Questions tagged [pid-control]
154 questions
7
votes
2 answers
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 implement a PID control with a filtered…
bluecore
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5
votes
1 answer
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 $T=0.12\,s$ which leads to a approx. 13 samples per oscillation…
Lageos
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5
votes
1 answer
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 table with four legs.
The four legs move up and down…
KKS
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5
votes
4 answers
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 of proportional gain) correction, so why won't…
ergon
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5
votes
1 answer
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 a strict asymptotic convergence to the set value.…
solid
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4
votes
2 answers
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!
ergon
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4
votes
1 answer
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 outputs, or with more inputs than outputs. And…
Thomas
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4
votes
2 answers
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):
$$Q = \int_0^\infty \epsilon^2(t) \ dt $$
The object being…
user24139
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4
votes
1 answer
what's wrong with this robust control scheme?
I'm learning how to control a double integrator with $H_\infty$.
my model is simply
$$\begin{gather}
\dot{r} = v \\
\dot{v} = F/m \\
r(t_0) = 0\text{ m}, $v(t_0) = 0\text{ m/s}, m = 1000\text{ kg}
\end{gather}$$
so I want to be able to track a step…
venom
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4
votes
1 answer
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 ramping reference signal (i.e. one that changes at a…
nibot
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3
votes
0 answers
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 object, that include inner-loop with…
dtn
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3
votes
2 answers
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. First I have the bod plot which has a consistently…
alcopo63q
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3
votes
1 answer
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 standard Laplace-transform, looking-for-poles-type…
Steven Sagona
- 139
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3
votes
1 answer
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 can only measure the grid load and the PV inverter…
AF7
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- 3
3
votes
1 answer
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 a 3rd order system or higher.
The problem that I…
Jaycob Jones
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