• Physical Therapy Rehabilitation Science
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• v.9 no.3
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• pp.197-200
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• 2020

Objective: The purpose of this study was to develop and investigate the feasibility of a sit-to-stand assistive chair using a pneumatic cylinder. Design: Cross-sectional study. Methods: The sit-to-stand assistive chair was developed to assist the sit-to-stand movement by rising up of the chair by a pneumatic cylinder. After the user is seated on the chair, if the pneumatic cylinder pulls the seat plate when standing up, the spring of the pneumatic cylinder, which has been stretched, assists in rising the rear end of the seat plate so that the user can stand conveniently and comfortably. A feasibility test was performed in 10 heathy adults. The electromyographic muscle activation of the trunk and lower extremity muscles was analyzed, which included the erector spinae, rectus abdominis, quadriceps, tibialis anterior, gastrocnemius when standing up from sitting using the developed chair and standing up without using the developed chair. Results: As a result, the sit-to-stand assistive chair using a pneumatic cylinder was developed. In the feasibility test, the use of the developed chair had a decrease in rectus abdominis, quadriceps, tibialis anterior activation compared to those who did not use the device in the healthy adults. Conclusions: The sit-to-stand assistive chair using a pneumatic cylinder may be helpful to reduce the activation of the rectus abdominis, quadriceps, tibialis anterior muscles when performing a sit-to-stand movement. Through the results, the efficacy of the sit-to-stand assistive chair can be confirmed. In the future, further studies are warranted to investigate for the safety and efficacy of its use in the elderly population or those who are disabled.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.799-807
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• 2014

This paper describes the development of an indoor locomotion assistive robot, Ball-Chair, comprising a novel drive system. This robot facilitates locomotion assistive operation in narrow spaces, in which common wheelchairs cannot move easily. The Ball-Chair has two main features: its structural feature and driving mechanism. The exoskeleton frames of the Ball-Chair have been designed with octagonal shapes resembling a circle, for minimizing its volume and weight. Additionally, all its driving parts (including the ball) are mounted within of the robot to enhance its safety. The Ball-Chair features a reverse ball-mouse driving mechanism comprising two driving omni-wheels in the x- and y-axes. By controlling the speed of each omni-wheel, a holonomic driving system that can facilitate omnidirectional locomotion has been achieved using only two wheels. The effective movement of the Ball-Chair in any direction within narrow indoor spaces was experimentally verified. The paper outlines the development procedure in detail.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.591-597
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• 2022

Objective: The sitting and standing are motions that correspond to the previous stage of rehabilitation to go to walking for daily life. The purpose of this study was to measure task times, path length of the center of pressure (COP) and activity on the vastus femoris muscle using surface electromyography (EMG) when standing up and sitting down. Design: One group cross-sectional design Methods: Fifteen elderly subjects (8 male, 7 female) participated. All subjects were tested three times according to four assist levels (non-assist, lower, middle, and maximal assist) using adjusts the length of spring at sit-to-stand and stand to sit on a chair. The task duration, and COP path length were recorded for the balance function on the Nintendo Wii fit board. The activity of the rectus femoris muscle was recorded on both legs using surface EMG. Results: The results showed that the task duration of the sit-to-stand and stand-to-sit were significantly increased compared to without assist (p<.05). The activation of the rectus femoris muscle more significantly decreased compared to without assistance at standing or sitting (p<.05). Conclusions: The assistive chair showed less quadriceps muscle activation during sitting and standing compared to without assistance. We suggest that our assist-standing chair can help with activities of daily living such as standing up and sitting down movements adjusting the spring length for control assist level by safely.

• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.191-197
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• 2011

Lifting chair is a typical assistive product to aid for standing up and sitting down for persons with disability. It is particularly useful for the elderly persons whose muscular system is weakened by degenerative joint disease. This paper describes biomechanical assessments of lifting chair with hip-up function. In experiments we measured 3D motion and electromyographic(EMG) signal on the femoral muscle when subject performs the standing motion on the predetermined seat height. Based on assessment of the standing motion, we select the hip-up angle as 15 degrees to cover the relative femoral angle when EMG peak value is appeared. Using an implemented prototype lifting chair with hip-up function we perform standing experiments with five subjects. The experimental results show that the lifting and hip-up functions are effective to assist for standing up motion with less muscle force.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.222-224
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• 2007

Social participation of the elderly and the disabled continuously becomes more active due to the improvement of social systems and technological development. Various systems such as intelligence robots and intelligence home systems have been developed to support their social participation, and those systems obviously contribute to the independent lives of the elderly and the disabled. Those systems, however, usually require special hardware, which make them very expensive. Considering the economic difficulties of the users, the problem should be tackled with software-oriented approaches using existing hardware such as laptops. The software should be adapted to users with limited capabilities by enabling them to utilize the system without much knowledge related to computers and also without keyboards and mice. This paper suggests software-oriented approaches to solve those problems with the description of the unified user interface for a special work chair, and introduces an actual development procedure of the program together with real application of related theories.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.4 s.316
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• pp.8-14
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• 2007

