• Journal of the Korean Society for Precision Engineering
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• v.32 no.12
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• pp.1065-1072
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• 2015

This paper is about the development of an insole sensor system that can determine the model of an exoskeleton robot for lower limb that is a multi-degree of freedom system. First, the study analyzed the kinematic model of an exoskeleton robot for the lower limb that changes according to the gait phase detection of a human. Based on the ground reaction force (GRF), which is generated when walking, to proceed with insole sensor development, the sensing type, location, and the number of sensors were selected. The center of pressure (COP) of the human foot was understood first, prior to the development of algorithm. Using the COP, an algorithm was developed that is capable of detecting the gait phase with small number of sensors. An experiment at 3 km/h speed was conducted on the developed sensor system to evaluate the developed insole sensor system and the gait phase detection algorithm.

• The Journal of Korea Robotics Society
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• v.15 no.4
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• pp.323-329
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• 2020

This paper presents a control algorithm for a wearable walking aid robot for subjects with paraplegia after stroke. After a stroke, a slow, asymmetrical and unstable gait pattern is observed in a number of patients. In many cases, one leg can move in a relatively normal pattern, while the other leg is dysfunctional due to paralysis. We have adopted the so-called assist-as-needed control that encourages the patient to walk as much as possible while the robot assists as necessary to create the gait motion of the paralyzed leg. A virtual wall was implemented for the assist-as-needed control. A position based admittance controller was applied in the swing phase to follow human intentions for both the normal and paralyzed legs. A position controller was applied in the stance phase for both legs. A power controller was applied to obtain stable performance in that the output power of the system was delimited during the sample interval. In order to verify the proposed control algorithm, we performed a simulation with 1-DOF leg models. The preliminary results have shown that the control algorithm can follow human intentions during the swing phase by providing as much assistance as needed. In addition, the virtual wall effectively guided the paralyzed leg with stable force display.

• 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.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.359-366
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• 2023

In order to fully utilize the functions of the hand which is the end effector of the upper limb, other parts of the upper limb have to perform their own roles. Among them, the pronation and supination of the forearm, which allows the hand to rotate along the longitudinal direction of the forearm, play an important role in activities of daily living. In this paper, a soft wearable robot that assists the pronation and supination of the forearm for individuals with weakened or lost upper limb function is proposed. The wearable robot consists of an anchoring part with polymer (wrist strap, elbow strap), a tendon with a belt and wire, and an actuation module. It was developed based on the requirements with respect to friction of anchoring part, forearm compression, and friction of the tendon. It was confirmed that these requirements were satisfied through literature review and experiments. Since all components exist within the forearm when worn, it is expected to be easy to combine with the already developed soft wearable robots for the hand, wrist, elbow, and shoulder.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.1
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• pp.73-80
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• 2015

In this paper, we propose the robotic arm control method based on upper extremity electromyogram for lower upper extremity amputation patient. The muscle activity of the forearm flexor, forearm extensor and biceps was analyzed to utilize distribution of muscle activity to a specific position in order to the control input. This control input is converted into a control command for controlling the robotic arm through the algorithm. For the experiment and verify the proposed method, 5DoF robotic arm control system was constructed with 1 channel EMG Module and PC applications through the interworking with each module to perform a three-channel EMG analysis. For accuracy and performance evaluation of control, Experiments were performed with robotic arms moving objects. As a result of experiments which after training for 10 hours by middle 20's man, Validity of the proposed method was evaluated based an average accuracy of 92.5%.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.265-272
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• 2009

In this paper, a simple optical method that uses an infrared(IR) cut filter is proposed to minimize variation of eye image by external infrared(IR) sources in a video based head mounted eye tracking system that is used in the field of sports. For this, the IR cut filter is attached to a head mount of the eye tracking system, and the camera with an IR LED is located between the IR cut filter and eye. In this structure, external IR is blocked by the IR cut filter, and the IR intensity on the eye can be controlled by the IR LED. Therefore, the illumination condition of the camera to capture the eye can be stable without being affected by external IR illuminations. To verify the proposed idea, variation of the eye image and intensity of the IR with/without the IR cut filter is measured under various illumination conditions. The measured data show that the IR cut filter method can block external IR effectively, and complex pupil detection algorithms can be replaced by a simple binarized method.

• 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.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.4
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• pp.313-323
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• 2023

The wearable robot system is designed to assist human skeletal and muscular systems for enhancing user's abilities in various fields, including medical, industrial, and military. The military has an expanding need for wearable robots with the integration of surveillance/control systems and advanced equipment in unstructured battlefield environments. However, there is a lack of research on the design and mechanism of wearable robots, especially for power assist systems. This study proposes a lightweight wearable robot system that provides comfortable wear and muscle support effects in various movements for soldiers performing high-strength and endurance missions. The Power assist mechanism is described and verified, and the tasks that require power assist are analyzed. This study explain the system including its driving mechanism, control system, and mechanical design. Finally, the performance of the robot is verified through experiments and evaluations, demonstrating its effectiveness in muscle support.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.10
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• pp.837-843
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• 2016

This paper presents a position control strategy for a pump-controlled electro-hydrostatic actuator (EHA) using feedforward control with disturbance compensation. As the disturbance observer is used to estimate nonlinear dynamics of EHA, which has valve-opening conditionals, as well as external disturbances, an additional feedforward control is adopted to achieve rapid response. The effectiveness of the proposed control strategy is verified through experiment using an EHA test bench. The proposed controller shows better tracking performance compared with a conventional PID controller.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1791-1792
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• 2007

본 논문에서는 착용 가능한 모션 캡쳐 시스템을 설계하고 구현한다. 이 장치는 사람의 두 관절의 움직임을 각도로 표현하도록 디자인 되었다. 이를 위해 flex sensor를 사용했으며 센서의 히스테리시스를 확인하고 3차 다항식을 사용하여 근사적인 모델을 만들었다. 이 모델을 통해서 센서에서 가져온 전압을 각도로 표현하였으며 이 각도로 손목과 팔꿈치의 움직임을 시뮬레이션 했다. 시뮬레이션의 결과를 바탕으로 인간형 로봇과 통신을 통해서 움직임을 확인하였다.