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12 votes

How do the PID parameters (Kp, Ki, and Kd) affect the heading of a differential driving robot when they are increased individually?

Proportional term: this controls how quickly to turn the steering when the heading is not at the set value. A low P will lead to sluggish steering, reacting only slowly to set heading changes. It may ...
Andy's user avatar
  • 1,051
11 votes
Accepted

Quadcopter PID Algorithm

The glaring issue I see at the moment is that you are forcing polarity on the I and D terms. In general, you are using a lot of sign checks, sign assignments, and conditional programming. None of that ...
Chuck's user avatar
  • 16k
10 votes
Accepted

How can we use the accelerometer for altitude estimation?

The barometer carried on the pixhawk has an altitude resolution of 10 cm. If that isn't enough, you could write a kalman filter that uses the accelerometer data in the prediction step and the ...
holmeski's user avatar
  • 1,853
9 votes
Accepted

How to tune the PID parameters using Fuzzy Logic?

The paper Controlling of Quadrotor UAV Using a Fuzzy System for Tuning the PID Gains in Hovering Mode by E. Abbasi, M. J. Mahjoob explains how to tune PID gains with fuzzy logic. You can find many ...
acs's user avatar
  • 1,124
7 votes

Do I need to use separate function in PID algorithm to make the bot go LEFT or RIGHT?

No, but you do need to calculate the P/I/D terms correctly. You have: I = I + previous_I; followed by: previous_I = I; ...
Chuck's user avatar
  • 16k
7 votes
Accepted

PID control: zero out integral on error sign change?

Generally, in a well-tuned PID, most of the job is done by the P term, which is responsible for driving PV to SP. Then, D and I serve as corrections: the D term regulates the profile as of how we ...
Ugo Pattacini's user avatar
6 votes

PID with position and velocity goal?

In the case of MIMO systems (Multi-Input, Multi-Ouput), my warm suggestion is to go with State Space Control, which will give you enough freedom to move the closed-loop poles and thus achieve your ...
Ugo Pattacini's user avatar
6 votes
Accepted

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

Find here a similar question. A well-tuned position PID is most of the time capable of accomplishing the task of reaching a target with zero velocity. The central point here is that you shall provide ...
Ugo Pattacini's user avatar
5 votes
Accepted

What's wrong in controlling Roll+Roll rate in a quad-copter instead of using 2 separate loops for each?

That only works when the desire roll angle is 0. What happens if you are trying to turn and have a desired roll angle of 1deg? Even changing your sum to match the angle error, $w_1 (\theta - \theta_d) ...
ryan0270's user avatar
  • 2,814
5 votes
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Meaning of a negative step response with quaternion

Welcome to Robotics, PaoloH! This is a fantastic question for Robotics - It has some Matlab/Simulink, some control theory, some spatial (quaternion) representations, etc. Robotics is the place to come ...
Chuck's user avatar
  • 16k
5 votes

Which controller (PI or PD) is generally more robust to noisy sensor measurements and why?

Proportional control amplifies equally across all frequencies. Integral action amplifies low frequencies more, and high frequencies less (in fact, its gain at DC is infinite, and at infinite frequency ...
TimWescott's user avatar
  • 1,891
5 votes
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Inverted pendulum controller

Without going into the details of the underlying equations of motion, I could argue that the D part is needed to damp out the oscillations of the pole while reaching for the (unstable) equilibrium ...
Ugo Pattacini's user avatar
5 votes

How to control a 4 wheel mechanum wheel robot with PID?

Let's consider first the task you are wanting to accomplish: following some sort of Cartesian space trajectory. So, you are wanting to make sure your robot is only moving in the x-direction. However, ...
domo_arigato's user avatar
4 votes

Fixed Wing UAV: Do inherently unstable systems desire to be stable for all cases when a closed loop control is implemented on them?

