• Title/Summary/Keyword: three legs

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A Study on the Optimal Solution for the Manipulation of a Robot with Four Limbs (4지 로봇의 최적 머니퓰레이션에 관한 연구)

  • Lee, Ji Young;Sung, Young Whee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.8
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    • pp.1231-1239
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    • 2015
  • We developed a robot that has four limbs, each of which has the same kinematic structure and has 6 degrees of freedom. The robot is 600mm high and weighs 4.3kg. The robot can perform walking and manipulating task by using the four limbs selectively. The robot has three walking patterns. The first one is biped walking, which uses two rear limbs as legs and two front limbs as arms. The second one is biped walking with supporting arms, which is basically biped walking but uses two arms as supporting legs for increasing stability of the robot. The last one is quadruped walking, which uses all the four limbs as legs. When a task for the robot is given, the robot approaches the task point by selecting an appropriate walking pattern among three walking patterns and performs the task. The robot has many degrees of freedom and is a redundant system for a three dimensional task. We propose a redundancy resolution method, in which the robot’s translational move to the task point is modeled as a prismatic joint and optimal solutions are obtained by optimizing some performance criteria. Several simulations are performed for the validity of the proposed method.

Modular Crawler with Adjustable Number of Legs and Performance Evaluation of Hexapod Robot (다리 수 조절이 가능한 모듈러 크롤러의 설계 및 6족 로봇의 주행 성능 평가)

  • Yim, Sojung;Baek, Sang-Min;Lee, Jongeun;Chae, Soo-Hwan;Ryu, Jae-Kwan;Jo, Yong-Jin;Cho, Kyu-Jin
    • The Journal of Korea Robotics Society
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    • v.14 no.4
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    • pp.278-284
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    • 2019
  • Legged locomotion has high mobility on irregular surfaces by touching the ground at discrete points. Inspired by the creature's legged locomotion, legged robots have been developed to explore unstructured environments. In this paper, we propose a modular crawler that can easily adjust the number of legs for adapting the environment that the robot should move. One module has a pair of legs, so the number of legs can be adjusted by changing the number of modules. All legs are driven by a single driving motor for simple and compact design, so the driving axle of each module is connected by the universal joint. Universal joints between modules enable the body flexion for steering or overcoming higher obstacles. A prototype of crawler with three modules is built and the driving performance and the effect of module lifting on the ability to overcome obstacles are demonstrated by the experiments.

Thallium-201 Perfusion Scan in Peripheral Arterial Disease (말초성 동맥 질환에 있어서 $^{201}T1$을 이용한 말초혈관 관류스캔의 유용성)

  • Nah, Jung-Il;Woo, In-Sook;Kim, Deog-Yoon;Koh, Eun-Mi;Kim, Jin-Woo;Kim, Young-Seol;Kim, Kwang-Won;Choi, Young-Kil
    • The Korean Journal of Nuclear Medicine
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    • v.25 no.2
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    • pp.192-199
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    • 1991
  • Peripheral arterial disease, because of it's significant and prolonged morbidity and related mortality is a major medical and surgical problem. Contrast angiogram remains the essential standard for the anatomic demonstration of disease. It does not, however, provide data suitable for quantification or any evaluation of the microcirculation. For these reasons, radionuclide studies are playing an increasingly important role by not only confirming the diagnosis and offering objective data on the physiologic significance of anatomic lesions, but by offering prognosis of healing and prediction of therapeutic results. In addition, radionuclide procedures offer means to safely and repeatedly monitor response to therapy and long term follow up. The object of this study was to evaluate the clinical availability of $^{201}T1$ perfusion scan in patients with peripheral arterial diseases. We performed $^{201}T1$ perfusion scans in patients with five Buerger' s disease (10 legs), six DM gangrenes (12 legs) and classified three perfusion pattern groups. Finally we compared treatment modalities among each groups and compaired T1-201 perfusion scan findings with angiographic findings in six patients with Buerger's disease. The results were as follows: 1) Seven legs showed increased perfusion in stress image and normal or increased perfusion in resting image (type 1). Six legs showed decreased perfusion in stress image and improved in resting image (type II). Of total 13 legs, only 1 leg needed to amputation. 2) Three legs showed decreased perfusion in stress and resting image (type III), and subsequently all cases were received surgical amputation. 3) In six Buerger's disease patients, there were disagreements in two patients (2 legs) between $^{201}T1$ scan and angiography, in which angiograms were normal but $^{201}T1$ scans showed 'type II' perfusion patterns.

