Questions tagged [pid-control]
The pid-control tag has no usage guidance.
162
questions
7
votes
2
answers
3k
views
Writing a filtered derivative term of the PID controller into the C++ code
Everywhere I look, be it a PID, lead, lag control or anything else, there are Simulink schematics with transfer functions. This is all nice for system response simulation, however currently I have to ...
- 81
5
votes
1
answer
167
views
When are overshooting controllers preferred over asymptotic ones?
Disclaimer
Designing the behavior of controllers is an important task for many applications. Every application needs its own requirements fulfilled. For example a CNC machine needs a controller with ...
- 165
5
votes
4
answers
4k
views
Why can't proportional gain alone, reduce the error to zero?
I was told that the proportional gain alone cannot the drive the error signal to zero in a feedback loop. Why is that? If there is a tiny error, there will be a tiny or larger (depending on the number ...
- 521
5
votes
2
answers
5k
views
what is a quarter wave decay response after Ziegler–Nichols tuning?
Ziegler–Nichols tuning creates a "quarter wave decay". What does that mean? I cannot find anything online!
- 521
5
votes
1
answer
133
views
Square shaped position error
I got a position error measured by a linear encoder like in the picture below.
Could anyone explain some possible reasons for this kind of shape to occur in control theory?
My system looks like ...
- 354
5
votes
1
answer
351
views
PI-Controler: Comparison of characteristic equations
I have to design a PI-controller with zero order hold for the plant
$G_s(s) = \frac{0.24}{(s+4)(s+12)}$ to meet the specifications of $\omega_n=5\,s^{-1}$ and $\zeta = 0.6$.
I choose a $T=0.12\,s$ ...
- 61
4
votes
1
answer
96
views
What's a control system architecture that can track a ramping reference signal?
It's well-known that a control system with integral control can track a constant reference signal (command) with zero steady-state error.
What is needed to generate a controller that can track a ...
- 271
4
votes
2
answers
649
views
Finding coefficients for a PID controller that minimize the integral of the squared error (ISE)
The problem
The problem is to find the coefficients for the P, I and D terms of a PID controller used to regulate the object that minimize the the integral of the squared error (ISE):
$$Q = \int_0^\...
- 49
4
votes
1
answer
4k
views
How to design a PID controller for MIMO systems in which there are more outputs than inputs?
How do you design a PID controller for MIMO systems in which the outputs outnumber the inputs?
It's typical to design a PID controller for MIMO industrial process with the same number of inputs and ...
- 68
4
votes
1
answer
286
views
what's wrong with this robust control scheme?
I'm learning how to control a double integrator with $H_\infty$.
my model is simply
$$\begin{gather}
\dot{r} = v \\
\dot{v} = F/m \\
r(t_0) = 0\text{ m}, $v(t_0) = 0\text{ m/s}, m = 1000\text{ kg}
\...
- 183
3
votes
1
answer
1k
views
Advantage of anti-windup
What is the definition of anti-windup? How does it impose the constraints?
What are the advantages of MPC and anti-windup over each other?
Does anti-windup guarantee the constraints or does it just ...
- 115
3
votes
2
answers
755
views
How do I interpret the following Bode, Nyquist and Nichols diagrams?
I am working with an arbitrarily complicated and long-winded transfer function that looks something like this:
$$
H(s) = \frac{as^4+\cdots+b}{cs^6+\cdots+ds^2}
$$
where letters represent constants. ...
- 75
3
votes
3
answers
8k
views
Best PID autotuning algorithm/library for simple heater problem
It's the 21st century, anything is possible. Except for PID autotuning for a simple problem, heating/cooling system - make robust and ready to use solution. I've found only one library for PID ...
- 141
3
votes
2
answers
168
views
Controlling temperature using PIDs on two separate controllers
I have a pellet smoker, and I am customizing it for tighter temperature control. Currently, I am controlling how much material is burning to control temperature using a PID loop. I want to achieve ...
- 33
3
votes
2
answers
758
views
Limiting the integral to a time window in PID controller
Would it make sense to integrate e(t) from t - c to t instead of 0 to t for the integral part of the PID controller?
What are the most common deviation from classic PID controller definition?
- 131
3
votes
3
answers
8k
views
Can a PID controller have a simple on/off output?
The crux of a PID controller is:-
output = Kp * error + Ki * integral + Kd * derivative
So typically there is proportionality and a continuously varying (analogue) output. In the case of a simple ...
- 916
3
votes
1
answer
80
views
Are all motors controlled with G-Code?
