# Questions tagged [pid]

Proportional Integral Derivative Controller. A type of control algorithm used in many control situations, especially servo systems.

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### How to tune the two PIDs for quadrotor

I'm trying to implement two PIDs for stabilizing quadrotor for position tracking. The inputs are $x_{d}(t), y_{d}(t), z_{d}(t)$ and $\psi_{d}(t)$. For position tracking, usually the small angle ...
2answers
1k views

### My PID Controller in Java is not operating correctly

I was looking for an implementation of a PID controller in Java and I found this one: https://code.google.com/p/frcteam443/source/browse/trunk/2010_Post_Season/Geisebot/src/freelancelibj/...
2answers
699 views

### Micro Quadcopter PID problem

I designed a mini quadcopter which is about 4.5x4.5cm(Main Body). The main body is the PCB. ![enter image description here] It weighs about ~20 grams with the battery. I'm using the MPU6050 with ...
3answers
102 views

### Help to dimension the right controller for the following Tranfer Function

I have a generic problem to create a controller for the following system: $$\ddot{x}(t) = a y(t)$$ where $a$ is a constant real value. The system could be seen as an equivalent of a mass-spring-...
4answers
6k views

### how to implement tracking problem with PID controller

I'm trying to implement the tracking problem for this example using PID controller. The dynamic equation is $$I \ddot{\theta} + d \dot{\theta} + mgL \sin(\theta) = u$$ where $\theta$ : joint ...
2answers
200 views

### Basic general question about controllers

Suppose I have a mechanical system which is free to move on a given rail [-5m, 5m] like a motorized cart. The whole system can be mathematically expressed through a linear timeinvariant system ...
1answer
61 views

### How can I know which system is easier to control using PID controller?

I have a inverted inertia wheel pendulum. I suppose that if I have a wheel with larger inertia at its top, the system would be more stable. How can I prove or disprove my conjecture?
2answers
137 views

### In the PID equation K[((s+a)^2)/s] what values correspond to the PID coefficients Kp, Ki, Kd?

I'm trying to understand how to obtain the Kp, Ki, Kd values after finding a combination of K and a that works for me. Do I just expand the equation and take the coefficients?
3answers
470 views

### Minimising lateral drift in a PID (Arduino) controlled quadcopter using a 6DOF IMU

I'm developing a stabilisation system for an 'off-the-shelf' quadcopter by using an Arduino Mega and an IMU. The IMU is reading the angle of the quad, calculating motor commands by using a PID ...
5answers
571 views

### Raspberry Pi quadcopter thrashes at high speeds

I am attempting to build a Raspberry Pi based quadcopter. So far I have succeeded in interfacing with all the hardware, and I have written a PID controller that is fairly stable at low throttle. The ...
1answer
483 views

### Converting a linear acceleration command into a DC motor command?

I'm constructing a 2 wheels balancing robot which uses a PID controller. I've tuned my parameters on numerical simulations based on a continuous inverted pendulum system so that the simulated ...
2answers
674 views

### DC Motor PID control with unstable velocity feedback

Currently I am building a omnidirectional robot with 4 DC Motors with embedded incremental encoder. However, with a constant pwm input, i am not able to control the motor to rotate in a "relatively ...
1answer
402 views

### Do you have to have a rate controller for a Quadcopter?

Most academic papers characterise the rate of rotation along the x axis as φ"=(1/Jx)τφ. As far as I cant tell, this characterises the rate and not the actual angle φ itself and yet the PID controllers ...
4answers
2k views

### PID control of tank-like robot and IMU

Consider a tank like robot with a motor driver channel for each side of the robot (two motors on the left and two motors on the right) and an IMU. I'm interested in driving the robot in a straight ...
1answer
504 views

### PID controller for trajectory with mutliple setpoints

We implemented a PID controller for our quadcopter which allows us to fly from point A to B. The precise position of the quadcopter is measured using an external tracking system. Now that we can fly ...
2answers
396 views

### Multiple PIDs in quadcopter

I am wondering what the use is of two PID loops to control a quadcopter. One PID for stability control and another PID for rate control. Why can't you just use one PID per axis to control a ...
2answers
973 views

