• 한국전문물리치료학회지
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• 제11권3호
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• pp.19-24
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• 2004

The purposes of this study were to analyze gait patterns of patients with chronic lumboscaral radiculopathy and to investigate gait parameters which can reflect a functional deficit in relation to the level of lumbosacral radiculopathy. The study population consisted of 25 patients of chronic lumbosacral radiculopathy and 25 healthy control subjects. Conventional physical examinations and three-dimensional gait analyses were performed on all participants. The data were analyzed using an independent sample t-test. The results were as follows: (1) In the patients' group, cadence, walking velocity, stride length and double support time were less than in the control group (p<.05). (2) In the patients' group, maximum flexion of hip, maximum flexion of loading response, maximum flexion of swing phase on the knee and maximum plantar flexion of pre-swing were less than the control group (p<.05). Using three-dimensional gait analysis, we could identify specific gait parameters to reflect a functional deficit related to the level of lumbosacral radiculopathy.

• 한국엔터테인먼트산업학회논문지
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• 제14권6호
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• pp.221-230
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• 2020

본 연구는 진동자극 저항운동이 허리통증 경험자의 균형 및 보행에 미치는 영향을 연구하였다. 30명의 히리통증 경험이 있는 성인 대학생을 대상으로 8 Hz 진동자극 저항운동(n=10), 30 Hz 진동자극 저항운동(n=10), 허리 안정화운동(n=10)으로 무작위로 나누었다. 각 그룹의 중재는 6주동안 주 3회, 1회에 30분을 적용하였다. 실험 전에 정적균형과 보행패턴을 측정하였고, 6주 후에 실험전과 동일한 방법으로 측정하였다. 연구결과 세 그룹 모두에서 운동전과 후의 시간에 따른 정적균형, 디딤기율, 흔듦기율, 한걸음 길이, 한발짝률의 변화는 통계적으로 유의한 차이가 있었다(p<.05). 허리 안정화운동이 정적균형과 디딤기율에서는 그룹 간의 유의한 차이가 있었고(p<.05), 흔듦기율 및 한걸음 길이와 한발짝률은 그룹 간의 차이가 없었다. 결론적으로 진동자극 저항운동이 근수축 유발 기전에 의해 다리근육의 근력을 강화하였고, 강화된 다리 근력은 균형능력에 긍정적인 영향을 미쳤으며, 향상된 균형능력은 신체가 움직이는 동안 안정적으로 자세를 조절할 수 있게 하여 보행능력의 긍정적 측면에 영향을 미친 것으로 판단된다.

• 드라이브 ㆍ 컨트롤
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• 제15권3호
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• pp.8-13
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• 2018

This paper presents a phase portrait analysis-based safety control algorithm for excavators, using adaptive sliding mode control. Since working postures and material types cause the excavator's rotational inertia to vary, the rotational inertia was estimated, and this estimation was used to design an adaptive sliding mode controller for collision avoidance of the excavator. In order to estimate the rotational inertia, the recursive least-squares estimation with multiple forgetting was applied with the information of the swing velocity of the excavator. For realistic evaluation, an actual working scenario-based performance evaluation was conducted. Based on the estimated rotational inertia and an analysis of estimation errors, sliding mode control inputs were computed. The actual working scenario-based performance evaluation of the designed safety algorithm was conducted, and the results showed that the developed safety control algorithm can efficiently avoid a collision with an object in consideration of rotational inertia variations.

• 한국정밀공학회지
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• 제15권3호
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• pp.157-167
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• 1998

In this paper it is purpose that reduces joint torques and their rate of change through optimizing trajectory planning of biped walking machine. The motion of biped walking machine is divided into leg motion for walking and body motion for keeping balance. The leg motion is planned by three phases, that are deploy, swing, and place phases, in terms of the state of foot against floor. The distribution of time assigned to each phase is optimized and that causes leg joint torques and their rate of change to minimize. The body notion is produced by using optimal control theory which minimizes body joint torques and satisfies Z.M.P. constraints defined as region of each phase.

