• The Journal of Korean Physical Therapy
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• 제34권4호
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• pp.161-167
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• 2022

Purpose: The purpose of this study was to investigate the effects of regular training on the uneven surface that stroke patients encounter in their daily life on their ankle joint muscle activity and balance ability. They were divided into two groups: the gait training group on uneven surfaces and the gait training group on normal surfaces. Methods: In this study, 30 patients diagnosed with stroke and undergoing rehabilitation were selected. 15 people in the uneven surface gait training group and 15 people in the flat gait training group were selected. The muscle activation of the ankle muscles was measured when walking again on a even surface after walking on an uneven surface and on a flat ground. After each gait training, the limit of stability and Romberg test were performed to evaluate the balance ability. Results: As a result of the experimental results before and after walking by group, the tibialis anterior muscle activity of the paralyzed side was significantly decreased in the uneven surface walking group. As a result of measuring balance ability after training, the limit of stability in all directions was significantly increased in the uneven surface gait training group, and the area and length moved significantly decreased in the uneven surface gait training group in the Romberg test as well (p<0.05). Conclusion: After walking on uneven surface, it was confirmed that the muscle activity of the ankle joint decreased in normal flat walking, and thus the efficiency of muscle activity was increased. In addition, it was possible to confirm the improvement of the balance ability of the gait training on the uneven surface, and in conclusion, it could be confirmed that it had an effect on the improvement of the walking ability.

• 한국운동역학회지
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• 제20권1호
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• pp.33-39
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• 2010

The purpose of this study was to investigate the changes in walking pattern of the elderly during inclined walkway with uneven surfaces and level walking. 10 young($26.3{\pm}1.3$ years, $174.3{\pm}5.3\;cm$, $69.5{\pm}9.5\;kg$) and 13 elderly($72.4{\pm}5.2$ years, $164.5{\pm}5.4\;cm$, $66.1{\pm}9.6\;kg$) male subjects were participated in the experiment. Experiment consisted of 2 walking conditions: horizontal and inclined walkway with uneven surfaces. 3D motion capturing system were used to acquire and analyze walking motion data with sampling frequency of 120 Hz. To compare differences between conditions, kinematic variables(walking speed, stance-swing ratio, hip joint angle, knee joint angle, ankle joint angle, pelvic rotation angle) were used. Results showed that there were some changes of elderly walking pattern in inclined walkway with uneven surfaces: hip joint(adduction and rotation) and pelvic movement pattern. These changes by inclination and surface may affect gait pattern of young subjects as well as elderly subjects. However, in case of elderly it revealed more unstable gait than the young. Further study is necessary to clarify changes in walking pattern for elderly by considering various gait variables including head movement and various walkway conditions.

• 한국정밀공학회지
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• 제26권10호
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• pp.47-55
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• 2009

In this study, a robot foot having toes for firm stepping on uneven surface is proposed. The toes are connected to the lower leg by parallel links so that the lower leg can rotate in the rolling and pitching directions during stance phase without ankle joint. The landing performance of the foot on uneven surface was evaluated by relative comparison with that of the most common foot making point contact with the walking surface, since the test conditions considering real uneven surface could be hardly defined for its objective evaluation. Anti-slip margin(ASM) was defined in this study to express the slip resistance of a robot foot when it lands on a projection with half circular-, triangular- or rectangular cross section, assuming that uneven surface consists of projections having these kind of cross sections in different sizes. Based on the ASM analysis, the slip conditions for the two feet were experimentally confirmed. The results showed that the slip resistance of the new foot is not only higher than that of the conventional point contact type foot but also less sensitive to the surface friction coefficient.

• 제어로봇시스템학회논문지
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• 제19권12호
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• pp.1152-1159
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• 2013

This paper proposes an effective walking system for a hexapod robot on uneven terrain. To overcome the deficiencies of two-pair walking systems, which are effective on even terrain, the use of only three legs changes the steps required for movement. The proposed system receives feedback data from switches attached to the bottom of the legs and gyro sensor to carry out stable walking using the Bezier curve algorithm. From the coordinates of the Bezier curve, which guarantees the circular motion of legs, the motor's angle value can be obtained using inverse kinematics. The angle values are sent to each motor though RS-485 communication. If a switch is pushed by the surface during navigation in the Bezier curve pattern, the robot is designed to change its circular course. Through the changed course, each leg can be located on an optimal surface and the wobble phenomenon is reduced by using a normal vector algorithm. The simulation and experiment results show the efficiency of the proposed algorithm.

• 한국정밀공학회지
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• 제28권1호
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• pp.56-62
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• 2011

Terrain recognition ability is crucial to the performance of legged robots in an outdoor environment. For instance, a robot will not easily walk and it will tumble or deviate from its path if there is no information on whether the walking surface is flat, rugged, tough, and slippery. In this study, the ground surface recognition ability of robots is discussed, and to enable walking robots to recognize the surface state and changes, a central moment method was used. The values of the sensor signals (load cell) of robots while walking were detected in the supported section and were analyzed according to signal variance, skewness, and kurtosis. Based on the results of such analysis, the surface state was detected and classified.

