• Journal of Institute of Control, Robotics and Systems
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• v.13 no.5
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• pp.399-405
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• 2007

This paper deals with the controller for a stable walking of a humanoid robot using genetic algorithm. A humanoid robot has instability during walking because it isn't fixed on the ground, and its nonlinearities of the joints increase its instability. If controller isn't robust, the robot may fall down at the ground during walking because of its nonlinearities. To solve this problem, robust controller is required to reduce the effect of nonlinearities and to gain the good tracking performance. In this paper, motion controller that is based on fuzzy-sliding mode controller is proposed. This controller can remove the effect of the saturation by limitation of the input voltage. It also includes compensator for reducing the effect of the nonlinearity by backlash and PI controller improving the tracking performance. In here, genetic algorithm is used for searching the optimal gains of the controller. From the given controller, a humanoid robot can moved more preciously. All the processes are investigated through simulations and are verified experimentally in a real joint system for a humanoid robot.

• Transactions of Materials Processing
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• v.24 no.3
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• pp.167-175
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• 2015

In the current study, the design methodology has been developed to produce shoe mold for a suitable walking shoes of the general Korean using ANN (Artificial Neural Network). To design the suitable and comfortable shoes for the Korean, the shapes of foots were measured for 513 people. In this research, the foot length, breadth and ankle were considered as design parameters. In order to find the optimal foot shape for the average value of design parameters, the average value of design parameters and the other measurements were used as input and output to the ANN. After training, the various foot measurements were predicted by ANN. Base on the ANN results, the walking shoes were manufactured by considering these measurements and designing a shoe mold. From the results, the proposed method could give a more systematic and feasible means for manufacturing walking shoes with greater usefulness and better generality.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.04a
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• pp.328-329
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• 2000

A viscosity resistance control method of the intelligent prosthetic legs is studied using an optimal control theory. The simulated results suggests that it is important to control the viscosity of the prosthetic knee joint in one period of walking to improve the usability. In this paper we describe modeling of the thigh prosthetic legs, optimal control and simulated results.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.3
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• pp.31-38
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• 2020

In this paper, we compare and analyze smart technologies and present six obstacle detection features to help visually impaired people walk. Traditionally, visually impaired people walk with the white cane or a guide dog. With the development of IoT technology, various smart walking aids systems have been developed. Those intelligent walking aids systems have obstacle-detecting systems and route-guidance systems. Many researchers are developing the walking aids system, which detects an obstacle and provides the obstacle information by haptic feedback. Also, they are designing the database server system to share the obstacle information. Particularly the composed system can quickly give an obstacle-avoidance route using shared obstacle information. Smart walking aids systems for visually impaired people will advance more rapidly by applying machine learning and intelligent systems.

• Journal of Korean Society of Transportation
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• v.23 no.3 s.81
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• pp.149-159
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• 2005

The paper presented not only the difference of the marginal walking time by passenger. but also the derivation of the bus service determination model by passenger attributes. The marginal walking distance to bus stop is a basic parameter to estimate bus service coverage area in certain area. And the marginal walking distance could be transformed from the marginal walking time, which is the focus of this paper. The result of analysis revealed that the age and income of passenger are strongly related to the marginal walking time. In planning or regulating the spacing of bus routes or bus stops in certain area, the model suggested in this paper help for the planner to choose optimal alternative.

• Physical Therapy Korea
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• v.26 no.1
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• pp.1-7
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• 2019

Background: The Microsoft Kinect which is a low-cost gaming device has been studied as a promise clinical gait analysis tool having satisfactory reliability and validity. However, its accuracy is only guaranteed when it is properly positioned in front of a subject. Objects: The purpose of this study was to identify the error when the Kinect was positioned at a $45^{\circ}$ angle to the longitudinal walking plane compare with those when the Kinect was positioned in front of a subject. Methods: Sixteen healthy adults performed two testing sessions consisting of walking toward and $45^{\circ}$ obliquely the Kinect. Spatiotemporal outcome measures related to stride length, stride time, step length, step time and walking speed were examined. To assess the error between Kinect and 3D motion analysis systems, mean absolute errors (MAE) were determined and compared. Results: MAE of stride length, stride time, step time and walking speed when the Kinect set in front of subjects were investigated as .36, .04, .20 and .32 respectively. MAE of those when the Kinect placed obliquely were investigated as .67, .09, .37, and .58 respectively. There were significant differences in spatiotemporal outcomes between the two conditions. Conclusion: Based on our study experience, positioning the Kinect directly in front of the person walking towards it provides the optimal spatiotemporal data. Therefore, we concluded that the Kinect should be placed carefully and adequately in clinical settings.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.2
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• pp.142-150
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• 2002

