• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.3
• /
• pp.305-311
• /
• 2012

In this paper, we propose a gait generation method for quadruped robots using the xz-axis sway of the quadruped robot, which minimizes the shake of the quadruped robot and maximizes the stability margin. In the proposed method, the gait is generated based on wave gaits and the stability analysis uses the body tilt information of the quadruped robot according to the leg's height of leg. In addition, to reduce the impact on the body caused by the z-axis sway while walking, the proposed method generates the smooth walking movement trajectory with less impact by using Fourier series. Finally, to verify the applicability and effectiveness of the proposed method, we carry out the computer simulations and the real walking experiments with the implemented quadruped robot.

• Physical Therapy Korea
• /
• v.23 no.1
• /
• pp.87-93
• /
• 2016

Background: Posture balance control is the ability to maintain the body's center of gravity in the minimal postural sway state on a supportive surface. This ability is obtained through a complicated process of sensing the movements of the human body through sensory organs and then integrating the information into the central nervous system and reacting to the musculoskeletal system and the support action of the musculoskeletal system. Motor function, including coordination, motor, and vision, vestibular sense, and sensory function, including proprioception, should act in an integrated way. However, more than half of stroke patients have motor, sensory, cognitive, and emotional disorders for a long time. Motor and sensory disorders cause the greatest difficulty in postural control among stroke patients. Objects: The purpose of this study is to determine the effect of visual and somatosensory information on postural sway in stroke patients and carrying out a kinematic analysis using a tri-axial accelerometer and a quantitative assessment. Methods: Thirty-four subjects posed four stance condition was accepted various sensory information for counterbalance. This experiment referred to the computerized dynamic posturography assessments and was redesigned four condition blocking visual and somatosensory information. To measure the postural sway of the subjects' trunk, a wireless tri-axial accelerometer was used by signal vector magnitude value. Ony-way measure analysis of variance was performed among four condition. Results: There were significant differences when somatosensory information input blocked (p<.05). Conclusion: The sensory significantly affecting the balance ability of stroke patients is somatosensory, and the amount of actual movement of the trunk could be objectively compared and analyzed through quantitative figures using a tri-axial accelerometer for balance ability.

• Journal of the Korean Institute of Navigation
• /
• v.18 no.4
• /
• pp.11-21
• /
• 1994

Final aim of this paper is a study on simulation of automatic steering of a ship in random seas. In order to achieve this aim, we need excitation due to random seas. The excitation may be estimated from energy spectrum of irregular waves and response functions of manoeuvring motion of a ship in regular waves. This paper deals with response functions of manoeuvring motion of a ship in regular waves. We discussed New Strip Method(NSM) of sway-yaw-roll coupled motions in regular waves. NSM is defined in space axes system and that has been used to predict seakeeping performance of a ship in waves. But ship manoeuvring is defined in body fixed axes system. So we cannot use NSM theory itself in predicting manoeuvring performance of a ship in waves. We introduced relationship between space axes system and body fixed axes system. And we developed modified NSM which was defined in body fixed axes system and was able to be used in manoeuvring motion of a ship in waves. We calculated sway and yaw response functions of manoeuvring motion of a bulk carrier in regular waves.

• The Journal of Korean Physical Therapy
• /
• v.27 no.2
• /
• pp.112-117
• /
• 2015

Purpose: The purpose of this study was to examine the effects of a task-specific obstacle crossing rehabilitation program on functional gait ability in patients with cerebellar ataxia. Overall, we sought to provide ataxia-specific locomotor rehabilitation guidelines for use in clinical practice based on quantitative evidence using relevant analysis of gait kinematics including valid clinical tests. Methods: Patients with cerebellar disease (n=13) participated in obstacle crossing training focusing on maintenance of dynamic balance and posture, stable transferring of body weight, and production of coordinated limb movements for 8 weeks, 2 times per week, 90 minutes per session. Throughout the training of body weight transfer, the instructions emphasized conscious perception and control of the center of body stability, trunk and limb alignment, and stepping kinematics during the practice of each walking phase. Results: According to the results, compared with pre-training data, foot clearance, pre-&post-obstacle distance, delay time, and total obstacle crossing time were increased after intervention. In addition, body COM measures indicated that body sway and movement variability, therefore posture stability during obstacle crossing, showed improvement after training. Based on these results, body sway was reduced and stepping pattern became more consistent during obstacle crossing gait after participation in patients with cerebellar ataxia. Conclusion: Findings of this study suggest that task-relevant obstacle crossing training may have a beneficial effect on recovery of functional gait ability in patients with cerebellar disease.

