Sehoon Oh

Sungwon Shin

Hyeongjun Kim

Mingoo Jeong

Gwangtae Kim

Jungsoo Cho

Hanseung Woo

Pyeong-gook Jung

Hyunjin Choi

Byeonghun Na

Jungsu Choi

Mia Song

Eunseok Song

Seongbin An

Minjun Kang

Hyeonseok Seo

Daeho Lee

Sumin Lee

Dongha Nam

Youngsik Kim

Kyeongwon Park

Hyunjune Song

Heiseok Moon

Cheolmin Kwon

Yooseok Kim

Seungho Youn

Minkyu Choi

Kanghyun Kim

Jangmok Lee

Yeongsik Seo

Joonyoung Jung

Kyoungduk Park

Myoungseok Lee

Eunyoung Baek

Seok-ki Song

The goal of Exo Lab’s research is the development of mechatronic and robotic systems that improve the quality of human lives. Based on fundamentals in Controls and Dynamic Systems, the major applications of Exo Lab include the design and control of legged locomotive robot systems that assist the human mobility. Recent achievements include wearable robots for assistance of people with physically demanding works or people with complete paraplegia, and rehabilitation of paretic patients.

Flexi-SEA: Flexible-Shaft-Driven Series Elastic Actuator for Wearable Robots

Real-time Gait Recognition of Multiple Stair-climbing Modes for Hip-assisting Wearable Robots

Adaptive Inertial Orientation Estimation Robust to Inherent Impact on Human Motion

Design of a front-enveloping powered exoskeleton considering optimal distribution of actuating torques and center of mass

Leaf-Inspired FSR Array and Insole-Type Sensor Module for Mobile Three-Dimensional Ground Reaction Force Estimation

State Estimation of a Powered Exoskeleton with Dynamic Motion Using Kinematic and Inertial Odometry

Precise Torque Control in High Temperature with Heat Transfer Model based Torque Constant Compensation Algorithm

Efficacy of a Soft Wearable Robot for Hip Assistance in Chronic Stroke Patients: A Randomized Crossover Trial

Plantar flexion muscle force estimation with a soft wearable pneumatic sensor system

Hybrid model control of WalkON suit for precise and robust gait assistance of paraplegics

Measurement of Force Myography in Level Gait and Stair Gait

A soft three-axis force sensor based on radially symmetric pneumatic chambers

Bio-inspired cable-driven knee orthosis for tibiofemoral joint load distribution

Precise torque-output estimation of a reaction-force-sensing series elastic actuator for human-robot interaction

Active Temperature Limitation Algorithm to Maximize Potential Driving Current Capability of Electric Motors

Soft Sensing Brace for Monitoring Knee Joint Kinetics and Kinematics During Squatting

Soft sensor unit for measurement of large scale multi-axis force

High-accuracy hand gesture recognition on the wrist tendon group using pneumatic mechanomyography (pMMG)

Adaptive gait pattern generation of a powered exoskeleton by iterative learning of human behavior

착용자 중심의 인간-외골격 로봇 상체 도킹 메커니즘 설계

High-Precision Motion Control of a Lower-Limb Wearable Robot for People with Walking Disability by Hybrid Filtered Disturbance Observer

Development of wireless pneumatic myography sensor for real-time muscle contraction measurement

룩업 테이블 기반 보정 기법을 이용한 증분형 엔코더 기반 절대 엔코더 비선형 오차 보정

정적 서기 자세에서 하지 외골격 로봇의 균형 유지를 위한 압력 중심 기반의 발목 관절 힘 제어

A compact transmitted-force-sensing series elastic actuator with optimized planar torsional spring for exoskeletons

지면 반발력 기반 하지 외골격 로봇 착용자의 상체 자세 추정

Optimal level of assistance and weight of hip-joint wearable robot considering influences to the human body

Inertial Orientation Estimation Robust to Impact for Bipedal Robot Locomotion

A User Interface System of a Robot-Aided Gait Training System for Complete Paraplegics

Hybrid filtered disturbance observer for precise motion generation of a powered exoskeleton

Phase portrait 을 통한 보행 비대칭성 평가

Mechanism design of a robotic leg for running considering radial force producibility and tangential mobility

Bioinspired knee joint of a lower-limb exoskeleton for misalignment reduction

Thermal Characteristic Modeling and Compensation for the Improvement of Actuator Homeostasis

Data-driven modeling for gait phase recognition in a wearable exoskeleton using estimated forces

Iterative learning of human behavior for adaptive gait pattern adjustment of a powered exoskeleton