### 2 wheeled, 2 motor robot control

I decided to work on a 2 wheeled robot position mapping problem. For that I have 2 DC motors with encoders from pololu. I have the following two questions: Do I need to know the model of each motor ...
1answer
348 views

### How do you design Quadcopter PID algorithm?

Just to give a bit a context, here are the equations I'm using for the Angular accelerations. φ** =(1/Jx)τφ and θ** =(1/Jy)τθ So my plant gains would be φ**/τφ =(1/Jx) along x axis and θ**/τθ =...
3answers
248 views

### Quadcopter multiple ESC angles glitch

I'm developing my fligth controller board on Tiva Launchpad for quadcoper and while calibrating PID I discovered an unexpected behaviour: sometimes quadcopter seems to experience random angle errors. ...
1answer
4k views

### Comparing LQR and PID controllers for inverted pendulum problem

As far as i can tell, both LQR and PID controllers can both be applied to the cart-pole (inverted pendulum) problem. What are the pros/cons to using one controller over the other for this particular ...
2answers
404 views

### Dealing with position inaccuracy and latency in PID Loop

Background: I am new to PID, for my first PID project I am using a simple P-Loop and 300 degree linear potentiometers for position feedback. I am using the roboclaw 2x60A motor controller. The motor ...
3answers
2k views

### How to program parallel PID control loops? So I can give my robot multiple set points to follow

So I'm in the process of building my robot and it has encoders on every wheel measuring speed and position and a compass sensor measuring heading. I have 3 seperate PID loops at the moment, I can ...
1answer
2k views

### The aerial refueling problem: sketch of a feedback controller

At first happy new 2015!!! I'm looking for my next simulator development: a Tanker is flying at constant speed (350 Knots) (no acceleration, no change of altitude or direction). The Tanker is ...
1answer
92 views

### The algorithm for the following analog controller => digital controller?

I have found a continous control in the following form: $$u(s) = \left( K_{p} + \frac{K_{i}}{s} + K_{d} \frac{N}{1 + \frac{N}{s}} \right)e(s)$$ but since I need it to "convert" in a digital ...
1answer
222 views

### PID for Quadcopters

As already mentioned the PID output values that correspond to the error from the desirable error and current error has no units. Let's say we are using only the proportional part of the PID. Is it ...
1answer
6k views

### How to find a solution for quadcopter PID control

I've built a quadcopter and a rig to safely test it on. I'm working on the PID for controlling the roll pitch and yaw. I understand how a PID works on a more simple plant like say a robot with wheels ...
1answer
2k views

### How to tune the PID parameters using Fuzzy Logic?

I previously used the Ziegler method to tune the parameters of my PID controller to control my robot's position. I then implemented fuzzy logic for self-tuning the parameters. I have two inputs to ...
3answers
3k views

### How to control PID Yaw

My yaw angle varies from -180 degree to 180 degree. ...
1answer
195 views

### Implementing a position control for UAV through a flight controller. Plant model is unknown

We are using Naza-M-Lite for our flight controller without GPS. The localization is obtained through our RGB-D camera sensor. We are able to teleoperate and even implement PID controllers for Roll, ...
1answer
291 views

### Is the input of ESC really limited at 50 Hz and will the PID controllers work properly?

Based on the wiki page of ESC, the ESC generally accepts a nominal 50 Hz PWM servo input signal whose pulse width varies from 1 ms to 2 ms http://en.wikipedia.org/wiki/Electronic_speed_control For ...
0answers
532 views

### RNN instead of a PID controller

I am building a drone using the raspberry pi and I am using 6*PID controllers to control the speed and the value for each angle, can I use a recurrent neural network (RNN) or other neural network to ...
0answers
626 views

### PID Control Tuning [duplicate]

Im currently designing a robot for my undergraduate project. One of the task of this robot is to follow the wall. For the purpose I'm using a PID control system, where the reference is given from a ...
2answers
319 views

### A general question about PID Controller

I have a basic question because I'm trying to understand right now a concept that I thought it was obvious. Looking at this video he is going to feedback the variable state x with the input of the ...
2answers
7k views

