Questions tagged [pid]

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

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8 views

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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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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52 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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52 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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21 views

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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47 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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66 views

How can I improve DC Motors rise time?

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79 views

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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58 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
186 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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42 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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51 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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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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48 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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42 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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116 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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57 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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49 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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78 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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41 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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171 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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50 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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68 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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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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190 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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24 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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35 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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59 views

Tuning a cascaded attitude and attitude rate PID controller

Assume that I have an object in 3D, and I want to have a controller that stabilizes its orientation (also referred to as "attitude"). To be sure we are clear: attitude is measured in "degrees" or "...
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37 views

Good Software Projects for Aspiring Engineers [closed]

With the pandemic going on, our school has decided to officially shutdown all sponsored club meetings. Now that we are all digital, our robotics club was looking for projects that students can do at ...
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72 views

How do “process gain” and “proportional gain” affect the Steady State Error in a PID Controlled machine?

I came across this doubt while reading the Wikipedia page on PID Control. The section on Steady-state error states: Steady-state error (SSE) is proportional to the process gain and inversely ...
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149 views

Motor acceleration and position with PID control

I'm working on a robot with differential drive (2 drive wheels equipped with rotary encoders and 4 free spinning omni wheels for stability) and each wheel is controlled via a separate arduino nano. I ...
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55 views

PD controller tuning for flexible joint robotic arm

I am trying to tune the gains of my PD controller for a single axis flexible joint robot. The controller output is the motor torque. My question is: how can i tune the PD gains if the output (torque) ...
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68 views

How to determine actuator and process for PID, and how to intepret the output

Imagine there is a web service (let's say Twitter) that handles tons of requests from around the world. I want to figure out how to let the web service pick a certain amount of (let's say 1 billion) ...
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390 views

Implementation of Velocity Control Algorithm Based on PID

I'm very familiar with the traditional position form of PID. The error is just the difference between some setpoint encoder value and the current encoder value. Although this suffices for basic ...
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70 views

How to create a 4 sensor PID wall follower

I need help creating a 4 sensor PID wall follower, which has two walls either side of the robot and the goal is to keep the robot central and not crash into the walls, the sensors are positioned in ...
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207 views

Why am I unable to tune the PID parameters on my quadcopter?

I am building a nano quadcopter in X-Configuration with coreless DC motors, 65mm 2 blade propellers and a 1S Lipo battery (860mAh, 25C). The weight of the assembly is around 70g in total. I am ...
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54 views

How to make a diff robot (2 traction wheels front and 2 castor wheels back) to go straight?

I’m developing a differential robot. My wheeled robot has two castor wheels in the back and two driven wheels in the front. The motor controller I’m using can handle two motors each with 90 cpr. Each ...
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56 views

Is it possible to make a self balancing robot using small or medium scale integrated circuits?

Almost all the information I've seen about self-balancing robots implies the use of an Arduino to implement the control. I'm wondering if it is possible to implement the control using just small or ...
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130 views

Inverted pendulum controller

I had an exam yesterday, and I was asked the following question: Why PID controller is necessary for stabilizing the inverted pendulum on a cart, why not we just use PI or PD? Now I've seen some ...
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111 views

Compensator design

I got a plant $G(s)=\left(0.13s+1\right)/s^2$ to design a compensator which provides below demands: Settling time : max 2s Overshoot : max %35 Gain margin : min 10 dB Phase margin : min 30 deg ...
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461 views

How to control the velocity of a mobile robot?

I have a differential drive robot whose linear velocity and angular velocity is to be controlled. The current strategy for doing that is: A high level path tracking module spits out the reference ...
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159 views

IR sensor spacing in sensor array relative to line width

I'm trying to build a line follower bot that follows a 3cm wide black line. I have a line sensor array with 6 analog sensors spaced 1cm apart. This means that in an ideal situation, i.e bot going ...
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38 views

effect of three terms of PID controller on output response? [duplicate]

What is the effect of each of the three terms on output response of a pid controller? i mean how will P term shape/effect the output response similarly what is the effect of I and D terms on output ...
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71 views

Confused about I and D in PID controller?

I am trying to learn PID controllers from basics and i came to know that "P" term looks for current error "I"term looks for past error "D"term looks for future error I have some how understood "P" ...
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46 views

Fuzzy logic controller for controlling a four-bar linkage

I am trying to design a control system to move a joint of four bar linkage according to desired trajectory. A dc-motor is used to move the joint. Can fuzzy logic controller be used to solve this ...
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63 views

Sampling time selection

I'm trying to design a compensator for a pendulum type plant with arduino mega. As you can see from the picture, the system bandwidth is 9 rad/sec. I calculated the sampling time as ws=10*wb=90, so, ...
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153 views

PID tuning - can't get stiffness without going unstable

I'm trying to tune a low-friction actuator. This actuator is controlled via a 24peak amp drive. I'm running into the problem where the system goes unstable prior to reaching good stiffness. I start ...

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