• The Journal of Korean Physical Therapy
• /
• v.24 no.2
• /
• pp.73-81
• /
• 2012

Purpose: The aim of the present study was to measure the standing balance symmetry of stroke patients using a force-plate with computer system, and to investigate the correlation between the standing balance symmetry and that of the walking function in stroke patients. Methods: 48 patients with stroke (34 men, 14 women, $56.8{\pm}11.72$ years old) participated in this study. Static standing balance was evaluated by the weight distribution on the affected and the nonaffected lower limbs, sway path, sway velocity, and sway frequency, which reflected the characteristic of body sway in quiet standing. Dynamic standing balance was evaluated by anteroposterior and mediolateral sway angle, which revealed the limit of stability during voluntary weight displacement. Symmetry index of static standing balance, (SI-SSB) calculated by the ratio of the affected weight distribution for the nonaffected weight distribution, and symmetric index of dynamic standing balance (SI-SDB) by the ratio of the affected sway angle for the nonaffected sway angle. Functional balance assessed by a Berg balance scale (BBS), and the functional walking by 10m walking velocity, as well as the modified motor assessment scale (mMAS). Results: Static balance scales and SI-SSB was the only correlation with BBS (p<0.05). Dynamic balance scales and SI-DSB, not only was correlated with BBS, but also with 10m walking velocity and mMAS (p<0.01). Additionally, there was a significant difference between SI-SSB and that of SI-DSB (p<0.01). Conclusion: The balance and the walking function relate to real life in the stroke showed strong relationships with the dynamic standing balance symmetry in the frontal plane and the ability of anterior voluntary weight displacement in sagittal plane.

• Journal of the Ergonomics Society of Korea
• /
• v.28 no.2
• /
• pp.35-55
• /
• 2009

The purpose of this study was to analyze the somatotypes of women in the early 20's, which were likely to deform due to bad posture in growth period. Accordingly, bodies of women aged 20 to 24, whose growth stopped, were measured directly and indirectly, and factors related to body shapes were extracted, body shapes were categorized based on the data, and the characteristics of each body shape were analyzed. As a result, 10 factors related to body shapes were extracted in the factor analysis, and body shapes were categorized into 6 types. Type 1 was the volume of body that was big and the longest; and the general frame was large. The straight body shape with small back protrusion; the shoulder is relatively thick and the width of the shoulder was normal. Type 2 was the volume of body that was the biggest and the upper body was the longest; the general frame was of average height. The forward body shape with the back flat; the shoulder was very thick, wide, and serious leaning forward. Type 3 was a body that was thin and the shortest. The sway-back body shape with big curvature at the back; the shoulder was thin, narrow, and straight. Type 4 was a body that was short stature, and the general frame was of average build. The forward body shape with the most serious back protrusion; the shoulder was normally thick, narrow, and straight. Type 5 was a group with small body, and the lower body and general frame are long. The sway-back body shape with protrusion at the upper shoulder and the sides leaning backward; the shoulder was thin, wide, and leaning forward. Type 6 was a thin and short body; and the general frame was small. The lean-back body shape with the smallest back protrusion and leaning backward; the shoulder was thin, narrow, and leaning backward. Characteristics of the classified body shapes can be used in producing ready-made clothes, and it is hoped that there will be follow-up studies on clothing pattern design and production based on this result.

