Questions tagged [control-systems]

Questions on the use of Mathematica to analyze, design, and simulate continuous- and discrete-time control systems.

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14 views

Is there any formula to get the IRR from the slope of the Cumulative Cash Flow?

I've simulated a monthly regular cash flow with Excel, and the Internal Rate of Return (IRR) calculated from the first date to the current row. The curve of the IRR is very similar to the Transfer ...
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1answer
62 views

State Space Model in Controllable Canonical Form

Mathematica by default puts state space model realizations in controllable companion form, as seen here: ...
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61 views

Problem with the analytical study of transient processes in nonlinear systems with linear dynamic links

I ask for advice and help. I am having difficulties of this nature. There is a nonlinear system of the following type: I need to analyze analytically the transient process in such a system. The ...
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2answers
893 views

Can we use Mathematica to design an electronic active filter?

How can we use Mathematica to design an electronic implementation of an active filter?
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1answer
86 views

Linear Quadratic Integrator

With a given linear drive system ...
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1answer
37 views

Compiling RiccatiSolve LQRegulator gains

Given some specific matricies, numA, numB, numP, q and r to calculate LQR gains, one can use simply LQRegulatorGains or solve the same via ...
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2answers
67 views

Limiting transfer function of PID to upper and lower bounds

I have a question about Limiting the output of a transfer function in my system model. (Im fairly new to control theory and control systems) I have a model where a PID controller is directly ...
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66 views

How to solve Partial differential equation (PDE) with delay!

I just have one question please, I searched on Mathematica documents concerning partial differential equations with delay, all I had found is ordinary differential equations(EDO), that's means ...
4
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1answer
173 views

Estimation of parameters of limit cycles for systems of high-order differential equations (n> = 3)

There is a system of differential equations: Then, call the limit cycle the projection of the phase trajectory onto the plane in a pairwise combination of state variables ($x-y,y-z,x-z$). where $x,y,...
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1answer
70 views

TransferFunctionModel produces large coefficients

First, I define the following transfer functions using TransferFunctionModel: ...
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1answer
70 views

Finding group delay of transfer function

I'm having trouble finding the group delay of a transfer function. I've seen a solved question on here about finding the group delay, but I want to understand why my method doesn't work. Here is some ...
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1answer
85 views

How to use RiccatiSolve with symbolic matrix

According to the RiccatiSolve documentation the Eigensystem method can apply to symbolic matrices. However, I can not get it to ...
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1answer
31 views

Get the greatest time contant of a system's output given its expression

Let $y(t)$ be a function that consists of a sum of terms, each of which is in general a product of an exponential function $e^{\sigma t}$, and a sine function $\sin{\omega t}$ or cosine function $\cos{...
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59 views

Simple neural network with feedbacks in state-space form

Having studied more or less in detail the mechanisms of working with the state-space that Mathematica provides us with, I asked myself: can these tools be applied to neural networks? This article ...
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1answer
94 views

Implicit Riccati Equation Solver (to find the anti-stabilizing solution)

I've found that the latest MATLAB icare() solver includes the possibility to find also the anti-stabilizing solution of the Riccati equation. I haven't found a ...
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2answers
206 views

Converting a backward/forward sweep code for optimal control to _Mathematica_

I'm trying to convert to Mathematica a simple backward/forward sweep (with RK4 integrator) code to solve an optimal control problem in epidemiology, but I'm getting some error messages and I cannot ...
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1answer
208 views

Solution to the inverted pendulum problem (system of non-linear ODE)

A classic control systems problem is that of the translational inverted pendulum, as shown below. By applying a force $f(t)$ to the car (e.g. through a DC motor attached to the car), the goal is to ...
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1answer
262 views

Understanding code generated by MicrocontrollerEmbedCode

I've been using MicrocontrollerKit for a while now to generate code for little projects, inverse pendulums, filters, etc. Generally it works well. I am now currently trying to design a LQI (Linear ...
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2answers
194 views

Lagrangian of three-mass system with Mathematica

Before proceeding to calculations in Mathematica, I would like to clarify with knowledgeable people. There is an ordinary linear three-mass system. If we write its Lagrangian, we get the following ...
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1answer
63 views

Representation in state-space of a system with ideal and real differentiating links in feedback

There are two systems in the state space with an ideal and a real differentiator. For the first system, the code in Mathematica is as follows. ...
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1answer
58 views

Closed-Loop Systems and System Response Modeling [closed]

I'm testing out code from a textbook for possible bugs. This chapter demonstrates a plot of a motor's angular position response in accordance to it's transfer function model: ...
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1answer
101 views

Output response for state-space with piecewise nonlinear elements

In addition to the previous topic: System model merge with multiple input and one output For example, I am trying to reproduce a system from simulink, a diagram of which is shown in the figure below:...
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3answers
761 views

Mathematica and MatLab giving different results from inverse Laplace transform [closed]

The questionis is as this Given the transfer function gs = (5*s + 4)/(s^4 + 4*s^3 + 2*s^2 + 3*s); and the input signal ...
3
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1answer
99 views

System model merge with multiple input and one output

I was curious, and I used the built-in functions of Mathematica to analyze the following scheme: I used SystemModelMerge as: ...
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1answer
89 views

Problem when solving Kalman filter in Mathematica: How to define a spectral density matrix and calculate the covariance matrix?

I am reading the classic book on state-space control theory by Bernard Friedland. In order to strengthen my understanding of Kalman filter, I want to reproduce Example 11A (Inverted pendulum on page ...
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1answer
80 views

Why doesn’t x’ = a.x + b.u, y = c . x + d.u hold in this state-space model?

