Real-time sitting posture correction system based on highly durable and washable electronic textile pressure sensors

Kim, Minjeong,Kim, Hyoungjun,Park, Jinwoo,Jee, Kwang-Koo,Lim, Jung Ah,Park, Min-Chul Elsevier Sequoia 2018 Sensors and actuators. A Physical Vol.269 No.-

<P><B>Abstract</B></P> <P>A real-time sitting posture correction system based on highly durable and washable textile pressure sensors was demonstrated. Textile pressure sensors consisted of conducting Ni-Ti alloy fiber with an excellent fatigue resistance and a pressure-sensitive polyurethane elastomer resulted in reliable capacitance change by an applied pressure in a range from 10 to 180 kPa with a sensitivity of 2.39 kPa<SUP>−1</SUP>. The sensing performance was 100% maintained even upon repeated sitting action over 1000 times and harsh washing in detergent-solution. By analyzing the pressure detected at the different positions under the hip, thigh, and back, seven types of sitting postures including upright sitting, sitting with one leg crossed, and sitting with both legs lifted were successfully classified. Finally, real-time display on a monitor of the changes in sitting posture was simulated in order to allow the users to recognize and correct their body balance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A real-time sitting posture correction system based on highly durable and washable textile pressure sensors was developed. </LI> <LI> Conducting Ni-Ti alloy fiber coated with polyurethane elastomer resulted in highly durable and washable textile pressure sensors. </LI> <LI> By analyzing the pressure detected at the different positions under the hip, thigh and back, seven types of sitting postures were successfully classified. </LI> <LI> The real-time display on a monitor of changes in sitting posture, which makes users recognize and correct their body balance was simulated. </LI> </UL> </P>

모듈러형 자세유지기구 시트의 전방 높이에 따른 뇌성마비인의 착석 압력 연구

이진현,이근민 한국지체.중복.건강장애교육학회 2014 지체.중복.건강장애연구 Vol.57 No.1

The objective of this study was to provide basic data that could be helpful in selecting seat of modular seating system by examining how the seat wedge height of Polyurethane foam affected the seating pressure. In order to achieve the objective of this study, 4 seats were produced with height of 0, 3, 6, and 9cm. In order to measure the sitting pressure distribution depending on the characteristics of the produced seats, 7 subjects with cerebral palsy participated in the experiment. XSENSOR was used as a measurement device, and wheelchair simulation. This study measured the sitting pressure of each seat for 5 minutes, calculated and analyzed the obtained data, Average Pressure(AP), Peak Pressure(PP), Contact Area(CA) and Body Pressure Ratio(BPR). This experiment showed the following results. First, there were significant differences in all the AP and CA on the height of the 9cm seat wedge, the pressure was low(p < .05). Second, the result of the BPR analysis was significant depending on the seat height(p< .05). The left ischial tuberosity area located in the BP2 had the highest pressure as a whole. Based on the above results, it showed the seat wedge hight had an impact on the pressure change when sitting down. This study also showed that seat height should be preferentially considered when selecting sitting seat. If polyurethane foam was used in recommending a sitting seat, it would be desirable to recommend 9cm for the proper height for modular seat. 본 연구는 모듈러형 자세유지기구 시트의 전방 높이에 따른 착석 압력에 미치는 영향을 살펴봄으로써 자세유지기구 시트의 적절한 높이와 디자인을 선택하기 위한 기초자료를 제공하는데 그 목적이 있다. 이러한 연구의 목적을 달성하기 위해 시트 재질로 폴리우레탄 폼의 경도 18의 시트 전방 높이 0cm, 3cm, 6cm, 9cm로 구성된 시트를 총 4개를 설계 및 제작하였다. 실험에는 뇌성마비인 7명이 참여하였으며, 측정도구로는 XSENSOR를 사용하였고 휠체어 시뮬레이션에 시트를 올려 실험하였다. 각 시트마다 착석압력 측정은 5분간 실시하였으며 획득한 데이터 중 평균압력, 최대압력, 접촉면적과 체압 비율(Body Pressure Ratio; BPR) 분석을 통해 높이에 따른 영향을 살펴보았다. 이에 본 실험을 통해 얻은 결과는 다음과 같다. 첫째, 시트 높이에 따라 평균압력은 높이 9cm에서 가장 낮게 나타났으며 0cm에서 높게 나타났고, 접촉 면적은 9cm에서 가장 넓게 분포되었다(p< .05). 둘째, 시트 높이에 따라 각 체압 구역들 간에 압력의 차이가 나타났으며(p< .05), 체압 비율로 살펴보면 좌측 엉덩이(BP2)와 우측 엉덩이(BP1)의 부위가 가장 높은 평균 압력을 나타났다. 이상의 결과에서 시트의 전방 높이는 착석 시 압력변화에 영향이 있음을 알 수 있었으며, 본 연구에서는 높이 9cm가 적절한 것으로 파악되었다.

