• 로봇학회논문지
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• 제11권2호
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• pp.108-114
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• 2016

This paper presents a sensor-based cane mechanism for walking aid of the visually impaired person. We also describe an approach to decide properly the length of the specified cane mechanism. The cane mechanism has some sensors to identify the possibility of a collision between the cane user and an object and/or a person, and a signal processing unit that enables the user to recognize such a collision is attached in the mechanism. Thus, the walker using this cane can recognize in advance the possibility of such a collision in his walking process. Consequently, it is helpful for the visually impaired person to walk on a pedestrian road safely. The feature of the proposed cane mechanism and its availability have been shown through experimental works in a typical walking environment.

• 한국정밀공학회지
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• 제29권3호
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• pp.346-353
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• 2012

The purpose of this study is to verify the energy efficiency of the integrated system combining human and a lower extremity exoskeleton robot when it is applied to the proposed gait pattern. Energy efficient gait pattern of the lower limb was proposed through leg function distribution during stance phase and the dynamic-manipulability ellipsoid (DME). To verify the feasibility and effect of the redefined gait trajectory, simulations and experiments were conducted under the conditions of walking on level ground and ascending and descending from a staircase. Experiments to calculate the metabolic cost of the human body with or without the assistance of the exoskeleton were conducted. The energy consumption of the lower extremity exoskeleton was assessed, with the aim of improving the efficiency of the integrated system.

• 제어로봇시스템학회논문지
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• 제16권10호
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• pp.933-938
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• 2010

In this paper, we propose the organization of a sensor system and user's intent detection algorithm for walking assist rehabilitation robots. The main purpose of walking assist rehabilitation robots is assisting SCI patients to walk in normal environment. To use walking assist rehabilitation robot in normal environment, it is needed to consider various factors about user's safety and detection of user's intent and so on. For these purposes, we have analyzed the use case of rehabilitation robots and organized the system of sensors for walking assist rehabilitation robots and finally, we have developed the algorithm which is used to detect user's intent for those. We applied our proposal method in the rehabilitation robot, ROBIN, and verified their effectiveness by normal, not patient.

• 센서학회지
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• 제26권2호
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• pp.114-121
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• 2017

This paper describes the design and fabrication of a three-axis force sensor with parallel plate beams (PPSs) for measuring the calf force while a patient with a walking assist robot is walking. Current walking assist robots can't measure the weight of the patient's leg and the robot's leg which required for robot control. So, the three-axis force sensor in the calf link is designed and manufactured, it is composed of a Fx force sensor, a Fy force sensor and a Fz force sensor. The three-axis force sensor was designed using by FEM(Finite Element Method), and fabricated using strain-gages. The characteristics experiment of the three-axis force sensor was carried out respectively. The test results indicated that the repeatability error and the non-linearity error of three-axis force sensor was less than 0.04% respectively. Therefore, the fabricated three-axis force sensor in the calf link can be used to measure the patient's calf force in the walking assist robot.

• 센서학회지
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• 제27권2호
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• pp.105-111
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• 2018

In this paper, a torque sensor is designed and fabricated to measure the knee joint torque of a walking assist robot for stroke patients. The torque sensor sensing part was modeled on the link of the part connected to the knee joint motor. The torque capacity of the knee joint was calculated by simulation and the size of the torque sensor sensing part was designed using the finite element method. The torque sensor was fabricated by attaching a strain gauge to the sensing part. Characteristic experiments were conducted to characterize the torque sensor, and the torque sensor was calibrated to utilize it for the control of the walking assist robot. As a result of the characteristics test, the reproducibility error and the nonlinearity error of the torque sensor were 0.03% and 0.04%, respectively. Therefore, it is considered that the developed torque sensor can be used to measure the torque applied to the knee joint when walking on a walking assist robot.