I have noted that sometimes state variables may change (thanks Thomas’s help :)), due to the Mathematica’s internal automatic transformation from a descriptor state-space model to a standard state-...
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1answer
48 views

Confusing behavior of LQR control that strongly depends on system output (with odes solved by NDSolve)

I am implementing a LQR control of a 3-floors structure. Firstly, I obtained a reasonable result with my first code (Code 1 as shown below). In this code, the ...
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1answer
190 views

How to implement a Kalman or LQG regulator in the control of classical pendulum problem

My final purpose is to realize an LQG control of inverted pendulum. To this end, my first step I think is to build a Kalman regulator in Mathematica. The original Matlab version of Kalman filter is ...
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1answer
79 views

Strange output of a simple statespace model

The output of statespace model seems strange. In the follwing code, the odes are governing equations of a three floors structure, and the output are three accelerations of floors. If I ...
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1answer
49 views

Does NonlinearStateSpaceModel work with symbolic constants?

I'm trying to put a nonlinear system of two 2nd order ODEs given by: ...
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1answer
116 views

Experiments with Feedback Linearization and StateTransformLinearization in Mathematica

I have some nonlinear system, and i have three big question: Non-linear ODE from closed-loop system and Response 1. how correctly use such terms, like "Feedback Linearization and StateTransform ...
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1answer
170 views

Non-linear ODE from closed-loop system and Response

I started using Mathematica 12 and ran into difficulties. Namely, I want to compare the results of the calculation of a closed system from Simulink and in Mathematica. I rummaged around a bit on the ...
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1answer
55 views

Error with StateSpaceTransform: the rule based transformation must be of length 2

I would like to perform a change of variables on the following dynamics system: ...
2
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3answers
140 views

PIDTune and characteristic equation of zero

I have a BLDC electric motor, I'm currently trying to control via a PIDTune. This is mostly an attempt to reduce (remove) a small run away drift that ends up ...
6
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1answer
181 views

Extended Kalman Filter by hand

While trying to learn a bit about control theory, observers and most importantly, to use Microcontroller Kit in version 12 of MMA, I've stumbled upon the KalmanEstimator. After reading a bit (and ...
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2answers
686 views

Can we use Mathematica for electronics design?

A spoiler alert: I intend to answer my own question. I am posting this because I would like to share my excitement regarding the control theory tools in Mathematica, and also to promote further ...
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1answer
74 views

Speeding up the calculations by Reduce and NSolve

I have a non-linear system of equations with numeric parameter values as shown below. I first tried FindRoot with given initial values and it did not converge. Then ...
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1answer
77 views

StateTransformationLinearize - references?

I am impressed by StateTransformationLinearize, and I feel terribly bad for not having noticed this function before. How does it work? Does it attempt to find a $...
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1answer
293 views

Solving Differential Equation System for HIV Treatment Model

I was working on a project about optimal strategies for HIV treatment, models used from [Butler, Kirschner, and Lenhart] 1997. This model explains the spread of HIV viruses in the human body, where ...
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1answer
67 views

Manual control plots differ from StateResponse and OutputResponse

So In my quest to try to learn some control theory inspired by the following link, I have been modeling an inverse pendulum regulated with a flywheel. The system model is pretty ok I think, and when ...
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1answer
80 views

OutputResponse and contradictory control models

So I'm trying to learn some control theory for a little project I'm working on and decided I'd try the examples of pendulum and cart one can find all over the internets, and I'm following this post ...
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2answers
421 views

BodePlot with magnitude in db or log scale

I have to plot a BodePlot with magnitude in db or log, but i could not find the option for setting the magnitude scale. ...
3
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1answer
556 views

Analyze stability of equilibria using Routh-Hurwitz conditions

For an assignment, I need to analyze the stability of a system very close to equilibrium, using "Routh-Hurwitz conditions". I have already obtained the characteristic equation of my system, but I do ...
3
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2answers
128 views

Inconsistencies when using BodePlot with `StateSpaceModel` and `TransferFunctionModel`

Consider a linear system . ...
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0answers
72 views

Accuracy problem with BodePlot

Hoping to find a quick answer to a question of frequency response of multiple band-pass filters in closed loop, I opened up Mathematica,and entered the first set of ...
2
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1answer
253 views

Simulating a combination of PDEs and ODEs

I am trying to simulate a combination of PDEs and ODEs, given below. $$ \begin{matrix} -L\dfrac{\partial}{\partial t}I(t,z)&=&\dfrac{\partial}{\partial z}V(t,z)+RI(t,z)\\ C\dfrac{\...
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1answer
104 views

BodePlot of Warburg impedance - Errors

I'm trying to plot the Bode diagrams of the Warburg impedance (A=1, s=jw): $$Z=\frac{A}{\sqrt{\omega}}+\frac{A}{j\sqrt{\omega}}$$ $$Z=A \sqrt{\frac{j}{s}}+\frac{A}{j}\sqrt{\frac{j}{s}}$$ ...
2
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1answer
93 views

Event Trigger Ode's

I am trying to simulate a Hybrid system using the WhenEvent function in Mathematica. I have asked this question earlier. It was not an MWE. Now I tried to make an ...
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1answer
121 views

AxesLabel in a phase plot in the BodePlot command

I've the following code: ...
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0answers
47 views

Finding the mathematical function is plotted by using the bodeplot command

I've the following code: ...