The use of muti-modal haptic feedback to convey various aspects of touch sensitivity

Abstract

Despite much progress in the development of prosthetic limbs, the lack of touch sensitivity remains a significant problem: prosthetic limbs still do not provide any tactile feedback to users, requiring continuous visual attention from the user during task accomplishment. This thesis examines how haptic technology, based on exteroceptive feedback from the motion of the prosthesis, can be used to remedy this situation. We hypothesize that a portable haptic device can complete the communicational loop between the prosthetic limb and the user, by stimulating the mechanoreceptors in the skin of an unimpaired part of the user’s body. We began our research by investigating the relative effectiveness of three types of haptic feedback - normal stress, tangential force, and vibrotactile stimulation - in order to determine which type of haptic feedback performs best under static conditions. Results indicated that normal stress stimulation is the most effective under static conditions; it is therefore the best of the three options at conveying a sense of pressure to the user, such as the grasping force applied by the prosthetic limb during object manipulation. Based on this result, we developed a novel wearable haptic device that provides the user with knowledge of a normal force, by applying pressure at three different locations on the user’s body. We then investigated how the simultaneous application of two different types of haptic feedback impacts human sensory perception, how vibrotactile stimulation can be used to convey a sense of texture, and how the amount of training that the human subjects receive affects their ability to successfully use the haptic system. Finally, our haptic device was integrated within a robotic system and we verified its effectiveness for use during pressure and texture recognition tasks. Ultimately, our work contributes new knowledge about the relative effectiveness of different types of haptic feedback under static and dynamic modalities, so that haptic systems may be optimized for use under the conditions demanded by industrial and biomedical applications.

Date	4 Sept 2015
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Vincent Duchaine (Supervisor) & Pascal Bigras (Co-supervisor)