Combining morphological interpolation and biomechanical
inverse kinematics to simulate bipedal locomotion

Nicolas Pronost Guillaume Nicolas Georges Dumont Franck Multon
University of Rennes 1 University of Rennes 2 ENS Cachan University of Rennes 2

An initial (solid line) and reconstructed (dashed line)
poulaine in the (x,z), (x,y) and (y,z) planes

Abstract :

The method presented in this paper aims at calculating a plausible bipedal locomotion based on anatomical data and biomechanical locomotor hypotheses. To this end, inverse kinematics and motion interpolation are used. In classical inverse kinematics approaches, the resolution of the primary task ensures that the effector follows a given trajectory. This trajectory, considered in this work as the Cartesian displacement of the ankle as seen in the coordinate frame of the center of the pelvis, is computed using movement adaptation and interpolation in a wide database. Initially, bipedal motions are captured thanks to a motion capture system and then, mathematically modeled. After the database is built, interpolation is performed according to three locomotor constraints: step length, spacing of the feet and reference posture of the character. In this paper, we include secondary tasks that enable to take biomechanical laws for bipedal locomotion into account: respecting joint limits, resembling a given reference posture and minimizing rotational kinetic energy. A weighted sum of the resulting derivable cost functions enables us to select a specific solution in the null space of the primary task. After comparative validations related to biomechanical literature for bipedal locomotion (internal work, mechanical energy, jerk), we demonstrate that our method produces trajectories that are very close to captured ones.

Keywords :

Motion retargeting - Biomechanics - Morphological and multidimentional interpolations - Inverse kinematics

Paper :
IASTED Visualization, Imaging & Image Processing (VIIP) 2005 - Pdf paper :

BibTeX :

author = {N. Pronost and G. Nicolas and G. Dumont and F. Multon},
title = {Combining morphological interpolation and biomechanical inverse kinematics to simulate bipedal locomotion},
booktitle = {IASTED - Visualization, Imaging & Image Processing (VIIP) Conference, Benidorm - Spain},
year = {2005},
month = sep,
pages = {39-45},
editor = {J.J. Villanueva},
publisher = {ACTA Press},
series = {ISBN: 0-88986-528-0}