• Title/Summary/Keyword: Passive Joint

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Design and Control of a Dexterous Multi-fingered Robot Hand

  • Chung, Woo-Jin;Lee, Hyung-Jin;Kim, Mun-Sang;Lee, Chong-Won;Kang, Bong-Soo
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.83.1-83
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    • 2001
  • This paper presents a three-fingered robot hand, called the KIST hand, Which have one active joint and one passive joint. The thumb is fixed on the palm, and the index and the middle take lateral motions symmetrically. A mechanical clutch and an embedded force sensor, attached on the distal link of the fingers, enable the KIST hand to perform human-like functions. A result of experiment shows reliable grasping performance of the hand which maintain stable grasp under disturbances.

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Hard Contact Transition Control Laws : :Three Different Approaches

  • Doh, Nakju;Chung, Wankyun;Youm, Youngil
    • 제어로봇시스템학회:학술대회논문집
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    • 1999.10a
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    • pp.17-20
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    • 1999
  • In this paper, we consider on hard contact transition control strategies. Hard contact transition phase can be divided into two definitely different phases,“Pre-Transition Phase”and“Transition Phase”. Here we focus on the“Pre-Transition Phase”and we propose three control methods. First, we propose a novel con-troller named as “Suppression Controller”which is not only stable but also simple to implement. Second, we present passive damper named as“Flexible-Damped Joint”Which is good solution in Circumventing pre-transition Phase. Third, We suggest a stable and simple controller which can maximize joint damping and minimize recontact velocity in flexible-damped joint. It is named as“Joint Damping Controller”.

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Relationship between Hip Medial Rotation Range of Motion and Weight Distribution in Patients with Low Back Pain

  • Kim, Sang-Kyu;Kim, Won-Bok;Ryu, Young-Uk
    • Journal of the Korean Society of Physical Medicine
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    • v.9 no.3
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    • pp.279-284
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    • 2014
  • PURPOSE: This study intended to verify whether there was actual correlation between weight-bearing asymmetry and a limitation in hip joint rotation range in patients with low back pain. METHODS: Thirty five low back pain patients voluntarily participated this study. For each participant, hip joint medial rotation symmetry rate and the weight-bearing symmetry rate were calculated. The correlation between the two variables was investigated. RESULTS: A decrease in the left hip joint medial rotation range of motion (ROM) was observed more often than a reduction in the right hip joint medial rotation ROM. However, similar number between right and left side was observed in ground reaction force more weighted. The coefficient between the passive hip joint medial rotation symmetry rate and the weight loading symmetry ratio was -0.19 (p < 0.05). CONCLUSION: The present study demonstrated a weak correlation between the hip joint medial rotation ROM and the weight distribution of both feet. Such result suggests that careful evaluation by separating each element is needed in treating patients with low back pain. Future research should take into account asymmetric alignment and abnormal movement in different joints of the body as well as asymmetry in the bilateral hip joint rotation and the unilateral weight supporting posture.

The Immediate Effect of Wrist Joint Mobilization with Taping on Range of Motion, Grip Strength, Spasticity in Stroke Patients

  • Park, Shin-Jun;Youn, Pong-Sub
    • The Journal of Korean Physical Therapy
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    • v.29 no.4
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    • pp.187-193
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    • 2017
  • Purpose: The purpose of this study was to confirm the immediate effect of wrist joint mobilization with taping on the range of motion, grip strength, and spasticity. Methods: Thirty stroke patients were randomly divided into two groups: the joint mobilization with taping group (n=15) and a taping group (n=15). For measurement of spasticity and joint range of motion, the modified Tardieu scale, active and passive range of motion of wrist flexion, as well as extension were measured by the Rapael smart glove, and for grip strength measurement, grip dynamometer was performed. Results: The experimental group showed a significant improvement in the range of motion, grip strength, and spasticity after 10 minutes of taping (p<0.05), no significant difference was found in the control group (p>0.05). However, there was no significant difference between the two groups (p>0.05). Conclusion: The study found that wrist joint mobilization with taping has an immediate effect on wrist range of motion, grip strength, and spasticity in stroke patients, whereas it was not effective in the control group with just taping. The long-term change still needs to be evaluated, when taking into consideration of the carryover effect.

