Generation of multi-contact motions with passive joints: Improvement of Sitting Pivot Transfer strategy for paraplegics

In this paper, we present a motion generation method to improve the Sitting Pivot Transfer (SPT) strategy. We propose to analyze the impact of the torque generated on lower limbs by using Functional Electrical Stimulation (FES) on the maximal forces underneath the hands needed for the SPT. This method, based on an optimization process considers a 3D whole body biomechanical model and produces multi-contact motions with desired constant knee torque value. From the generated motions, we study the impact of legs muscle stimulation on the arm forces during the SPT motion. This approach highlights the relationship between the lower limbs stimulation and the maximal forces underneath the hands. The generated motions provide a good tradeoff between the minimization of the maximal hand forces and an excessive increase of the lower limb muscular fatigue.