• Journal of Biosystems Engineering
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• 제34권2호
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• pp.120-126
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• 2009

The purpose of this study was to develop a visibility evaluation system for cabin type combine. Human's field of view was classified into five levels (perceptive, effective, stable gaze, induced, and auxiliary) depending on rotation of human's head and eye. Divider, reaper lever, gearshift, dashboard, and conveying part were considered as major viewpoints of combine. Visibilities of combine was evaluated quantitatively using the viewpoints and the human's field of view levels. The visibility evaluation system for cabin type combine was consisted of a laser pointer, stepping motors to control the direction of view, gyro sensors to measure horizontal and vertical angle, and I/O interface to acquire the signals. Tests were conducted with different postures ('sitting straight', 'sitting with $15^{\circ}$ tilt', 'standing straight', and 'standing with $15^{\circ}$ tilt'). The LSD (least significant difference) multiple comparison tests showed that the visibilities of viewpoints were different significantly as the operator's postures were changed. The results showed that the posture at standing with $15^{\circ}$ tilt provided the best visibility for operators. The divider of the combine was invisible due to blocking with the cabin frame at many postures. The reaper lever showed good visibilities at the postures of sitting or standing with $15^{\circ}$ tilt. The gearshift, the dashboard, and the conveying part had reasonable visibilities at the posture of sitting with $15^{\circ}$ tilt. However, most viewpoints of the combine were out of the stable gaze field of view level. Modifications of the combine design will be required to enhance the visibility during harvesting operation for farmers' safety and convenience.

• 로봇학회논문지
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• 제14권2호
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• pp.94-103
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• 2019

The optimal grasping point of the object varies depending on the shape of the object, such as the weight, the material, the grasping contact with the robot hand, and the grasping force. In order to derive the optimal grasping points for each object by a three fingered robot hand, optimal point and posture have been derived based on the geometry of the object and the hand using the artificial neural network. The optimal grasping cost function has been derived by constructing the cost function based on the probability density function of the normal distribution. Considering the characteristics of the object and the robot hand, the optimum height and width have been set to grasp the object by the robot hand. The resultant force between the contact area of the robot finger and the object has been estimated from the grasping force of the robot finger and the gravitational force of the object. In addition to these, the geometrical and gravitational center points of the object have been considered in obtaining the optimum grasping position of the robot finger and the object using the artificial neural network. To show the effectiveness of the proposed algorithm, the friction cone for the stable grasping operation has been modeled through the grasping experiments.

• 한국지능시스템학회논문지
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• 제24권4호
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• pp.450-456
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• 2014

휴머노이드 로봇은 인간-로봇 상호작용에 가장 효과적인 로봇 플랫폼이지만 20개 이상의 관절로 구성되어 있을 만큼 복잡한 구조여서 전통적인 역기구학적 방법으로 안정되면서도 정교한 자세를 생성하기가 어렵다. 본 논문에서는 고속 연산최적화 기법인 Particle Swarm Optimization 기법을 사용해서 앞쪽 지면에 놓인 물체를 단측지지 상태로 상체를 굽혀서 왼팔이나 오른팔로 집는 고난도의 자세를 생성하고, 이를 상용 휴머노이드 로봇 플랫폼에 적용하여 검증함으로써 제안 된 방법의 적용 가능성을 확인한다.

• The Journal of Korean Physical Therapy
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• 제27권2호
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• pp.112-117
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• 2015

