• Journal of rehabilitation welfare engineering & assistive technology
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• v.3 no.1
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• pp.7-13
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• 2009

Recently, the interest on walking assistances in order to assist aged people has increased due to the increase of the aged. However, most walking aid systems have a weakness for a slope because they don't have power. So, they have a weak point which makes users difficult to move when they are weak in the legs. That is why the interest on walking assistances with power has increased. The use of the walking aid systems should be easy because most users are old people. Thus, we produce module to grasp walking intent of users by using various sensors such as potentiometer, FSR(Force Sensing Resistance) Sensor and Stretch Sensor and calculate the response time to the module. Firstly, the response time of handlebar which is a kind of potentiometer is 420ms and Resilience of it is 140ms. Secondly, the response time of handlebar which use FSR Sensor is 320ms and Resilience of it is 220ms. Finally, the response time of the Stretch Sensor is 160ms and Resilience of it is 140ms. The performance of Stretch Sensor is the best among the three kind of sensors.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1141-1146
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• 2014

As life expectancy becomes longer, reduction of human muscular strength threatens quality of human life. Many robotic devices have thus been developed to support and help human daily life. This paper deals with a new type of in-wheel actuator that can be effectively used for the robotic devices. BLDC motor, drive board, brake, ARS (Attribute Reference System), and torque sensor are combined in the single actuator module. The torque sensor is used to recognize human intention and the in-wheel actuator drives walking aids in our system. Its feasibility was tested with the active walking aid device equipped with the in-wheel actuator. Based on it, we designed an admittance filter algorithm to react on uphill and downhill drive. By adjusting mass, damping, and spring parameters in accordance with the ARS output, it provided convenient drive to the old on uphill and downhill walks.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.5
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• pp.393-400
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• 2015

This paper describes the development of a chest-wearable robot that can efficiently perform self walking rehabilitation without a helper. The features of the developed robot are divided into three parts. First, as a mechanical characteristic, the conventional elbow crutch is attached at the forearm. However, the proposed robot is attached to the patient's chest, enabling them to feel free to use their hands and eliminate the burden of the arms. Second, as a characteristic of the driving algorithm, pressure sensors attached to the chest automatically perceive the patient's walking intention and move the robot-leg thereafter. Also, for safety, it stops operating when an obstacle is found in front of the patient by using ultrasonic sensors and generates a beeping sound. Finally, by using the scotch yoke mechanism, supporting legs are moved up and down using a rotary servo motor without excessive torque that is generated by large ground reaction forces. We showed that the developed robot can effectively perform self walking rehabilitation through walking experiments, and its performance was verified using Electromyograph (EMG) sensors.

• The Journal of Korea Robotics Society
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• v.9 no.3
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• pp.133-139
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• 2014

This paper proposes a wearable and motorized crutch control system for the patients using the conventional crutches. The conventional crutches have a few disadvantages such as the inconvenience caused by the direct contact between the ground and the armpit of the patients, and unstable gait patterns. In order to resolve these problems, the motorized crutch is designed as a wearable type on an injured lower limb. In other words, the crutch makes the lower limb to be moved forward while supporting the body weight, protecting the lower limb with frames, and rotating a roller equipped on the bottom of the frames. Also the crutch is controlled using the electromyography and two force sensing resistor (FSR) sensors. The electromyography is used to extract the walking intention from the patient and the FSR sensors to classify the stance and swing phases while walking. As a result, the developed crutch makes the patients walk enabling both hands to be free, as if normal people do.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.124-131
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• 2017

This paper present a novel approach to control the lower body power assistive exoskeleton system of a HEXAR-CR35 aimed at improving a muscular strength. More specifically the control of based on the human intention is crucial of importance to ensure intuitive and dexterous motion with the human. In this contribution, we proposed the detection algorithm of the human intention using the MCRS which are developed to measure the contraction of the muscle with variation of the circumference. The proposed algorithm provides a joint motion of exoskeleton corresponding the relate muscles. The main advantages of the algorithm are its simplicity, computational efficiency to control one joint of the HEXAR-CR35 which are consisted knee-active type exoskeleton (the other joints are consisted with the passive or quasi-passive joints that can be arranged by analyzing of the human joint functions). As a consequence, the motion of exoskeleton is generated according to the gait phase: swing and stance phase which are determined by the foot insole sensors. The experimental evaluation of the proposed algorithm is achieved in walking with the exoskeleton while carrying the external mass in the back side.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.4
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• pp.259-265
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• 2014

