• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.105.1-105
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• 2002

$\textbullet$ This paper deals with obstacle avoidance of a quadruped robot with a vision system and a PSD sensor. $\textbullet$ The vision system needs for obstacle recognition toward robot. $\textbullet$ Ths PSD sensor is also important element for obstacle recognition. $\textbullet$ We propose algorithm that recognizes obstacles with one vision and PSD sensor. $\textbullet$ We also propose obstacle avoidance algorithm with map from obstacle recognition algorithm. $\textbullet$ Using these algorithm, Quadruped robot can generate gait trajectory. $\textbullet$ Therefore, robot can avoid obstacls, and can move to target point.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.25 no.1
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• pp.37-43
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• 2019

Background: This study was conducted to investigate the effects of obstacles gait on balance and fall-efficacy in patients who underwent total knee arthroplasty. Methods: The 24 subjects of this study were recruited from individuals diagnoses with degenerative arthritis who had undergone total knee arthroplasty. The 24 patients were randomly divided into a control groups and experimental groups, obstacles gait exercise was conducted for 4 weeks three exercises. Balance and falls-efficacy were measured to compare the effects of the exercises. Results: The results of the balance ability and falls-efficacy showed that the experimental group showed significantly enhanced results than the control group(p<.05). Conclusions: Based on these results, Obstacles gait exercise effectively improves the recovery of patients with total knee arthroplasty.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.539-547
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• 2009

The purpose of this study was to investigate the changes of kinetic and kinematic parameters in obstacle gaits after 12 weeks of an aquatic exercise program. Eight female elders walked in four different heights of obstacles(0, 2.5, 5.1, & 15.2cm) on their self-selected speed. The ROM of hip was significantly increased after the aquatic exercise program. Swing and Stance duration were decreased. The step length was significantly increased and the step width was decreased. After the exercise program the clearance between the right foot and the top of obstacle(except 15.2cm) increased and the crossing speed was increased. The braking force, propulsive force, braking impulse, and propulsive impulse were significantly changed after the aquatic exercise program. The 12 weeks of the aquatic exercise program resulted in lower body strength and balance gains in female elders. The improvements were associated with changes in kinetic and kinematic parameters leading to an obstacle-crossing speed and a safer lower-limb control. The aquatic exercise program is suggested as an effective intervention to promote gait ability and prevent fall-related to the injuries.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1926-1930
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• 2004

We suggest a turning gait planning of a quadruped walking robot with an articulated spine. Robot developer has tried to implement a gait more similar to that of natural animals with high stability margin. Therefore, so many types of walking robot with reasonable gait have been developed. But there is a big difference with a natural animal walking motion. A key point is the fact that natural animals use their waist-oint(articulated spine) to walk. For example, a crocodile which has short legs relative to a long body uses their waist to walk more quickly and to turn more effectively. The other animals such as tiger, dog and so forth, also use their waist. Therefore, this paper proposes discontinuous turning gait planning for a newly modeled quadruped walking robot with an articulated spine which connects the front and rear parts of the body. Turning gait is very important as same as straight gait. All animals need a turning gait to avoid obstacle or to change walking direction. Turning gait has mainly two types of gaits; circular gait and spinning gait. We apply articulated spine to above two gaits, which shows the majority of an articulated spine more effectively. Firstly, we describe a kinematic relation of a waist-joint, the hip, and the center of gravity of body, and then apply a spinning gait. Next, we apply a waist-joint to a circular gait. We compare a gait stability margin with that of a conventional single rigid body walking robot. Finally, we show the validity of a proposed gait with simulation.

• Physical Therapy Korea
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• v.15 no.4
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• pp.27-33
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• 2008

The purpose of this study was to investigate the changes of the center of pressure (COP) trajectory in healthy elderly subjects while crossing an obstacle before and after participation in Tai Chi training. Forty healthy elderly subjects participated either in a 12-week intervention of Tai Chi training or in a health education program. The participants were divided into two groups (the experimental group and the control group). Subsequently, the participants were pre- and post-tested on crossing over an obstacle from a quiet stance. Participants in the experimental group received Tai Chi training that emphasized the smooth integration of trunk rotation, a shift in weight bearing from bilateral to unilateral support and coordination and a gradual narrowing of the lower-extremity stance three times weekly. The participants in the control group attended a health education program one hour weekly and heard lectures about general information to promote health. Performance was assessed by recording the changes in the displacement of the COP in the anteroposterior (A-P) and mediolateral (M-L) directions using a force platform. Participants in the Tai Chi group significantly increased the A-P and M-L displacement of the COP after Tai Chi training (p<.05). No significant differences in the A-P and the M-L displacement of the COP between pre-testing and post-testing in the control group were found. This study has shown that participation in Tai Chi exercise increased the magnitude of the A-P and M-L displacement of the COP, thereby improving the ability of healthy elderly participation to generate momentum to initiate gait. These findings support the use of Tai Chi training as an effective fall-prevention program for the elderly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.471-479
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• 2015