Purpose: The purpose of this study was to examine the effects of a task-specific obstacle crossing rehabilitation program on functional gait ability in patients with cerebellar ataxia. Overall, we sought to provide ataxia-specific locomotor rehabilitation guidelines for use in clinical practice based on quantitative evidence using relevant analysis of gait kinematics including valid clinical tests. Methods: Patients with cerebellar disease (n=13) participated in obstacle crossing training focusing on maintenance of dynamic balance and posture, stable transferring of body weight, and production of coordinated limb movements for 8 weeks, 2 times per week, 90 minutes per session. Throughout the training of body weight transfer, the instructions emphasized conscious perception and control of the center of body stability, trunk and limb alignment, and stepping kinematics during the practice of each walking phase. Results: According to the results, compared with pre-training data, foot clearance, pre-&post-obstacle distance, delay time, and total obstacle crossing time were increased after intervention. In addition, body COM measures indicated that body sway and movement variability, therefore posture stability during obstacle crossing, showed improvement after training. Based on these results, body sway was reduced and stepping pattern became more consistent during obstacle crossing gait after participation in patients with cerebellar ataxia. Conclusion: Findings of this study suggest that task-relevant obstacle crossing training may have a beneficial effect on recovery of functional gait ability in patients with cerebellar disease.

• 소성∙가공
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• 제27권1호
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• pp.18-27
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• 2018

As one of the functional metal parts in steam turbine diaphragm assembly, the hollow-partitioned turbine nozzle (stator) has large and thick geometries, as well as an asymmetric configuration. Therefore it is hard to support a metal blank in the die cavity. To ease this situation and control posture and position of metal blank (workpiece), a blank support structure is newly introduced. The blank support structure is basically composed of enlarged arms from the blank, guide pins and linear bearings. It can help to control the intermediate blank without a critical sliding phenomenon. The operation mechanism of this blank support structure, during thick plate forming for the hollow-partitioned turbine nozzle stator, is first evaluated. A series of FEM-based numerical simulations, with respect to the width of the guide arm as geometric design parameters, are carried out to investigate its applicable range. As the results, it is observed the blank support structure for this thick plate forming can guide the workpiece to have stable posture during the plate forming process.

• 로봇학회논문지
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• 제15권3호
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• pp.240-247
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• 2020

This paper presents a novel knitted data glove system for pattern classification of hand posture. Several experiments were conducted to confirm the performance of the knitted data glove. To find better sensor materials, the knitted data glove was fabricated with stainless-steel yarn and silver-plated yarn as representative conductive yarns, respectively. The result showed that the signal of the knitted data glove made of silver-plated yarn was more stable than that of stainless-steel yarn according as the measurement distance becomes longer. Also, the pattern classification was conducted for the performance verification of the data glove knitted using the silver-plated yarn. The average classification reached at 100% except for the pointing finger posture, and the overall classification accuracy of the knitted data glove was 98.3%. With these results, we expect that the knitted data glove is applied to various robot fields including the human-machine interface.

• 한국컴퓨터정보학회논문지
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• 제15권10호
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• pp.129-136
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• 2010

본 논문은 2바퀴로 수직 자세를 유지하며 원하는 방향으로 이동할 수 있도록 다수개의 센서를 혼합하여 정확한 각도 정보를 얻을 수 있는 방안과 이를 이용한 로봇주행 방법을 연구하였다. 로봇이 2바퀴로 수직 자세를 취하면 시스템이 안정하기 위하여 항상 앞, 또는 뒤로 넘어지려는 성질을 가진다. 따라서 이를 지속적인 수직상태로 유지하기 위하여 기울어지는 각도 정보가 필요하며 이를 이용하여 기울어지는 방향으로 신속한 자세 제어를 필요로 하게 된다. 본 논문에서는 각속도 정보를 얻을 수 있는 자이로센서와 이를 보상하기위한 방안으로 가속도 센서를 혼합하여 사용하였다. 현재 자이로센서와 가속도센서를 혼합하는 알고리즘은 Kalman Filter가 일반적으로 이용되고 있으며 많은 연구가 진행되고 있다. 그러나 이러한 알고리즘을 수행하기 위해서는 고성능의 DSP 프로세서 및 성능이 우수한 시스템을 요구하고 있다. 본 논문에서는 간단하면서 고 효율의 성능을 발휘할 수 있는 자이로센서와 가속도 센서의 혼합 알고리즘과 PID제어를 이용한 자세제어를 연구하였다.