### Position Controller for a Quadrotor

I have a question regarding the implementation of a quadrotor's position controller. In my Matlab model the quadrotor takes 4 inputs: a desired altitude ($Z_{des}$) and desired attitude angles(\$\Phi_{...
2answers
130 views

### Deducing single wing plane transfer function Aka Transfer function estimation through set of points

I'm trying to control a plane via roll using PID controller , I had a problem finding the transfer function thus I used the following method :- Fix the plane in an air tunnel change the ...
1answer
103 views

### What is a PID as is related to quadcopters [duplicate]

I'm trying to make a Quadcopter from scratch, I have a fair amount of experience with adruinos, and I'm trying to understand how to necessary systems work, and I can't seem to figure out what PID ...
1answer
767 views

### Yaw angle calculation for drone PID from two distance sensors

I'm building a control system with a Parrot AR 2.0 drone where I have access to thrust controls for up/down (z), left/right (y), forward/backwards (x), turn left and turn right (yaw) through a Ruby ...
2answers
434 views

### PID Tuning Quadcopter Problem

I am tuning PID for quadcopter, the problem i have is that with different base Throttle, i seems that i have to adjust different PID gains in order for the quadcopter to balance!
2answers
350 views

### PID in a system with pole at origin

I've seen in a lot of places some methods of tuning a PID controller. Most of them will say that one should apply a step input to the system and based on that response you can tune the PID parameters ...
2answers
1k views

### Natural frequency computation (for PID gains computations)

I am currently trying to parametrize the low-level gains of a robotic arm. This arm uses a classical PID for each joint. I am trying to use a method based on computation rather than a trial-and-error/...
2answers
1k views

### Position Control of an Omni Wheel Drive Robot

I want to create a robot that will navigate on a desired path! That path can be a straight line or a circular path with a given radius. I will use 3 or 4 omni wheel drive platform and for positioning,...
2answers
4k views

### Cascading PID DC Motor Position & Velocity Controllers

I'm trying to build a robot with a differential drive powered by two DC Motors. First I implemented a PID Controller to control the velocity of each motor independently. Estimated the TF using the ...
3answers
508 views

### PID Integration over not constant dt (∆time)

Is integration over not constant dt (∆time) a possible thing? Let's say you have a PID loop with differentiating frequency, can the integral part of it still work? (Assuming you know the dt from the ...
2answers
397 views

### Good method for Retuning a PID After Detecting Oscillation

Given a PID controller with an anti-windup, what are some practical ways to retune the controller once oscillation has been caused and detected? I have access to the magnitude and period of the ...
2answers
1k views

### Electronic Speed Control Concepts

I am a programmer who has never worked with electronics before. I am learning the concepts and hoping to build a quadcopter, with the control software entirely written by me. Motor control seems to be ...
4answers
689 views

### Controlling a system with PID that resists backdrive

I'm controlling the angular position of a pendulum using a DC motor with a worm gearbox. Mechanically, worm gears are impossible to backdrive. Using a PID controller on a pendulum system with a ...
2answers
98 views

### Velocity Control via Vibration

I am working on a robot that has an accelerometer. This accelerometer measures the vibration of the robot. When the robot hits a certain vibration, I would like it to slow down in order to reduce the ...
4answers
9k views

### How to use quaternions to feed a PID quadcopter stabilization loop?

I'm making a quadcopter. I have set up a PID loop to stabilize it to a given Euler angle (pitch and roll). The problem arises when the roll approaches 90 degrees (45 degrees and up). The values don't ...
1answer
293 views

### PWM PID control for small 2 watts brushed DC motor

It is "good enough" for PID output directly controls, without further modelling, the PWM duty cycle? Logic behind the question is, In case of pure resistance heater, PWM duty cycle percentage ...
3answers
106 views

### Are there any problems with a variable frequency PID?

I am working on a quadrotor and am trying to solve the problems described here. In attempts to bring the refresh rate to 100 Hz, I did an analysis of the functions and most of the time 35+ ms is ...