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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1
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1answer
95 views

BodePlot with wrong phase [closed]

I'am trying to plot the function: BodePlot[1/(1 + 0.1 s), s] The phase plot is wrong (I'm using Mathematica 11.2): Why does this happens and how can I get the ...
11
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1answer
642 views

Solving optimal control problem when input is constrained

Given a linear time-invariant system: $$x'(t)=Ax(t)+Bu(t)$$ with initial state $x(0)=x0$ and final state $x(T)=xT$. The performance measure to be minimized is: $$∫_0^Tu(t)^2dt$$ The most important ...
6
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1answer
123 views

What does BodePlot actually calculate?

I'm using Mathematica v12.3 student edition, running on Windows 10 Home (AMD Ryzen 5 4500U with Radeon Graphics 2.38 GHz). I'm trying to get a Bode plot of an example function. I try to do it with the ...
0
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1answer
56 views

Asymptotic bode plot [closed]

Is it possible to plot an asymptotic bode plot. I am interested in verifying my straight line bode plot approximations done by hand by using mathematica but the bodeplot function generates the curved ...
4
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2answers
696 views

Is it possible to find the transfer function of these three differential equations using Mathematica

Imagine you are attempting to obtain a model of a device with two inputs [u1, u2] and three outputs [O1, O2, x] from the Lagrangian. After some of Lagrangian work, you find the following three ...
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0answers
82 views

Linearization of the ODE system: Problems

I have summarized the issues covered in the topics: Linearization of ODE without an equilibrium I ask for help with commands TransferFunctionModel + StateSpaceModel Plot3D + WhenEvent + NDSolve ...
1
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1answer
56 views

I ask for help with commands TransferFunctionModel + StateSpaceModel

Given system of ODE: $\begin{cases} \dot{x}=G+u_1 \\ \dot{z}=-z+\frac{df}{dt} \\ \dot{G}=-G+z \cdot u_2 \end{cases}$ where $f=-x^2$, $u_1=\frac{d}{dt}(\alpha \sin(\omega \cdot t))$ and $u_2=\alpha \...
-1
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1answer
137 views

Problem with Lagrangian and Matrix Calculus in Mathematica

Continuing the questions: Lagrangian of three-mass system with Mathematica Equations of motion for two-mass torsional oscillator with the gear train Derivation of equations of motion for a multi-body ...
2
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2answers
59 views
3
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1answer
177 views

Equations of motion for two-mass torsional oscillator with the gear train

This is my first topic and I continue work on that: Lagrangian of three-mass system with Mathematica I found interesting problem here, and try reproduce results. Assumption: $d_1=0$ Algorithm: Write ...
1
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1answer
146 views

How can I solve this system please?

I need to solve the following impulsive heat equation: $$ \left\{\begin{array}{ll} \partial_{t} \psi(x,t)-\partial_{xx} \psi(x,t)=0, & (x,t)\in (0,1) \times((0, 2) \backslash\{1\}) \\ \...
1
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3answers
103 views

BodePlot to calculate the amplitude and phase at a specific frequency

I have transfer function: $W=\frac{1}{s+1}$ tf = TransferFunctionModel[{{1/(s + 1)}}, s] BodePlot[tf, {.01, 100}] It is very simple to construct a Bode diagram, ...
1
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1answer
90 views

Asymptotic Output Tracking: Compensator properties

Asymptotic Output Tracking: Code Issues The question is, rather, of a theoretical nature (practical applications can be viewed in the topic at the link). Asymptotic Output Tracking is said to be based ...
1
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1answer
135 views

Tuning the optimal control synthesized according to the Pontryagin maximum/minimum principle and choosing the cost function

I continue to study the topic I started here: Problem with optimal control and Pontryagin's maximum principle A simple ODE system $(1)$ is given: $F=\begin{cases} \dot{x}=g \\ \dot{g}=-g+\frac{df}{...
2
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1answer
56 views

OutputResponse numerical error?

It shoud approach to 1 and remains at 1, but when time over 20s it deteriorates. Mathematica 12.1 ...
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2answers
73 views

Notation parse rule does parse when it acts as a argument

https://reference.wolfram.com/language/Notation/tutorial/NotationSymbolizeAndInfixNotation.html Notation[boxes ⟹ expr] set boxes to be parsed to expr I want a simplified notation for entering a ...
1
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0answers
69 views

Multidimensional obstacle avoidance in ODE. Part II

Multidimensional obstacle avoidance in ODE (Visualization) https://math.stackexchange.com/questions/4146255/multidimensional-obstacle-avoidance-in-ode For some time, I studied this question more ...
5
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1answer
102 views

Is there a better way to simulate quadratic cost MPC problems?

Question I would like to know if there is a more straightforward or a better way to simulate MPC problems in terms of code length and accuracy as compared to what I am doing. I am looking to know if ...
4
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1answer
122 views

Multidimensional obstacle avoidance in ODE (Visualization)

A simple 3-dimensional ODE system is given: $F=\begin{cases} \dot{x}=g+g_{U_{rep}} \\ \dot{g}=-g+\frac{df}{dx} \\ \dot{h}=-h+\frac{d^2f}{d^2x} \end{cases} $ Task: Make the variable $g$ move so that ...
6
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1answer
395 views

Problem with optimal control and Pontryagin's maximum principle

For dynamic system: $\dot{x}=\frac{df}{dx}+u$ where $f=e^{-x^2}$ It is necessary to develop optimal control, minimizing criterion: $J= \int_{0}^{t_f} ((\frac{df}{dx})^2+u^2) \,dt $ Algorithm: We ...
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0answers
33 views

