have a battery which is connected to a dc bus via a battery charger which has a bypass contactor in parallel. The charger is ...
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1answer
60 views

How do I calculate this inverse Laplace Transform

I have this transfer function and input, and I have to manually calculate what the systems response will be. The transfer function is: and the input is: I multiplied the two functions and used ...
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1answer
153 views

Does a low-pass filter average the higher-order frequencies into a “DC offset”?

In a Pound-Drever-Hall lock, an electronic signal is produced of the form: We are interested in electronically isolating the term: My question is: how can we filter to get exactly this term (listed ...
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Boost converter load regulation

I am currently building a boost converter with PID control to control the output based on the discharge. The output will be fed into a DC/AC converter which, ideally, will power different loads. As of ...
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4answers
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Motor fader PID control

I'm trying to control a motorized fader (linear slide potentiometer) using an Arduino. PID control gives good results for "jumping" to a specific target position, but tracking ramps is a problem, it's ...
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57 views

Steady State Error to Ramp Input Using Derivative of Complementary Sensitivity

I know that to find the steady state error to a ramp input, we can use the final value theorem. However, I was reading up on the Internal Model Control and the article uses a different form of steady ...
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1answer
74 views

Trying to wire in LED to show cooker element is on/off

Hi I'm a mechanical engineer so please bear with me. I'm trying to wire in an LED to show whether a cooker element is on or off. Looking at the diagrams below, the easiest way to do this would be to ...
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82 views

Guidelines and design considerations for designing a controller for a grid tie inverter?

I'm working on designing a controller for a grid tied inverter. I'm not able to find a suitable reference or book that might help in this case. What I have understood now is: There must 2 loops (...
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PI or PID vs Manual Controller design using Control theory

Why should we design a controller manually using Bode plots and control theory instead of using PI or PID controllers and tune them? Or more specifically when should I design a controller and when ...
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1answer
34 views

Derivative and Integral Controllers' Form

A derivative controller \$C_{d} = s-z_{d}\$ adds a zero to a system, placed at \$s=z_{d}\$. I know that a derivative controller is not used alone but for the same of the argument let's say it is. In ...
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1answer
92 views

PI controller - DC voltage regulation

I a voltage source converter, in order to control the DC-Bus voltage a PI controller can be used. The control method is illustrated in the figure below: I would like to ask why the input of the PI ...
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1answer
41 views

PID motor controller using simulink semantic errors when changing reference values

My aim is to design a pid - motor controller in simulink, and i also have to use h-bridges and PWM generator. The motor is a single phase dc-motor. And the aim is to control the speed. The reference ...
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3answers
344 views

Not sure how to go from PID error to PWM duty

I am trying to learn the basics of PID. I have made a contraption to try to implement a PID controller. I am not using carbon fiber, but rather a chopstick. So I am controlling the speed of the ...
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1answer
255 views

PID - Integrator Anti Windup limit values

I'm implementing a PID controller in software. Using P+D only doesn't bring me close enough to my set-point so I decided to also use an Integrator with Anti-Windup. Question: In my Anti-Windup code - ...
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120 views

How do I calculate a PID controller gain for a certain damping coefficient?

I have a third order process and I have to design a PID controller by cancelling out the two most dominant poles of the process. The process transfer function is: The controller is of the form, where ...
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1answer
58 views

PID Control - Actuator non-linearity

I'm writing code for a PID controller. The system is a "see-saw" with a motor attached to a propeller on one end and nothing on the other - you can call it a 1DOF helicopter. I use an angle sensor ...
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2answers
172 views

PID vs Bang-Bang - which one is more stressing on components?

This question is regarding a 3D printer, specifically its heat bed. The head bed is a PCB heater with a resistance of 0.9 Ohms, so it's drawing around 13 Amps when supplied with 12 Volts. I recently ...