• 융합신호처리학회논문지
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• 제14권2호
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• pp.124-129
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• 2013

6족 보행 로봇은 2족 또는 4족 보행 로봇에 비하여 안정적인 보행이 가능한 장점이 있다. 따라서 6족 보행 로봇은 이러한 보행의 안정성을 기반으로 다양한 지능적인 동작을 수행하기에 유리한 구조이다. 본 논문에서는 전형적인 6족 보행 로봇과는 달리 로봇의 진행 방향에 대하여 전후 다리와 좌우에 각각 한 쌍의 다리를 갖는 6족 보행 로봇을 제안하고 제안된 로봇을 사용하여 다양한 지능형 동작을 수행한다. 26개의 모듈형 모터를 사용하여 로봇 기구부를 구성하고 호스트 PC, DSP 주제어기, AVR 보조 제어기, 스마트폰/스마트패드로 구성되는 제어기를 구현한다. 구현된 로봇은 스테레오 카메라, 적외선 센서, 초음파 센서, 접촉 센서 등 다양한 센서 데이터를 사용하여 비평탄면 보행, 공차기, 원격 제어 및 3차원 모니터링 등 다양한 지능형 동작을 수행할 수 있음을 실험을 통하여 검증한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.639-644
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• 2003

An unstructured environment requires a robot to possess outstanding mobility and advanced control algorithms since there exist complicated configurations such as obstacle, uneven surface, etc. Especially, when a quadruped robot walks in these environments, obstacles in the walking route will obstruct the walking or may give rise to a serious trouble. In this paper, we introduce a strategy for the stable walking in unstructured environment. The proposed strategy consists of two control algorithms. One is a collision{free algorithm to avoid obstacles and the other is an algorithm to overcome any obstacle. These are based on the obstacle detection method and a shape reconstruction algorithm, Which algorithms are described in detail. In addition, the validity of these algorithms have been demonstrated through experiments using a quadruped walking robot called "MRWALLSPECT III(Multifunctional Robot for Wall inSPECTion version 3 )".

• 로봇학회논문지
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• 제2권4호
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• pp.353-360
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• 2007

This paper proposes the trot gait pattern generation and online control methods for a quadruped robot to carry heavy loads and to move fast on uneven terrain. The trot pattern is generated from the frequency modulated pattern generation method based on the frequency modulated oscillator in order for the legged robots to be operated outdoor environment with the static and dynamic mobility. The efficiency and performance of the proposed method are verified through computer simulations and experiments using qRT-1/-2. In the experiments, qRT-2 which has two front legs driven by hydraulic linear actuators and two rear casters is used. The robot can trot at the speed up to 1.3 m/s on even surface, walk up and down the 20 degree inclines, and walk at 0.7 m/s on uneven surface. Also it can carry over 100 kg totally including 40 kg payload.

• 한국정밀공학회지
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• 제26권4호
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• pp.72-81
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• 2009

The purpose of this paper is to accomplish the stable humanoid robot walking on the soft terrains. The goal of the humanoid robot development is to make the robotic system perform some tasks in human living environment. However, human dwelling environments are very different from those of laboratories, where varied experiments are performed by the robot. In many cases, the ground is soft or elastic unlike the floor of a laboratory. When a robot walks on the soft ground, the sole of robot contacts the uneven ground. This results in unstable walking or walking may be impossible according to the degree of softness. Therefore, the algorithm that facilitates stable walking on the soft ground surface is required. In this paper, we suggest an algorithm that controls the ankle to help the robot walk stably on the soft ground using the humanoid robot (ISHURO-II) as a real model. A humanoid robot walking on the soft ground was simulated to verify that the proposed algorithm results in stable walking.

• 한국운동역학회지
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• 제19권2호
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• pp.387-397
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• 2009

여가시간의 증대로 인한 개인의 신체활동이 증가하고 있다. 또한 대한민국의 지형적인 조건과 더불어 등산은 대중적인 야외 신체활동으로 각광을 받고 있다. 한편 바닥이 평평하지 않은 경사진 지면을 장시간 이동하는 데는 견교하고 안정 적이면서도 편안함을 제공할 수 있는 등산화가 제공되어져야 한다. 5명의 피험자들이 실험에 참여하였으며 4가지 조건하(맨발, 일반등산화, 경도 60의 등산화, 경도 65의 등산화)에서 압력분포가 측정되었다. 경도 60과 65의 등산화는 아웃솔의 바닥이 여러개로 분리되어 충격흡수에 적합한 디자인으로 설계되었다. 연구결과 경도 60과 65의 등산의 경우 일반 등산화에 비해 접촉면적이 넓고 신체의 추진과 관련된 압력분포 변인에 긍정적인 영향을 미치는 것을 나타내었다. 따라서 등산 시 착용하는 신발 및 의류나 기구의 운동역학적 적용을 통하여 건강한 신체를 유지할 수 있을 것이라 판단되어 진다.