Biomechanical cost quantification for wheelchair accessible cities – CapaCITIES

The project rely on a biomechanical evaluation of MWU performing various senarii of controlled displacements on a dedicated MWC simulator. This require developments on the tools for biomechanical evaluation, the development of a haptic and immersive MWC simulator, and the ability to aggregate several biomechanical parameters with different units in a single index.

Biomechanical evaluation: The objectives of this part of the project are: 1) to implement a musculoskeletal model including a close loop definition of the shoulder kinematic chain, and to associate muscle paths; 2) to provide a scaling method to obtain subject-specific models without resorting to medical imaging; and 3) to implement a computationally efficient method for the assessment of all the biomechanical parameters. All the extracted biomechanical parameters will have to be sorted in terms of importance in order to study the physical demand of an environmental situation. The assessment of all these data simultaneously for several environmental situations will be a significant contribution to the state of the art.

MWC simulator: Biomechanical data must be obtained in realistic and controlled locomotion conditions. For that purpose, we choose to reproducing the MWC locomotion on a simulator. Among the existing MWC simulators, their realism were restricted by either i) the poor immersion, ii) the absence of haptic feedback, or iii) the lack of sensors necessary to reproduce the mechanical behavior of the MWC or to quantify biomechanical parameters. To face these limitations, our aim is to develop a dynamic, haptic and immersive simulator based on a Stewart platform and a controlled roller ergometer. Another major originality of this simulator will be the possibility to change the settings by a remote command with the subject sat on the chair because the configuration of a MWC has a drastic impact on the mobility. The sensors embedded on the ergometer will provide measurements for both the biomechanical analysis and the control of the simulator, which includes the haptic, visual and vestibular feedbacks.

Biomechanical costs: In the literature, even if several indices were already proposed in the field of MWC locomotion, no study has sought to quantify the accessibility on a continuous scale (i.e. not just 0 vs 1) by the association of a cost to the different environmental situations. Besides, depending on the situation, the relevant biomechanical parameters for classifying the situations can be different (work vs joint stress, for instance). As a consequence, it is important to associate different biomechanical costs related to environmental situations and ideally to provide a synthetic and comprehensive biomechanical index integrating the different aspects of the physical demand of the situations.

Musculoskeletal modeling: limitations of current model in terms of shoulder mobility and model personalization to MWU characteristics and pathologies have required strong developments, in particular for solving dynamics in close loop (shoulder, forearm) in CusTOM (modeling and computation software). Model personalization have been implemented and deeper works are still in progress. Significant improvements in computational efficiency was achieve, more especially by the automatic generation of muscular path and implementation of soft constrains.
MWC simulator: the simulator will be both haptic, dynamic and immersive. The haptic aspect requires precise modeling of the User/MWC/environment interactions an the development of control algorithm allowing the reproduction of the MWC mechanical behavior. Two control approaches were developed: explicit predictive control to which an anticipatory control is added; and more recently, a direct adaptative control by reference model was implemented. For the MWC mechanical model, two new rolling and swiveling resistance torques models have been proposed and validated on horizontal ground. The validation of the model, taking into account the characteristics of the road (slope, cross-slope, grip) and the development of the identification method are in progress. The visual immersive aspect was done using SCANeR Studio software, in which the use cases were implemented. The interface with the MWC kinematics has been developed, in such way that position, speed and acceleration information output from the model is sent to the visual space to make it evolve.
Experimental campaign: if experiments on the simulator have not started yet, first experiments were performed using reproduced situations (horizontal, slope, cross-slope, thresholds) in a motion capture lab and data are currently in processing.
Biomechanical cost: the first experiments have already allowed demonstrating that classifying environmental situation based on constrain level is depending of the parameter that is chosen. Indeed, for instance, the ranking of the situations based on the propelling torque is different than the ranking based on total force applied on the handrims, while these parameters are a priori very close, confirming the muti-criteria approach chosen for the project.

