• Title/Summary/Keyword: passive joint

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A Motion Control of a Two Degree of Freedom Inverted Pendulum with Passive Joint using Discrete-time Sliding Observer Based VSS Controller (슬라이딩 관측기를 갖는 가변구조제어기에 의한 도립진자의 운동제어)

  • Suh, Yong-Seok;You, Wan-Sik;Kim, Young-Seok
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.468-471
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    • 1994
  • This paper presents the digital implementation of an optimal and robust VSS controller with sliding observer. Firstly, a discrete-time VSS control law which enables the system state to move into a sliding sector where the closed-loop system is stable is designed. Then optimal control theory is used to design an optimal sliding sector. Secondly, a sliding observer which provide robust state estimation against model-plant mismatches due to parameter uncertainties is designed for the sampled-data multivariable systems. Finally, modified sliding observer which effectively reduce chattering of state variables in state estimation was proposed. The proposed scheme was applied 10 a two degree of freedom inverted pendulum with passive joint to verify robust motion control. Computer simulation results confirm the viability of the proposed observer-based controller.

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Design and Control of a Passive Compliant Joint for Human-friendly Service Robots

  • Yoon, Seong-Sik;Sungchul Kang;Kim, Seung-Jong;Kim, Munsang;Yim, Heung-Soon;Kim, Young-Hwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.119.2-119
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    • 2002
  • In this paper a passive compliant joint (PCJ) for human-friendly service robots is presented. The PCJ is composed of a magneto-rheological damper and a spring for elasticity. In the magneto-rheological damper, a braking force proportional to the electric current is generated. It works as a viscous damper by controlling the electric current according to the angular velocity of spring displacement. The compliance property and position control of the PCJ are verified through experiments and simulations to a single DOF simple arm with the PCJ.

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Control Methodology of Multiple Arms for IMS : Experimental Sawing Task by Nonidentical Cooperating Arms (IMS를 위한 로봇 군 제어방법 : 이종 협조 로봇의 톱질 작업)

  • Yeo, Hee-Joo;Suh, Il-Hong;Lee, Byung-Ju;Oh, Sang-Rok
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.4
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    • pp.452-460
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    • 1999
  • Sawing experiments using a two-arm system have been performed in this work. The two-arm system under consideration of two kinematically-nonidentical arms. A passive joint is inserted at the end-point of one robot in order to increase the mobility up to the motion degree required for sawing tasks. A hybrid control algorithm for control of the two-arm system is designed. We experimentally show that the performance of the velocity and force response are satisfactory, and that one additional passive joint not only prevents the system from unwanted yaw motion in the sawing task, but also allows an unwanted pitch motion to be notably reduced by an internal load control. To show the general applicability of the proposed algorithms, we perform experimentation under several different conditions for saw, such as three saw blades, two sawing speeds, and two vertical forces.

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Arthrokinetic Analysis of Knee Joint (슬관절의 운동학적 분석)

  • Kim, Jae-hun
    • PNF and Movement
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    • v.6 no.1
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    • pp.53-60
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    • 2008
  • Purpose : To describes the important aspects of knee joint movement and function used when applying PNF technique to the lower limb. Method : The knee was a very important roles in the lower limb movement and ambulation. This study summarizes the physiologic movement of knee to the PNF lower extremity patterns. Result : The tibiofemoral joint is usually described as a modified hinge joint with flexion-extension and axial rotation by two degrees of freedom movement. These arthrokinematics are a result of the geometry of the joints and the tension produced in the ligamentous structures. The patellofemoral joint is a sellar joint between the patella and the femur. Stability of the patellofemoral joint is dependent on the passive and dynamic restraints around the knee. In a normal knee the ligaments are inelastic and maintain a constant length as the knee flexes and extends, helping to control rolling, gliding and translation of the joint motions. Conclusions : It is important to remember that small alterations in joint alignment can result in significant alterations in patellofemoral joint stresses and that changes in the mechanics of the patellofemoral joint can also result in changes in the tibiofemoral compartments. Successful treatment requires the physical therapist to understand and apply these arthrokinematic concepts. When applied to PNF low extremity patterns, understanding of these mechanical concepts can maximize patient function while minimizing the risk for further symptoms or injury.

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Stairs Adaptable Wheeled Mobile Robotusing Passive Linkage Mechanism

  • Woo, Chun-Kyu;Kim, Soo-Hyun;Kwak, Yoon-Keun;Kim, Mun-Sang
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.30.3-30
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    • 2001
  • In this paper, we designed the 6-wheeled mobile robot (6-WMR) with the passive linkage mechanism which enables 6-WMR to passively adapt to the given stairs. To overcome the limit of adaptability to the terrain of conventional WMR and improve the energy efficiency, we proposed the new WMR using the passive linkage mechanism. The passive linkage mechanism consists of the simple four-bar linkage mechanism which allows 6-WMR to climb stairs with adaptability and an additional link which is connected to the four-bar linkage mechanism by a pin-slot joint to enable 6-WMR to passively go up the stairs. We made a miniature model of the proposed 6-WMR ...