Not all fixed wing aircraft are inherently instable. That feature greatly depends on the center pressure and gravity center designed position. Passenger aircrafts are quite stable, and fight planes ...
galtor's user avatar
  • 470
4 votes
Accepted

Quadrocopter PID

Technically, you can do it either way, but consider the following scenario: You are flying with a heavy load, and there is a wind gust. Each rotor is operating at almost 100% capacity due to the heavy ...
Chuck's user avatar
  • 16k
4 votes

PID with position and velocity goal?

If in fact you need the robot to be at the same speed as the tracked object at the time it arrives with it, you might need to employ more sophisticated methods. However, a controller that is the ...
Bryan's user avatar
  • 41
4 votes

PID with position and velocity goal?

In many cases, a single traditional PID controller is adequate to track an object and match both position and velocity of the object. With the error term of the PID in terms of position, the integral ...
David Cary's user avatar
  • 4,545
4 votes

Balance Bot PID tuning

Just a hint from my extensive experience from self balancing robots: The most important aspect of a self balancing robot, is the actuator acceleration (torque) control. (...) the motors start ...
vmatos's user avatar
  • 71
4 votes
Accepted

PID Controller Output Mapping for Motor Speed Control

Convert your PWM units to belt velocity units, or vice-versa. The quick and dirty way of doing this is to multiply your P, I, and D terms by $16,393 \over 0.5$. The PWM-to-belt velocity mapping won'...
SteveO's user avatar
  • 4,396
4 votes

What is the best adaptive controller for robotic arms?

The given strategies can be divided into two groups: model-based and model-free control. The AMPC and MARC suggestions are model-based the other are model-free. Theoretically, a pid controller can be ...
Manuel Rodriguez's user avatar
4 votes
Accepted

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

These two concepts are complementary and you use them together, the motion profile providing the input to your control scheme. At each time-step the motion profile gives you the reference values for ...
50k4's user avatar
  • 6,682
4 votes

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

Don't disengage your controller. The purpose of a controller is not only to steer your system to the desired setpoint according to a predetermined dynamical response but also to counteract potential ...
Ugo Pattacini's user avatar
4 votes

Inner current controller benefits

What would be the benefits of implementing this full nested control architecture for the control compared to my current implementation Textbooks are always a great source of information! Reference: &...
Ugo Pattacini's user avatar
4 votes

Impact of using PID Output as a Change (Delta) vs Absolute

All PID controllers are relative in the sense that they act on a reference error, which is the difference between the reference signal and the sensed signal. Assuming the integral error starts at the ...
Chuck's user avatar
  • 16k
4 votes

Does PID controller work on every actuator

does the PID controller work on every actuator? The short answer to this is yes. PID controllers are used to stabilise a plant/system. They are heavily used in ...
WittyDimension's user avatar
3 votes

Why do I need I-gain in my outer-loop?

Integral gain is how you eliminate steady state error. An integral gain in the inner loop means you'll (eventually) have no steady state error on the angular velocity. What ensures no steady state ...
Chuck's user avatar
  • 16k
3 votes
Accepted

Why do I need I-gain in my outer-loop?

In my own experience, it is not necessary Integral term in any of these loops. I got a fine PD tuning of both inner and outer loop. See for instance this paper, where I firstly tuned PD only with PSO. ...
galtor's user avatar
  • 470
3 votes

Can we simulate a actuator with a very strong torque with a PID controller

What you're asking for cannot be accomplished with a PID controller. As I understand your question, you want to be able to choose PID gains that would always produce a "good" trajectory, ...
BarbalatsDilemma's user avatar
3 votes
Accepted

How to create a model for temperature control?

Generally you would only develop a model if (as in your case), you have something that you want to control. In that case, you should start by: List the outputs that you want to control. List the ...
Chuck's user avatar
  • 16k
3 votes
Accepted

PID tuning with (Deep) Reinforcement Learning

I read a bit more and realized that in RL states and rewards accept a wide variety of interpretations and this is the real complexity nowadays of this learning problem. In case of PID values, problem ...
galtor's user avatar
  • 470

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