A study on weight support and balance control method for assisting squat movement with a wearable robot, angel-suit

재활 로봇의 실시간 보행 능력 평가를 위한 FSR-크러치 모듈의 개발과 활용방안

What is the proper gait pattern for people with paraplegia who wear powered exoskeletons?: Re-examining gait patterns of existing powered exoskeletons

착용형 로봇을 이용한 불완전마비 환자의 보행 보조

착용형 로봇의 제어방법

케이블 견인 구동장치 및 이를 포함하는 착용형 슈트

동작의도 측정센서 및 동작의도 측정 시스템

하체 보조로봇

다족 로봇용 다리유닛

탄성 감속 구동기 및 이를 구비하는 착용형 보조장치

착용형 보조장치

가변강성 구조를 갖는 착용형 로봇

시트형 근력 보조 슈트

착용형 보조장치의 슬관절 구조 및 이를 구비하는 착용형 보조장치

공압 구동기 및 이를 이용한 외골격 로봇

다족 로봇용 다리유닛 및 이를 구비하는 다족로봇

Device For Joint Assistant Force Generator

Upper Body Assisting Device

Design and control of an exoskeleton for the elderly and patients

Control of rotary series elastic actuator for ideal force-mode actuation in human–robot interaction applications

A compact rotary series elastic actuator for human assistive systems

A gait monitoring system based on air pressure sensors embedded in a shoe

High-precision robust force control of a series elastic actuator

A wearable gesture recognition device for detecting muscular activities based on air-pressure sensors

Smooth and continuous human gait phase detection based on foot pressure patterns

Impedance compensation of SUBAR for back-drivable force-mode actuation

Control of exoskeletons inspired by fictitious gain in human model

A rotational micro biopsy device for the capsule endoscope

Fast gait mode detection and assistive torque control of an exoskeletal robotic orthosis for walking assistance

A robotic biopsy device for capsule endoscopy

Design and analysis of force-sensor-less power-assist control

Active impedance control of a lower limb exoskeleton to assist sit-to-stand movement

A generalized control framework of assistive controllers and its application to lower limb exoskeletons

Frequency-shaped impedance control for safe human–robot interaction in reference tracking application

Recognition of gait cycle phases using wearable sensors

A mobile motion capture system based on inertial sensors and smart shoes

A mobile gait monitoring system for abnormal gait diagnosis and rehabilitation: A pilot study for Parkinson disease patients

Nominal model manipulation for enhancement of stability robustness for disturbance observer-based control systems

Masayoshi Tomizuka

Beomsoo Hwang

Sehyuk Yim

Kyoungchul Kong

Recently, the exoskeletal power assistive equipment, which is a kind of wearable robot, has been widely developed to help human body motion. The exoskeleton for elderly people and patients, however, has some limitations due to the weight and volume of the equipment. In this paper, a tendon-driven exoskeletal power assistive device, exoskeleton for patients and the old by the Sogang University (EXPOS), is proposed as a feasible solution. In case of EXPOS, the caster walker carries heavy items such as motors, drivers, controllers, and batteries so that the weight and volume of the wearable exoskeleton are minimized. The tendon-connecting motors and pulleys of hip and knee generate the assistive power according to the requirement of the users. In this paper, the design concepts of the EXPOS, sensing techniques, and control methods are discussed

To realize ideal force control of robots that interact with a human, a very precise actuating system with zero impedance is desired. For such applications, a rotary series elastic actuator (RSEA) has been introduced recently. This paper presents the design of RSEA and the associated control algorithms. To generate joint torque as desired, a torsional spring is installed between a motor and a human joint, and the motor is controlled to produce a proper spring deflection for torque generation. When the desired torque is zero, the motor must follow the human joint motion, which requires that the friction and the inertia of the motor be compensated. The human joint and the body part impose the load on the RSEA. They interact with uncertain environments and their physical properties vary with time. In this paper, the disturbance observer (DOB) method is applied to make the RSEA precisely generate the desired torque …

Precise and large torque generation, back drivability, low output impedance, and compactness of hardware are important requirements for human assistive robots. In this paper, a compact rotary series elastic actuator (cRSEA) is designed considering these requirements. To magnify the torque generated by an electric motor in the limited space of the compact device, a worm gear is utilized. However, the actual torque amplification ratio provided by the worm gear is different from the nominal speed reduction ratio due to friction, which makes the controller design challenging. In this paper, the friction effect is considered in the model of cRSEA, and a robust control algorithm is designed to precisely control the torque output in the presence of nonlinearities such as the friction. The mechanical design and dynamic model of the proposed device and the design of a robust control algorithm are discussed, and actuation …