Social participation of the elderly and people with disabilities continuously becomes more active due to improvement of social systems and technological development. Various assistive systems, such as intelligence robots and intelligence home systems, have been developed to support the social participation, and obviously contributed to independent lives of the elderly and people with disabilities. These systems, however, usually require expensive special hardware. To relieve a financial burden software-oriented approaches, which utilizes existing hardware such as laptops, can be an alternative. The software should be developed considering users with physical limitation and without much knowledge of computers. This paper suggests software-oriented approaches to solve these problems and describes an actual development procedure of the software with related theories. We also introduce an unified user interface for a special work chair as a real application.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.3
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• pp.271-277
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• 2017

The purpose of this study was to develop a balance chair for improving pelvic correction and postural balance through postural balance training using tactile feedback by a vibration motor provided in real time according to the user's attitude. We built a body frame using mono cast(MC) Nylon, Touch thin film transistor(TFT) for user interface, a main control module using Arduino, a 9-axis acceleration sensor for user's posture determination, and a vibration module for tactile feedback. The prototype of the Balance Chair which surrounds the outside was made with cushion for sitting conformability. In order to verify the effectiveness of the postural balance training system using the built prototype, the muscle activity (% MVIC) of the left and right iliocostalis lumborum those are the main muscles of the spinal movement was measured with ten female subjects. And the balance ability before and after training was measured using Spine Balance 3D, a posture balance ability evaluation device. The muscular activities of the left and right iliocostalis lumborum showed the balance activation according to vibration feedback during exercise protocol and postural balance improved after balance exercise training using balance chair. This study could be apply to use the fundamental research for developing the various postural balance product.

• International journal of advanced smart convergence
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• v.12 no.2
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• pp.76-83
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• 2023

Squatting of agricultural work can cause musculoskeletal disorders due to excessive pressure and rotational force on the knee joint In order to improve the assistive chair used in squatting agricultural work so that it can be used in a narrow groove, it is intended to improve the musculoskeletal harm of squatting work by attaching a spring on the assistive chair. Therefore, in the presenty study, 3D drawing was done using ProEngineer (3D), and a mock-up was produced and tested. Using pro-Engineer, it was judged that it was rare for plastic to be broken by a spring, so the analysis was conducted with a focus on springs. It was found that the structure that can absorb the shock according to the rigidity of the tape spring and balance the body is that the power to withstand the load of the weight is distributed as a whole when five springs are used. Electromyography was measured using ME600 (Mega Electronics, Finland) Measuring equipment attached to the waist, thighs, calves, and shins. EMG values were measured and compared with the prototype in two ways, when the worker did not wear the product and when he wore an existing product on the market. As a result of the experiment when using the prototype, the maximum EMG value for each part is considered to be helpful in preventing musculoskeletal diseases as the amount of muscle used is reduced in the waist, thighs, calves, and shins.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.1
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• pp.73-79
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• 2016

In this paper a cervical rehabilitation robot for Mckenzie exercises to be effective to neck pain relief is proposed. The robot has two degrees of freedom (DOF) for Lateral flexion and extension, Dorsal and Vental flexion which enable user to perform cervical stretching and isometric exercises for neck muscles. The mechanical parts of the cervical rehabilitation robot can be mounted on a back- or head-rest of chair, and user can perform the Mckenzie exercise with seated. In experiments we measured the range of motion of cervical part, EMG signals from neck muscles and the contact forces of a head bracket fixing the head part of user, and then evaluated their performances. From the experimental results, we showed a feasibility of the cervical rehabilitation robot proposed in this study.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.63-68
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• 2013

Manual wheelchair is one of the most used assistant device in Korea and the size of the wheelchair is defined as KS P ISO 7176-5 which follows the ISO 7176-5 standard size. But the standard often doesn't fit to Korean people because the ISO was enacted by foreigners' body sizes. Actually the result of survey from the Korean Agency for Technology and Standards showd that the designated sizes of height, width, deep of seat except armrest and the height of backrest of a chair in the present KS P ISO 7176-5 are much bigger and the height of armrest is smaller than the sizes investigated by the survey. In case the disabled person has a long wheelchair use time everyday, the posture of user should be uncomfortable because the mismatched size should cause user's pelvis rotations, slouching pose and low stability. Also, inside of knee may touch the wheelchair seat and user can't keep a correct posture. In this paper, the body sizes of Korean disabled person were investigated and the correct wheelchair sizes for Korean people are provided.