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Three New Genera and Species of Siphonostomatoid Copepods (Crustacea) Associated with Sponges from Samar Island in the Philippines, with a Proposal of a New Family

  • Lee, Jimin;Kim, Il-Hoi
    • Animal Systematics, Evolution and Diversity
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    • v.34 no.2
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    • pp.79-91
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    • 2018
  • Three new genera and species of siphonostomatoid copepods are described as associates of sponges from shallow water of Samar Island in the Philippines: Samarus filipes n. gen., n. sp., Paurocheres dentatus n. gen., n. sp., and Platymyzon umbonatum n. gen., n. sp. A new family Samarusidae is proposed to accommodate Samarus n. gen. which has rudimentary legs 1-5 represented only by filiform setae. Paurocheres n. gen. is characterized by 2-segmented endopod of leg 4 and reduced setation of legs, and Platymyzon n. gen. by missing of mandibular gnathobase.

Lower Body Shape Classification of Chinese Males in Their 20s by Analyzing Photographic Measurement (사진측정(寫眞測定)에 의한 중국(中國) 20대(代) 남성(男性)의 하반신(下半身) 형태(形態) 분류(分類))

  • Lee, So-Young;Shim, Boo-Ja
    • Journal of Fashion Business
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    • v.11 no.1
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    • pp.61-74
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    • 2007
  • Photographic measurement was first made with the subjects of 190 males in their 20s residing in the Ningbo area, Zhejiang Province in China. In this second report, lower body shapes were classified and discriminated by using indirect measurement, measurement items, and lower body analysis. The following sums up the research: 1. The subjects were $8.85^{\circ}$ (hip breadth angle), $1.58^{\circ}$ (abdomen upper angle), $11.80^{\circ}$ (hip upper angle), and $5.12^{\circ}$ (lateral lower body posture angle). 2. The subjects of Chinese males in their 20s showed three types of lower bodies: Bow Legs & Slight Slant of Lateral Lower Body Type (30.5%)-gap between legs, curve waist-hip contour, average abdomen-hip profile, and lateral lower body posture were slightly slanted forward. Adjacent Straight Legs & Slight Slant of Lateral Lower Body Type (35.8%)-adjacent straight between legs, curve waist-hip contour, slim abdomen-hip profile, and lateral lower body posture were slightly slanted forward. Balance Legs & Large Slant of Lateral Lower Body Type (33.7%)-average between legs, straight waist-hip contour, protruding hip profile, and lateral lower body posture were largely slanted forward. 3. Eight useful variables for the categorization of the subjects' lower body types were chosen through stepwise discriminant analysis, and the hit ratio of discrimination was 97.9%.

A Case Study of Soyangin Patient with Restless Legs Syndrome Treated with Hyeongbangsabaeksan (형방사백산(荊防瀉白散)으로 호전된 소양인(少陽人) 하지불안증후군 환자 치험 1례)

  • Kim, Jin-Young;Lee, Ji-Won;Oh, Hye-Won;Lee, Jun-Hee;Lee, Eui-Ju;Koh, Byung-Hee
    • Journal of Sasang Constitutional Medicine
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    • v.27 no.4
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    • pp.419-428
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    • 2015
  • Objectives The aim of this study was to report an improvement on the symptoms of Restless Legs Syndrome (RLS) after using Hyeongbangsabaeksan.Methods The patient was diagnosed with Soyangin Soyang-sangpung Symptomatology and treated with Hyeongbangsabaeksan. The patient's subjective symptoms of pain on the lower limb and discomfort in sleeping were observed using the Numerical Rating Scale(NRS) and Visual Analogue Scale(VAS) respectively during the treatment period. And other specific symptoms of RLS were assessed once per week for a total of three times with Korean Versions of the International Restless Legs Scale.Results and Conclusions The pain on the patient's lower limb decreased from NRS 4 to NRS 0 after one week of treatment. And discomfort in sleeping decreased from VAS 5.5 to VAS 0 after one week of treatment. Furthermore, the score of Korean Versions of the International Restless Legs Scale decreased from 40 to 5 after two weeks of treatment. In conclusion, this study shows that Sasang Constitutional Medicine can be an effective treatment for Soyangin patient with Restless Legs Syndrome as Soyangin Soyang-sangpung Symptomatology.