Measurement of ground contact forces (GCFs) provides necessary information to detect human gait phases. In this paper, a new analysis method of the GCF signals is discussed for detection of the gait phases. Human gaits are complicated, and the gait phases cannot be exactly distinguished by comparing sensor outputs to a threshold. This paper proposes a method by fuzzy logic for detecting the gait phases continuously and smoothly. The smooth and continuous detection of the gait phases enables a full use of information obtained from GCF sensors. For advanced rehabilitation systems, this paper also introduces a higher level algorithm that quantitatively monitors the amount of abnormalities in a human gait. The abnormalities detected by the proposed method include an improper GCF pattern as well as an incorrect sequence of the gait phases. To realize the monitoring algorithm, the gait phases are analyzed …

A series elastic actuator (SEA) is a promising actuation method in force control applications that intelligently interacts with environments. The SEA is characterized by a spring placed between a load and an actuator, which is an electric motor in most cases. Since the spring plays the role of a transducer between position (i.e., the spring deflection) and force, it is able to control the output force (torque) precisely by utilizing typical position control methods. However, the force control performance of the SEA is considered to have limitations due to its elasticity, and thus, to be inferior to rigid actuators in terms of bandwidth. This paper proposes that the force control performance of the SEA can be improved by exploiting the dynamic model of the SEA. To this end, the SEA is modeled and analyzed utilizing the two-mass dynamic model, which is a well-known and widely accepted model of the flexible system. The disturbance …

Recognition of human gestures plays an important role in a number of human-interactive applications, such as mobile phones, health monitoring systems, and human-assistive robots. Electromyography (EMG) is one of the most common and intuitive methods used for detecting gestures based on muscle activities. The EMG, however, is in general, too sensitive to environmental disturbances, such as electrical noise, electromagnetic signals, humidity, and so on. In this paper, a new method for recognizing the muscular activities is proposed based on air-pressure sensors and air-bladders. The muscular activity is detected by measuring the change of the air pressure in an air-bladder contacting the interested muscle(s). Since the change of the air pressure can be more robustly measured compared with the change of electric signals appeared on the skin, the proposed sensing method is useful for mobile devices due …

Measurement of ground contact forces (GCF) provides necessary information to detect human gait phases. In this paper, a new analysis method of the GCF signals is discussed for detection of the gait phases. Human gaits are complicated, and the gait phases can not be exactly distinguished by comparing sensor outputs to a threshold. This paper mainly discusses how to detect the gait phases continuously and smoothly. The proposed analysis method is intended for applications to power assistive devices for patients, as well as diagnostics of pathological gait. Smooth and continuous detection of the gait phases enables a full use of information obtained from GCF sensors. For experimental verification, smart shoes have been developed. Each smart shoe has four GCF sensors embedded between the cushion pad and the sole. The performances are experimentally verified for both normal and abnormal gaits, and a …

The Sogang University biomedical assistive robot (SUBAR), which is an advanced version of the exoskeleton for patients and the old by Songang (EXPOS) is a wearable robot developed to assist physically impaired people. It provides a person with assistive forces controlled by human intentions. If a standard geared DC motor is applied, however, the control efforts will be used mainly to overcome the resistive forces caused by the friction, the damping, and the inertia in actuators. In this paper, such undesired properties are rejected by applying a flexible transmission. With the proposed method, it is intended that an actuator exhibits zero impedance without friction while generating the desired torques precisely. Since the actuation system of SUBAR has a large model variation due to human-robot interaction, a control algorithm for the flexible transmission is designed based on a robust control method. In this paper …

A human wearing an exoskeleton-type assistive device results in a parallel control system that includes two controllers: an exoskeleton controller and a human brain that includes the spinal cord and the cerebrum. Unknown and complicated characteristics of the brain dynamically interact with the exoskeleton controller, which makes the controller design challenging. In this paper, the motion control system of a human is regarded as a feedback control loop that consists of the brain, muscles, and the dynamics of the extended human body. The brain is modeled as a control algorithm amplified by a fictitious gain (FG). The FG is adjusted to compensate for characteristic changes in the muscle and human body dynamics due to physical impairment, varying load, or any other causes. In this paper, an exoskeleton controller that realizes the FG is designed, and its performance and robustness are discussed.

