Questions tagged [pid]

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

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4answers
4k views

How frequently should a PID controller update?

I am developing a quadcopter platform on which will be extended over the next year. The project can be found on Github. Currently, we are using an Arduino Uno R3 as the flight management module. At ...
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2answers
12k views

Quadcopter PID output

I'm trying to develop a control system to a quadcopter and one of my options is to use a PID controller (which I think is the most used method). From what I've read, the commom strategy is to run a ...
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1answer
3k views

PID tuning method based on Pole placement

Is it possible to determine PID parameter using pole placement. I mean by solving the ch. eq. of close loop transfer functions which consists of either P,PI,PD or PID controllers?? Because i've ...
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1answer
116 views

What does this “inverse” peak mean? (step function)

I identified my system and now I am trying to tune PI regulator since I think I do not need D. I came across this graph while Matlabing and I do not know what does it mean. I am using pidtune() to ...
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1answer
809 views

Quad copter attitude control

I have built a quad copter completely from scratch (electronics, mechanics and software). I am now at the point where all my sensor data looks correct and when I tilt the quad copter the correct ...
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5answers
6k views

Why does a ID controller not exist?

Why doesn't a PID only consisting of ID exist?
7
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1answer
1k views

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),...
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1answer
99 views

How do i use the Nicolas ziegel approach if my system never becomes unstable?

How do i use the Nicolas Ziegel approach when the root locus plot of my system never becomes marginally stable , for any gain (unless it is negative).. ?? How do i estimate my ultimate gain value????
3
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1answer
651 views

Effect of adding a Pole and Zero to PID

I am confused about how adding a D (which adds a zero to the complete system) decreases the speed of the system. But when we normally add a zero to the system, it causes the system to overshoot. The ...
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2answers
2k views

Differential Drive Robot Control

Edited: I have a differential drive robot that needs to drive down a hall and stay in the center. I have 4 ultra sonic sensors, 2 on each side. Currently, I thought of implementing pure pursuit and ...
5
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2answers
241 views

What kind of motor control can I implement if I cannot use an Encoder?

Every time I see a PID control for a motor, it involves an Encoder, so the algorithm knows the real position of the motor or wheel. But with the robot I have, I cannot use an encoder. I only have ONE ...
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3answers
641 views

Differential Drive Robot on uneven surfaces

So I am building a differential drive robot and I want it to autonomously drive in a straight line on an uneven surface. I know I need a position and velocity PID. As of now, I am deciding on which ...
6
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4answers
5k views

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 ...
5
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1answer
5k views

Quadcopter Throttle and PID mixing to Motor Speed

I've been writing some quad copter software and I am not sure what the best way is to map the throttle and PID inputs to ESC power. My throttle range is 0-1 and my PID outputs are 0-1. My ESC's have ...
5
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4answers
6k views

differential drive PID controller

I have a differential drive robot that works fine (good PD parameters) driving at say 1 m/s. Now, if it speeds up (to 1.2 m/s) it starts wobbling again. What would be a good strategy for a controller ...
7
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1answer
1k views

Differential drive trajectory following control

I have a robot platform with differential drive which knows it's position and orientation. Lets say that the space through which the robot moves is known and it has only static obstacles. The task is ...
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2answers
2k views

PID control against sine wave error

I'm writing a PID to control a toy car that follows a black line on a circuit. I've tuned my PID and it works at high speed for all the circuit except the winding section. For that, the error signal ...
13
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3answers
19k views

Quadcopter PID tuning

In continuation of the question I asked here: Quadcopter instability with simple takeoff in autonomous mode ...I'd like to ask a few questions about implementing a basic PID for a quadrotor ...
7
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2answers
4k views

How to know the desired orientation of a quadcopter?