The Effects of Sitting in a Crossed Legs Posture on the Vertebral Angle, Chest Wall Mobility, Pulmonary Function, and Respiratory Muscle Activity: A Preliminary Study

  • Ahn, Hee-Eun;Yoon, Tae-Lim
    • Journal of the Korean Society of Physical Medicine
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    • v.14 no.3
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    • pp.13-20
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    • 2019
  • PURPOSE: Sitting with crossed legs may have an effect on maintaining a healthy body posture and proper functioning of the respiratory system. Thus, this study's objective was to identify whether or not sitting with crossed legs affects the vertebral angle, chest wall mobility, the pulmonary function, and the activity of the respiratory muscles. METHODS: Thirty healthy subjects were recruited for this study (16 males and 14 females). The vertebral angle, chest wall mobility, pulmonary function, and the activity of the respiratory muscle were measured while the subjects sat in the correct posture and these factors were again measured with the subjects seated with their legs crossed. Three-dimensional motion analysis was used to determine the trunk and lumbar vertebral angles. Surface electromyography was employed to measure the sternocleidomastoid, the rectus abdominis, and the external and internal oblique abdominis muscles. A tapeline was utilized to evaluate the subjects' chest wall mobility. Spirometry was assessed to determine the forced vital capacity and forced expiratory volume in one second. Paired t-tests were then performed (p<.05). RESULTS: There were significant differences in the trunk and lumbar flexion angles, the chest wall mobility, the activity of the right external oblique muscle, and the left internal oblique abdominis muscle. However, the difference in pulmonary function did not reach statistical significance. CONCLUSION: A crossed leg posture caused slight thoracic extension and lumbar flexion, which may lead to a decrease of the chest wall mobility and also to an imbalance of the abdominal muscles. Therefore, sitting with a crossed leg posture should be avoided. Yet a crossed leg posture did not have any clinical effect on the pulmonary function of healthy people. It may be necessary to study the effects of sitting with crossed legs over an extended period of time for patients suffering with impaired respiratory function.

Stiffness Analysis of Planar Parallel Manipulators with Serially Connected Legs (직렬체인 다리를 갖는 평면 병렬형 기구의 강성해석)

  • Kim, Han Sung
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.2
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    • pp.164-172
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    • 2014
  • This paper presents a method for analyzing the stiffness of full and low DOF (degree of freedom) planar parallel manipulators with serially connected legs. The individual stiffness of each leg is obtained by applying reciprocal screws to the leg twist using passive joints and elastic elements consisting of actuators and links. Because the legs are connected in parallel, the manipulator stiffness is determined by summing the individual leg stiffness values. This method does not require the assumption that springs should be located along reciprocal screws and is applicable to a planar parallel manipulator with a generic or singular configuration. The stiffness values of three planar parallel manipulators with different DOFs are analyzed. The numerical results are confirmed using ADAMS S/W.

Simulation of Spider forging Processes and Verification of the Results (스파이더 단조공정의 시뮬레이션 및 결과의 검증)

  • Kim, H.T.;Lee, M.C.;Eom, J.G.;Jun, B.Y.;Joun, M.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.10a
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    • pp.183-188
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    • 2007
  • We simulated a hot forging process for the spider with four legs and an enclosed die forging process for the spider with three legs using an intelligent forging simulator AFDEX 3D and compared the predictions with the experiments in terms of the deformed shape. The formation of characteristic lines was emphasized in the simulation to simulate the extruded legs with higher accuracy.

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Leg-Balancing Control of the DC-link Voltage for Modular Multilevel Converters

  • Du, Sixing;Liu, Jinjun;Lin, Jiliang
    • Journal of Power Electronics
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    • v.12 no.5
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    • pp.739-747
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    • 2012
  • This paper applies carrier phase shifted pulse-width modulation (CPS-PWM) to transformerless modular multilevel converters (MMC) to improve the output spectrum. Because the MMC topology is characterized by the double-star connection of six legs consisting of cascaded modular chopper cells with floating capacitors, the balance control of the DC-link capacitor voltage is essential for safe operation. This paper presents a leg-balancing control strategy to achieve DC-link voltage balance under all operating conditions. This strategy based on circulating current decoupling control focused on DC-link balancing between the upper and lower legs in each phase pair by considering the six legs as three independent phase-pairs. Experiments are implemented on a 100-V 3-kVA downscaled prototype. The experimental results show that the proposed leg-balancing control is both effective and practical.