# Questions tagged [pid-control]

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### I need to design a controller for a system, need to choose between P, PI, PD, and PID, given only the desired ss, settling, and overshoot %

(Apologies for terrible formatting, first post and don't know how to make equations look nice) The system is $$G(s)=\frac{10}{4s^2+7s+23}$$ and the requirements are steady state error of zero, $10ms$ ...
156 views

### What is the physical intuition behind an "integrator" in control theory

I am watching some videos on control theory by John Rossiter, and they are very good. So far I have watched most of the videos on classical control, including transfer function, feedback, etc. One ...
45 views

### Inverted pendulum PID: controller causes cart to move at constant velocity?

I am trying to understand the PID controller of an inverted pendulum on cart system through this MATLAB article: https://ctms.engin.umich.edu/CTMS/index.php?example=InvertedPendulum&section=...
39 views

### Iterative Method through FEM

Due to reasons, I can not fully describe the process explicitly so I will be using substitutes to represent the variables. Nomenclature: x - an independent variable y - another independent variable Fz ...
51 views

### How to implement H-infinity controller in STM32 platform?

I used matlab to simulate some H infinity controllers, and I have some understanding of the related theory. But I don't know how to implement H-infinite controller on STM32 platform using C/C++ code. ...
140 views

### What is the Z transform of the Discreate PI control model？

I have a discreate PI controller implemented in stm32 MCU, it has the following form: $$PI=K_p\cdot[r(t_i)-y(t_i)] + (K_I)\cdot\sum_{n=0}^{i}[r(t_n)-y(t_n)]\cdot\Delta t$$ where $r(t_i)$ is the ...
41 views

### Designing a PID controller for a Type 1 System

I don't know if this is the right place to ask this so I'll give it a try. Given the following system, for example $$P(s) = \frac{40}{s(s+4)},$$ I have to design a PID controller that must satisfy ...
69 views

### How to calculate the integral and derivative term and integral and derivative time in a PID controller?

I am designing a PID controller. While calculating integral controller, should you calculate mean of all the past errors or only calculate mean of past n samples? In the case of latter, how to pick n?...
34 views

### steering wheel angle control

I am working on an autonomous vehicle's control, specifically the steering wheel angle control. Knowing that I used kinematic bicycle model, my questions are: How do I choose the actuator for my ...
46 views

### State Space Model of a transfer function

where we will attempt to stabilize it using the proportional control law u(t) = Ke(t). My Question is, how do I obtain the open-loop transfer function from this dynamics system ? I assume that the ...
1 vote
59 views

### why Type III systems has at least two gain margins?

I heard the following statement https://engineering.stackexchange.com/a/54322/40848 if we have a type III system, or one that has three or more low-frequency poles that we're closing around, then we ...
77 views

### Why are the phase indicators different between the open loop bode plot and the closed loop bode plot?

I have an open-loop transfer function G num=105*conv([1 1],[1 2 43.25]); den=conv([2 0 0],conv([1 2 82],[1 2 101])); G=tf(num,den); and a closed-loop function of G/(1+G). Here are the open-loop bode ...
58 views

### What is the effect of the resonant frequency of the system function Porter diagram on the stability of the system and how to analyze it?

I am a novice in automatic control, the theoretical basis is not very good. We have a large electric clamping jaw, single degree of freedom, the motor is controlled by the torque output, the motor has ...
338 views

### Do you need to reset the Integral part of a PID controller?

I'm learning about PID controllers and one thing I don't quite understand from the pseudocode and formulas is the apparent persistence of the "Integral" portion. For example, imagine the ...
27 views

### Discharge through a gate - Feedback needed

I need to make a PI feedback loop for a hydro power plant. The discharge through one gate is given by Q in equation 4.2. I need to keep (regulate) H = 116 m.a.s.l (meters above sea level) where H = Hg ...
59 views

