error in the process of symbol operation of the matrix
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It is convenient to use symbol operation to explore the relationship during the multiplication of matrices. And here is my code.
clc;clear;
theta = sym('theta',[1,4])
d = sym('d',[1,4])
a = sym('a',[1,4])
alpha = sym('alpha',[1,4])
T = ones(4,4)
for i = 2:1:4
T = T*[cos(theta(i)) -sin(theta(i)) 0 a(i-1);
sin(theta(i))*cos(alpha(i-1)) cos(theta(i))*cos(alpha(i-1)) -sin(alpha(i-1)) -d(i)*sin(alpha(i-1));
sin(theta(i))*sin(alpha(i-1)) cos(theta(i))*sin(alpha(i-1)) cos(alpha(i-1)) d(i)*cos(alpha(i-1));
0 0 0 1];
end
T
the answer is :
What is wrong with T?
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Answers (2)
Matt J
on 29 May 2023
Edited: Matt J
on 29 May 2023
Nothing is wrong with T, though possibly you didn't scroll down far enough to see the definitions of all the sigmas.
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John D'Errico
on 29 May 2023
Edited: John D'Errico
on 29 May 2023
I would specuulate the issue is that T ends up as a rank 1 matrix, which it MUST, since T starts out as a rank 1 matrix, as ones(4).
John D'Errico
on 29 May 2023
Edited: John D'Errico
on 29 May 2023
Why do you think there is something wrong with T? We don't know why you wrote this code. It computes what you told MATLAB to compute.
T is displayed there TWICE. The first time it is an array of all ones. A BAD IDEA. I think you wanted T to start as an IDENTITY matrix, not a matrix of all ones.
help eye
The point is, if you are looking at this as a sequence of rotations, then you need to start with an identity matrix.
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