Development of Rehabilitation Robot Systems for Ambulatory Recovery

이춘영(Choon-Young Lee) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.4

This paper presents a mobile gait training system with body weight support (BWS), which relieves the patient of body weight of a prescribed amount by supporting the subject with a harness. The system is based on electrical motors to achieve system mobility according to the subject's motion of walking while it maintains a constant force on the body based on pneumatic actuators. The mobility of the system seems to be important for a correct gait pattern since the subject is able to walk on the ground actually. The system has a simple architecture to construct, and is practical to the gait rehabilitation.

색채선별기 곡물 이미지 가시화 및 선별기법에 관한 연구

이춘영(Choon-Young Lee),얀레이(Lei Yan),이상룡(Sang-Ryong Lee),박철우(Cheol-Woo Par) 한국가시화정보학회 2008 한국가시화정보학회지 Vol.6 No.2

The color sorting technique utilizing the image processing method is very applicable tool to analyze motion of a free-falling object in many agricultural and industrial research fields. In the present study, we have developed an image processing system and algorithm to sort good quality rice grains effectively from the bad ones. The system employs a high speed rate line-scan CCD camera with 2K-pixels and worked with a high speed DSP and FPGA in-line. It can accumulate acquired line-scan image data and visualize each grain image clearly. As a result, we can easily calculate the number of pixels occupied by grain(=grain size), gray level and its correct position by visualizing grain images rapidly.

자동운항장치를 위한 레이저 스캐닝 센서의 데이터 처리 알고리즘

이춘영(Choon-Young Lee),엄태덕(Tae-Dok Eom),이주장(Ju-Jang Lee) 한국자동차공학회 1999 한국 자동차공학회논문집 Vol.7 No.4

Not merely running at the designated constant speed as the classical cruise control, the adaptive cruise control maintains safe headway distance when the front is blocked by other vehicles. One of the most essential part of adaptive cruise control system is the range sensor which can measure the position and speed of all objects in front continuously, ignore all irrelevant objects, distinguish vehicles in different lanes and lock on to the closest vehicle in the same lane. In this paper, the rule-based object recognition algorithm is proposed to process raw laser scanning data and obtain valid distance to target vehicle. The algorithm proposed has two key concepts : life index and level transition. The concept of life index qualifies the reliability of the recognized object and the concept of level transition gives us robust and reliable data under critical cases when other noisy objects interfere a target object.<br/>

2 자유도 병렬형 매니퓰레이터의 지역 성능지수에 관한 연구

이종규(Jong Gyu Lee),양승한(Seung Han Yang),이상룡(Sang Ryong Lee),이춘영(Choon Young Lee) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.6

족압패턴에 의한 보행보조기를 위한 입각기 감지기법

이상룡,허근섭,강오현,이춘영,Lee, Sang-Ryong,Heo, Geun-Sub,Kang, Oh-Hyun,Lee, Choon-Young 제어로봇시스템학회 2011 제어·로봇·시스템학회 논문지 Vol.17 No.3

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.

2 자유도 병렬형 매니퓰레이터의 지역 성능지수에 관한 연구

이종규(Jong Gyu Lee),양승한(Seung Han Yang),이상룡(Sang Ryong Lee),이춘영(Choon Young Lee) 대한기계학회 2013 大韓機械學會論文集A Vol.37 No.1

본 연구에서 병렬형 매니퓰레이터는 두 개의 평행판 위를 움직이는 슬라이더와 말단장치가 임의로 조정될 수 있는 링크를 가지고 있고, 두 개의 슬라이더에 각각 연결된 링크는 커플링운동을 한다. 매니퓰레이터의 정기구학 및 역기구학 해석을 통하여 슬라이더의 위치 및 말단장치의 위치 사이의 관계식을 나타내는 변위방정식을 유도하고, 유도된 방정식으로부터 정기구학 및 역기구학의 자코비안 행렬들을 구한다. 이러한 행렬들을 이용하여 매니퓰레이터의 지역 성능지수를 제안한다. 성능지수의 시뮬레이션 결과로부터, 매니퓰레이터는 한 사분면에서만 원활한 운동을 할 수 있고, 링크 길이 비와 말단장치의 자세가 최대 성능지수가 분포하는 영역의 변화에 중대한 영향을 미친다. This study investigates a parallel manipulator that can move over two parallel sliders and in which the end-effector of the manipulator can be adjusted arbitrarily. Through the direct and inverse kinematics of the manipulator, position equations are derived. These equations represent the relationship between the positions of the sliders and the position of the end-effector. The Jacobian matrices of the direct and inverse kinematics are obtained by these equations. By using the condition number defined from these matrices, the local performance index of the manipulator is proposed. By using the simulation results of the performance index, we find that the manipulator can smoothen movements in only one quadrant and that the distribution of the maximal performance index is affected by the ratio of the length of links and the orientation of the end-effector.

