• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2142-2148
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• 2015

This paper proposes novel real-time footstep planning and following methods for the navigation of humanoid robots. A footstep command is defined by a walking direction and step lengths for footstep planning. The walking direction is determined by a uni-vector field navigation method, and the allowable yawing range caused by hardware limitation is considered. The lateral step length is determined to avoid collisions between the two legs while walking. The sagittal step length is modified by a binary search algorithm when collision occurs between the robot body and obstacles in a narrow space. If the robot body still collides with obstacles despite the modification of the sagittal step length, the lateral step length is shifted at the next footstep. For footstep following, a walking pattern generator based on a 3-D linear inverted pendulum model is utilized, which can generate modifiable walking patterns using the zero-moment point variation scheme. Therefore, it enables a humanoid robot to follow the footstep command planned for each footstep. The effectiveness of the proposed method is verified through simulation and experiment.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.9
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• pp.133-144
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• 2000

The dynamic walking planning and the inverse dynamics of the biped robot is investigated in this paper. The biped robot is modeled with 14 degrees of freedom rigid bodies considering the walking pattern and kinematic construction of humanoid. The method of the computer aided multibody dynamics is applied to the dynamic analysis. The equations of motion of biped are initially represented as terms of the Cartesian corrdinates then they are converted to the minimum number of equations of motion in terms of the joint coordinates using the velocity transformation matrix. For the consideration of the relationships between the ground and foot the holonomic constraints are added or deleted on the equations of motion. the number of these constraints can be changed by types of walking patterns with three modes. In order for the dynamic walking to be stabilizable optimized trunk positions are iteratively determined by satisfying the system ZMP(Zero Moment Point) and ground conditions.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.344-351
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• 2014

In order to accomplish complex navigational commands, humanoid robot should be able to modify its walking period, step length and direction independently. In this paper, a novel walking pattern generation algorithm is proposed to satisfy these requirements. Modification of the walking pattern can be considered as a transition between two periodic walking patterns, which follows each navigational command. By assuming the robot as a linear inverted pendulum, the equations of motion between ZMP(Zero Moment Point) and CM(Center of Mass) state is easily derived and analyzed. After navigational command is translated into the desired CM state, corresponding CM motion is generated to achieve the desired state by using simple ZMP functions. Moreover, when the command is not feasible, feasible command is alternated by using binary search algorithm. Subsequently, corresponding CM motion is generated. The effectiveness of the proposed algorithm is verified by computer simulation.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.1
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• pp.127-138
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• 2019

This study was to evaluate the walking speed of elderly people by using the travel route big data collected by travel diary and smart phone application. We analyzed the change of walking behavior in the residential street environments of the elderly whether they had a company or not. We interpreted the meaning based on previous studies. In addition, the characteristics of elderly people's use of the residential street environment were analyzed by comparing the change in spatial speed according to the companion. The result reveals that the usage patterns of the residential street environments change depending on whether they were accompanied or not. First, the elderly tend to do more social activities while walking alone than when they were accompanied. When they were accompanied the social activities occur in empty lot near the residential area. However, the social activities of the elderly occur in open space such as neighborhood park or playground while walking alone. Finally, This study has strength that it empirically analyzes the elderly's walking behavior and usage paths in small outdoor spaces, including residential streets.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.61-71
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• 2006

The purpose of this study was to compare kinematic characteristics on the limbs at 3 different walking speed during the energy and the normal walking. Eight subjects performed energy walking and normal walking at the slow speed(65 beats/min), the normal speed(115beats/min), the fast speed(160 beats/min). The 3-d angle was calculated by vector projected with least squares solution with three-dimensional cinematography(Motion Analysis corporation). The range of motion was calculated on the trunk, shoulder, elbow, hip, knee joint. The results showed that stride length was no difference of the two walking pattern. The duration of support phase was also no difference of the two walking pattern. The range of motion of shoulder joint significantly increased in the sagittal and frontal planes, and the range of motion of elbow joint significantly increased as the energy walking. The range of motion of hip joint had no significant difference in the any planes in changing of walking speed. But the most remarkable difference of the two walking patterns revealed at the trunk. The range of flexion/extension angle had significant increasing $2.36^{\circ}$ at normal speed, and the range of the right/left flexion angle had significant increasing below $4^{\circ}$ at the 3 walking speed, and The range of rotation angle had significant increasing $7.35^{\circ}$, $9.22^{\circ}$, respectively at the normal and slow speed. But there was no significant difference of range of motion at the hip and knee joints between energy walking and normal walking.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.2
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• pp.65-72
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• 2011

Since walking and physical activity are critical for older adults to maintain their health, it is important to provide neighborhood environments which encourage their walking in daily life. The purposes of the present study were to investigate walking activity patterns of older people in an urban setting and to identify environmental correlates with walking of older adults. This study examined spatial and temporal patterns of physical activities, environmental barriers and motivations, satisfaction levels and demands on the physical environment. In-depth interviews with older adults over age sixty residing in Seoul metropolitan areas revealed that most respondents have a positive perception on walking in daily life, and many of them walk regularly for their health. A primary purpose of walking for older adults was exercise for health rather than transportation. The study result demonstrated that parks and trails were the most preferred places for walking by older adults, and there is an association between frequency of walking participation and access or convenience to parks, traffic safety, and street lights. Most respondents were concerned about traffic safety when they walk in their neighborhoods due to traffic speeds and unsafe streets. Lack of separate sidewalks or benches, stairs and slopes were barriers to older adults' walking habits. This data suggests that the promotion of walking behavior among older adults, some level of public health action, and community support are needed to ensure safe physical environments within communities.