• 대한의용생체공학회:의공학회지
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• 제22권1호
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• pp.29-34
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• 2001

본 연구의 목적은 대퇴부가 절단된 다리의 생체 역학적 기능을 복구할 수 있게 하는 의지의 개발을 위하여 5축 링크, 슬관절 완충장치를 사용하여 보행시 입각기를 제어할 수 있는 대퇴 의지 시스템 개발에 있다. 이를 위하여 입각기시 대퇴의지와 지면간 접촉 중 충격 에너지 흡수를 하는 슬관절 완충장치의 기계적 특성 및 거동을 분석하였다. 임상시험을 통하여 개발된 대퇴의지의 성능을 검증한 결과 대퇴 절단 피검자들의 보행특성은 정상인의 보행에 근접한 경향을 보였다. 결론적으로 본 연구에서 개발된 입각기 대퇴의지는 입각기시 현저한 보행 안전성을 보였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.244-244
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• 2000

We proposed the above-knee prosthesis using rotary MR damper in which knee joint is semi-actively controlled by microprocessor. Dissipation torque in the knee joint can be controlled by the magnetic field which is induced by applying current to a solenoid, Tracking control of knee joint angle was tested by 3-DOF Leg simulator. The experimental results show that the proposed above-knee prosthesis system had good performance in swing phase tracking and repetitive controller in conjunction with a computed control law and PD control law, reduced RMS tracking error as the repetitions of tracking. Moreover, desired knee angle trajectory was generated based on the estimation of gait period with the gyro signal and the tracking control was performed.

• 한국산학기술학회논문지
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• 제14권1호
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• pp.199-205
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• 2013

본 연구는 네 가지의 가방 휴대방법에 따라 세 가지 가방의 무게를 달리하여 보행의 변화를 분석하고자 시행하였다. 20명의 건강한 성인이 연구에 참여하였다. 첫 번째 조건은 한쪽 어깨에 가방을 메고 보행하였고, 두 번째 조건은 한쪽으로 가로질러 가방을 매고 걸었다. 세 번째 조건은 양쪽 어깨에 가방을 메고 걸었고, 네 번째 조건은 한쪽 손으로 가방을 들고 걸었다. 각 네 가지 조건에 모든 대상자가 참가하였고, 오른쪽 신발에 SmartStep의 깔창을 깔고 오른쪽 발목에는 압력제어장치를 묶었다. 모든 대상자는 각각 4가지 조건에서 2.5 kg, 5 kg, 7.5 kg의 무게를 지닌 가방을 휴대하여 10 m를 걸었다. 각 조건에서 2.5 kg, 5 kg, 7.5 kg의 가방의 무게에 따라 입각기 비율, 유각기 비율과 보행속도는 통계학적으로 유의한 차이가 있었다.

• 로봇학회논문지
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• 제12권2호
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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.

• 제어로봇시스템학회논문지
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• 제21권6호
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• pp.518-523
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• 2015

This paper proposes a gait phase classifier using a Recurrent Neural Network (RNN). Walking is a type of dynamic system, and as such it seems that the classifier made by using a general feed forward neural network structure is not appropriate. It is known that an RNN is suitable to model a dynamic system. Because the proposed RNN is simple, we use a back propagation algorithm to train the weights of the network. The input data of the RNN is the lower body's joint angles and angular velocities which are acquired by using the lower limb exoskeleton robot, ROBIN-H1. The classifier categorizes a gait cycle as two phases, swing and stance. In the experiment for performance verification, we compared the proposed method and general feed forward neural network based method and showed that the proposed method is superior.

• 한국운동역학회지
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• 제31권2호
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• pp.95-103
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• 2021

Objective: The aim of this study was to investigate the differences in spatiotemporal gait performance, function, and pain of lower-extremity according to foot morphological characteristics. Method: This case-control study recruited 42 adults and they were classified into 3 groups according to foot morphology using navicular-drop test: pronated (≥ 10 mm), normal (5~9 mm), and supinated (≤ 4 mm) feet. Spatiotemporal gait analysis and questionnaires including Foot and Ankle Ability Measure activities of daily living / Sports, Western Ontario and McMasters Universities Osteoarthritis Index, Lower Extremity Functional Scale, International Physical Activity Questionnaire, and Tegner activity score were conducted. One-way analysis of variance was used for statistical analysis. Results: The pronated feet group showed longer loading response and double limb support in both feet and increased pre-swing phase in non-dominant feet. The supinated feet group demonstrated a longer swing phase in non-dominant feet and single limb support in dominant feet. However, there was no significant group difference in function and pain of knee joint and lower-extremity between groups. Conclusion: Our results indicated that abnormal spatiotemporal gait performance according to foot morphology. Although there was no difference in lower extremity dysfunction and pain according to the difference in foot morphology, they have the possibility of symptom occurs as a result of continuous participation in activities of daily living and sports. Therefore, individuals with pronated or supinated foot should be supplemented by utilizing an orthosis or training to restore normal gait performance.