Wearable sit-to-stand-up (STS) Guiding Device Using Asymmetric Vibration Speaker

Abstract: The lack of physical therapist (PT) resources has become a global problem [1]. The sit-to-stand-up (STS) training is one of the most important PT programs to improve the elderly’s mobility and prevent falling. In this research, a wearable (STS) motion navigation system utilizing asymmetric vibration techniques has been developed. Aiming to help the elderly do PT programs at their own house instead of paying the high cost and difficulty of making an appointment for PT.The asymmetric vibration method in this research uses a vibration speaker to play the asymmetric amplitude signal that drives the speaker to generate a vibration that could have a practical feeling, like pushing or pulling [2]. This kind of poke feeling is similar to the guiding training that the PT doctor is poking the shoulder to direct the motion. Based on this method, our lab has developed an upper-limb rehabilitation training system [3] and a walking training system [4][5]. For this research, the STS motion has been picked up from the PT program. The guiding system mainly has two functions. (a) the first is according to the user’s current STS motion by using an IMU sensor. The system could generate an asymmetric vibration from the vibration model which is attached to the front side of the chest or the back side of the neck to guide the user to lean the body. This will match the key index of the PT training of the recommended STS motion. This will decrease the required torque on the body joint due to this kind of motion [6]. User under the guidance could stand up easily. (b)The Second function is for the sitting down motion, the system will calculate the COG position according to the age, height, and gender information that is input to the system. It will calculate the balanced COG moving tunnel and according to the detected angular data and acceleration for judge the current situation needs what kind of revise. Guide the user through the asymmetric vibration to sit down in a balanced way, preventing falling down.To achieve these two functions, the following points have been researched. 1) The definition of the recommended STS motion was calculated from the simplified 3-D human model by the condition of COG position and the muscle simulation 2) The suitable asymmetric vibration setting was researched in the wave shape frequency and the power. We invite volunteers to vote for the poke feeling and choose the sensitive position around the upper body, 3) The guiding quality was evaluated by the volunteer experiment in the repeated test and the STS motion timing judgment. 4) the guided learning angular data from the volunteer was recorded by motion capture system and compared to the recommended database for evaluating the quality of this system. From the motion comparison results, our proposed device's effectiveness could be evaluated.Reference：[1] N. Hori S., et al., “Trends in outpatient rehabilitation practices in Japan: analysis using the National Database of Health Insurance Claims Open Data,” J. Rural, pp. 125–130, 2022. [2] T. Tanabe, H. Yano, and H. Iwata, “Properties of proprioceptive sensation with a vibration speaker type non-grounded haptic interface,” IEEE Haptics Symposium, pp. 21–26, 2016. [3] H.Y. Duan, T. Q. Wang, H. Lee, E. Tanaka, A Wearable Haptic System for Rehabilitation Based on the Asymmetric Vibration, SII2021, pp. 815-816, (2021).[4] E. Tanaka, H. Y. Duan, K. Osawa, K. Nakagawa, H. Lee, L. Yuge, Development of a Walking Promoter Using Vibration Speaker, LIFE2022, pp. 20-23.(in Japanese)[5] E. Tanaka, K. Osawa, J.-R. Zhuang, X. Wu, Y. Hua, K. Nakagawa, H.-H. Lee, and L. Yuge, “Development of walking assistance devices considering the users’ psychological and physical status,” The 16th IFToMM World Congress (WC2023), pp. 152–162, 2023. [6] E. Tanaka, K. Osawa, J.-R. Zhuang, X. Wu, Y. Hua, K. Nakagawa, H.-H. Lee, and L. Yuge, “Mechanical design of a standing-up assistance apparatus of leaning forward the upper body which can be transformed into a flat-lying posture,” JSME, pp. 712–727, 2011.

Keywords: Outpatient, Vibration speaker, Motion navigation, Asymmetric vibration, ADL.

DOI: 10.54941/ahfe1006198

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