Human-System Interaction

Summary

The development of computing capacity and the associated algorithms make it possible to implement detailed co-simulations of humans and the systems with which they interact, whether from a sports (athlete-sports equipment), ergonomics (worker-assistive device) or clinical (patient-medical device) point of view. In particular, these simulations and the study of the resulting interactions can be used to predict the impact of systems on the performance of a given task, thereby accelerating their prototyping or optimizing their use. These objectives raise a number of scientific challenges, such as modelling the human-system interface, integrating control into the simulation and rigid-deformable coupling in the simulation loop. It also raises questions about the interpretability of the results and their analyses.

Long term scientific objective

This research axis is focused on the development, adaptation and integration of frameworks able to analyse and simulate the interaction of the human with a system, in order to use those simulation a priori for training, ergonomics or rehabilitation, or a posteriori for evaluation. In the field of physical assistance at work, understanding and formalising the tasks to be assisted and human capabilities are essential to the design of devices capable of assisting humans in carrying out the task, particularly portable devices such as exoskeletons. From the specification of systems to the evaluation of their effectiveness, their design benefits greatly from this knowledge. With this in mind, modelling and simulation of the human-exoskeleton system is a powerful and effective way of testing the functionality of the exoskeleton and its potential interaction with the human it is intended to assist. In a similar manner, rehabilitation and assistive devices can get profit from such a framework to be designed and controlled with regard to the specifics of the user, i.e. a disabled person, and optimize the efficiency of the device. This remark is clearly asking the question of the fidelity of the biomechanical model as well, being deeply linked to the first axis of research of ComBO. At last, the biomechanical interaction is a fundamental piece of the performance in sports, asking for the development of integrated and detailed interaction models able to guide the athlete and his coaching staff to a given performance using a given material. Another way to think about this issue is to highlight the need of multiscale approaches in the study human-system interaction.
In many ways, this interaction has local consequences (stress, strain, injuries) that would benefit from an accurate analysis framework, and unexpected effects (muscle compensatory recruitment, motor control changes…) that would benefit from a larger scale analysis framework.

Figure 1: From top to bottom, left to right: a) Springboard diving energetics, b) wrist exoskeleton cosimulation model, c) shoe stiffness assessment through motion capture analysis, d) a human-exoskeleton cosimulation for overhead work assistance

Short term goals and actions

We are currently working on the following goals:

Wrist exoskeleton simulation: within the frame of the exoscarne project, we seek at developing a wrist exoskeleton being able to render meat cutting tasks sustainable for the workers. This project is particularly focusing on the development of a virtual prototyping framework including a detail forearm and hand musculoskeletal model and a virtual prototype of the exoskeleton, coupled with non linear visco-elastic contact models.
Reach and grasp exoskeleton: through a collaboration with the Rainbow inria team and the rehabilitation center “pôle saint hélier” in Rennes, we seek at developing specific models of disabled people to adapt the control of a reach and grasp exoskeleton currently developed in the rainbow team (Exoptim SAD post doctoral grant). In this approach, we try to develop a cosimulation framework able to provide a pretuning of the system to the subject in both geometrical and control terms, able to guide practicioners in their rehabilitation choices with the system.
Pole Vault energetics: in collaboration with the digisport project and the common inria-insep team, we are currently lauching a PhD thesis on the subject of the energy transfer between the pole and the vaulter in elite pole vault. The aim is to provide coaches and athletes with elements to guide them in improving their technique with regard to maximizing mechanical energy during the jump. To do so, we seek at developing a cosimulation framework, able to take into account the motion of the athlete, the deformation of the vault, and the force transferred between both.
External forces estimation: The team has a strong background in developing motion-based external forces estimation methods and will continue to work on those subjects by extending their applicability to specific surfaces and systems (landing mats and other apparatus in gymnastics, moving platforms such as skateboarding,…).