• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.10
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• pp.1269-1279
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• 1995

A mobile robot in a nuclear power plant is usually needed to equip the ability of going up and down stairs for a some kind of inspection. For this purpose, it is necessary for the mobile robot to figure out the size of stairs laid on a navigation path to gurantee robot's moving freely. In this paper, to measure the size of stairs existing in front of a mobile robot we designed the stair size recognition unit which can measure the stair's height and width using an ultrasonic sensor and/or a CCD camera. Also to obtain higher reliability of ultrasonic sensing data we proposed the horizontal sensing method. On the assupmtions that the mobile robot generates a trajectory while ascending stairs, we simulated it on a IBM compatible computer. The result showed that the suggested method satisfied our purpose. In a stair size estimation, the detected stair's height error was about .+-.3mm, and width was about .+-.5mm.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.3
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• pp.3-7
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• 2007

There have been numerous studies directed toward the development of driving mechanisms for off-road mobility and rescue robots. To achieve surveillance, reconnaissance, and rescue, it is necessary for robots to have a driving mechanism that can handle off-road environments, We propose a new type of single-track driving mechanism with a variable geometry for a rescue robot, This mechanism has a symmetric configuration so that the robot can advance in two directions and also remain operable when overturned. By transforming its geometry, the robot can reduce energy consumption in steering and rotating as well as maximize its ability to climb obstacles such as stairs. The robot is also designed to have a compact size and low center of gravity to facilitate driving when on a set of stairs. In this paper, we analyzed the design parameters of the robot for the four phases of climbing stairs and determined the specifications needed to enhance its adaptability.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1764-1766
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• 2007

This paper aims to generate the static walking pattern of a biped robot on stairs and to show the effectiveness of the proposed algorithm using its ankle and pelvis. Differently from the previous biped robots, our biped robot has the peculiar mechanism on its ankle and pelvis. By using this mechanism, we can reduce the load in the knee when a biped robot ascends the stairs. This means that a biped robot can climb up a higher step. The stairs walking trajectory that is separated into a ankle trajectory and a pelvis trajectory is generated by cubic spline interpolation. Finally, we confirm the feasibility of the proposed algorithm through the computer simulation and the real walking experiment.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.30.3-30
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• 2001

In this paper, we designed the 6-wheeled mobile robot (6-WMR) with the passive linkage mechanism which enables 6-WMR to passively adapt to the given stairs. To overcome the limit of adaptability to the terrain of conventional WMR and improve the energy efficiency, we proposed the new WMR using the passive linkage mechanism. The passive linkage mechanism consists of the simple four-bar linkage mechanism which allows 6-WMR to climb stairs with adaptability and an additional link which is connected to the four-bar linkage mechanism by a pin-slot joint to enable 6-WMR to passively go up the stairs. We made a miniature model of the proposed 6-WMR ...

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.43-50
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• 2014

The purpose of this study was to analyze of the GRF (ground reaction force) parameters according to the change of positions and weights of bag during downward stairs between dominant and non-dominant in upper & lower limbs. To perform this study, participants were selected 9 healthy women (age: $21.40{\pm}0.94yrs$, height: $166.50{\pm}2.68cm$, body mass: $57.00{\pm}3.61kg$, BMI: $20.53{\pm}1.03kg/m^2$), divided into 2 carrying bag positions (dominant arm/R, non-dominant arm/L) and walked with 3 type of bag weights (0, 3, 5 kg) respectively. One force-plate was used to collect GRF (AMTI OR6-7) data at a sample rate of 1000 Hz. The variables analyzed were consisted of the medial-lateral GRF (Fx), anterior-posterior GRF (Fy), vertical GRF (Fz), impact loading rate and center of pressure (COPx, COPy, COP area, COPy posterior peak time) during downward stairs. 1) The Fx, Fy, Fz, COPx, and COP area of GRF were not statistically significant between dominant leg and non-dominant leg, but non-dominant leg, that is, showed the higher COPy, and showed higher impact loading rate than that dominant leg during downward stairs. 2) In bag wearing to non-dominant arm, Fx, Fz, COPx, COPy, impact loading rate and COP area showed increase tendency according to increase of bag weights. Also, against bag wearing to dominant arm, non-dominant showed different mechanism according to increase of bag weights. The Ground Reaction Force parameters showed different characteristics according to the positions and weights of bag during downward stairs between dominant and non-dominant arm.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.241-248
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• 2015