This paper presents a systematic method of the zigzag gait planning for quadruped walking robots. When a robot walks with a zigzag gait, its body is allowed to move from side to side, while the body movement is restricted along a moving direction in conventional continuous gaits. The zigzag movement of the body is effective to improve the gait stability margin. To plan a zigzag gait in a systematic way, the relationship between the center of gravity(COG) and the stability margin is firstly investigated. Then, new geometrical method is introduced to plan a sequence of the body movement which guarantees a maximum stability margin as well as monotonicity along a moving direction. Finally, an optimal swing-leg sequence is chosen for a given arbitrary configuration of the robot. To verify the proposed method, computer simulations have been performed for both cases of a periodic gait and a non-periodic gait.

• Safety and Health at Work
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• v.9 no.1
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• pp.17-24
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• 2018

Background: Increasing the slip resistance of floor surfaces would be desirable, but there is a lack of evidence on whether traction properties are linearly correlated with the topographic features of the floor surfaces or what scales of surface roughness are required to effectively control the slipperiness of floors. Objective: This study expands on earlier findings on the effects of floor surface finishes against slip resistance performance and determines the operative ranges of floor surface roughness for optimal slip resistance controls under different risk levels of walking environments. Methods: Dynamic friction tests were conducted among three shoes and nine floor specimens under wet and oily environments and compared with a soapy environment. Results: The test results showed the significant effects of floor surface roughness on slip resistance performance against all the lubricated environments. Compared with the floor-type effect, the shoe-type effect on slip resistance performance was insignificant against the highly polluted environments. The study outcomes also indicated that the oily environment required rougher surface finishes than the wet and soapy ones in their lower boundary ranges of floor surface roughness. Conclusion: The results of this study with previous findings confirm that floor surface finishes require different levels of surface coarseness for different types of environmental conditions to effectively manage slippery walking environments. Collected data on operative ranges of floor surface roughness seem to be a valuable tool to develop practical design information and standards for floor surface finishes to efficiently prevent pedestrian fall incidents.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.175-182
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• 2020

The calculation of the optimal trajectory of the stepped top-down robot was made using a genetic algorithm and a computational torque controller. First, the total energy efficiency was minimized using the Red-Cold Generic Algorithm (RCGA) consisting of reproductive, cross, and mutation. The reproducibility condition related to the position assembly of the start and end of the stride and the joints, angles, and angular velocities are linear constraints. Next, the unequal constraint accompanies the condition for preventing the collision of the swing leg at the corner with the outer surface of the stairs, the condition of the knee joint for preventing kinematic peculiarity, and the condition of no moment in safety in the traveling direction. Finally, the angular trajectory of each joint is defined by fourth-order polynomial whose coefficient is to approximate chromosomes. This is to approximate walking. In this study, the energy efficiency of the optimal trajectory was analyzed by computer simulation through a biped robot with seven degrees of freedom composed of seven links.

• Fashion & Textile Research Journal
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• v.21 no.3
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• pp.300-307
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• 2019

This study develops a user centered outdoor jacket capable of energy harvesting based on consumer needs. Jackets are designed for typical outdoor activities such as hiking, trekking, and climbing, integrated with an energy harvesting module that can generate electric power from arm swing in outdoor and daily life walking. Textile based energy generators developed by the previous research of Lee & Roh (2018) were used. A prototype was created based on the arm swing motion experiment for location options and energy harvesting system functions, the simulation by the design sketch, and evaluation of the wearing test by experts. In-depth interviews were later conducted for the prototype with 10 outdoor experts to derive the optimal location of an energy harvesting system in three ways, and the prototype was revised to 5 styles that reflected reviews by experts on function and appearance. Research indicated that the energy harvesting jacket design signifies a user-centered design based on expert interviews and usability evaluation as well as previous research on energy generation and storage device. The jacket is convenient because it combines an energy generator in an optimal position to maximize energy generation with a storage and charging device that can be inserted into various position options for accessibility.