### Orientation and horizontal position control of a bar in 2D

I have a scenario where I have a bar of 0.1 m in length, 10N weight is applied in the center. Two forces are applied on the bar at both ends vertically, right one if 5.1 N and the left one is at ...
1 vote
69 views

### What is the original source of the common Ziegler-Nichols PID tuning coefficients?

In many places, including but not limited to the Wikipedia page about PID controllers, I see the following PID coefficients: $K_P = 0.6K_U$, $K_I = 1.2 K_U / T_U$, and $K_D = 0.075 K_UT_U$. When were ...
51 views

### What is the gain of a purely integrating process?

Consider a system where: $\frac{Y(s)}{U(s)}=\frac{k}{s}$. Is the gain k, or infinity? Given that to a step response, steady state is never reached, but it increases linearly with no end. Thanks!
105 views

### How do you find the gains for a PI controller with a first order plant and 2nd order low pass filter?

How can analytically work out the gains knowing the required bandwidth and damping? The plant to be controlled is first order. The low pass filter is 2nd order in the feedback path.
93 views

### What exactly do I do with the output of a PID controller?

Let's say my setup is something simple: I'm trying to heat some liquid to a temperature $T$. I can influence the temperature of the liquid by applying some potential difference $V$ across the liquid. ...
45 views

### PC based real time control system

I am newbie, and I want to update an existing control system, which works with a 486 PC with AD/DA card currently. Is it a good idea to find a solution with a windows 10 PC, and a USB AD/DA card? The ...
107 views

### Real examples of complex PID regulators

I am currently developing the C library for easy implementation of PID controllers. Can you give some examples of complex PID controllers from real life? I don't mean a simple DC motor with a speed ...
146 views

### Boeing 747 Autopilot Vertical Speed Function (PID Controller)

I originally asked this over at the math stack-exchange but was told I might have better luck here. I have simply copy-pasted the question. I am working on a Boeing 747 autopilot control system for an ...
1 vote
86 views

### Which controller is more suitable in this scenario? P, I or PI controller?

Scenario: A robot has a ultrasonic sensor which measures the distance to the nearest object in centimetres. The robot has two motors, a motor for the left wheels and a motor for the right wheels. The ...
43 views

### How to determine the components of a feedback control loop given following context?

Based on this feedback control loop where $w$ is the desired setpoint, $x$ the process variable, $e$ the error value, $y$ the correcting value and $z$ the disturbance value. Did I interpret the ...
76 views

### How can I find characteristic equation of complex systems?

I am working on an Overhead crane, where I am supposed to design a controller that controls the position of the crane while minimizing the load's sway angle. I have derived the transfer functions for ...
47 views

### Deadbeat gain for system with measurement delay

Say we have SISO system (e.g. the velocity of a permanent-magnet motor) that we're controlling with proportional feedback, with the condition that our measurements of the process variable are delayed ...
33 views

### Modelling an S-shaped Second Order Process Response

I am trying to model an S-shaped second order process response as a transfer function in Simulink, as shown in figure 3 in the linked article. Ideally the response should be overdamped. I have tried ...
78 views

### Finding optimal PID gain values with no Transfer Function or Plant model

Background: I have a Matlab simulation model with .m files. The functions simulate a speed control system of a vehicle. I can control the vehicle's speed by adjusting the vehicle’s acceleration and ...
37 views

### Control scheme for roll compensation

I'm working on an application that rotates a cylindrical mass in a manner to compensate for roll in a boat. The roll of the boat is rather slow so I was thinking it might be possibly to simply use a ...
1k views

### Control Systems: 3rd order system project [duplicate]

I'm in need of help finding a third-order or higher system in which I can derive a transfer function. We have a class project in which we need to find a real-life example of the system that equates to ...
46 views

### Best Techniques to design a cascaded precision position controller

I'm looking to design a cascaded controller to transform a BLDC into a servomotor. The system has a motor current controller in the inner loop, which is controlled by a torque controller, which is ...
186 views