• 센서학회지
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• 제26권5호
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• pp.353-359
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• 2017

This paper describes the design and manufacture of a ankle two-axis force sensor of a walking assist robot for hemiplegic leg patient. The walking assist robot for the hemiplegic leg patient can safely control the robot by detecting whether the foot wearing the walking assist robot is in contact with the obstacle or not. To do so, a two-axis force sensor should be attached to the robot's ankle. The sensor is used to measure the force of a patient's ankle lower part. The two-axis force sensor is composed of a Fx force sensor, a Fy force sensor and a pulley, and they detect the x and y direction forces, respectively. The two-axis force sensor was designed using by FEM(Finite Element Method), and manufactured using by strain-gages. The characteristics experiment of the two-axis force sensor was carried out respectively. The test results indicated that the interference error of the two-axis force sensor was less than 1.2%, the repeatability error and the non-linearity of the two-axis force sensor was less than 0.04% respectively. Therefore, the fabricated two-axis force sensor can be used to measure the force of ankle lower part in the walking assist robot.

• 제어로봇시스템학회논문지
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• 제17권3호
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• pp.223-228
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• 2011

In this paper, we proposed a technique to recognize three states in stance phase of gait cycle. Walking assistive devices are used to help the elderly people walk or to monitor walking behavior of the disabled persons. For the effective assistance, they adopt an intelligent sensor system to understand user's current state in walking. There are three states in stance phase; Loading Response, Midstance, and Terminal Stance. We developed a foot pressure sensor using 24 FSRs (Force Sensing/Sensitive Resistors). The foot pressure patterns were integrated through the interpolation of FSR cell array. The pressure patterns were processed to get the trajectories of COM (Center of Mass). Using the trajectories of COM of foot pressure, we can recognize the three states of stance phase. The experimental results show the effective recognition of stance phase and the possibility of usage on the walking assistive device for better control and/or foot pressure monitoring.

• 제어로봇시스템학회논문지
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• 제12권6호
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• pp.568-572
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• 2006

This paper presents the device of recognizing image of the studded paving blocks, transmitting, the information by vibration to a visually handicapped person. Usually the blind uses the walking stick to recognize the studded paving block. This research uses a PCA (Principal Component Analysis) based image processing approach for recognizing the paving blocks. We classify the studded paving blocks into 5 classes, that is, vertical line block, right-declined line block, left-declined line block, dotted block and flat block. The 8 images for each of 5 classes are captured for each block by 112*120 pixels, then the eigenvectors are obtained in magnitude order of eigenvectors by using principal component analysis. The principal components for images can be calculated using projection of transformation matrix composed of eigenvectors. The classification has been executed using Euclidean's distance, so the block having minimum distance with a image is chosen as matched one. The result of classification is transmitted to the blind by electric vibration signals with different magnitudes and frequencies.

• 한국생산제조학회지
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• 제26권1호
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• pp.89-99
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• 2017

This paper describes the development of a thigh wearable robot for power assistance during stair climbing. In the wearable robot developed in this study, high-power BLDC motors and high-capacity harmonic reduction gears are used to effectively assist the thigh muscle during stair climbing. In particular, normal ground and stair are distinguished accurately by using wireless smart shoes, and the stair climbing assistance is performed by activating the actuators at an appropriate time. Impedance of the hip joint was effectively reduced by performing friction compensation of the gears, and a wearing adjustment mechanism was designed to fit the robot to the thigh by conveniently modifying the width and tilting angle of the robot using set collars. Consequently, the performance of the developed thigh wearable robot was verified through stair climbing experiments with EMG measurement.

• 센서학회지
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• 제16권4호
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• pp.286-293
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• 2007

For safe walking of the people who are blind, walking assistance robot which can detecting and avoiding the obstacle was investigated. The implemented prototype walking assistance robot consists of a obstacle detecting module, a user interface using acoustic signal and a driving module. The obstacle detecting module uses 6 ultrasonic sensors those located at the front part of the robot can perceive the obstacle which is in 3 meter distances and $180^{\circ}$ degrees. It calculates the distance and degree from the obstacle using TOF (time of flight) method and decides the 3-dimensional location of the obstacle. The obstacle information is delivered to the user using acoustic alarm and guide sound. The robot is designed to avoid by itself when the obstacle is detecting and the user only follows it to safe walking. After the designed robot was implemented, driving and obstacle detecting experiments were carried out. The result showed that the designed walking assistance robot will help the people who are blind to walk around safe.