I am trying to simulate a quadcopter model on Simulink. I want to implement a PID controller for each of X,Y,Z and phi,theta, psi angles. PID gets the error, as input, which is to be minimized. For ...
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5answers
7k views

Quadcopter instability with simple takeoff in autonomous mode

I'm trying to get a quad rotor to fly. The on board controller is an Ardupilot Mega 2.6, being programmed by Arduino 1.0.5. I'm trying to fly it in simple autonomous mode, no Radio controller ...
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3answers
2k views

Pre-built PID motor controller [closed]

I lead a university robotics team that needs PID controllers for four drive motors and two additional motors that are used in a secondary system. I would strongly prefer to buy pre-built PID ...
6
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1answer
241 views

Field oriented control of brushless motors

If I was controlling a normal brushed motor as a servo, I would measure the motor's position, and adjust the PWM signal to control the voltage. This way I could achieve a precise velocity/position ...
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2answers
4k views

How to control the position of a pneumatic piston?

How can I control the position of a pneumatic piston? The only way I know about is using a magnetic reed switch (magnetic sensor) with a matching piston and use some type of control algorithm, like ...
13
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2answers
10k views

Approach to using PID to get a differential robot driving straight

Consider a differential drive robot that has two motorized wheels with an encoder attached to each for feedback. Supposed there is a function for each DC motor that takes a float from -1 to 1 and sets ...
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2answers
3k views

Help with PID “units” in a quadcopter control system

I'm in the process of writing my own simple quadcopter controller for experimental use, and I'm having trouble getting my head around how to convert from the degrees which my PID controller demands to ...
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2answers
6k views

Line Follower optimization

I'm working on building a line follower robot and want to optimize its performance. It was suggested that I use a PID algorithm. I read a lot about PID but am confused a bit regarding following: I've ...
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2answers
350 views

PID Conundrums for Legged Robots

I am currently working on a legged hexapod which moves around using a tripod gait. I have two sets of code to control the tripod. Set 1: Time based control In this code set, I set the tripod motor ...
7
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1answer
686 views

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 ...
6
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1answer
825 views

Quadrotor control using ArduIMU

We are using ArduIMU (V3) as our Quadrotor's inertial measurement unit. (we have a separate board to control all motors, not with ArduIMU itself). As mentioned here , the output rate of this module ...
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4answers
20k views

How can I use the Arduino PID library to drive a robot in a straight line?

I would like to create an Arduino based robot with 2 wheels, quadrature encoders on each wheel, a H-bridge driver chip (or motor controller) and a caster. I want to use the PID library to ensure the ...
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0answers
217 views

PID tuning to make my balancing robot better [duplicate]

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 ...
9
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3answers
394 views

What is the actual physical actuated quantity when controlling the position of a servo?

I'm trying to learn about servo control. I have seen that the most generic position control method for servos is PID, where the control input is position error. However, I am not sure about what is ...
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3answers
5k views

How is PIV control performed?

I'm considering experimenting with PIV control instead of PID control. Contrary to PID, PIV control has very little explanation on the internet and literature. There is almost a single source of ...
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3answers
9k views

I don't understand Integral part of PID controller

I dont understand integral part of PID controller. Let's assume this pseudocode from Wikipedia: ...
11
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3answers
8k views

In PID control, what do the poles and zeros represent?

Whenever I read a text about control (e.g. PID control) it often mentions 'poles' and 'zeros'. What do they mean by that? What physical state does a pole or a zero describe?
15
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3answers
5k views

How can I automatically adjust PID parameters on the fly?

I have a simple servo system that uses a PID controller implemented in an MCU to perform the feedback. However, the properties of the system change dynamically, and so the PID parameters can never be ...
2
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1answer
500 views

Suitable control algorithm for Air Muscle based joint?

I have a joint actuated by an antagonistic pair of Pneumatic Muscles. There are two valves per muscle, one to fill and one to empty each muscle. The joint has an angle sensor, and each muscle also ...
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9answers
285k views

What are good strategies for tuning PID loops?

Tuning controller gains can be difficult, what general strategies work well to get a stable system that converges to the right solution?

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