FeedBack linearization and stabilization error

Consider nonlinear system: \begin{cases} \dot{x_1}=x_4+u \\ \dot{x_2}=-x_2+\frac{(\tanh(k \cdot x_5)+1)}{2}+U(t)+u \\ \dot{x_3}=-x_3+\dot{f} \\ \dot{x_4}=-x_4+x_3 \cdot s(t) \\ \dot{x_5}=-x_5+x_3 \...
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0answers
41 views

Nonlinear system with time-optimal control

Given nonlinear system: \begin{cases} \dot{x_1}=x_3+u \\ \dot{x_2}=-x_2+\dot{f} \\ \dot{x_3}=-x_3+x_2 \cdot \alpha \sin(\omega t) \\ \dot{x_4}=-x_4+x_2 \cdot (\frac{16}{\alpha^2}(\sin(\omega t)-\frac{...
2
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1answer
40 views

AsymptoticOutputTracking for output with boundary condition

I want to try asymptotic output tracking, but with inequality. There is a differential equation: $\frac{dx}{dt}=\frac{d}{dx}(-x^4)$ With output $y=\frac{d}{dx}(-x^4)$, The output should strive for $0$,...
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0answers
44 views

Asymptotic Output Tracking - How to Track?

Asymptotic Output Tracking: Code Issues Abstract state-space: \begin{cases} \dot{x_1}=x_3 \\ \dot{x_2}=-x_2+\frac{df}{dt} \\ \dot{x_3}=-x_3+x_2 \cdot \alpha \sin(\omega t) + u \\ \dot{x_4}=-x_4+x_2 \...
1
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1answer
67 views

AsymptoticOutputTracker to Matlab-Simulink

What is the structural scheme for AsymptoticOutputTracker in Mathematica? I need this in order to transfer the feedback signals received with the help of ...
1
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1answer
48 views

Comparison of NDSolve and Asymptotic Output Tracking results: Problem identified

My question is a continuation of the topic: Asymptotic Output Tracking: Code Issues Edit: Take system of ODE for example: $\begin{cases} \frac{dx}{dt}=H \cdot \alpha \sin(\omega t)+\alpha \omega \cos(\...
2
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1answer
169 views

Asymptotic Output Tracking: Code Issues

My question is a continuation of the topic Which way of solving from nonlinear control to choose?, and in the future I plan to expand this question. I want to try to apply this article https://www....
2
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0answers
43 views

Affine state-space: Nonlinear output

I am using a system of equations to experiment: $\begin{cases} x_1'=x_2 \\ x_2'=x_1^2-x_2+u \end{cases} $ As an output, I want to use the following non-linear output: $y=e^{-x_1^2}$ ...
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0answers
37 views

Which way of solving from nonlinear control to choose?

I have a nonlinear system: \begin{cases} x'=f(x)+u \\ y=f(x) \end{cases} where $f(x)$ - gradient of some one-extremal function (for example $f=e^{-(x)^2}$), i.e. $\frac{df}{dx}$. I want to construct a ...
1
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1answer
368 views

Lyapunov exponent and stability of limit cycles

I have a four dimensional dynamical system where I have a Hopf bifurcation. My aim is to figure out if limit cycles are stable or not. The calibration in the system is ...
0
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0answers
97 views

NDSolve Error - There are fewer dependent variables, than equations, so the system is overdetermined

I have a program in which I am simulating the motion of two-wheel vehicle. I have four global parameters xo (position x of rear wheel), yo (position y of rear wheel), teta (the angle of inclination of ...
6
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3answers
848 views

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

Given the transfer function gs = (5*s + 4)/(s^4 + 4*s^3 + 2*s^2 + 3*s); and the input signal ut = Sin[t + π/6; I want to get ...
2
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1answer
368 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 ...
0
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0answers
63 views

How to solve this linear complementarity problem with NDSolve or other functions? The arguments should be ordered consistently

I want to find a numerical solution of $\omega(t,q)$, where $t\in[0,T]$ and $q\in[0,N]$. $q_t$ is a determinstic w.r.t $t$, other unmentioned parameters can be fullfilled or given by the user. I met ...
3
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1answer
59 views

How to code a Sum Block when working with Transfer Functions?

I am working using transfer functions models with Mathematica and i am missing a basic feature like the ability to use a Sum Block. How could the model above be modeled? Considering: ...
1
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0answers
84 views

Do Loop contained in a function defined within a custom package doesn’t work as expected but works fine when function is defined directly in a script

Below is my code and I am having problems running the StdMPC function that I am trying to define. Running my code gives me the error that the matrix A and Xopt[[i]] are not of compatible shapes for ...
1
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1answer
54 views

Changing the quality of the transient process in a nonlinear system (in Mathematica)

I urgently need advice and help. I have a system of differential equations like this: $\begin{cases} \frac{dx}{dt} == y[t] \cdot \alpha \cdot sin(\omega t) + \frac{d}{dt}(\alpha \cdot sin(\omega t)) ...
2
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1answer
77 views

How to combine Manipulate and OutputResponse to manipulate a transfer function

The webpage on Manipulate provides an example on section Examples > Applications of how to manipulate two parameters (the initial conditions) of an Initial Value Problem (ODE with initial ...
0
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1answer
50 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 ...
3
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1answer
155 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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0answers
75 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 ...
2
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1answer
117 views

Linear Quadratic Integrator

With a given linear drive system ...
22
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2answers
943 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?
3
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2answers
97 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 ...
0
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0answers
142 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 ...
3
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1answer
82 views

TransferFunctionModel produces large coefficients

First, I define the following transfer functions using TransferFunctionModel: ...
6
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1answer
409 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,...
2
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1answer
668 views

TransferFunctionModel and BodePlot shows different result between Mathematica and MATLAB

I was doing the TransferFunctionModel and BodePlot. But the result from Mathematica and MATLAB are different. The function is ...
6
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1answer
112 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 ...
4
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1answer
102 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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