The Influence on the Walking Ability by the Different Load Support with a Robot Suit for Clinical Application of Robot Therapy

Toshiaki Tanaka, Ryo Matsumura, Norio Kato, Nobuya Hashimoto 　　

robot therapy, robot suit, assist level, gait training, motion analysis.

Purpose: The use of robots in rehabilitation is a relatively recent development and a growing area that is rapidly making inroads in clinical practice. This research examined changes in parameters when a gait-assist robot was worn and the use of a kinematic measurement method to examine the effects of differences in support and loading resulting from the use of a gait-assist robot on gait. Methods: The measured task was a walking task performed on a treadmill equipped with a robot suit. The measurement involved recording images with four digital video cameras, with one trial measured under each condition and a rest period between trials. The treadmill speed was set to 1.5 km/h, and steady-state gait was measured with a robot suit mounted over the treadmill. A motion analysis system was used for the analysis. The sampling rate was 60Hz. Three-dimensional motion analysis was used to calculate joint angles (degrees) during the walking task. The joint angles and the robot suit and the body joint angles were then compared under two conditions, the condition 1 (Assist 1) and the condition 2 (Assist 3).  Each condition was performed five times (five gait cycles). Results: according to the comparison of joint angles under the condition of Assist 1 and Assist 3, the mean peak flexion of hip, knee, and mean peak dorsiflexion of ankle joints of assist 3 was greater than that of assist 1 during the swing phase of one gait cycle. For the comparison of HAL and the body joint angles, the misalignment may arise between the assist robot (robot suit) and the body during the period of swing phase of one gait cycle walking as a characteristic of exoskeleton-type gait-assist robots. The value (mm) of the knee joint of misalignment between the robot suit and body of Assist 1 was significantly greater than that of Assis 3. Conclusion: The misalignment that may arise between the assist robot (robot suit) and the body during walking will need to be investigated in detail.  Robot therapy should be used by understanding the characteristic of assist level of an exoskeleton-type gait-assist robot for effective gait training of versatile patients.

https://doi.org/10.31871/IJNTR.7.4.7