what's the code inside angle2dcm?

I saw angle2dcm on Mathworks but don't know how scalars of x,y,z or vectors of x,y,z become matrix after using angle2dcm.

Can anyone explain the code embedded?

Thanks very much.

Answer 1

[Mathieu NOE]

hello

here you are

notice that there are some issues / questions about orientation convention with this function

angle2dcm3(rot1, rot2, rot3, order) - File Exchange - MATLAB Central (mathworks.com)

angle2dcm convention - (mathworks.com)

rotation - Matlab angle2dcm different definition - Stack Overflow

function [dcm] = angle2dcm(r,seq)
% dcm = angle2dcm(r1,r2,r3,seq)
% builds euler angle rotation matrix
% 
% r = [r1 r2 r3]
% seq = 'ZYX' (default)
%       'ZXZ'
% dcm = direction cosine matrix

if nargin == 1
  seq = 'ZYX';
end

switch seq
  case 'ZYX'
    dcm = Tx(r(3))*Ty(r(2))*Tz(r(1));
  case 'ZXZ'
    dcm = Tz(r(3))*Tx(r(2))*Tz(r(1)); 
end

function A = Tx(a)
A = [1 0 0;0 cosd(a) sind(a);0 -sind(a) cosd(a)];

function A = Ty(a)
A = [cosd(a) 0 -sind(a);0 1 0;sind(a) 0 cosd(a)];

function A = Tz(a)
A = [cosd(a) sind(a) 0;-sind(a) cosd(a) 0;0 0 1];

[yunya liu]

Very detailed description. Thanks so much.

Answer 2

[Jan]

While I cannot find the code of angle2dcm , the equivalent function eul2rotm is useful for the explanation also. It produces the transposed matrix compared to angle2dcm.

See:

edit eul2rotm

3 angles define the attitude of a coordinate system. The "dcm" matrix (direction cosine matrix) contains the 3 unit vectors of the base of a rotated coordinate system.

[yunya liu]

Thank you