03 July 2023

Nour SGHAIER – PhD defense

"Biomechanics of collective load transport"

PhD defense in french

 Zoom link coming soon

Team : CAB

Supervisors : Pierre Moretto (CRCA-CBI) and Nicolas Turpin (IRISSE)

Committee members :

  • BARBIER Frank (Rapporteur), Université Polytechnique Hauts-de-France, Laboratoire d’Automatique, de Mécanique et d’Informatique industrielles et Humaines (LAMIH UMR-CNRS 8201)
  • CHEZE Laurence (Rapporteure), Université Gustave Eiffel, Laboratoire de biomécanique et mécanique des chocs (LBMC UMR_T9406)
  • MARIN Frédéric (Examinateur), Université Technologie de Compiègne, Biomécanique et Bioingénierie (BMBI – UMR CNRS 7338)
  • CHAVET Pascale (Examinatrice), Université Aix-Marseille, Institut des Sciences du Mouvement (ISM – UMR 7287)
  • MORETTO Pierre (Directeur de thèse), Université Paul Sabatier, Centre de Recherches sur la Cognition Animale (CRCA – UMR 5169)
  • TURPIN Nicolas (Codirecteur de thèse), Université de la Réunion, Ingénierie de la Santé, du Sport et de l’Environnement (IRISSE – UR 4075)

Abstract :

Collective load transport is a common task that we perform in our daily and professional lives. It involves the collaboration of two or more people to lift and move an object. Until now, the mechanisms underlying this movement and the collaboration have not been widely discussed in the literature. This thesis is part of the ANR CoBot project (Projet-ANR-18-CE10-0003) which aims to make a humanoid robot collaborative during load carrying. The objective of this work is to study the human-human interaction during a load transport, more particularly during a table or stretcher transport, and to extract biomechanical parameters that account for the control of this task. Three main questions motivate this project: (1) Does the participants’ individual and collective efficiency is altered with the task complexity? (2) Are locomotor involvement and strategies affected by backward and forward walking? and (3) Is the energy transfer occurring in the upper limbs efficient during load transport?

To answer these questions, the analysis carried out was based on techniques and methods already described in the literature and focused more specifically on: (i) an analysis of the locomotor pattern, (ii) an analysis of joint efforts and (iii) an analysis of energy transfer in the upper limbs. Our results show an alteration in the pendulum-like-behaviour of the participants’ centre of mass when adding a precision task to load transport. We also identified backward walking as the major factor impacting the locomotor patterns and efficiency in stretcher transport. The results show a distinct involvement and role for each participant. Depending on their placement and perceived environmental feedback, one participant will guide the movement, while the other will lift the load and follow the movement. These results are supported by the third study which shows that the participant who guides the movement generates and dissipates the energy required for handling the load, while the ‘follower’ is neutral. These results provide further insight into the interactions required during load transport and offer a wide range of potential applications. Indeed, the results can be used to improve control in cobotics, securing human-machine interactions, both during interactions with cobots and during tasks assisted by exoskeletons. Finally, our results should help to specify new ergonomic recommendations.


03 July 2023, 14h0017h00
Salle de conférence du CBI - Bâtiment 4R4
Campus Université Paul Sabatier Toulouse III