getWorldTransform.m

function w_H_frame = getWorldTransform(KinDynModel,frameName)

    % GETWORLDTRANSFORM gets the transformation matrix between a specified
    %                   frame and the inertial reference frame.
    %
    % This matlab function wraps a functionality of the iDyntree library.
    % For further info see also: https://github.com/robotology/idyntree
    %
    % FORMAT:  w_H_frame = getWorldTransform(KinDynModel,frameName)
    %
    % INPUTS:  - frameName: a string that specifies the frame w.r.t. compute the
    %                       transfomation matrix, or the associated ID;
    %          - KinDynModel: a structure containing the loaded model and additional info.
    %
    % OUTPUTS: - w_H_frame: [4 x 4] from frame to world transformation matrix.
    %
    % Author : Gabriele Nava (gabriele.nava@iit.it), Francisco Andrade
    % (franciscojavier.andradechavez@iit.it)
    %
    % SPDX-FileCopyrightText: Fondazione Istituto Italiano di Tecnologia (IIT)
    % SPDX-License-Identifier: BSD-3-Clause

    %% ------------Initialization----------------

    % get the transformation between the frame and the world in Matlab format
    w_H_frame = KinDynModel.kinDynComp.getWorldTransform(frameName).asHomogeneousTransform.toMatlab;

    % Debug output
    if KinDynModel.DEBUG
        w_R_frame          = w_H_frame(1:3,1:3);

        disp('[getWorldTransform]: debugging outputs...')

        % w_R_frame must be a valid rotation matrix
        if det(w_R_frame) < 0.9 || det(w_R_frame) > 1.1

            error('[getWorldTransform]: w_R_frame is not a valid rotation matrix.')
        end

        IdentityMatr = w_H_frame(1:3,1:3)*w_H_frame(1:3,1:3)';

        for kk = 1:size(IdentityMatr, 1)

            for jj = 1:size(IdentityMatr, 1)

                if jj == kk

                    if abs(IdentityMatr(kk,jj)-1) > 0.9

                        error('[getWorldTransform]: w_R_frame is not a valid rotation matrix.')
                    end
                else
                    if abs(IdentityMatr(kk,jj)) > 0.1

                        error('[getWorldTransform]: w_R_frame is not a valid rotation matrix.')
                    end
                end
            end
        end
        disp('[getWorldTransform]: done.')
    end
end