The aims of this study are to investigate the walking intention detection of a rollator based on Infraed (IR) sensor measuring knee joint anterior displacement and leg muscle activities. We used Active Walker attached IR sensor to measure the knee joint anterior displacement and EMG signal of leg muscles(rectus femoris, biceps femoris, tibialis anterior, gastrocnemius) were taken by Delsys bagnli-8ch. Subjects were eight healthy males(age $23.7{\pm}0.5years$, height $175.4{\pm}2.3cm$, weight $70.6{\pm}5.6kg$) and they were involved in experiments which had been proceeded 30 minutes a week, during 3 weeks. This system indicates that the knee joint anterior displacement had the distinction increases according to the gait slope and velocity. We showed the increase of the femoral muscle activities along the anterior tilt and the increase of the crural muscle activities along the posterior tilt.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.1
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• pp.1-16
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• 2022

Recently, e-scooters have been attracting attention as eco-friendly modes of transportation in cities due to an increasing interest in the environment. Accordingly, various studies on usage behavior are being conducted, but studies that reflect individual travel attitudes are insufficient. Therefore, this study surveyed commuters in Seoul and analyzed respondents' traveling attitudes through factor analysis. It also built a binary logistic regression model for the intention to use shared e-scooters to determine how individual travel behaviors are affected. In particular, the model results showed that age, the main mode of transportation (car), walking time to the bus stop, and four travel attitude variables (disutility of travel, preference to self-drive, internet/smartphone friendliness, and willingness to pay extra money for services) significantly affected the intention to use shared e-scooters. This study is expected to be used as basic data, with aspect to travel behavior, for the efficient operation and use of shared e-scooters in the future.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.4
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• pp.321-328
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• 2016

In this paper, we propose a walk status method which can be fused with conventional walk intention method to improve convenience of an electric assistive walking system for elder people with restricted walking capabilities. The system uses a handlebar as a trigger and regards grabbing a handlebar as expressing will to walk. And the system uses a user's linear velocity and angular velocity as linear velocity and angular velocity of a system, checked by laser range finder. To achieve this, we propose a method to find a virtual central point of a human body by estimating a central point between two legs. The experiments are carried out by comparing user's linear velocity and angular velocity, and system's linear velocity and angular velocity. The results show that the error of linear velocity and angular velocity between a user and a system are 1% and 2.77%, which means the linear velocity and angular velocity of a user can be applied to a system. And it is confirmed that the proposed fusion method can prevent a user from being dragged by an assistive walking system or a malfunction caused by lack of experience

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.411-412
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• 2022

In recent years, the number of foot disease patients is increasing due to bad walking habits and wearing shoes. With the development of shoes and living environment, no one can be relieved from foot disease. A study on the effect of shoe design characteristics on satisfaction and purchase intention when a patient with foot disease purchases orthopedic shoes. The shoe design characteristics consisted of functionality, convenience, and aesthetics. This study is conducted from various perspectives, such as frequency of participation in social activities, purpose of wearing, and status and characteristics of each foot disease. It is expected that the research results will lead to the development of orthopedic shoe designs that can be usefully worn by patients with orthopedic mild foot disease in their daily life, and to lead to practical use and satisfaction.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.496-504
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• 2023

This paper recognizes the motion intention of the wearer using a muscle stiffness sensor and proposes a control system for a wearable robot based on this. The proposed system recognizes the onset time of the motion using sensor data, determines the assistance mode, and provides assistive torque to the hip flexion/extension motion of the wearer through the generated reference trajectory according to the determined mode. The onset time of motion was detected using the CUSUM algorithm from the muscle stiffness sensor, and by comparing the detection results of the onset time with the EMG sensor and IMU, it verified its applicability as an input device for recognizing the intention of the wearer before motion. In addition, the stability of the proposed method was confirmed by comparing the results detected according to the walking speed of two subjects (1 male and 1 female). Based on these results, the assistance mode (gait assistance mode and muscle strengthening mode) was determined based on the detection results of onset time, and a reference trajectory was generated through cubic spline interpolation according to the determined assistance mode. And, the practicality of the proposed system was also confirmed by applying it to an actual wearable robot.