pykinematics.omc.angles.hip

pykinematics.omc.angles.hip(pelvis_frames, thigh_frames, side)

Compute hip angles.

Parameters:

pelvis_frames : numpy.ndarray

Nx3x3 array of anatomical frames of the pelvis in a world frame. N time samples of 3x3 matrices, of which the first column is the pelvis X-axis, second column is the pelvis Y-axis, and third column is the pelvis Z-axis

thigh_frames: numpy.ndarray

Nx3x3 array of anatomical frames of the thigh for N time points in the world frame. Each 3x3 matrix is comprised of columns of thigh x-axis, y-axis, and z-axis, in that order.

side : {‘left’, ‘right’}

Side the angles are being computed for. Used for sign determination of angles.

Returns:

hip_angles : numpy.ndarray

Nx3 array of hip angles, with the first column being flexion-extension, second column being ad/abduction, and third column being internal-external rotation.

References

Wu et al. “ISB recommendations on definitions of joint coordinate systems of various joints for the reporting of human joint motion - part I: ankle, hip, and spine.” J. of Biomech. Vol. 35. 2002. Dabirrahmani et al. “Modification of the Grood and Suntay Joint Coordinate System equations for knee joint flexion.” Med. Eng. and Phys. Vol. 39. 2017. Grood et al. “A joint coordinate system for the clinical description of three-dimensional motions: application to the knee.” J. of Biomech. Engr. Vol. 105. 1983.