So I have laser cutter. And I am thinking about buying a control unit (this one, to be exact).
But my concern here is the following: If the input DXF file contains splines, they will be converted to ...
- 133
3
votes
1
answer
165
views
Does this PID-like algorithm make any sense for a solar inverter?
The application
I want to implement the control of a photovoltaic inverter. The goal would be to keep the consumption of a microgrid (the power absorbed from the grid) to a constant value.
Notes:
I ...
- 81
3
votes
1
answer
2k
views
Controls Project: Help needed finding 3rd order system
I'm in need of help finding a third-order or higher system in which I can derive a transfer function. We have a class project in which we need to find a real-life example of the system that equates to ...
- 31
3
votes
1
answer
135
views
Differential Equation for: Locking a laser's frequency with a PI controller
I think I have a good understanding of differential equations, so I would like to first try to understand my system in terms of differential equations before transforming my system into the more ...
- 139
3
votes
2
answers
4k
views
Replacing PID with Lead–lag compensator?
I have a vehicle (I bought it and it proprietary and I have no information about any internals) which I want to integrate into my simulation environment. So far I have a physical model of it which I ...
- 131
3
votes
0
answers
211
views
PI or PID-regulator for control system with hysteresis relay in inner loop
I have such control system (sorry for rough drawing :) )
$G(s)$ - stable object with proper transfer function.
$1/s$ - integrator.
I need to clarify, how synthesized PI or PID controller for such ...
- 226
3
votes
1
answer
210
views
Model-based Ziegler-Nichols tuning of a hover PID controller
Doing a fun project to reconnect with my engineering training: I would like to design a control scheme for hovering in-place at a set altitude with a vertically-oriented propeller, rocket, etc. Right ...
- 33
2
votes
3
answers
470
views
How to convert a DC motor into a servo motor using a rotary encoder and a microcontroller?
Operating/ Rated Voltage: 24V
No load Speed: 350 rpm
No load Current: 150mA (max)
Max efficiency: 1.4 Kg-cm/300 rpm/ 14.2W/ 0.87A
Max power: 4.5 Kg-cm/180 rpm/28.2W/1.4A
Stall Current: 2.9 A (max)
...
- 71
2
votes
1
answer
952
views
Is the PID just an outdated control method and state-space is superior?
So I've been wondering this for a while; is PID just a simple but slightly outdated control method / isn't state-space (SS) a far superior method in pretty much every way?
SS allows for MIMO, PID just ...
- 88
2
votes
1
answer
77
views
Stepper motor speed control problem
For brushless DC motors we have hall sensors to keep track of rotor; however, for stepper motor we don't know the actual position of the rotor and therefore while changing pulses with some speed it ...
- 147
2
votes
1
answer
115
views
analysis of PD controller vs static-gain
I have a plant $G(s)$ which gives position and velocity as output
$$ G = [G_{ru}(s)\quad G_{vu}(s)]^T $$
where $G_{ru}$ is the integral of $G_{vu}$, and $u$ is the input to the system. Now if I want ...
- 183
2
votes
1
answer
3k
views
PI controller for second order system
I have a second order system and I need to control it using a PI controller. I need to tune the gains of the controller in order for the system to satisfy the below specifications:
$$ OS\% < 10\% \...
- 1,019
2
votes
1
answer
977
views
Design op-amp circuit from transfer function? [closed]
What is the best way to design a circuit based on the following transfer function: (0.0364*s)/(0.0002*s + 1) ? I am trying to design the derivative stage of a PIDF controller using op-amps
EDIT: This ...
- 35
2
votes
2
answers
258
views
Why does accuracy of temperature PID controller drop over time and how to eliminate it?
What am I trying to control?
I have a container with approximately 3*2*6 meters (width, height, length).
I am controlling through PID the ...
- 125
2
votes
2
answers
724
views
How can we control the output temperature of a multi-input single-output pipe air-flow system?
I am trying to optimize the heat control of a test bench at our facility. The test bench is basically a pipe with an air flow that can be heated up to desired temperature. To heat the air flow up, ...
- 95
2
votes
2
answers
357
views
How does a closed loop control system actually work?
I'm currently taking classical control theory and have some questions regarding basic concepts related to closed loop systems.
Let's say I have a simple servo motor controlled by an electric current....
- 245
2
votes
1
answer
767
views
Is lead filter same as PD combined with a low pass filter?
I am curious to know the difference between a lead compensator (lead filter) and a PD controller with a low pass filter. From the theory I can see that the transfer function of both these controllers ...
