Finding Symbolic Matrix Derivative

3 visualizaciones (últimos 30 días)
JPS
JPS el 8 de Mayo de 2021
Respondida: Paul el 8 de Mayo de 2021
I have the following Matrix and I wish to find its derivative,
A =
Please note that ϕ and θ in this matrix are functions of time t.
I have the following MATLAB code,
syms phi theta t real
A = [1 , 0 , -sin(theta) ;...
0 , cos(phi) , cos(theta) * sin(phi) ;...
0 , -sin(phi) , cos(phi) * cos(theta)];
Adot = diff(A); % this isn't giving the result I expect
So I tried,
syms phi theta t real
A = [1 , 0 , -sin(theta) ;...
0 , cos(phi) , cos(theta) * sin(phi) ;...
0 , -sin(phi) , cos(phi) * cos(theta)];
phi(t) = phi;
theta(t) = theta;
Adot = diff(A , t); % this also isn't working
The result I want is,
Please help me to get this result.

Respuestas (1)

Paul
Paul el 8 de Mayo de 2021
Declare theta and phi as functions, and then substitute after differentiating A
syms phi(t) theta(t) phi_dot(t) theta_dot(t)
A=[1 0 -sin(theta);0 cos(phi) cos(theta)*sin(phi);0 -sin(phi) cos(phi)*cos(theta)]
A(t) = 
subs(diff(A,t),diff([phi(t) theta(t)]),[phi_dot(t) theta_dot(t)])
ans(t) = 
Note that this result is not the same as the expected result in the question, which appears to have some terms that are incorrect.

Categorías

Más información sobre MATLAB en Help Center y File Exchange.

Etiquetas

Productos


Versión

R2020a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by