Questions tagged [control-theory]

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1answer
28 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 ...
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2answers
26 views

How to convert output of controller (control signal) into PWM signal?

I am trying to control a mechanical system with some transfer function T (output is position & input is voltage). I have implemented a state feedback controller in order for the output of the ...
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0answers
34 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^\...
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1answer
78 views

Is it necessary to use PID control in my use case?

I have a workflow of two functions. Both of them aggregate the items that are receiving and only the first is adjustable. I mean that I can decide how many items to aggregate on the first function <...
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1answer
40 views

what is the physical interpretation of poles and zeros of a mechanical system?

what is the physical interpretation of poles and zeros of a mechanical system? I'm asking things like the meaning if I have only 0 or only complex numbers. And about the number of the poles and zeros, ...
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1answer
45 views

Optimal control vs. nonlinear control

I have tried to compare between two courses, and there seems to be some overlap, but not as much. Which method is better when controlling a nonlinear system? Also, what is the main difference between ...
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1answer
25 views

Aircraft Longitudinal and Lateral Transfer Function Terms

The figure shows input and output variables for both longitudinal and lateral stability transfer functions. I completely understand what each term stands for but I was wondering what would be the ...
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0answers
11 views

Distributed consensus matrix form , is this form correct?

$\dot \xi = −(L_{n}\otimes I_{m})\xi$ This equation is commonly cited in works about the distributed consensus of cooperative control, in fact, it's the matrix form of the basic consensus algorithm ...
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1answer
25 views

Doubt on zero pole cancellation

I am looking at a control system which has an unstable pole in the process. The transfer functions of process and controller are the following: ...
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0answers
35 views

Why a zero too close to the imaginary axis gives bad berformances?

I am studying control systems, and I have found that if I consider I control scheme where I filter the reference , if the zero of the pre-filter is too close to the imaginary axis, we have a ...
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1answer
26 views

Predict egg drop outcome in random container

What elements affect the outcome of a raw egg drop in a random container? I’ve considered friction, mass, size of container, size and type of padding. Are there other elements?
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15 views

Complementary sensitivity function in waterbed effect

I am studying the waterbed effect in control systems, and so I have studeird that from the Bode Integral, if I increase the sensitivity to avoid low frequency disturbances, I have amplification of ...
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1answer
20 views

Control each axis separately - quadcopter

I would like to know why axis can be controlled independently in a quadcopter. I mean, I was told that you can control $x$ and $y$ independently but I couldn't find a demonstration Edit: the ...
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1answer
39 views

Limitations on the control effort

I am studying the mixed sensitivity design for control systems, and I have seen that the control effort has limitations given by the bandwidth of the process and by the bandwidth of the sensitivity ...
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0answers
27 views

Design compensator to improve yaw rate control performance for aircraft

I am trying to design a compensator to improve the yaw rate ($\dot{r}$) control performance of an aircraft. The lateral dynamics for this aircraft is given in steady space form as following: where A (...
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0answers
21 views

Control effort in mixed sensitivity design

I am dealing with mixed sensitivity controller design in SISO systems and I am comparing this approch with the classic approch. In particular, I have placed a weight for the sensitivity function in ...
2
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1answer
18 views

Stability with eigenvalues' real part equal to zero

I know, from Lyapunov criteria, that a system is stable (not asymptotically) if the system has eigenvalues with negative real part or it has eigenvalues with real part equals to zero, but in this case ...
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0answers
19 views

Relationship between conjugate poles and resonance peak in frequency response

I have two root locus of two closed loop transfer fuctions, which differ just by a different value of the gain. I have that the one with a larger gain has a reasonance peak bigger in the frequency ...
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0answers
13 views

Gradient-free optimal control solver?

I have a dynamics simulation that provides the state derivative $\dot x = f(x,u)$, implemented in C. I'd like to solve the optimal control problem (given an initial state and cost function). Because ...
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1answer
28 views

Time constant of second order system

I have a second order system with open-loop transfer function $G(s)={a\over(s+b)(s+c)}$, $a,b,c$ are already known. This system has unity feedback. I am interested in the time consant of this system, ...
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1answer
20 views

Design the equivalent electric circuit (using op-amps) describing open loop transfer function G(s)

How can I convert the Standard form of the second –order system transfer function into op-amp circuit ? G(s) = wn^2 / (s^2 + 2ζwns + wn^2)
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0answers
25 views

Problem reading control effort frequency response plot

I am trying to plot the frequency response control effort of a control scheme in Matlab, and in particular I want to do this for different values of tau, which is a constant used to add a pole at high ...
2
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1answer
52 views

Problem with performances of a control scheme

I am trying to prove with Matlab that if I have an improper system and I place poles at higher and higher frequencies the performances of the system improves. In particular I am considering the ...
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1answer
24 views

Transfer function for a quadcopter with linear velocity inputs

I found the control for a quadcopter using the angular velocities or thrust power as the input, but I need a model where I can set the initial and final position (for example, from (0,0,1) to (0,1,1))....
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0answers
25 views

H infinity control problem - changing eigenvalues of plant

I'm applying $H_\infty$ approach to control a system with a given input $u$, and I can measure and feedback position and velocity errors. The plant is described by the following transfer function $$...
2
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1answer
37 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 ...
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0answers
19 views