• The Journal of Korean Physical Therapy
• /
• v.10 no.1
• /
• pp.149-154
• /
• 1998

This study was designed 1) to quantitatively observe changes in static platform and 2) to observe balance performance using vision. Seventy-five subjects participated in the study. Subjects comprised 39 males and 36 females(mean ages=23.8 years) without neurologic and orthopaedic impairments. Static balance was measured with eyes open and closed. Subjects was required to move the cneter of balance curser in a counterclockwise for 30 sec. The effect for the COBx(-) suggests that subjects tended to maintain their weight slightly In the left. The time taken and the accuracy to move the center of balance from target to target was 14 sec, $49.47\%$. The body sway upon reaching the target was 7.3 AP sway and 11.88 LR sway distance. In this study, the data developed could be appropriate to use for sine comparisons when balance training patients with neurologic or orthopaedic impairments.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.23 no.4
• /
• pp.149-166
• /
• 2021

This study tried to suggest a drafting method to draft tight fit torso patterns suitable for adult males with a sway back somatotype and a bend forward somatotype by setting and distributing the ease through the completion of the somatic surface pattern using the 3D body surface segment method. It was intended to be presented as a drafting method. As for the research method, the suitability of the somatic surface patterns and the tight fit torso patterns were confirmed by the evaluation of virtual wear, and the patterns were modified and supplemented. The research results are as follows. In the first evaluation of the tight fit torso patterns, the average, for 55 evaluation items, was 3.92 points for the sway back somatotype and 3.89 points for the bend forward somatotype. In the second evaluation, the bend forward somatotype was 4.51 points and the sway back somatotype was 4.62 points. The chest circumference ease amount for the bend forward somatotype and the sway back somatotype are 6.5% (6.8 cm) and 7% (6.8 cm) of the chest circumference, respectively, and the distribution of the front and back ease is the same at 4:6 (2.72 cm:4.08 cm). The waist circumference ease amount is 6.5% (5.8cm) and 6.5% (5.6 cm) of the waist circumference dimensions, and the distribution of the front and backease are 5:5 (1.45 cm: 1.45 cm) and 4:6 (2.24 cm: 3.36 cm), respectively. The completed tight fit torso patterns were converted into institutional formulas and presented as a drafting method.

• The Journal of Korean Physical Therapy
• /
• v.34 no.6
• /
• pp.321-325
• /
• 2022

Purpose: Temporomandibular disorder (TMD) is a condition defined as pain and dysfunction of temporomandibular joints and masticatory muscles. Abnormal interconnections between temporomandibular muscles and cervical spine structures can cause the changes of postural alignment and balance ability. The aim of this study was to investigate changes in static balance ability in subjects with painrelated TMD. Methods: This study conducted on 25 subjects with TMD and 25 control subjects with no TMD. Pressure pain thresholds (PPTs) of the masseter and temporalis muscles were measured using a pressure algometer. Static balance ability was assessed during one leg standing using an Inertial Measurement Unit (IMU) sensor. During balance task, the IMU sensors measured motion and transfer movement data for center of mass (COM) motion, ankle sway and hip sway. Results: PPTs of masseter and temporalis muscles were significantly lower in the TMD group than in the control group (p<0.05). One leg standing, hip sway, and COM sway results were significantly greater in the TMD group (p<0.05), but ankle sways were not different between group. Conclusion: We suggest pain-related TMD is positively related to reduced PPTs of masticatory muscles and to static balance ability. These results should be considered together with global body posture when evaluating or treating pain-related TMD.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.6
• /
• pp.678-686
• /
• 2011

When one sensor cannot provide information by sensory deficit or loss, the sensory information can be provided by substituting other sensors for the defected sensor. This sensory substation might be influence on the deteriorated motion perception that consists of multi-sensory information such as visual, vestibular and somatosensory information. In this study, to investigate whether the additional sensation by sensory substitution could be integrated into the motion perception, we examined the effect of substituted postural sway sensation on the directional perception of body movement. Deteriorated motion perception by the reduced plantar sensation was enhanced under sensory substitution condition that provided the body sway information as the plantar vibratory stimulus. These results imply that the additional sensation might be integrated into and improve the motion perception.