Questions tagged [pid]

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

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Differential Drive Control Techniques

I have a mobile robot that has a differential drive technique. I try to control the robot with PID controller. Is the best way for controlling differential drive robots? If I want to compare different ...
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Servo motor control algorithm with potentiometer feedback

I am making a big servo motor, which should work exactly like those small SG90 servos. I receive position from it and I can control it through it's torque. But problem is - I cannot use simple ...
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control of a rod attached to a motor

I have a 76 cm, aluminum rod, attached to the shaft of a 12v DC banebot motor. The rod is hanging vertically initially, and rotates in the vertical plane. The task is to control the rod to make it ...
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33 views

How to avoid oscillations caused by backlash in position control?

I am working with a ball screw mechanism driven by a brushless dc motor with an encoder mounted on the load side. We are using a PID position controller with tuning settings by optimization however ...
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24 views

Center line steering with differential drive

I’ve got 2 motors that drives my unit and I can easily steer it manually by simply adding more speed to one wheel vs the other. Now I’m automating the rover using image processing to follow a driveway....
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Detailed resources for control of linear actuators including backlash/friction compansation and controller design?

I am working on a project where I would like to control a linear actuator with a ball screw mechanism. I feel I need a reference book for position/servo control systems for dc motors as there are many ...
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The math behind minimum controller sample rate compared to actual error frequency spectrum

It seems intuitive to me that, in a digital system, a system sampling the error rate "too slowly" will fail to stabilize the system. Is there a theory/set of metrics/equation I can use to ...
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Strategies for tuning with low sample rate

I’m designing an arduino robot that’s objective is to find and drive towards a light using a photo resistor mounted on a servo. I want to write my program with PID control to sweep the photo-resistor ...
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116 views

How do I find the transfer function for my quadcopter altitude system?

This is not so much of a how but if I am right so far. I am looking at the z-axis now only. The linearized equation of motion for the thrust in the z-direction is: $$ T=m\cdot \ddot{z}+mg, $$ where $m$...
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Outer Position Loop to Control Inner Velocity Loop

I'm trying to control the position of a brushless DC gearmotor. To drive the motor, I have a controller box that provides a velocity that is proportional to a 0 to 5 V input. The motor has it's own ...
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PID control for robotic manipulator servoing

I'm trying to enable robotic manipulator servoing using MoveIt servo implementation. However, I'm having some questions regarding reference following and error compensation. The thing is, I roughly ...
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204 views

Self balancing bike using a flywheel: ROS implementation

I have a bike with two stands and a flywheel like this: The stands can be adjusted so that they don't touch the ground. Now, the task is to implement a self balancing mechanism: when I run the script,...
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67 views

Implementing PID on a line following bot using turtlebot

I am using ROS melodic,turtlebot 2 on Ubuntu 18.04. The idea is to create an environment consisting of lines as a path (slightly curved), and to program the turtlebot to follow the lines. Basically, a ...
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57 views

Mapping Joystick Inputs to Quadcopter

hope you are all doing well. We are doing a project where a quadcopter is controlled by an ordinary joystick. We have constructed the Control Algorithm and the joystick to move the quadcopter in ...
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50 views

Bug in code of Self-Balancing Bot

I am making a Self balancing bot as my project in which I am using MPU6050, Arduino Uno, motor driver l298n and DC motors. I am making this using data from accelerometer and gyroscope and combining ...
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PI controller for skew angle on a train wagon like robot

I have a robot very similar to a train wagon, it has 4 actuated wheels controlled by 2 motors. The two wheels that are located on the same rail are controlled by the same motor. On each wheel it's ...
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40 views

Identifying active PID-Controller parameters

A metric of a physical system is being controlled by a PID controller (in this case a valve controls the temperature of a liquid by mixing hot liquid into a stream of cold liquid). All measurement ...
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32 views

Rotate a certain angle using PID and mpu6050

Currently I'm working with a 4 wheel robot and I'm trying to rotate a certain amount of angle. I used PID_V1 library to rotate this. But when I upload and test the code Robot rotate continously. ...
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61 views

How to design a PID controller for boat?

I have a boat with two trusters and a trajectory planner which is based on the bicycle model. In order to control the boat, the linear velocity of each truster has to be provided. The following ...
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65 views

Robots Following Robots with Safety Distance Planning and Coordination

I have two robots, I wish for the second robot to follow the first one while keeping a constant distance d_safe between them. I am trying to implement a PID ...
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Find viscous friction for DC motor transfer function

How do I find the viscous friction for my DC motor without measuring the input current and output torque. I have to do a theoretical model on simulink and can't find any answers on how to find it
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How to implement PID position control for 4wheel mecanum robot?

I want to implement PID control on my 4 wheel mecanun robot. I want to give a position instruction to my robot and that it follow the following curves of velocity and position. The only feedback that ...
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73 views

Inner current controller benefits

I am currently working on a system with a BLDC motor attached to a non linear spring on which a user can apply a force. Meaning the torque applied on the motor's output is most of the time unknown. ...
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1answer
70 views

How to choose closest angle when crossing -180 degrees

I'm applying a PID for position control on a diff drive robot, got the angles (orientation )between -pi and pi. It works fine until it needs to change its orientation from (let's say) -170 degrees to ...
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139 views

PID controller for motor speed control and distance control

I am building a robot rover comprised of dual DC motors each with hall sensors to obtain rotaional speed. I currently have a PID controller for each DC motor that is able to control the speed of the ...
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How to prove the stability of trajectory tracking with PD control using Lyapunov method?