Dynamic Threshold Model of Spasticity that Can Predict Various Pendulum Motions (다양한 진자운동을 재현가능한 경직의 동적 역치 모델)

  • Kim Chul-Seung;Kong Se-Jin;Kwon Sun-Duck;Kim Jong-Moon;Eom Gwang-Moon
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.7 s.184
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    • pp.152-158
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    • 2006
  • The objective of this work is to develop the knee joint model for representing various pendulum motions and quantifying the spasticity. Knee joint model included the extension and flexion muscles. The joint moment consists of both the active moment from the stretch reflex and the passive moment from the viscoelastic joint properties. The stretch reflex was modeled as nonlinear feedback of muscle length and the muscle lengthening velocity, which is Physiologically-feasible. Moreover, we modeled the spastic reflex as having dynamic threshold to account far the various pendulum trajectories of spastic patients. We determined the model parameters of three patients who showed different pendulum trajectories through minimization of error between experimental and simulated trajectories. The simulated joint trajectories closely matched with the experimental ones, which show the proposed model can predict pendulum motions of patients with different spastic severities. The predicted muscle force from spastic reflex appeared more frequently in the severe spastic patient, which indicates the dynamic threshold relaxes slowly in this patient as is manifested by the variation coefficient of dynamic threshold. The proposed method provides prediction of muscle force and intuitive and objective evaluation of spasticity and it is expected to be useful in quantitative assessment of spasticity.

A Study for Hip Joint in Children with Cerebral Palsy (뇌성마비 아동의 엉덩관절에 관한 연구)

  • Oh, Tae-young
    • The Journal of Korean Society for Neurotherapy
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    • v.22 no.3
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    • pp.43-48
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    • 2018
  • Purpose The purpose of this study is to identify the prevalence, risk factors, characteristics, and interventions of hip joint problems in children with cerebral palsy, and to be able to serve as leverage for early detection, prevention, and function recovery. Method The electronic journal site was searched by the search terms "cerebral palsy", "hip joint", "hip joint dislocation", we analyzed and descript the cited articles from domestic and foreign papers in Pubmed 9, Science Direct 7, and K RISS analysis and analysis. Results Children with cerebral palsy showed the different prevalence according to their disability type, severity, and functional level, and we knew that abnormal neuromuscular control, stiffness, and biomechanical changes could be risk factors. Migration Index, Acetabolum Index, Neck shaft angle using by radiography and passive ROM test, special tests were available for the diagnosis and evaluation of the hip joint. Combination of physical therapy and orthopedic surgery was very important intervention, and complementary alternative therapy, orthosis, and postural assistant are effective. Conclusion We suggested that early detection and prevention is the most important periodic examination and that a multidisciplinary approach is a major factor in intervention.

Comparison of Hip Joint Strength between Young Woman Patient with Chronic Low Back Pain with Lumbar Instability and Normal Subjects

  • Cha, Hyun Gyu
    • Physical Therapy Rehabilitation Science
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    • v.11 no.3
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    • pp.370-375
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    • 2022
  • Objective: The purpose of this study was to compare the hip joint muscle strength of patients with chronic back pain with lumbar instability and normal subjects. Design: A case control study. Methods: Five types of lumbar instability test were conducted on forty young women with chronic low back pain for more than six months, and those who had 3 or more positive tests were selected as subjects. To select chronic back pain patients with lumbar instability group, aberrant movement patterns during lumbar flexion test (FMT), prone instability test (PIT), posterior-anterior mobility test (PAT), passive lumbar extension test (PLE), and pressure bio-feedback (PBF) were applied. In addition, a digital muscle strength meter was used to measure the hip flexor, extensor, adductor, and abductor muscles of chronic low back pain patients with lumbar instability group (n=20) and normal subject group (n=20). Results: As a result of comparing the hip joint muscle strength between the chronic back pain patient group with lumbar instability and the normal group, there were significant differences in the hip extensor, abductor, and adductor muscles (p<0.05). Conclusions: Patients of chronic back pain with lumbar instability were found to have weak hip joint muscle strength. Therefore, this study suggest that include hip joint strength exercise for functional recovery of chronic back pain patients.

Design and Analysis of Above Knee Prosthetic Leg Using MR Damper (유동모드 MR 댐퍼가 구비된 대퇴의족의 설계 및 해석)

  • Park, Jinhyuk;Kang, Je-Won;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.2
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    • pp.165-171
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    • 2016
  • A prosthetic knee for above-knee (AK) amputee is categorized into passive and active type. The passive prosthetic knee is generally made by elastic material. Although AK amputee can easily walk by using passive prosthetic leg, knee joint motions are not similar to ordinary persons. The active prosthetic leg can control the knee angle owing to the actuator and microprocessor. However, the active type is not cost-effective and the stability may be lost due to the malfunction of sensors. In order to resolve these disadvantages of passive and active type, a semi-active prosthetic knee which can control the knee angle is proposed in this work. The proposed semi-active one requires a less input energy but provides active type performance. In order to achieve this goal, in this work, a semi-active prosthetic knee using magneto-rheological (MR) damper for AK amputees is designed. The MR damper can support the weight of body by using less energy than actuator of active prosthetic. It can control knee angle by inducing the magnetic field at the time of stance phase. This salient characteristic is evaluated and presented in this work.