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Robotic Clothing for Tactile Interaction for Kinesthetic Learning
People in physical rehabilitation, those with improper posture, and those wanting dance lessons all face a similar task – namely, motor learning. Most people benefit from a teacher who can give real-time feedback through a variety of channels: auditory (high level behavioral instructions), visual (by demonstrating the motion themselves), and tactile (by physically guiding the student). Although tactile feedback presents the most direct form of motor information, it is the most difficult for a teacher to give, especially while performing a task themselves. Further, due to human limitations, instructors cannot give tactile feedback over all human joints simultaneously.

This research proposes an extension to the human teacher – a robotic wearable suit that analyzes the target movement (e.g., performed by the teacher) and applies real-time corrective vibrotactile feedback to the student’s body, simultaneously over multiple joints. This tactile feedback can supplement the visual or auditory feedback from the teacher. After a period of acclimation, the student can utilize this novel high bandwidth vibrotactile information to more quickly and deeply learn new motor skills. We call this system as TIKL: Tactile Interaction for Kinesthetic Learning. This research is intended for use in a diverse set of applications including sports training, motor rehabilitation after neurological damage, dance, postural retraining for health, and many others.

The publications below describe the technical details of the system and report our results using a 5-DOF robotic suit. The motor learning feedback system consists of four modules. First, the teacher performs a movement that the student tries to mimic. Their performance is currently tracked optically by a Vicon optical motion capture system. Results from tracking are fed into our software that compares the performance of the student and teacher to generate feedback commands for the student. These feedback signals are then sent to the wearable vibrotactile feedback suit, worn by the student. Joints moving in error will receive vibrations proportional to the amount of error (for both flexion and rotational joints). Wherever the student’s body is different than the teacher’s, direct tactile feedback indicates the discrepancy to those specific joints. Zero feedback indicates that the student’s body is in the correct configuration over time.

We have found that the addition of tactile feedback to motor training induces a statistically highly significant change in performance. It lowers real-time errors by up to 27%; learning rate is improved by up to 23%; and steady-state learning errors, the measure of performance over time, are improved by up to 27%. Given our experimental setup we hypothesize that in more complex tests, improvements will increase. Subjects with feedback showed higher level of attention, correcting their motions at times when those without feedback stood idle. Importantly, this all occurred while users felt there was no significant loss of comfort through the addition of the wearable.

The long-term goal of this system is to become a low latency, full-time, wearable, highly parallel robotic motor skills teacher that can provide constant motor-system feedback to the student as he or she attempts to learn new motor skills. It is possible that over long-term usage, users may become accustomed to the system, and the more complex feedback paths may become subconscious. We may eventually be able to learn these motions faster, deeper, without even realizing that we are doing so.
Papers
Lieberman, J. & Breazeal, C. (2007) “Development of a Wearable Vibrotactile Feedback Suit for Accelerated Human Motor Learning.” Proceedings of the 2007 IEEE International Conference on Robotics and Automation (ICRA). 4001-4006.

J. Lieberman & C. Breazeal (in press) “
TIKL: Development of a Wearable Vibrotactile Feedback Suit for Improved Human Motor Learning”. IEEE Transactions in Robotics (T-RO).