Comparison of Center of Pressure Displacement during Sit to Stand to Sit and Balance Ability of Subjects with and without Chronic Ankle Instability

김현성,오승준 대한통합의학회 2023 대한통합의학회지 Vol.11 No.1

Purpose : The purpose of this study is to compare the balance ability between subjects with chronic ankle instability and normal people and the center of pressure displacement during the sit to stand and stand to sit. Methods : The subjects of this study were 63 who met the inclusion criteria and were classified into normal group (n=33) and chronic ankle instability group (n=30). The displacement of the center of pressure during sit to stand and stand to sit was measured. And the limit of stability and Y-balance tests were performed to measure the balance ability. Independent t-test was conducted to compare center of pressure displacement and balance ability between groups, and pearson correlation was conducted to analyze the correlation between the center of pressure displacement and balance ability. Results : In the case of the center of pressure displacement, there was a significant difference between the two groups during sit to stand and stand to sit. In the case of balance, both limit of stability and Y-balance test showed significant differences between the two groups. At the time of sit to stand, the center of pressure displacement showed a significant correlation with balance abilities, and at the time of stand to sit, the center of pressure displacement showed a significant correlation with Y-balance test. Conclusion : Chronic ankle instability shows that there is a lot of sway in the body due to compensation to replace the decrease in ankle joint range of motion when performing sit to stand and stand to sit due to sensory input damage such as decrease in ankle range of motion and decrease in ankle proprioception. Chronic ankle instability is expected to have a negative effect on our daily lives in life. The results of this study will serve as the basis for the dynamic approach to objective evaluation, treatment, and prevention of chronic ankle instability.

Seating Comfort Measurement using FSR sensors

( Ramnaath M ),( Aryan Mohan ),( Murali Subramaniyam ) 한국감성과학회 2023 한국감성과학회 국제학술대회(ICES) Vol.2023 No.-

With the increase in white-collar jobs and work from home being more prevalent, the average time a person sits is steadily increasing, which is causing a lot of health complications. For people sitting in a chair for a prolonged time, Interface pressure is one of the most important parameters as it affects the seaters mental health, and physical well-being and causes various medical diseases like pressure ulcers and decreasing blood circulation. Our pressure-sensitive mat will help monitor the interface pressure by dividing the lower thigh and buttock region into 4 quadrants and designating 4 FSR sensors for each quadrant. The sensors measure the interface pressure by change in their resistance while sitting. Interface pressure is the pressure between the skin and the seat. We use an Arduino code to program the sensors and then use Labview to extract the data into excel. This data will help us to provide individual solution and formulate a strategy to relieve the stress. In automobile and passenger’s seats, the pressure sensitive mat will have to be modified to meet that particular demand. This is not only be ergonomic but also economic and will provide long-term solution to an increasingly common problem.

뇌성마비 장애인의 앉은 자세에서 무릎 각도 변화에 따른 착석압력에 대한 고찰

이진현,윤창교 한국디지털콘텐츠학회 2019 한국디지털콘텐츠학회논문지 Vol.20 No.10

This study analysed the effects of changes in knee angle in people with cerebral palsy disabilities on seated pressure. The experiment was conducted on children with cerebral palsy disorder who can sit on their own using XSNSOR pressure measuring equipment. The experiment results found that the average pressure was the highest at 80° knee angle and lowest at 110° (p<0.01). The maximum pressure was also greatest at 80° knee angle and lowest at 110° (p<0.01). The contact area was the narrowest at 80° knee angle and the widest at 100° position (p<0.01). And diplegia showed a good tendency to distribute pressure as the balance control of the body is better than hemiplegia and quadriplegia. Second, the analysis of the data images by the measurement program showed that the knee angle increased as the seat was raised, and the pressure applied around the left bone was distributed as the front of the thigh moved. 본 연구에서는 뇌성마비 장애인의 무릎 각도 변화가 착석 압력에 어떠한 형태로 나타나는가를 살펴보았다. 이를 위해 XSENSOR 압력 측정 장비를 사용하여 스스로 앉기 자세가 가능한 뇌성마비 장애 아동을 대상으로 실험을 수행 하였다. 실험의 결과 첫째, 평균압력은 무릎각도 80°에서 가장 높게 나타났고, 110°에서 가장 낮게 나타났다(p<0.01). 최대압력도 무릎각도 80°에서 가장 높게 나났으며, 110°에서 가장 낮게 측정되었다(p<0.01). 접촉면적은 무릎 각도 80° 에서 가장 좁게 나타났으며, 100° 자세에서 가장 넓게 나타났다(p<0.01). 그리고 양하지마비은 몸통의 균형 조절력이 편마비, 사지마비에 비해 좋아서 압력 분산이 되는 잘 되는 경향을 알 수 있었다. 둘째, 측정 프로그램에서 보여주는 데이터 이미지를 분석한 결과 좌석이 높아짐에 따라 무릎 각도가 커지게 되며 좌골을 중심으로 가해지던 압력이 넓적다리 전방부로 이동하면서 분산이 되는 것을 파악할 수 있었다. 즉, 본 연구를 통하여 뇌성마비 장애인에게 무릎의 각도가 앉기 자세의 압력에 영향을 미칠 수 있음을 확인하였다.