• Physical Therapy Rehabilitation Science
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• 제5권1호
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• pp.29-33
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• 2016

Objective: This study compared the muscle activities of the erector spinae (ES), the external oblique (EO), and the rectus abdominis (RA) on three different surfaces. The purpose of this study was to determine which surface induces the highest muscle activity during the plank exercises. The information from this study can be used to recommend plank exercises to athletes and patients with weak core muscles. Design: Cross-sectional study. Methods: The subjects include 20 adult males attending S University in Seoul. Participants completed each plank exercise on three different surfaces. To measure muscle activities, researchers used the values from electromyography. The measurement excluded the initial two and final two seconds and collected information on the RA, EO, and ES in each posture of each subject. Results: The left external oblique showed significant differences between the plank position on stable ground (ST) and the plank position using a suspension device (SL) (p<0.05) and between the plank position on the unstable ground (US) and SL (p<0.05). The right rectus abdominis and left rectus abdominis displayed statistically significant differences between the ST and the US (p<0.05) and between the ST and the SL (p<0.05). The right erector spinae had a statistically significant difference between ST and US (p<0.05). Conclusions: The plank exercise strengthens the core muscles effectively, and muscle activity is related to the posture of the exercise and the location of the muscle. These results suggest that plank exercises improve muscle activities. Additionally, plank exercises can be applied to general medical care.

• 한국컴퓨터정보학회논문지
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• 제18권5호
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• pp.53-60
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• 2013

본 논문에서는 키넥트 센서에 의해 획득한 스켈레톤 정보를 이용하여 스노보드 동작을 시각화 할 수 있는 도구를 제안한다. 스노보드 동작에서 가장 기본이 되는 동작은 BBP(Balanced Body Position)자세로서 안정된 턴 동작을 위한 기본 기술이다. 본 논문에서는 BBP자세를 분석하여 가장 이상적인 동작을 실현할 수 있는 시각화 도구를 구현한다. 키넥트 센서로 부터 획득한 좌표정보를 이용하여 발목, 무릎, 엉덩이 관절의 각도와 몸의 중심축을 추적하여 표준 자세와 비교분석한다. 분석결과는 OpenGL 라이브러리를 통하여 최종 결과 화면을 구성하였다. 본 연구결과는 스노보드 턴 동작을 분석하는 기초자료로 활용될 수 있을 것이다.

• 대한통합의학회지
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• 제9권2호
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• pp.93-103
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• 2021

Purpose : This study aimed to investigate the effect of trunk postural stability maintained wearing a spiral elastic band on the upper extremity function of patients with stroke who undertook a functional activity program and to provide fundamental data useful for the application of therapeutic interventions in the clinical environment of occupational therapy. Methods : The research subjects included 16 patients with stroke who were evenly divided into an experimental group and a control group. The eight-week intervention consisted of a functional activity program aimed at improving the function of the affected-side upper extremity. The experimental group performed the functional activity program while maintaining a stable trunk posture by wearing a spiral elastic band. The control group followed the program without wearing the band. Upper extremity function was assessed before and after the intervention using a manual function test (MFT) and a motor activity log (MAL), and the effectiveness on the upper extremity function of the affected side was confirmed. Results : First, in the within-group comparison of the upper extremity function scores before and after the intervention, the experimental group showed a statistically significant difference in the MFT and MAL assessment(p<.05). The control group showed a statistically significant difference in the MAL assessment(p<.05). Second, in the between-group comparison of the change in scores after the intervention, a statistically significant difference was observed between the two groups in all assessments(p<.05). Conclusion : This study confirmed the positive effect on upper extremity function of trunk stabilization posture using a spiral elastic band. The results could be useful when implementing a task-oriented training program in the clinical environment of occupational therapy in the future, as application of the training while maintaining trunk postural stability by wearing a spiral elastic band could be more effective for improving the upper extremity function of patients with stroke.