Conversion to double from struct is not possible.

Can you please help me with this error message?

Conversion to double from struct is not possible.

Error in STABLE (line 80)
    qs(i,:) = qSol;

Find attached the STABLE.m

https://it.mathworks.com/matlabcentral/answers/362553-conversion-to-double-from-struct-is-not-possible#comment_841695

This is what i get in the command window:

    qSol = 

  1×7 struct array with fields:

    JointName
    JointPosition

Answer 1

[Ameer Hamza]

Chage following lines

Line 4:

robot = rigidBodyTree('DataFormat', 'row');

Line 85:

show(robot,qs(1,:));

Line 95

show(robot,qs(i,:),'PreservePlot',false);

[Massimo Lucia]

thank you! It works properly now. Just a matter of rows and columns!

[Ameer Hamza]

I am glad to be of help.

[Massimo Lucia]

I get the same error when in the same file i replace the line 4 with the following:

robot = importrobot('xxxxxxx.urdf');

How can i set the dataformat to row or column in this case?

[Ameer Hamza]

Do it like this

robot = importrobot('xxxxxxx.urdf');
robot.DataFormat = 'row'; % or 'column'

[Massimo Lucia]

got it

Answer 2

[Bjorn Gustavsson]

This is obviously an operation that's not supported. If you look at the contens of one struct, you might find that the Jointname is a string, or a char-array. Those might be of different lengths (Al Dee or Vishvanatan Axelsson-Johnsson) - this makes it difficult to convert into a double array. Try with the fields of the struct separately:

Allpos = [qSol(:).JointPosition];
Allnames = char(qSol(:).Jointname)

HTH