Vers des environnements virtuels plus écologiques : étude des modifications du comportement moteur en réalité virtuelle lors de l'ajout d'informations haptiques par un mécanisme parallèle entraîné par câbles

Authors: Faure, Céline
Advisor: Bouyer, LaurentMcFadyen, Bradford James
Abstract: Introduction: New technologies that capture and analyze user movement are constantly developing and represent a great potential in healthcare. Thanks to the recent technological advances, turnkey virtual reality (VR) systems are progressively integrated into the rehabilitation setting, and studies have demonstrated their ability to optimise sensorimotor rehabilitation and clinical assessment of people with motor control disorders. The market for VR is growing and adding haptic feedback that provides physical characteristics to virtual entities represents a great potential to improve the ecological validity of virtual environments (VE) and to the transfer of learning to daily tasks. However, the impact that adding haptic feedback has on motor behavior remains poorly understood. The main objective of this thesis was to assess the impact of adding haptic feedback, using a novel cable-driven parallel robot, on the motor control of healthy participants during complex, functional tasks in VEs. The two mains hypotheses were that haptic feedback improves motor control during a handling task with static environmental constraints and modifies proactive locomotor strategies in the presence of dynamic constraints. Method: The motor behavior of healthy participants was analysed during two tasks. First, a manual handling task was studied during which participants grasped and moved a crate while standing. This task was realised in a real environment and in VEs with the absence and the presence of haptic information. The latter simulated the physical constraints of the shelf and the crate to be manipulated using a cable-driven robot (Chapter 3, N=12). Second, avatar avoidance tasks were realised when participants walked on a self-paced treadmill in the absence and then in the presence of a risk of physical contact with avatars. Contact was simulated by a cable-driven robot (Chapter 4, N=10). VEs were viewed through a head mounted display for all tasks. Results: The first study showed that adding haptic feedback to the VE improved spatial parameters of movement realised in a VE during all phases of movement (reaching, ascent and descent phases). The spatial organisation of movement was closer to those observed in a physical environment, and better respected environmental constraints (higher clearances from the shelf and longer trajectories). Moreover, movement control was influenced by task precision required to avoid any contact with the shelf in the presence of haptic feedback only. The second study demonstrated that when avoiding avatars in VR, more cautious behavior was measured in the presence of potential physical contact. Participants tended to start their avoidance strategy earlier and increased minimum clearance along with a larger personal space regardless of the avatar’s approach angle. Conclusion: Adding haptic feedback in VEs impacts the proactive motor strategies of healthy participants during a manual handling task as well as a locomotor task involving the avoidance of avatars. These results suggest that adding haptic feedback enhances one’s consideration of virtual entities during movement planning. Haptic information imposes more realistic restrictions on the actions afforded by EVs, and likely modifies the perceived consequences of potential contact with virtual entities. It will be important to continue to study the impact of haptic feedback within VEs to provide even more ecological environments to people with motor deficits in order to improve assessment and the consideration of implicit risks posed by the environment.
Document Type: Thèse de doctorat
Issue Date: 2019
Open Access Date: 22 January 2020
Grantor: Université Laval
Collection:Thèses et mémoires

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