• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.5
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• pp.640-647
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• 2007

This paper presents a joint controller for a humanoid robot based on genetic algorithm. h humanoid robot has basically instability during walking because it isn't fixed on the ground. Moreover nonlinearities of the joints increase its instability. If one of them isn't satisfied, the robot may fall down at the ground during walking. To attack one of those problems, joint controller is proposed. It can perform tracking control preciously and reduce the effect of nonlinearities by gear, limitation of the input voltage, coulomb friction and so on. This controller is based on fuzzy-sliding mode controller (FSMC) and compensator and control gains are searched by a proposed genetic algorithm. It can reduce the effect by nonlinearities. Also, to improve the tracking performance, the proposed controller has motion controller. From the given controller, a humanoid robot can moved more preciously. Here, all the processes are investigated through simulations and it is verified experimentally in a real joint system for a humanoid robot.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.9-14
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• 2018

The purpose of this study was to privide basic data for footwear development according to walking mechanics by comparing gait cycle difference between barefoot walking and walking shoes. The walking period was measured in 30 normal adult women with no foot deformity and abnormality. The first subject walked in sneakers and measured the cycle. And then, the subjects walked barefoot and the period was measured to obtain data. The data were taken form corresponding paired T-test. The results were as follows: In barefoot walking, the stance phase left side(p <.001), right side(p <.005), the loading response left side(p <.009), right side(p <.002) ), the pre-swing left side(p <.002), right side (p <.011), the double stance phase(p <.004) were increased and the mid-stance left side (p <.016), right side(p. 001), the swing phase left side(p<.001) was decreased. This suggests that barefoot walking increases the input of various senses of the foot, which makes stable walking possible. It is necessary to improve shoes based on the walking cycle in the future.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.317-318
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• 2007

휴머노이드 로봇이 인간에게 필요한 다양한 서비스를 제공하기 위해서는 정해진 동작이 아닌 상황에 따른 다양한 동작이 요구된다. 특히 보행에 있어서는 회전각도 보폭 등이 상황에 따라 변경이 가능해야 한다. 이에 따라 로봇에게 필요한 다양한 보행 궤적을 생성하기 위해서는 보행궤적의 생성과 안정성 판별을 위한 ZMP(Zero Moment Point), COG(Center Of Gravity)등의 생성을 위한 시뮬레이터가 필요하게 된다. 본 논문에서는 성행 연구를 통해 개발된 시뮬레이터 프로그램의 단점을 분석하고 보완하여, 보폭 및 회전 각도가 자유로운 회전 보행의 생성이 가능한 시뮬레이터 프로그램을 구현하였다. 그리고 구현된 시뮬레이터 프로그램을 사용하여 생성된 궤적 파일을 동역학 해석 프로그램인 NASTRAN을 이용 시뮬레이터를 검증한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.4
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• pp.555-561
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• 2008

This Paper introduces new approach to develop fast and reliable gaits for quadruped robot using GA(genetic algorithm). Planning gaits for legged robots is a challenging task that requires optimizing parameters in a highly irregular and multidimensional space. Recent approaches have problems to select proper parameters which are not known in advance and optimize more than ten to twenty parameters simultaneously. In our approach, the effects of major gait parameters are analysed and used to guide the search more efficiently. The experiments of Sony AIBO ERS-7 in Webots environment indicate that our approach is able to produce much improved results in fast velocity and reliability.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1937-1938
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• 2006

최근 들어 안정적인 보행 패턴 생성을 위해서 많은 방법들이 제안 되고 있다. 대부분의 논문에서 주기적인 보행에 대한 연구는 이루어지고 있으나 첫 보행 구간과 마지막 보행 구간에 대한 분석은 이루어지지 않고 있다. 본 논문은 첫 보행 구간과 마지막 보행 구간에 대한 분석을 통해 기존의 역 진자 모델(Inverted pendulum model)을 기반으로 부드러운 무게 중심의 궤적을 생성하는 해석적 방법을 제안한다. 이를 위해 먼저 정현파 함수를 이용해 영 모멘트 위치(ZMP, Zero Moment Point) 궤적을 설계한다. 영 모멘트 위치 궤적 설계 시 첫 보행 구간과 마지막 보행 구간에 대해 영 모멘트 위치와 무게 중심 간의 비 최소 위상(non-minimum phase) 시스템의 특성을 이용한다. 제안된 방법을 이용하여 주기적인 보행 구간 및 첫 보행 구간과 마지막 보행 구간에서 부드러운 무게 중심 궤적이 생성됨을 시뮬레이션을 통해 구현하여 제안된 방법의 유효성을 보인다.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.2
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• pp.124-129
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• 2013