I'm having a problem to prove the stability of PD control in trajectory tracking. Let say we have a system with double integrator dynamics and we what to minimalize the tracking error $\tilde{x} $. ...
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50 views

Quadcopter descends when rolled or pitched

I'm currently working on a quadcopter using f450 frame and YMF32 code. I was able to successfully build the quadcopter and It flies without having any vibrations or wobbles. Also, I tuned the PID ...
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122 views

How can I improve DC Motors rise time?

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PID Control: Is adding a delay before the next loop a good idea?

I am implementing PID control in c++ to make a differential drive robot turn an accurate number of degrees, but I am having many issues. Exiting control loop early due to fast loop runtime If the ...
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72 views

Can I measure torque from this motor by only measuring the current?

I am new to robotics, please forgive/correct any errors. My Project Plan I want to use a PID controlled motor in a human-interface device where I need to measure the user's exerted force on an end ...
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1answer
708 views

PID controller that targets a set rotation and a set velocity at that rotation?

I have a 3d physics simulation where I use a PID controller to reach a set orientation (orientation error drives a torque output). Which works well enough some cases, but in others it's not working ...
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65 views

pid tuning the wheel velocity

I am using diff drive controller to control the wheels of my robot. Here i am trying to use the control toolbox pid class for making the input velocity and velocity measured from wheel encoder to be ...
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66 views

High derivative gain in PD control

Why does high derivative gain in PD control results in motor noise or chatter? The graph that I see on MATLAB simulation is smooth enough, so following that it should not make noise..
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40 views

What is the difference between The state-space equation and The configuration-space equation

The craig(p.180) states that equations can be made to represent the dynamic equations. The first one being the state space equation. $\tau=M(\Theta)\cdot\ddot{\Theta} + V(\Theta,\dot{\Theta}) + G(\...
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Reliably enabling/disabling a PID loop via FSM in a microcontroller

I have a PID loop for a small vehicle implemented in a microcontroller. Currently the PID loop is implemented in a timer interrupt. I want to implement an FSM that will have states that enable or ...
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133 views

Motion profile and Motion control scheme, how do they interact?

I'm studying motion control and I start with the simplest case, I have to go from A to B in a straight line using a trapezoidal motion profile. I understand that in a real case, due to the fact that ...
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125 views

To calculate roll,pitch and yaw

How do I calculate roll,pitch and yaw value from the position co ordinates of the drone, that is x,y and z from the gps sensor??? Using the x,y and z co ordinates I have to calculate roll,pitch and ...
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38 views

How to compensate for back drive caused by gravity

I have a 24v DC motor with a planetary gear box, Hbridge, and encoder feedback that drives an arduino robot similar to a winch that moves a weight by spooling a strap up and down. The problem I am ...
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203 views

Quadcopter PID Controller for distance

I am trying to use a PID controller to stop a quadcopter at a specific location while travelling horizontally, however currently it overshoots/undershoots depending on the max velocity. I have tried ...
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63 views

Res-Scaling method beats PID controller. How?

Scenario: I have a robotic arm that has a (1D) lidar on its end, to orient itself with respect to the slant table in front of it. The lidar returns pretty accurate distance values in mm. The motor ...
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80 views

Imaginary part in result of inverse laplace transform

I am working with a system(closed-loop feedback control) that has a transfer function like this F = 20*(s+5)/(s^4+13.5s^3+41s^2+80*s+100) this one is in the s-domain but for the response analysis, I ...
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95 views

Finding the right PD values for a quadcopter simulator

I am working on this short assignment where I have to find the right PD values for a simulated quadcopter. I have to reach 0.9 meters under 1 second with an overshoot of less than 5%. This is my ...
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55 views

PID on DC motor turning on both directions

I have a skid steer robot where I have four individual DC motors with an H bridge so I can control speed and direction. There are also four quadrature encoders with 6000 ticks per revolution. The ...
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333 views

PID control brushed motors via PWM using Encoder Clicks at SetPoints/Measurements

I've read numerous posts (1 , 2, 3 ) about using PID to control motors. All examples I've seen deal with the control signal being in the same units as the measurement signal. For example, use PID to ...
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66 views

Feed both position and speed errors to one single PID

I have seen in the documentation of an old subcontractor's product that the controller of a robotic arm joint was basically feeding error position + error rate directly into one single PID. It feels ...
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149 views

Finding the PID values for a vehicle control system

I'm trying to design a PID system for the longitudinal control of an autonomous vehicle. I figured out about most of it but I'm trying to figure out the Kp, Ki and Kd values. This is an illustration ...
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1answer
57 views

PID controller issue

Recently I've successfully implemented PID controller for my robot's moving motors. Now the system can automatically adjust it's speed depending on different situations: increase it if something ...
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1answer
395 views

How to PID tune a four wheel robot?

Four wheel mecanum rover with a mass of approximately 50 Kg. Each wheel has a 20:1 gearbox with encoder at the wheel (rather than the motor). If this was something like a robot arm I would PID tune ...
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30 views

Can badly tuned Feedforward still decrease steady-state error?

Let's say we're trying to control the speed of a motor to 20 revs/sec, and we know that our controller output for that speed is approximately 5. We currently have a Proportional controller to drive ...
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52 views

Using Integral gain for motor positioning

I'm struggling to see how Integral gain is used for motor positioning (with an encoder on the shaft). Suppose we have an AC motor connected to a winch which drives an object forwards and backwards. ...

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