젊은 성인과 노인의 앉아서 일어서기 움직임과 정적 서기 균형 차이

신재욱 ( Shin Jaewook ),배원식 ( Bae Wonsik ),이현옥 ( Lee Hyunok ) 대한통합의학회 2016 대한통합의학회지 Vol.4 No.3

Purpose : The purpose of this study was to examine the differences in sit-to-stand movement and static standing balance between young adults and older adults Methods : Thirty young adults and thirty older adults participated in this study. The Good Balance System was used to assess participants`` sit-to-stand movement and static standing balance. The sit-to-stand movement was measured as mediolateral and anterioposterior displacement of the centre of pressure (mm/s) while sit-to-stand on a force platform, and time required to complete a sit-to-stand movement on a force platform. The static standing balance was measured as mediolateral and anterioposterior displacement of the center of pressure (mm/s) and velocity moment (mm2/s) while standing on a force platform with opened eyes and with closed eyes. Result : A significant difference was found in the mediolateral and anterioposterior center of pressure displacement and the time required to complete a sit-to-stand movement of the two groups (p<.05). A significant difference between the groups was found as to mediolateral centre of pressure displacement and the velocity moment when standing with opened eyes and with closed eyes (p<.05). Conclusion : In conclusion, older adults showed decreased sit-to-stand movement and static standing balance ability compared to the young adult. Clinicians should consider sit-to-stand and balance training for older adult.

폴리우레탄 폼 재질의 휠체어 좌석이 착석 압력에 미치는 영향

이진현(J. H. Lee) 한국재활복지공학회 2014 재활복지공학회논문지 Vol.8 No.3

본 연구는 휠체어 좌석의 재질 중 하나로 국내에서 주로 사용되는 폴리우레탄 폼의 경도에 따른 압력 분석을 통하여 압력 분산이 적절하게 이루어지는 재질을 제시하는 것에 목적이 있다. 이러한 연구의 목적을 달성하기 위해 폴리우레탄 폼의 경도 13㎏/㎠, 18㎏/㎠, 25㎏/㎠, 45㎏/㎠로 구성된 전방웨지 6cm 시트를 총 4개를 설계 및 제작하였다. 실험에는 비장애인 10명이 참여하였으며, 측정도구로는 XSENSOR를 사용하였고 휠체어 시뮬레이션에 시트를 올려 실험하였다. 각 시트마다 착석압력 측정은 5분간 실시하였으며 획득한 데이터 중 평균압력, 최대압력, 접촉면적 분석을 통해 경도에 따른 영향을 살펴보았다. 이에 본 실험을 통해 얻은 결과는 다음과 같다. 폴리우레탄 재질의 경도에 따라 평균압력, 최대압력 및 접촉면적은 경도 45㎏/㎠에서 높게 나타났고, 13, 18㎏/㎠에서 낮게 나타났다(p< .05). 이러한 결과를 통해 폴리우레탄 재질의 경도는 착석 시 압력변화에 영향이 있음을 알 수 있었으며, 향후 자세유지기구의 시트 재질로 폴리우레탄 폼을 사용한다면 경도 18㎏/㎠가 체압을 분산하기에 적절한 재질로 파악되었다. The purpose of this document is to provide basic data helpful in selecting seating device material by examining the affects of polyurethane foam material on seating pressure. In order to achieve this study objective, four seats, 6cm in height, were produced in hardness of: 13, 28, 25, and 45㎏/㎠. To measure the sitting pressure distribution (depending on the characteristics of the produced seats), 10 healthy subjects participated in the experiment. XSENSOR was used a measuring device, and each seat was mounted on a wheelchair simulation. By analyzing the obtained data with Average Pressure(AP), Peak Pressure(PP,), and Contact Area(CA), the sitting pressure was measured for five minutes on each seat. This experiment showed the following results: There were significant differences between the AP, PP, and CA in the seat material (p<0.5). While the hardness of 18㎏/㎠ showed low pressure, the hardness of 45㎏/㎠ showed high pressure. This study also showed that seat material made of polyurethane should be considered when selecting seats. If polyurethane foam is used in seat recommendations, it will be recommended to use 18㎏/㎠ for the proper hardness of the seat material.