Zero-state observability and strictly passive systems

I'm currently studying passivity theorems of nonlinear systems, and I find it difficult to understand the difference between the different kinds of strict passiveness. Are there any intuitive ...
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0answers
28 views

Offline Parameter Estimation for second order system - Ordinary Least Squares

I have a second order system which is described by the following differential equation: $\ \ddot{y}+α_{1}*\dot{y}=b_{0}*u $ where $\ y $ is the output of the system and $\ u $ is the input of the ...
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1answer
15 views

Nonlinear behaviour of control plant and adaptive or robust design

In a paper in the context of controller design for DEAP actuators I came upon the following sentence: Furthermore, the nonlinear behavior of the control plant requires either an adaptive or a ...
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1answer
29 views

Adjusting root locus to get a stable system from unstable system

Most of the books that I referred to, used compensators to improve transient performances of a stable system using root locus and compensator design. I got a system which is actually unstable for all ...
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0answers
23 views

value of $\gamma$ in the H-infinity norm

Suppose I have the system: $\dot{x} = Ax+Bu$ $y=Cx+Du$ and the following Hamiltonian matrix: $H=\begin{pmatrix} A & \frac{1}{2}B^TB\\ -CC^T&-A \end{pmatrix}$ I want to find the value ...
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0answers
41 views

effect of coupling in MIMO systems

I have a MIMO system with a 2x2 transfer matrix, for example consider: $\begin{pmatrix} \frac{2}{s+1} & \frac{1}{(s+1)(s+2)}\\ \frac{1}{(s+1)(s+2)}&\frac{2}{s+2} \end{pmatrix}$ I would ...
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1answer
353 views

Block diagram vs flow chart?

I was studying a book of control system where i read that a block diagram is a specialized high level type of flow chart So what will be the difference between a normal flow chart and a block diagram?...
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2answers
51 views

Root locus: ambiguity on which branch goes where?

I could not find a Controls Stackexchange, I hope this is the right place, otherwise I would be glad to post it in the appropriate section. My question concerns the root locus method. Given a plant ...
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1answer
43 views

Identification of control system type? Open loop or close loop,

What is the type of control system of door closer in attached photo?
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42 views

Adaptive feedforward cancellation (AFC) and least mean squares (LMS) for periodic disturbance cancellation

I already asked this question here, but since I did not get an answer yet I want to try it here as well: I want to implement an adaptive feedforward cancellation (AFC) for cancellation of the impact ...
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1answer
40 views

control systems vs artificial intelligence?(in nut shell for beginners)

i am confused in basic difference between control systems & artificial intelligence? since both techniques can be used for automation Please kindly try to give answer in nutshell depth/detail ...
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0answers
53 views

Maximising the trace of the observability Gramian

Suppose I have a matrix W. This matrix has an observability Gramian Q. Is there a way to see which changes in the matrix W will maximise the trace of Q? Is there a natural way to express maximising Q ...
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0answers
13 views

What non-Gaussian filter should I use

I am developing a filter to better predict my state of my system. I had previously tried an Extended Kalman Filter. I have all the data needed to predict my next step but I have few observations/...
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1answer
59 views

Gain and phase margin

Why Bode plots are on jw axis when determining gain and phase margin? Usually it is explained as 1+G(s)H(s) should not be zero and margins represent how far away from this we are. But for showing this ...
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0answers
28 views

Meaning of energy method in control theory

What qualifies a energy method in the context of control theory? Citing from a paper to give the context in which this expression came to my attention: One of the challenging problems of the double ...
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0answers
21 views

How does a digital controller's sampling period dictate the system's actuation requirements?

When selecting an actuator for a controls application - e.g. choosing a servo motor for a self-balancing robot - I understand that it's important for the actuators to have fast enough dynamics that ...
2
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1answer
63 views

Closed loop guidance and control: how to tune a system with multiple feedback controllers?

I'm trying to design a closed-loop guidance system for rockets - something that can be implemented in Kerbal Space Program, for example. To do this, I'm following the design process described in ...
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2answers
73 views

What kind of mechanism can be used to rotate a part in 180 degrees (Ψ (yaw)) and 30degrees in 𝜃 (pitch) direction?

Let's say we have a flat object. We are asked to create some mechanism so that the part can rotate in the shown angles above. What mechanisms can be used?
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1answer
39 views

Designing Block Diagrams For Control Systems

I'm looking for good software to design control systems, and more specifically to neatly design "block diagrams" for control systems. Is there something like that?
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1answer
70 views

Changing fields from mathematics to control engineering [closed]

I did my undergraduate in maths and physics and will be working in control theory for my future job. Not to my surprise, my engineering background is rather lacking. I have taken a look at materials ...
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1answer
50 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 ...
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1answer
130 views

Difference between Hysteresis, low pass filter and deadband in control theory?

I am trying to understand the fundamental difference between the following terms in the context of control systems: Hysteresis Low pass filter Deadband Are these just fancy names that can be ...
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1answer
50 views

How to find Performance assessment (IAE and ISE) of a PID Controlled system?

The Integral Absolute value Error (IAE) and the Integral Squared Error (ISE) is to be analysed. A PID Controller is given as follows: ...
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1answer
51 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 select the parameters of the controller in order for the system to satisfy a less than 10% overshoot requirement ...