### Limitations to consider when picking a cut-off frequency low-pass filter for PID control?

Considering a first-order low-pass filter transfer function: $$\frac{\omega_c}{s + \omega_c}$$ Where $\omega_c$ is the cut-off frequency. Are there any limitations on where to place this pole? For ...
46 views

### Block-diagram combining two controlled subsystems

I have two subsystems which are shown in the picture below. One of them is a system of stable and controlled differential equations of a mechanical system. Second is a block that implements a function ...
70 views

### Linearizing nonlinear system for PID control

I have a system where y = 1/x. (y=output, x=input) If I calculate the PID error not by reading y, but by reading 1/y (so linearizing the system), will my system be nicely linearized, and the PID ...
1 vote
106 views

### (Dominant) Poles very close to zeros in PID control

I have a plant transfer function $G(s)$: $$G(s) = \frac{1}{s^2(0.1s + 1) }$$ I want to control this with practical PID control: $$C(s) = k_p + k_i \frac{1}{s} + k_d \frac{N}{1 + N \frac{1}{s}}$$ ...
158 views

### How to tune a PID controller when plant's step response looks like a ramp?

The system is a boat and I want to specify a yaw angle and the PID controller would operate the rudder of the boat in order to reach the desired yaw angle. So, the step response of the plant (boat) ...
67 views

### How to determine time constant/cutoff frequency of the filters in the controlled loop

I was told to be careful to use filters in the control loops as it will add extra time delays in the system and degrade the system dynamic response, but I also saw there are lots of filters in ...
1 vote
130 views

### Can I design/tune the outer loop controller without knowing the details of the inner loop controller?

In cascade PID control loops as below, can I make an assumption that the inner loop will respond much faster than the outer loop, hence I could simplify U1_CMD as U1 and I could design/tune the gains ...
171 views

### Improving a PID controller from logged historical PID data

Part of our system involves a feedback loop with a PID controller. We log every call to the PID controller, and include in the log information about the Kp, Ki, Kd, the set point, the input, output, ...
64 views

### PID or AI or other approaches to this thermal control problem?

I have this boiler controlled manually at the moment, and I am wondering what would be the most proper approach to automate this process. The boiler in this question basically burns fuel (saw dust, ...
1 vote
63 views

### Servo Motor Input Voltage Equation

I'm working on a Ball & Beam project. As I'm doing it for an engineering project, I'm supposed to model the system mathematically, calculate the PID parameters, etc. to center the ball in the ...
54 views

### Is there an equation that can automatically tune a PID controller?

Is there an equation that can automatically tune PID controllers? or do I have to do manually/make an AI to do it for me?
211 views

### PI or PID-regulator for control system with hysteresis relay in inner loop

I have such control system (sorry for rough drawing :) ) $G(s)$ - stable object with proper transfer function. $1/s$ - integrator. I need to clarify, how synthesized PI or PID controller for such ...
102 views

### Discrete-time realization for continuous time domain controller/filter?

Let us say I simply design a low pass filter like (1/s+1) with the cutoff frequency as 1 rad/sec, when I implement it in real software, do I have to do the discrete-time realization? If not, what ...
152 views

### How to simulate open and close and control valve using a simple controller

I have successfully developed a mathematical model for my physical system. My objective is to control the mass of gas in and out of the system. The mass flowrate is given by: \$V_f = C_d.\sqrt{2.\frac{\...
1 vote
574 views

### How to get the performance index ISE and IAE for a Matlab-Simulink designed Line Follower Robot with PID control?

I am researching a method to determine the optimal PID gains for a line follower robot. The problem is, I don't know how to setup the performance index IAE and ISE in the matlab. Any tips on how to do ...
145 views

### What is the meaning of this symbol in Control System Diagram

I was reading the paper "Full-Speed Range Self-Balancing Electric Motorcycles Without the Handlebar" released in March 2016 by Professor Yang and Murakami in Keio University. I couldn't ...