상지 외골격 로봇 제어를 위한 인체 팔 동작의 기구학 및 동역학적 분석 - 파트 2 : 제한조건의 선형 결합

김현철(Hyunchul Kim),이춘영(Choon-Young Lee) 제어로봇시스템학회 2014 제어·로봇·시스템학회 논문지 Vol.20 No.8

The redundancy resolution of the seven DOF (Degree of Freedom) upper limb exoskeleton is key to the synchronous motion between a robot and a human user. According to the seven DOF human arm model, positioning and orientating the wrist can be completed by multiple arm configurations that results in the non-unique solution to the inverse kinematics. This paper presents analysis on the kinematic and dynamic aspect of the human arm movement and its effect on the redundancy resolution of the seven DOF human arm model. The redundancy of the arm is expressed mathematically by defining the swivel angle. The final form of swivel angle can be represented as a linear combination of two different swivel angles achieved by optimizing two cost functions based on kinematic and dynamic criteria. The kinematic criterion is to maximize the projection of the longest principal axis of the manipulability ellipsoid of the human arm on the vector connecting the wrist and the virtual target on the head region. The dynamic criterion is to minimize the mechanical work done in the joint space for each of two consecutive points along the task space trajectory. The contribution of each criterion on the redundancy was verified by the post processing of experimental data collected with a motion capture system. Results indicate that the bimodal redundancy resolution approach improved the accuracy of the predicted swivel angle. Statistical testing of the dynamic constraint contribution shows that under moderate speeds and no load, the dynamic component of the human arm is not dominant, and it is enough to resolve the redundancy without dynamic constraint for the realtime application.

상지 외골격 로봇 제어를 위한 인체 팔 동작의 기구학 및 동역핮거 분석

김현철(Hyunchul Kim),이춘영(Choon-Young Lee) 제어로봇시스템학회 2012 제어·로봇·시스템학회 논문지 Vol.18 No.12

To achieve synchronized motion between a wearable robot and a human user, the redundancy must be resolved in the same manner by both systems. According to the seven DOF (Degrees of Freedom) human arm model composed of the shoulder, elbow, and wrist joints, positioning and orientating the wrist in space is a task requiring only six DOFs. Due to this redundancy, a given task can be completed by multiple arm configurations, and thus there exists no unique mathematical solution to the inverse kinematics. This paper presents analysis on the kinematic and dynamic aspect of the human arm movement and their effect on the redundancy resolution of the human arm based on a seven DOF manipulator model. The redundancy of the arm is expressed mathematically by defining the swivel angle. The final form of swivel angle can be represented as a linear combination of two different swivel angles achieved by optimizing different cost functions based on kinematic and dynamic criteria. The kinematic criterion is to maximize the projection of the longest principal axis of the manipulability ellipsoid for the human arm on the vector connecting the wrist and the virtual target on the head region. The dynamic criterion is to minimize the mechanical work done in the joint space for each two consecutive points along the task space trajectory. As a first step, the redundancy based on the kinematic criterion will be thoroughly studied based on the motion capture data analysis. Experimental results indicate that by using the proposed redundancy resolution criterion in the kinematic level, error between the predicted and the actual swivel angle acquired from the motor control system is less than five degrees.

2 자유도 병렬 메니퓰레이터의 동적 모델링

이종규(Jong Gyu Lee),이상룡(Sang Ryong Lee),이춘영(Choon Young Lee),양승한(Seung Han Yang) Korean Society for Precision Engineering 2014 한국정밀공학회지 Vol.31 No.10

In this paper, two-DOF parallel manipulator has the sliders which execute a linear reciprocating motion depending on parallel guides and the end-effector which can be adjusted arbitrarily. To investigate the dynamic characteristics of the manipulator, the dynamic performance index is used. The index is able to be obtained by the relation between the Jacobian matrix and the inertia matrix. The kinematic and the dynamic analysis find these matrices. Also, the dynamic model of the manipulator is derived from the Lagrange formula. This model represents complicated nonlinear equations of motion. With the simulation results of the dynamic characteristic of the manipulator, we find that the dynamic performance index is based on the selection of the ranges for the continuous movement of the manipulator and the dynamic model derived can be used to the control algorithm development of the manipulator.

2개의 자유도를 가진 병렬 매니퓰레이터의 기구학 해석

이종규(Jong Gyu Lee),이상룡(Sang Ryong Lee),이춘영(Choon Young Lee),양승한(Seung Han Yang) Korean Society for Precision Engineering 2012 한국정밀공학회지 Vol.29 No.1

In this paper, a parallel manipulator is comprised of two sliders and four links. Sliders execute a linear reciprocating motion depending on parallel guides and make the connected links rotate. A couple of links connected by sliders do coupling motion. The end-effector called a link tip has orientation angle. Through the kinematics analysis of this manipulator, we found displacement, velocity and acceleration using direct and inverse kinematics. We used equations that derived from this analysis and determined five constraint conditions. These conditions had much to do with rotation states of links, the relative relation of link length and coupling motion state. To verify those, we suggest a new algorithm regarding constraint conditions of a manipulator. With the result which performed the algorithm, we found out that operation range of coupled links was limited by relative relation of link length and that manipulator was not able to carry out a series of link motion , in case of being the link vertical between two parallel guides.