Objective : The purpose of this study was to investigate the theta on the components of ground reaction force according to the ground conditions during gait. Method : Six healthy women(mean age: 22 yrs, mean height: $166.14{\pm}2.51cm$, mean body weights: $56.61{\pm}4.58kg$) participated in this study. The medial-lateral GRF(Fx 1), anterior-posterior GRF(Fy 1, Fy 2), vertical GRF(Fz 1, Fz 2, Fz 3), and impact loading rate were determined from time function and frequency domain. Also, GRF theta were time function and forces. Results : Fx 1, Fy 1 and Fy 2 of stair descending showed significant statistically higher forces than that of level walking, and ascending. Fz 1 of stairs descending showed significant statistically higher forces than that of level walking and stairs ascending(theta $88.62^{\circ}$). Also, Fz 2 of level walking showed significant statistically higher forces than that of stairs ascending and descending(theta $65.78^{\circ}$). Fz 3 of stairs ascending showed significant statistically higher forces than that of level walking and stairs descending($65.26^{\circ}$). Impact loading rate of stairs descending showed significant statistically higher forces than that of level and ascending walking. The GRF showed similar correlation with GRF theta(r=.603) according to the ground conditions during gait. Conclusion : These results suggest that the GRF theta can be used in conjunction with a gait characteristics, prediction of loading rate and dynamic stability.

• Fire Science and Engineering
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• v.31 no.1
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• pp.116-123
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• 2017

The purpose of this paper is to improve the evacuation stability of residents in apartment fire. For this purpose, the actual condition survey about the obstacles was conducted on 3,056 escape stairs in the 183 apartments. In addition, the questionnaire investigation was carried out a survey targeting the residents of apartments about their experience of fire safety education, perception on safety management of escape stairs, and perception on fire safety. As a result of investigation, we confirmed that the obstacles were formed in the 1,916 escape stairs among the 3,056 escape stairs of the 183 apartments (percent of barricades in escape stairs: 62.70%). Furthermore, it showed that fire safety education experience was found to be 83.10% of subject. The perception on safety management of the subjects in the escape step and the perception on fire safety were $3.84{\pm}0.75%$, and $3.49{\pm}0.61$, respectively. In the results, most of the subjects had a fire safety education and knew how to safety management the escape stairs but, the practice of the safety management action was low. Based on the results in the paper, the policy proposal is that the fire safety education is emphasized to change from the perception to action.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.181-189
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• 2015

Powered prosthesis is used to assist walking of people with an amputated lower limb and/or weak leg strength. The accurate gait phase classification is indispensable in smooth movement control of the powered prosthesis. In previous gait phase classification using physical sensors, there is limitation that powered prosthesis should be simulated as same as the speed of training process. Therefore, we propose EMG signal based gait phase recognition method to classify stairs ascending and stairs descending into four steps without using physical sensors, respectively. RMS, VAR, MAV, SSC, ZC, WAMP features are extracted from EMG signal data and LDA(Linear Discriminant Analysis) classifier is used. In the training process, the AHRS sensor produces various ranges of walking steps according to the change of knee angles. The experimental results show that the average accuracies of the proposed method are about 85.6% in stairs ascending and 69.5% in stairs descending whereas those of preliminary studies are about 58.5% in stairs ascending and 35.3% in stairs descending. In addition, we can analyze the average recognition ratio of each gait step with respect to the individual muscle.

• Fire Science and Engineering
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• v.23 no.1
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• pp.63-69
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• 2009

Article 36 of the Building Code Enforcement Ordinance requires that an exterior evacuation stairs be installed for the buildings of three stories and over with cultural facilities or gathering places which have over $1,000\;m^2$ floor area of public performance halls or recreational facilities. The concentration of population together with the increase of high-rise buildings in cities call for various precautionary measures to be taken against human disasters. For the past ten years high-rise buildings showed 85% of increase, marking a steep rise. This increase of high-rise buildings may lead to human disasters in urban areas and, in case of fire breakout, may cause great loss of human lives and property damages. The most difficult fire-fighting activities in high-rise building fires are those of evacuation. Because smoke spreads through the upper floors, the securement of evacuation route in high-rise buildings may be the only way to minimize loss of lives. In high-rise buildings exterior escape stairs are necessary because it is difficult to secure evacuation route with only direct stairs or interior stairs. The Building Code now in force provides insignificant coverage on the exterior evacuation route installment and therefore becomes an inadequate means for evacuation route securement in high-rise building fires. To compensate for this inadequacy the Building Code should be revised to include a mandatory clause that an exterior evacuation stairs be established for the buildings of ten stories and over which can be categorized into high-rise building group.

• Journal of Platform Technology
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• v.10 no.2
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• pp.10-19
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• 2022

Moving assistant devices for people who are difficult to move are becoming electric-powered and automated. These moving assistant devices are not suitable for moving stairs at which the height between floor surfaces is different because these devices are designed and manufactured for flatland moving. An electric-powered and automated moving assistant device should change direction or stop when it approaches stairs in a movement direction. If the user or automatic control system does not change direction or stop in time, a moving assistant device can roll over or collide with stairs. In this paper, we propose a stairs detection method by using oblique distance measured by one sensor tilted to flatland. The method proposed in this paper can detect upward or downward stairs by using a difference between a predicted and measured oblique distance in considering a tilted angle of a sensor for measuring an oblique distance and installation height of the sensor on a moving object. Before the device enters a stairs region, if our proposed method provides information about detected stairs to a device's controller, the controller can do adequate action to avoid the accident.