Hexapod walking robots are superior to biped or quadruped ones in terms of walking stability. Therefore hexapod robots have the advantage in performing intelligent tasks based on walking stability. In this paper, we propose a hexapod robot that has one fore leg, one hind leg, two left legs, and two right legs and can perform various intelligent tasks. We build the robot by using 26 motors and implement a controller which consists of a host PC, a DSP main controller, an AVR auxiliary controller, and smart phone/pad. We show by several experiments that the implemented robot can perform various intelligent tasks such as uneven surface walking, tracking and kicking a ball, remote control and 3D monitoring by using data obtained from stereo camera, infrared sensors, ultra sound sensors, and contact sensors.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2393-2395
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• 2003

최근 휴머노이드 로봇 기술의 발전으로 로봇 관련 기반 기술 및 주변 기술의 연구가 활성화되고 있다. 이러한 연구의 하나로 이족 보행 로봇의 보행 알고리즘의 개발이 국내외에서 진행되고 있다. 이족 보행 로봇의 핵심 기술은 로봇의 기구 설계와 보행 제어 알고리즘에 있다. 보행 제어 알고리즘에 있어서는 보행시 로봇의 각 관절에 대한 궤적을 생성하는 방법과 관절의 부하를 최소화하는 힘 제어 방법 등의 알고리즘들이 연구되고 있다. 본 논문에서는 자체 제작한 12자유도를 갖는 이족 보행 로봇의 안정적인 보행 제어를 수행하는 알고리즘을 제안하였다. 그리고, 다양한 보행 패턴에 대한 실험을 통해 제안한 알고리즘의 유용성을 검증하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.323-329
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• 1994

In the systems such as walking robots or high speed operating manipulators, the effect of nonlinear terms is important and can not be neglected. Therefore the application of linear control law to such systems is inadequate. Moreover, because of the mathematical modeling errors the systems may become unstable. In this study, we designed a nonlinear controller with sliding mode scheme, which is robust to the modeling errors and applied this control algorithm to the 5 DOF biped robot system. Throught the computer simulations, we examined walking characteris and walking stability of the 5 DOF biped robot system.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.5
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• pp.692-699
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• 2008

This paper describes optimal operation method using recognition of walker's will for a robotic walker. Recently, walking aid system has been required according to the increase of elder and handicapped person. However, most of walking aid system don't have actuator for its movement. Unfortunately, standard frames have weakness for the movement to upward/download direction of slope. So, active type walking aids are interested, but it is not easy to control. In this paper, we adapt user's will system that can recognize walking direction and speed. First, FSR(Force Sensing Register) is applied to measure user's will to walk. And then, fuzzy algorithm is used for determining optimal wheel velocity and direction of the walking aid. From the result, walking aid can move smoothly and safely following the user's will. The walking aid can help user to walk more optimally. Here, all the processes are verified experimentally in the real world.

• Journal of Korean Society of Forest Science
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• v.103 no.3
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• pp.503-509
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• 2014

The purpose of this study was to investigate the effect of Forest-walking exercise on gait pattern in the elderly. The subjects (n=37) were assigned to 2 groups: Forest-walking exercise (FWE) group (n=19, $66.34{\pm}4.31$ years old) and In-door treadmill-walking exercise (ITWE) group (n=18, $67.18{\pm}2.78$ years old). The subjects participated in FWE program or ITWE program (3 times/week, 80 min/day) for 12 weeks. The subjects were tested on functional fitness (strength, endurance, agility/balance, BMI) and gait pattern (cadence, velocity, and stability) at the beginning and the end of the 12-weeks program. For data analysis, mean and standard deviation scores were calculated, and independent t-test and repeated two-way ANOVA were used. The results of this study were as follow: First, FWE group was significantly more improved than ITWE group on functional fitness(lower-body muscular strength, lower-body flexibility, mobility, cardiorespiratory endurance) after 12-weeks exercise program. But both groups showed equally improvements on functional fitness (upper-body muscular strength, upper-body flexibility, BMI). Second, FWE group was significantly more improved than ITWE group on cadence, gait velocity, and gait stability after 12-weeks exercise program. Therefore, this study may suggest that Forest-walking exercise based on sensory-motor functional integration improves efficiently functional fitness and gait pattern in the elderly, and further becomes an effective exercise method that makes more dynamic life, and prevents from falling.