Recently the technology of capsule endoscopy has developed dramatically and many researchers are making efforts to combine surgical function into the capsule type endoscope. In this paper, the micro biopsy module which is a part of the capsule endoscope is proposed. The proposed module is less than 2 mm in thickness and has a diameter of 10 mm. It consists of a trigger with paraffin block, rotational tissue-cutting razor with a torsion spring and controller. This module makes it possible for the capsule endoscope to obtain a sample tissue inside the small intestine which can not be reached by a conventional biopsy device. Through dedicated experiments, tissue samples were successfully extracted using the proposed biopsy module and the cells in samples were extracted and tested by a microscope.

Gait modes, such as level walking, stair ascent/descent, and ramp ascent/descent, show different lower-limb kinematic and kinetic characteristics. Therefore, an accurate detection of these modes is critical for a wearable robot to provide appropriate power assistance. In this paper, a fast gait-mode-detection method based on a body sensor system is proposed. A fuzzy logic algorithm is used to estimate the likelihoods of gait modes in real time. Since the proposed fast gait mode detection makes it possible to select appropriate kinematic and kinetic models for each gait mode, assistive torques required for assisting the human motions can be obtained more naturally and immediately. The proposed methods are all verified by experiments with a lower-limb exoskeletal assistive robot with transparent actuation by series elastic actuators, called the exoskeletal robotic orthosis for walking assistance. Four healthy subjects …

This paper introduces a robotic biopsy device for capsule endoscopes. The proposed device consists of three modules for the complete process of biopsy, which includes monitoring the intestinal wall by a tissue monitoring module (TMM), aligning onto a polyp by an anchor module (AM), and sampling of the polyp tissue by a biopsy module (BM). The TMM utilizes a trigonal mirror as well as an on-board camera; since the TMM continuously takes images through lateral apertures, an operator such as a medical doctor is able to anchor the capsule endoscope onto the polyp and biopsy it with the visual feedback in real-time. When the operator finds a polyp using the TMM and the frontal camera of a capsule endoscope, then the AM is used to approach the polyp for biopsy. When the AM is in use, outriggers are extruded by shape-memory-alloy (SMA) springs, which results in the swelling of capsule endoscope body. In …

Due to the recent trend of the application of robots and other mechatronic devices to human life support, the force control draws more attention than ever. However, to use force sensors in all the required cases makes the system not only expensive but also bulky. Force-sensor-less power-assist control (FSPAC) which uses only encoders to obtain the external force information and provides force control performance can address this problem. Due to its simplicity and wide application, FSPAC is an essential technology to control a motor in a human-friendly way, but the design of FSPAC is different from the conventional feedback controllers so a new design methodology needs to be established. In order to attack this problem, this paper generalizes and analyzes the structure and characteristics of FSPAC. The generalized structure reveals how FSPAC can achieve the assistance, and the transfer function analysis …

As an important movement of the daily living activities, sit-to-stand (STS) movement is usually a difficult task facing elderly and dependent people. To provide appropriate power assistance for the sit-to-stand movement, a novel intention-based Active Impedance Control (AIC) strategy applied on a lower limb exoskeleton is proposed in this paper. The AIC is able to adapt the mechanical impedance of the human-exoskeleton system towards a desired one using the exoskeleton's power assistance. In the AIC structure, a human joint torque observer is designed to estimate the human joint torques using joint angles information instead of electromyography (EMG) or force/torque sensors; a time-varying desired impedance model is proposed according the wearer's lower limb motion ability. Simulations were implemented to illustrate the characteristics and performances of the proposed approach. Experiments with a …

Various control methods have been studied for the natural assistance of human motions by exoskeletal robots, i.e., wearable robots for assisting the human motions. For example, impedance control and compliance control are widely used for controlling interaction forces between a human and a robot. When an accurate measurement of the human muscular force is available (e.g., electromyography), a direct use of the estimated human joint torque is possible in the control of an assistive robot. The human motions in a daily living, however, are so complex that they are constituted by multiple phases, such as walking, sitting, and standing, where the walking can be further categorized into multiple sub-phases. Therefore, a single control method cannot be the best option for all the motion phases; a switch in the control algorithms may be necessary for assisting human movements in multiple motion phases. In this paper …

