Robotics Stack Exchange
Robotics Stack Exchange

Questions tagged [pid]

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

Questions about using an existing PID implementation connected to a device.

Possible topics include:

  • "loop tuning" -- ways of tuning and tweaking the Kp, Kd, Ki "constants", and the horrible things that go wrong when they aren't tuned right
  • how to deal with the fact that a PID for the elbow motor tuned perfectly when the shoulder is "down" isn't so perfect when the shoulder is "horizontal" or "up", or when the hand is empty vs. when the hand is holding a bowling ball, and ways to compensate.

Questions about implementing a PID controller itself are best asked on Electrical Engineering Stack Exchange.

380 questions
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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 motor that controls the roll in fixed steps and check the …
RoboMan
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understanding the PID controller

I am trying to understand the effects of P, I and D constants in a PID controller on a system. As far I've understood, P and I make the system 'faster', and D makes it 'slower'(which I read in books), but I don't actually understand what makes it go…
Control
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Can I use Ziegler-Nichols's rules to find PID parameters for a non linear system

I'm trying to use a PID to stabilize a system described from the following difference equation: $$y_{k+1} = a y_k \sqrt{(1-y_k)}~~~ + b y_{k-1} ~+ c u_k$$ Can I use Ziegler-Nichols's rules to find PID parameters in this situation? To be more…
Edge7
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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 being taken by the RC receiver input function. To…
asheeshr
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PID output does not reach setpoint precisely enough

I'm developing/tuning a software PID for a quadcopter. For now I'm only trying to stabilise the pitch angle using the front and back motors, and I'm only looking at Kp. The motors have a control resolution: input variations need to reach a…
marcv81
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PID with position and velocity goal?

I'm trying to design a control system for a robot that tracks moving object. Thus I want to robot to match the position and velocity state of the object. I don't want robot to simply to arrive at the position, but I want to arrive at the position…
fairuse
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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 regular DC motor (no worm gear), the integrator would…
Dan Laks
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How to control PID Yaw

My yaw angle varies from -180 degree to 180 degree. -170 170 -135 135 -90 90 …
Earthgod
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PID tuning to make my balancing robot better

See the video below of my balancing robot. Balancing robot I was having trouble getting it to balance on hard surfaces but finally got it after playing with the PID gains a lot. Previously it was balancing just fine on carpet. I set the PID gains…
JDD
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sum_error in PID controller

I'm trying to implement a PID controller by myself and I've a question about the sum_error in I control. Here is a short code based on the PID theory. void pid() { error = target - current; pTerm = Kp * error; sum_error = sum_error + error *…
Kevin Kuei
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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 system, which is a force f. Now, if I'm correct it…
Wilhelm
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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 following some rule of thumb. But what about a…
FELIPE_RIBAS
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Which controller to use for custom servo?

I am trying to build a microcontroller based higher payload version of a servo motor using geared induction motor with VFD as a control device. For this purpose I have selected a 1HP motor running at 1800RPM which is geared down to 30RPM. The…
Supreeth
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Choosing a proper sampling time for a PID controller

I have a robotic system I'm controlling with Arduino, is there an heuristic way to determine a proper sampling time for my PID controller? Considering I have some other things to compute on my sketch that require time, but of course a good sampling…
Gian Mauro Musso
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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!
Earthgod
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