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Design of a Variable-Stiffness Type Safety Joint for Service Robots (서비스 로봇용 가변강성 형 안전관절의 설계)

  • Jeong, Jae-Jin;Chang, Seung-Hwan
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.5
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    • pp.128-134
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    • 2009
  • This paper aims to design a variable-stiffness type economical safety joint for service robots. The safety joint was designed to have a passive shock absorbing mechanism for protecting human from a catastrophic collision under service condition of robots. A simple mechanism composed of two action disks for switching the load transfer, a spring and a screw for pre-load was proposed. In order to evaluate the performance of the safety joint a testing platform which can carry out the static and impact tests was also designed and fabricated. From the test results, the designed safety joint was proved to have a variable load-carrying capacity and about 42% impact absorption capacity with simple manipulation of the control screw.

Relationships Between Joint Attention and Language Development in Infancy (영아의 공동주의와 초기 언어발달의 관계)

  • Lee, Hae-Ryoun;Lee, Kwee-Ock;Lee, Young-joo
    • Korean Journal of Child Studies
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    • v.28 no.5
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    • pp.297-307
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    • 2007
  • This study investigated relationships between engagement in joint attention and the early language development in infancy. Subjects were 12 infants and their mothers. At 20 and 25 months of age, each child's spontaneous natural speech during interaction with his/her caregiver was videotaped for about 30 minutes. The EJA(Episodes of joint attention) focus between mother and child were identified and coded by Tomasello and Todd's(1983) and Bakeman and Adamson's(1984) including person engagement, object engagement, looking engagement, passive joint attention, coordinated joint attention. Results showed that a significant difference in infant's language development between within and outside EJA at 20 and 25 months of age; that is, during periods of EJA children talked more inside than outside EJA.

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Coping Patterns in Chronic Low Back Pain : Relationship with Locus of Control and Self-Efficacy (만성 요통 환자의 대처 유형과 건강 통제위, 자기효능감과의 관계)

  • Kim, In-Ja;Lee, Eun-Ok
    • Journal of muscle and joint health
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    • v.2 no.1
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    • pp.1-16
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    • 1995
  • Coping patterns were investigated in a sample of 126 patients with chronic low back pain by means of self-reported questionnaire. Based on the previous researches, coping pat terns were divided into the active cognitive coping, the active behavioral coping, the passive cognitive coping, and the passive behavioral coping. While all the above coping patterns were used, the passive behavioral coping was found to be used most frequently. Six subgroups were identified by cluster analytic procedure using their scores of the coping scale : active cognitive coper, general active coper, passive behavioral coper, general passive coper, multidimensional coper, and multi dimensional non-coper. Six subgroups were compared regarding locus of control, self-efficacy, pain and demographic variables. Distinct differences appeared among subgroups in internal locus of control, self-efficacy, and pain. General active coper and active cognitive coper had higher internal locus of control, higher self-efficacy, and lower pain. General passive coper and multidimensional non-coper had lower internal locus of control, lower self-efficacy, and higher pain. Passive behavioral coper had higher internal locus of control, lower self-efficacy, and higher pain. It supports the concept of learned helplessness due to prior experiences. Multi dimensional coper had higher internal, higher powerful others, and higher self-efficacy. So it corresponds to 'believer in control' group Identified by Wallston et at(1982). Unexpectedly this group also complained more pain. It could be interpreted in two ways. The more coping methods they use, the more they complain pain ; which is the result of Folkman et al (1986). Or they might be typical 'yea sayers'. These unique groups-passive behavioral coper and multidimensional coper-identified by this study supports the suggestion of Wallston et al(1982), about locus of control : individual's pattern of responses across the three scales may be more predictive than his or her scores on each of the scale seperately. The fact that passive coping was used more than active coping also suggests that self controlled active co ping is encouraged to chronic patients as well as acute patients. And it is necessary to articulate the coping scale and self-efficacy scale. It is also necessary to study the relationship of coping and adjustment by experimental design.

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Analysis of correlation between passive ankle movement range and knee joint kinetic variables during squat movement (스쿼트 동작 시 수동적 발목 가동범위와 무릎 관절 운동역학적 변인 간 상관성 분석)

  • Lee, JaeWoo;Park, JunSung;Lim, Young-Tae;Kwon, Moon-Seok
    • Journal of the Korean Applied Science and Technology
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    • v.37 no.3
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    • pp.509-515
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    • 2020
  • The purpose of this study was to analyze the correlation between passive ankle movement range and knee joint kinetic variables during squat movement. In this study, a total of 27 subjects participated in this study, 19 men and 8 women, who had no history of the musculoskeletal system of the lower extremity. To verify the correlation between the ankle joint flexibility and the knee joint kinetic variables during deep squat, it was performed pearson's correlation coefficient and variables showing statistically significant correlation were performed by simple regression analysis at a significant level of α .05. Through this study, the relationship between the peak joint moment and joint reaction force factors that determine ankle joint flexibility and knee joint pressure was confirmed. Therefore, when applying an exercise that can generate a lot of load on the knee joint such as deep squats during strength training, checking the degree of flexibility of the ankle joint among physical characteristics to the individual may reduce the stability of the body and the risk of injury to the knee joint. It is expected to be helpful in setting the intensity of exercise that can be done.

Control Algorithm of the Lower-limb Powered Exoskeleton Robot using an Intention of the Human Motion from Muscle (인체근육의 동작의도를 이용한 하지 근력증강형 외골격 로봇의 제어 알고리즘)

  • Lee, Hee-Don;Kim, Wan-Soo;Lim, Dong-Hwan;Han, Chang-Soo
    • 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.