2
votes
1
answer
172
views
Improving a PID controller from logged historical PID data
Part of our system involves a feedback loop with a PID controller. We log every call to the PID controller, and include in the log information about the Kp, Ki, Kd, the set point, the input, output, ...
2
votes
2
answers
127
views
Does it make sense to have a pressure and flow controller on a single closed line?
I have seen P&IDs in which a single line has both a pressure and flow control valve. Based on my understanding of Bernoulli's equation however this doesn't make sense to me - because ultimately ...
- 121
2
votes
2
answers
400
views
Analog PID Controller/Filter delay and stability
recently I had an exercise where I had to build and measure an analog PID controller/filter. The starting point was this circuit.
This is a tamed PID controller implemented with a single opamp. ...
- 23
2
votes
1
answer
253
views
Tuning PID Controller
I have to determinate the power (Watts) for an oven to reach the Temperature Reference. And I have been given only the function to apply power to the oven and read the temperature.
I've reading the ...
- 123
2
votes
1
answer
4k
views
Using a PID to control rotation
I've been working on simulating drone flight in Gazebo (an open source robotics simulator).
Currently, I'm trying to control the drone's pitch / roll rotation using PIDs. It's important to remember ...
- 23
2
votes
1
answer
217
views
What means the velocity constant of the integration in PI controller formulas?
I have an equation of a PI controller. What means here the velocity constant "R" exactly?
$$m(t)=K(e(t)+R{\int}e(t)dt)$$
$$R=1sec^{-1}$$
2
votes
1
answer
607
views
What is the mathematical basis for the Ziegler-Nichols method for tuning a PID loop?
The Ziegler-Nichols method of tuning PID control loops has been around since the 1940's, and has been widely applied in many areas of engineering. I understand that it is really only a heuristic ...
- 129
2
votes
1
answer
80
views
Interpreting Nyquist plot
When implementing the control for my application I got this Nyquist plot which made me flabbergasted.
If I zoom on the point $-1 + 0j$ I get the following image
How do I interpret this contour going ...
- 121
2
votes
3
answers
989
views
PID control of a DC motor with PWM from Raspberry Pi - how to cross dead area?
I'm driving a DC motor (actually a linear actuator) with a Polulu motor controller from a Raspberry Pi. The motor drives if you ask for anything between 20 and 100% duty cycle, so there is a dead zone ...
2
votes
1
answer
1k
views
Suggestion to control a gimbal bldc motor for positioning
I try to understand what the PID controller of a gimbal stabilizer boards
(e.g Storm32BGC) does influence?
From the IMU we get position and velocity after sensor funsion. The input variable of the ...
- 295
2
votes
0
answers
45
views
Inverted pendulum PID: controller causes cart to move at constant velocity?
I am trying to understand the PID controller of an inverted pendulum on cart system through this MATLAB article: https://ctms.engin.umich.edu/CTMS/index.php?example=InvertedPendulum§ion=...
- 21
2
votes
0
answers
39
views
Is this function common in PID controllers?
I'm reading some old microcontroller code for a PID algorithm. There's a strange function (to me) that seems to work like this:
$output = \frac{1}{n}input + \frac{n-1}{n}previous\_output$
The value $...
- 121
2
votes
0
answers
43
views
How to control an underactuated platform with a single servo
What's the best way to control the following type of platform so that it remains balanced and upright?
It's a box supported by a single leg that can pivot at the foot (F) and at the hip (H). The foot ...
- 121
2
votes
1
answer
202
views
Tricks for controlling process with logaritmich characteristics over 20 orders of magnitude
I'm building a machine that operates over 20 orders of magnitude with logarithmic process characteristics. I have tried regular PID and also all sorts of variations of PID and did not get good results....
- 145
1
vote
2
answers
711
views
Is this a PID cascade control loop?
I'm working on a balancing robot. I'm familiar with the simple PID control loop but i can't understand this PID control loop.
Is this actually a cascade control loop? The programming states that the ...
- 121
1
vote
1
answer
130
views
Can I design/tune the outer loop controller without knowing the details of the inner loop controller?
In cascade PID control loops as below, can I make an assumption that the inner loop will respond much faster than the outer loop, hence I could simplify U1_CMD as U1 and I could design/tune the gains ...
- 57
1
vote
4
answers
310
views
PID controller - Counterproductive derivative
I'm having trouble understanding the derivative part of a PID controller, because it sometimes seems to react the opposite way that I would like.
Let's use a simple example where :
the controlled ...
- 113