Project still in progress

Publications :
Claire Livet, Théo Rouvier, Georges Dumont, Charles Pontonnier. An automatic and simplified approach to muscle path modelling. Journal of Biomechanical Engineering, American Society of Mechanical Engineers, 2021, 144 (1), pp.1-9.

Théo Rouvier, Aude Louessard, Samuel Hybois, Emeline Simonetti, Joseph Bascou, Charles Pontonnier, Hélène Pillet, Christophe Sauret. Manual wheelchair biomechanics while overcoming various environmental barriers: a systematic review. PLoS ONE 17(6): e0269657.
Claire Livet, Théo Rouvier, Christophe Sauret, Hélène Pillet, Georges Dumont, Charles Pontonnier. A penalty method for constrained multibody kinematic optimization using a Levenberg-Marquardt algorithm. Comput Methods Biomech Biomed Eng (accepted)
Oukacha, O., Sentouh, C. and Pudlo, P. Minimising the User’s Effort during Wheelchair Propulsion using an Optimal Control Problem. In Proceedings of the 17th International Conference on Informatics in Control, Automation and Robotics (ICINCO 2020), pages 159-166
Communications :
Claire Livet, Théo Rouvier, Charles Pontonnier, Georges Dumont. Open vs closed articular architecture of the forearm for an analysis of muscle recruitment during throwing motions. ISB 2021 - XXVIII Congress of the International Society of Biomechanics, Jul 2021 Stockholm, Sweden.
Claire Livet, Théo Rouvier, Christophe Sauret, Georges Dumont, Charles Pontonnier. Expected scapula orientation error regarding scapula-locator uncertainty while studying wheelchair locomotion. Computer Methods in Biomechanics and Biomedical Engineering, 2021, 24(Sup1):72-74
Aude Louessard, Théo Rouvier, Joseph Bascou, Samuel Hybois, Hélène Pillet, Christophe Sauret. A preliminary investigation of handrim kinetics in various environmental situations crossed in manual wheelchair. Computer Methods in Biomechanics and Biomedical Engineering, 2021, 24(Sup1):272-274
Amel Ait Ghezala, Chouki Sentouh, Philippe Pudlo, Direct Model-Reference Adaptive Control Based EHO Tuning for Manual Wheelchair Simulator with a Haptic Feedback, submitted to 15th IFAC/IFIP/IFORS/IEA Symposium on Analysis Design and Evaluation of Human-Machine Systems, San José State University, September 12-15, 2022
Amel Ait Ghezala, Chouki Sentouh, Philippe Pudlo, Contrôle adaptatif direct par modèle de référence basé sur l'algorithme EHO pour le pilotage d'un simulateur de fauteuil roulant avec un retour haptique, Journées du CT Automatique et Transport Terrestre, Valenciennes, 6-7 avril 2022

Locomotion with a manual wheelchair (MWC) submits the upper-limbs of the manual wheelchair users (MWU) to an important stress, which varies according to the environment. To assist MWU in selecting the paths that preserve their upper limbs, a cost reflecting the physical demand of the successive situations along the possible paths must be attributed. In the current state of knowledge and accessibility standards, an obstacle has no graduation and can only be marked as crossable or not, which cannot reflect, neither the heterogeneity of the situations, nor the link between their accessibility and the physical and technical abilities of the MWU. To go beyond these limitations, this project aims at defining biomechanical costs that can be attributed to the environmental situations, and that could be implemented in future optimal path selection algorithms. This will make it possible to provide MWU with individualized paths taking into account their individual capacities. To do so, a musculoskeletal model will be developed to quantify various biomechanical quantities that will serve as input data for the definition of the biomechanical costs. These costs will be computed for various situations, reproduced in a realistic MWC locomotion simulator developed in the framework of this proposal. Such a project will provide original and useful data for accessibility evaluation, planning of urban development services and assistance adaptation. It will also be the basis for further work on MWU evaluation and paths characterization to provide personalized cost-optimal paths.