• Physical Therapy Korea
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• v.20 no.4
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• pp.55-64
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• 2013

The first purpose was to identify the plantar pressure distributions (peak pressure, pressure integral time, and contact area) during level walking, and stair ascent and descent in asymptomatic flexible flatfoot (AFF). The second purpose was to investigate whether peak pressure data during level walking could be used to predict peak pressure during stair walking by identifying correlations between the peak pressures of level walking and stair walking. Twenty young adult subjects (8 males and 12 females, age $21.0{\pm}1.7$ years) with AFF were recruited. A distance greater than 10 mm in a navicular drop test was defined as flexible flatfoot. Each subject performed at least 10 steps during level walking, and stair ascent and descent. The plantar pressure distribution was measured in nine foot regions using a pressure measurement system. A two-way repeated analysis of variance was conducted to examine the differences in the three dependent variables with two within-subject factors (activity type and foot region). Linear regression analysis was conducted to predict peak pressure during stair walking using the peak pressure in the metatarsal regions during level walking. Significant interaction effects were observed between activity type and foot region for peak pressure (F=9.508, p<.001), pressure time integral (F=5.912, p=.003), and contact area (F=15.510, p<.001). The regression equations predicting peak pressure during stair walking accounted for variance in the range of 25.7% and 65.8%. The findings indicate that plantar pressures in AFF were influenced by both activity type and foot region. Furthermore the findings suggest that peak pressure data during level walking could be used to predict the peak pressure data during stair walking. These data collected for AFF can be useful for evaluating gait patterns and for predicting pressure data of flexible flatfoot subjects who have difficulty performing activities such as stair walking. Further studies should investigate plantar pressure distribution during various functional activities in symptomatic flexible flatfoot, and consider other predictors for regression analysis.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.2
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• pp.157-166
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• 1995

To investigate walkability of ramps, walking patterns of 18 healthy adults,12 aged 20 to 26 and 6 aged 68 to 76,were studied at free,rhythm constrained walking up or down ramp using goniometer and footswitch Ramp inclinations were set 4,8,12,16,20 degrees. The results were as follows. 1)The step length of subjects were decreased significantly in12$^{\circ}C$′or 16′free downramp walking. With regard to step length, some subject groups walked abnormally in 16" or 20" ramp walking 2) The step width of subjects were increased significantly in 12" or 16" ramp walking. 3) The cadence duration of some subject groups were increased in 12" upramp walking. 4) The double stance duration and double stance ratio of some subject groups were increased significantly in 8",12", or 16"upramp walking. 5) The maximum knee flexion angle of stance phase were increased in 12" ramp walking. 6)Most temporal parameters and spatial parameters of gait were increased or decreassd greatly between 4" ramp and 8" ramp or between 8′ramp and 12′ramp. But statistics significancy were not recognized 7) The results suggest that ramp inclination less than 8′(14%) -12′(21%) is desirable for the normal gait the ramp inclination must not exceed 16" -20" in unavoidable circumstances.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.6
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• pp.750-763
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• 2013

This research suggests pattern design methods for motion through an evaluation of the appearance and motion of three existing kinds of original patterns (K type, N type, and L type) and modified patterns designed by the researcher. The results of the study are as follows. First, the evaluation of appearances showed that the modified patterns of a standing posture received a higher evaluation compared to the original patterns only in N type and in a sitting posture. In addition, the degree of lowering or a natural feel by the pulling of the slacks waist belt in a sitting posture received a higher evaluation than the original patterns. Second, the evaluation of motions showed that modified patterns received a higher evaluation than the original patterns in almost all items. Per each pattern, it showed meaningful differences in questions asking about the degree of comfort as the whole in N type in crouching motions. The L type showed low scores as a whole (both in original patterns and modified patterns) and the K type showed meaningful differences in questions asking about the degree of comfort of the crista iliaca and groin region in the motion of walking at a normal walking pace, ascending stairs and bending the waist 90 degree to the front. Third, the measuring distance the between back waist point of the body and the back waist point of original patterns and modified patterns during motions showed that the modified patterns of all three patterns (N type, L type, and K type) showed less lowering compared to the original forms in the whole pattern as well as individual patterns. The design method of back waist point developed in this research can be regarded as a design method appropriate for motions.

• Journal of Korean Physical Therapy Science
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• v.5 no.1
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• pp.573-581
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• 1998

Gait is a highly complex activity in which many variables can be observed and measured. Walking is a repetitious sequence of limb to move the body and to maintain stability. Normal gait is rhythmic and characterized by alternating propulsive and retropulsive motions of the lower extremities. Pathological gait patterns have four functional categories (deformity, muscle weakness, impaired control, pain). The purpose of this study was to assess the quantitive gait variables(the width of the base, length of a step, stride length, cadence, velocity) in patients with low back pain. Patients walked more slowly, took shorter steps and did not show the symmetrical gait patterns.