This study examined the effects of smart phone use while young adults negotiated an obstacle (2 cm high). Seventy-four young adults (mean age: $23.76{\pm}3.17years$, age range: 20-27 years) participated in the study. They were allocated randomly into two groups; smart phone group and no smart phone group. The smart phone group negotiated an obstacle while simultaneously using a smart phone at a self-paced speed whereas the no smart phone group negotiated an obstacle with no special option. A motion analysis system were used to measure the gait parameters, such as toe clearance, cadence, step length, step width, stride length, and walking velocity in two groups. The toe clearance, and step-width, cadence, and step-length were significantly greater for the smart phone group than the no smart phone group (p<.05) and the walking velocity was significantly lower in the smart phone group (p<.05). On the other hand, there was no significant difference in the stride length between the two groups. This study suggests that smart phone use degrades the obstacle avoidance abilities of healthy young adults, which may increase risk of falls.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.10
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• pp.939-947
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• 2010

With the rising numbers of elderly and disabled people, the demand for welfare services using a robotic system and not involving human effort is likewise increasing. This study deals with a mobile-robot system combined with a BWS (Body Weight Support) system for gait rehabilitation. The BWS system is designed via the kinematic analysis of the robot's body-lifting characteristics and of the walking guide system that controls the total rehabilitation system integrated in the mobile robot. This mobile platform is operated by utilizing the AGV (Autonomous Guided Vehicle) driving algorithm. Especially, the method that integrates geometric path tracking and obstacle avoidance for a nonholonomic mobile robot is applied so that the system can be operated in an area where the elderly users are expected to be situated, such as in a public hospital or a rehabilitation center. The mobile robot follows the path by moving through the turning radius supplied by the pure-pursuit method which is one of the existing geometric path-tracking methods. The effectiveness of the proposed method is verified through the real experiments those are conducted for path tracking with static- and dynamic-obstacle avoidance. Finally, through the EMG (Electromyography) signal measurement of the subject, the performance of the proposed system in a real operation condition is evaluated.

• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.1-9
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• 2008

The purpose of this study was to investigate the effect of different obstacle heights on the plantar foot pressure during obstacle crossing. Sixteen healthy adults who had no musculoskeletal disorders were instructed to perform unobstructed level walking and to step over obstacles corto 10cm, 20cm, 30cm. Plantar foot forces and pressures were recorded by the Footmat system(Tekscan, Boston, USA) during level and obstacle walking with barefoot. Plantar foot surface was defined as seven regions for pressure measurement; two toe regions, three forefoot regions, one midfoot region, one heel region. One-way ANOVA was used to compare each region data of foot according to various heights. The results indicated that there are significant differences on peak pressure and maximal forces regarding each region at stance phase. As height of obstacle became high, the pathway of COP had a tendency to be short and abducted. Plantar pressure of foot could be changed by obstacle height and these findings demonstrated that obstacle with different height have an effect on structure and function of the foot.

• Proceedings of the Korea Contents Association Conference
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• 2013.05a
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• pp.223-224
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• 2013

이 연구는 뇌졸중환자를 대상으로 낙상예방을 위하여 오타고운동과 요부안정화운동을 실시하고 신체기능 및 장애물 보행의 변화를 측정하였다. 뇌졸중환자 20명을 대상으로 신체기능은 근력, 균형능력을 측정하였고, 장애물 보행은 장애물 극복속도와 최대수직여유를 측정하여 운동 전과 운동 후, 각 운동군 간을 비교분석하였다. 근력은 30초 의자에서 앉았다 일어나기, 균형은 FRT와 TUG 검사, 그리고 장애물 보행은 장애물 극복속도와 최대수직여유로 측정하였다. 실험결과 운동 후 ?고운동군은 요부안정화운동군에 비해 FRT와 장애물 극복속도는 유의하게 증가되었으며, TUG는 유의하게 감소되었다. 결론적으로 오타고 운동이 뇌졸중 환자의 신체기능 및 장애물 보행에 긍정적인 영향을 미친다.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.734-741
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• 2020

This article proposes a new pedestrian avoidance algorithm for social robots that coexist and communicate with humans and do not induce stress caused by invasion of psychological safety distance(Social Distance). To redefine the pedestrian model, pedestrians are clustered according to the pedestrian's gait characteristics(straightness, speed) and a social distance is defined for each pedestrian cluster. After modeling pedestrians(obstacles) with the social distances, integrated navigation algorithm is completed by applying the newly defined pedestrian model to commercial obstacle avoidance and path planning algorithms. To show the effectiveness of the proposed algorithm, two commercial obstacle avoidance & path planning algorithms(the Dynamic Window Approach (DWA) algorithm and the Timed Elastic Bands (TEB) algorithm) are used. Four cases were experimented in applying and non-applying the new pedestrian model, respectively. Simulation results show that the proposed algorithm can significantly reduce the stress index of pedestrians without loss of traveling time.