Changes in Craniocervical and Trunk Flexion Angles and Gluteal Pressure during VDT Work with Continuous Cross-legged Sitting

Lee, Jung-Hoon,Park, Se-Yeon,Yoo, Won-Gyu Japan Society for Occupational Health 2011 JOURNAL OF OCCUPATIONAL HEALTH Vol.53 No.5

<P><B>Objectives:</B> This study investigated changes in craniocervical and trunk flexion angles and gluteal pressure on both sides during visual display terminal (VDT) work with continuous cross-legged sitting. <B>Methods:</B> The gluteal pressures of ten VDT workers, who were recruited from laboratories, were measured using a Teckscan system and videotaped using a single video camera to capture the craniocervical and trunk flexion angles during VDT work at 30 s, 10, 20 and 30 min. <B>Results:</B> The craniocervical angle was significantly increased at 10 and 20 min compared with the initial angle (<I>p</I><0.05). The trunk flexion angle was significantly decreased at 30 s, 10, 20 and 30 min (<I>p</I><0.05). The gluteal pressure of the crossed-leg side significantly increased at 30 s, 10 and 20 min (<I>p</I><0.05). The gluteal pressure of the uncrossed-leg side significantly decreased at 30 s (<I>p</I><0.05). Conclusion: We found that cross-legged sitting during VDT work may exert disadvantageous postural effects resulting from craniocervical and trunk flexion angles and gluteal pressure. Therefore, this posture could not be recommended during long-term VDT work.</P>

Optimal Hardness of Seat Cushion for Office Chairs by Using Body Pressure Distribution and Tactile Sense

Jae Hee Park,Yiyeon Park,Seung Hee Kim,Min Uk Kim,Young Soo Shim,Taeil Son 대한인간공학회 2012 대한인간공학회 학술대회논문집 Vol.2012 No.11

Objective: The aim of this study is to find the optimal hardness of seat cushion for office chairs. Background: The comfort or discomfort and subjective satisfaction for office chairs mainly are determined by the cushion of seat pan. However, the hardness of cushion has been empirically determined in chair companies. Method: In this study, we evaluated eight seat cushions which varied in materials(2 levels) and varied in hardness(4 levels). The body pressure distribution was measured during seven subjects were sitting on the eight different cushions. After then, they evaluated their preference for the cushions by using tactile senses of buttocks and fingers. Results: As expected, the harder the cushions were, the higher the average pressure on cushions was. Also the subjective discomfort was lowered proportionally to the lowering of the average body pressure. Conclusion: To lower the discomfort level of cushion of office chairs, it is recommended to lower the current hardness of cushions. Also it was showed that more elastic sponges were preferred than the current material. Application: The result of this study can be applied to the determination of optimal hardness of sponges used in seat cushions.

Wii Balance Board를 이용한 Sit-to-Stand와 보행시 지면반발력의 타당도 분석

정유진 ( Yu-jin Jeong ),박대성 ( Dae-sung Park ) 대한물리의학회 2016 대한물리의학회지 Vol.11 No.4

PURPOSE: A good, valid, and feasible tool for evaluating sit to stand (STS) is needed to help clinicians quantify the STS ability of stroke patients and people with balance disorders. The purpose of this study was to evaluate the concurrent validity of the Nintendo Wii Balance Board (WBB) and a force plate during STS and gait. METHODS: Seventeen healthy adults performed five trials of STS and gait on the WBB placed on the force plate. The force plate and the WBB were compared in regard to center of pressure (COP) and ground reaction force (GRF) data that were collected simultaneously. The variables used for analysis were time (s), integral summation (%), COP path length (㎜), COP x range, and COP y range, all of which were measured for both tasks. Counter (%), peak (%), and rebound (%) were analyzed for STS, and 1^st peak (%), min peak (%), and 2nd peak (%) were analyzed for gait. The concurrent validity was analyzed using an intraclass correlation coefficient (ICC) and a standard error of measurement (SEM) with a 95% confidence interval. RESULTS: The concurrent validity of the WBB for STS ranged from fair to good (ICC=.701∼.994, SEM=.029∼3.815). The concurrent validity for gait was good (ICC=.869 ∼.989, SEM=.007∼2.052) aside from path length and x and y ranges of COP (ICC=-.150∼.371, SEM=3.635∼4.142). CONCLUSION: The GRF of the WBB has a good validity for STS and gait analysis. The WBB is remarkably portable, easy to use, and convenient for clinically assessing STS and gait.