In the control of industrial robots, both safety and reference tracking performance are required. For safe human-robot interaction, robots should exhibit low mechanical (or controlled) impedance so that they react to the interaction forces in a compliant manner. On the other hand, the reference tracking requires for the robots to reject exogenous disturbances, which results in an increased impedance. In order to achieve these two conflicting objectives, a frequency-shaped impedance control (FSIC) method is proposed in this paper. The proposed method utilizes the two different functionalities of the disturbance observer (DOB): a disturbance estimation function as an observer and a disturbance rejection function as a feedback controller. Namely, the DOB is utilized as an observer at the frequencies where the robots interact with humans, while it is used as a feedback controller (i.e., disturbance rejection controller) at the …

The analysis and monitoring of the human daily living activities plays an important role for rehabilitation goals, fall prevention rehabilitation and general health-care treatments. Among these activities, walking is the most important daily motion. Studying the evolution of the gait cycle through the analysis of the human center of force is beneficial to predict any abnormal walking pattern. The analysis is based on the use of pressure-based mapping system that collects pressure and force measurement during the gait cycle. This paper deals mainly with the detection of the main characteristics of the gait phases. To this end, a segmentation of the center of force of the human body measure through the in-shoe pressure mapping system is performed to identify the gait phases. The proposed segmentation approach consists in modeling each segment by a regression model and using logistic functions to model the transitions …

Motion capture systems play an important role in health-care and sport-training systems. In particular, there exists a great demand on a mobile motion capture system that enables people to monitor their health condition and to practice sport postures anywhere at any time. The motion capture systems with infrared or vision cameras, however, require a special setting, which hinders their application to a mobile system. In this paper, a mobile three-dimensional motion capture system is developed based on inertial sensors and smart shoes. Sensor signals are measured and processed by a mobile computer; thus, the proposed system enables the analysis and diagnosis of postures during outdoor sports, as well as indoor activities. The measured signals are transformed into quaternion to avoid the Gimbal lock effect. In order to improve the precision of the proposed motion capture system in an open and outdoor space …

Conventional gait rehabilitation treatment does not provide quantitative information on abnormal gait kinematics, and the match of the intervention strategy to the underlying clinical presentation may be limited by clinical expertise and experience. Also the effect of rehabilitation treatment may be reduced as the rehabilitation treatment is achieved only in a clinical setting. In this paper, a mobile gait monitoring system (MGMS) is proposed for the diagnosis of abnormal gait and rehabilitation. The proposed MGMS consists of Smart Shoes and a microsignal processor with a touch screen display. It monitors patients’ gait by observing the ground reaction force (GRF) and the center of GRF, and analyzes the gait abnormality. Since visual feedback about patients’ GRFs and normal GRF patterns are provided by the MGMS, patients can practice the rehabilitation treatment by trying to follow the normal GRF patterns without …

Disturbance observer-based control systems often encounter the stability problem due to modeling uncertainties. In such cases, the disturbance observer (DOB) may have to be re-designed by narrowing the bandwidth of the Q-filter to enhance stability robustness, but this approach to stability enhancement deteriorates the performance of DOB. In order to improve robust stability while maintaining the performance of DOB, this paper proposes a method that manipulates the nominal plant model in the DOB; the parameters of the discretized nominal model are optimized to improve robust stability in the discrete time domain. For the optimization of nominal model, it is assumed that the closed-loop poles of DOB are subjected to multiplicative uncertainties, and the maximum allowable magnitude of uncertainties is utilized as the measure of stability robustness. Then, the proposed method changes the location of closed …

Department of Mechanical Engineering (B.ENG), Department of Physics (B.S.), SUMMA CUM LAUDE, with Honors in Engineering

Department of Mechanical Engineering, Thesis Title : Design and Control of Exoskeletal Robots for Patients and Elderly People

Mechatronic Considerations for Human Assistive and Rehabilitation Systems, Research Advisor: Professor Masayoshi Tomizuka

KAIST Exoskeleton Laboratory

교수님 소개

공경철

연구실 소개

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Flexi-SEA: Flexible-Shaft-Driven Series Elastic Actuator for Wearable Robots

Real-time Gait Recognition of Multiple Stair-climbing Modes for Hip-assisting Wearable Robots

Adaptive Inertial Orientation Estimation Robust to Inherent Impact on Human Motion

연구실 보유 특허

대학별 입시끈

우리 연구실 모집

교수님 소개

공경철

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Flexi-SEA: Flexible-Shaft-Driven Series Elastic Actuator for Wearable Robots

Real-time Gait Recognition of Multiple Stair-climbing Modes for Hip-assisting Wearable Robots

Adaptive Inertial Orientation Estimation Robust to Inherent Impact on Human Motion

연구실 보유 특허

최근 3년간 연구실적 높은 연구실

대학별 입시끈

우리 연구실 모집