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5 votes
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Root Locus and Routh–Hurwitz stability criterion

Suppose we have a third order polynomial in the form : $$ s^3+a_2s^2+a_1s+a_0 = 0$$ There is nice caveat for third order systems which is derived from the Routh-Hurwitz stability criterion. In order ...
4 votes

What are the Singular Values of a dynamic system and how are they calculated in the *sigma* function in Matlab?

For a MIMO system $y(s) = G(s)d(s)$, with $m$ inputs and $l$ outputs. Consider a fixed frequency $\omega$ where $G(j\omega)$ is a constant $l \times m$ complex matrix. For the sake of simplicity the ...
4 votes
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Design op-amp circuit from transfer function?

To my knowledge the simplest way to accomplish the transfer function... $$ G(s) = \frac{E_o(s)}{E_i(s)} = \frac{0.0364s}{0.0002s + 1} = \frac{KTs}{Ts +1} $$ ...is the following high-pass filter ...
4 votes

How do I create a graph of the phase angle and response of a harmonic excitation in Matlab?

With your code, and with $c = 0.3$, I get the following results: The amplitude and phase look OK. But the displacement does not show any damping. To see why read on below. I'm not sure about your ...
4 votes
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Nyquist plot - what is the meaning of circles with dB values on complex plane

See doc nyquist: The nyquist function has support for M-circles, which are the contours of the constant closed-loop magnitude. M-circles are defined as the ...
4 votes
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How to import a CATIA assembly into SimMechanics

Short answer: you can't directly import CATIA assemblies in SimMechanics. Long answer: SimMechanics supports import of CAD models (assemblies or parts) from Pro/Engineer, SolidWorks or Autodesk ...
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4 votes
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Problem with performances of a control scheme

Your closedloop crossover frequency (when the magnitude of $P(s)\,C(s)$ is equal to one) lies at roughly 1 rad/s. This means that the feedback controller already causes the system to track reference ...
  • 1,603
3 votes

Matlab Polynomial Curve Fitting with Known Relationship

The trick to this one is at the end there. You took the reciprocal of your y data but what you need is the reciprocal of the entire equation. Original: $y = a\frac{x}{b+x}$ Reciprocal: $\frac{1}{y}=\...
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3 votes

How to find closed loop transfer function and use it to identify τ and k?

The general form of a transfer function for a first order system is the following: $$ T(s) = \frac{K}{\tau s+1} $$ where: $\ K \rightarrow $ DC Gain of the system $\ \tau \rightarrow $ Time ...
3 votes

How do I interpret states in the MATLAB System Identification Toolbox?

When identifying a system, you effectively compute a system that happens to have the same response to your inputs as the physical system. However, this does not mean that the states do physically ...
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2 votes
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Closed loop response of a discrete system

The plant and controller: $$\text{sys}=\frac{4700 s^2+4393 s+3.245\times 10^8}{s^4+7.574 s^3+120200. s^2}$$ $$pid=0.287\, +0.008 s+\frac{0.5}{s}$$ The closed-loop system obtained as $\frac{pid*sys}{...
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2 votes

Question on sketching nyquist plot of transfer function with poles on imaginary axis

For the pole at $5 i$, the contour that has to be considered is $5 i+\epsilon e^{i \theta }$. Here $\epsilon \to 0$ and $\theta \in[-\frac{\pi }{2},\frac{\pi }{2}]$. The denominator of the transfer ...
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2 votes
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Laplace Equation -- Heated Plate -- Heat Flux Boundary Condition

You haven't specified which method you are using, so i am going to assume Finite Volume. In that case you have a staggered grid like so: The vertical lines are the faces of you cells and the circles ...
  • 157
2 votes

How to choose reference signal in a state space model?

So assuming that we are dealing with LTI systems of the form $$ \begin{align} \dot{x} &= A\,x + B\,u \\ y &= C\,x + D\,u \end{align} \tag{1} $$ with $x\in\mathbb{R}^{n_x}$, $u\in\mathbb{R}^{...
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2 votes

Is Matlab old versions usable with Win 10 on core i3

"Windows 2010" is not a Windows version so i'm guessing that you are referring to Windows 10. In general all software that came out since Windows Vista (2007) also runs fine on newer Windows versions ...
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2 votes

Model Reduction - Export matrices from ANSYS to MATLAB

So my first question would be - Should I build my flexible body with deformation model for each part (say it is a table, should I describe every leg of my table and the plate using rigid body and ...
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2 votes
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Calculating a derivative in a loop?

Your implementation is: ...
2 votes
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Analizing Vibrations Influence on Dynamic Weighing

So, look at the time history that you added in edit 3. Notice how it is never ever ever below 1. That's very telling. Let us assume that you have a MEMS accelerometer is able to read down to 0 ...
  • 2,526
2 votes

sinking speed of particle in water

I think I understand where you are stuck - it appears (I don't "speak" Matlab) you're trying to solve u directly, without adressing that u goes into Re. Here's what I'd do: Guess $u$ for the ...
  • 4,651
2 votes

How can I find deflection in a member that doesn't have a constant area moment of inertia?

There are two aspects to this problem that are each significantly more complicated than what you seem to have tried so far: The angle of 45 degrees by which the cross section is changing dimension is ...
  • 1,278
2 votes

How do I interpret states in the MATLAB System Identification Toolbox?

Due to the fact that you are mentioning the $A,B,C,D$ matrices I assume that your model is a linear one of the form: $$ \dot{x} = Ax + Bu$$ $$ y = Cx + Du $$ where $x$ is the state vector and $y$ the ...
2 votes

What meaning does the following sine wave have when it comes to amplitude?

It means that there is a positive offset of one. So your signal is $$ x(t) = 1 + 2 \cdot \sin(\omega t)$$ where: 1 is the offset 2 is the amplitude of your signal (not 4).
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2 votes
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Optimization with GA (genetic algorithm)

Taking the norm of a system is something different that taking the norm of a matrix. Luckily, matlab has you covered: https://nl.mathworks.com/help/control/ref/lti.norm.html This page even shows an ...
  • 1,079
2 votes

Pole placement with damping ratio and natural frequency

The natural frequency $\omega_n$ and damping ratio $\zeta$ of a system are computed by using the two dominant poles of the system. Dominant poles are the ones that are closer to the imaginary axis (i....
2 votes
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Do I need a feedback loop while testing PID controller?

I am having trouble imaging a PID controller without a feedback loop. The reason is that P, I and D controllers each calculate their response based on the error between the target and the current ...
  • 22.9k
2 votes

Do I need a feedback loop while testing PID controller?

Testing physical controller hardware in "open loop" isn't uncommon, but it would just be part of a test, and the feedback line can be split at a point and treated as both input and output of ...
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2 votes
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Extraction Flash Calculation - 4 Component and 2 Phase System

For reference, I am drawing from the chapter on isothermal VLE separations in Separation Process Principles by Seader, Henley, and Roper. Consider only the final state. The two starting statements in ...
1 vote

Temperature not changing in my code for 1-D heat equation: Explicit Scheme

This stackexchange doesn't really seek to solve these homework-like problems directly. However, I can offer some hints on how to proceed. Are you sure the scale of ...
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1 vote
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Get results of output for each one value of the input - MATLAB ODE

If you want $u$ to be considered as a smooth continuous function, then you should define it as such since you also have $t$ available as well. So you could use: ...
  • 1,603
1 vote

Is it possible to have open loop with same input term as the output?

The answer really boils down to how you define your system. If you say "this is my plant" and give that equation, then as long as $u$ does not depend on $y$ then the system is operating in open loop. ...
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