• The Journal of Korean Physical Therapy
• /
• 제25권6호
• /
• pp.379-385
• /
• 2013

Purpose: The purpose of this study is to compare kinematics on lower limbs between stair walking with high heel and barefoot in healthy adult women. Methods: 18 healthy adult women were recruited in this study. The subjects performed stair ascent and descent with high heels and barefoot. The experiment was conducted in random order and repeated three times for each stair walking with high heels and barefoot. The movements of lower limb joints were measured and analyzed using a three-dimensional analysis system. Results: The ankle, knee, and hip flexion angles on the sagittal plane exhibited statistically significant differences between stair ascent and descent with high heels and barefoot. The pelvic forward tilt angles showed statistically significant differences only during stair ascent. The ankle inversion, hip abduction and pelvic lateral tilt angles on the frontal plane showed statistically significant differences between stair walking with high heels and barefoot. On the transverse plane, the hip rotation angles showed statistically significant differences between the high-heeled and barefoot gait during stair ascent and descent. However, the pelvic rotation angles showed no statistically significant differences. Conclusion: Therefore, wearing high-heeled shoes during stair walking in daily life is considered to influence lower limb kinematics due to the high heel, and thus poses the risks of pain, and low stability and joint damage caused by changes in the movement of lower limb joints.

• 제어로봇시스템학회논문지
• /
• 제17권7호
• /
• pp.659-667
• /
• 2011

The study of bipedal robot is towards similar shape and function with human. In this paper, we propose a human-like walking pattern compatible to the flexible foot with toe and heel structure. The new walking pattern for a bipedal robot consists of ZMP, center of mass (CoM), and ankle trajectory and is drawn by considering human kinesiology. First, the ZMP trajectory moves forward without stopping at a point even in the single support phase. The corresponding CoM trajectory to the ZMP one is derived by solving differential equations. As well, a CoM trajectory for the vertical axis is added by following the idea of human motion. The ankle trajectory closely mimics the rotational motion of human ankles during taking off and landing on the ground. The advantages of the proposed walking pattern are demonstrated by showing improved stability, decreased ankle torque, and the longer step length capability. Specifically, it is interesting to know that the vertical CoM motion is able to compensate for the initial transient response.

• 한국운동역학회지
• /
• 제17권1호
• /
• pp.17-27
• /
• 2007

It is essential for gait analysis to know the distance information. The purpose of this study was to investigate the effects of start and finish distance on the gait variable during walking. Six adolescent participated in this study. Start condition was given by six conditions.: walking forward from (1) one step, (2) three steps, (3) five steps, (4) ten steps, (5) one step after standing walk, and (6) three steps after standing walk, before contacting the force plate. Stop condition was given by four conditions. : stop after (1) one step, (2) two steps, (3) three steps, and (4) ten steps, passing force plate. Repeated measured one-way ANOVA was utilized for data analysis, and the significant level was set at .05. The largest change from the difference of gait velocity exists between the variables of ground reaction force. There were no significant differences in spatio-temporal and posture(angle) variables, as well as ground reaction force variables with walking over the three steps. There were significant differences in gait velocity, knee angle at heel contact, vertical impulse and ankle angle at toe off in short distance.

• 제어로봇시스템학회논문지
• /
• 제17권10호
• /
• pp.1029-1036
• /
• 2011

An energy-efficient reference walking trajectory generation algorithm is suggested utilizing allowable ZMP (Zero-Moment-Point) region, which maxmizes the energy efficiency for cyclic gaits, based on three-dimensional LIPM (Linear Inverted Pendulum Model) for biped robots. As observed in natural human walking, variable ZMP manipulation is suggested, in which ZMP moves within the allowable region to reduce the joint stress (i.e., rapid acceleration and deceleration of body), and hence to reduce the consumed energy. In addition, opimization of footstep planning is conducted to decide the optimal step-length and body height for a given forward mean velocity to minimize a suitable energy performance - amount of energy required to carry a unit weight a unit distance. In this planning, in order to ensure physically realizable walking trajectory, we also considered geometrical constraints, ZMP stability condition, friction constraint, and yawing moment constraint. Simulations are performed with a 12-DOF 3D biped robot model to verify the effectiveness of the proposed method.

• 한국전문물리치료학회지
• /
• 제10권3호
• /
• pp.81-90
• /
• 2003

This study was conducted to assess the effects of the gait training method in incomplete spinal cord injured persons using an auto-walking machine. Persons with incomplete spinal cord injury level C or D on the American Spinal Injury Association impairment scale participated for eight weeks in an auto-walking training program. The gait training program was carried out for 15 minutes, three times per day for 8 weeks with an auto-walking machine. The foot rests of the auto-walking machine can be moved forward, downward, backward and upward to make the gait pattern with fixed on crank. The patient's body weight is supported by a harness during waking training. We evaluated the gait speed, physiologic cost index, motor score of lower extremities and the WISCI (walking index for spinal cord injury) level before the training and after the forth and eighth week of walking training. 1. The mean gait speed was significantly increased from .22 m/s at pre-training to .28 m/s after 4 weeks of training and .31 m/s after 8 weeks of training (p=.004). 2. The mean physiologic cost index was decreased from 4.6 beats/min at pre-training to 3.0 beats/min after 4 weeks and 2.0 beats/min after 8 weeks of training, but it was not statistically significant (p=.140). 3. The mean motor score of lower extrernities was significantly increased from 29.8 to 35.8 after 8 weeks of training (p=.043). 4. The mean WISCI level was significantly increased from level 10 to level 19 after 8 weeks of training (p=.007). The results of this study suggest that the gait training program using the auto-walking machine increased the gait speed, muscle strength and galt pattern (WISCI level) in persons with incomplete spinal cord injury. A large, controlled study of this technique is warranted.

• 제어로봇시스템학회논문지
• /
• 제9권11호
• /
• pp.943-951
• /
• 2003

A strategy for fault-tolerant gaits of autonomous legged robots is proposed. A legged robot is considered to be fault tolerant with respect to a given failure if it is guaranteed to be capable of walking maintaining its static stability after the occurrence of the failure. The failure concerned in this paper is a locked joint failure for which a joint in a leg cannot move and is locked in place. If a failed joint is locked, the workspace of the resulting leg is constrained, but legged robots have fault tolerance capability to continue static walking. An algorithm for generating fault-tolerant gaits is described and, especially, periodic gaits are presented for forward walking of a hexapod robot with a locked joint failure. The leg sequence and the formula of the stride length are analytically driven based on gait study and robot kinematics. The transition procedure from a normal gait to the proposed fault-tolerant gait is shown to demonstrate the applicability of the proposed scheme.

• 한국운동역학회지
• /
• 제21권3호
• /
• pp.289-296
• /
• 2011

The purpose of this study was to quantify the biomechanical characteristics of the ground reaction force(GRF) during the Taekwondo's Apkubi, one of the basic movement in Taekwondo and the walking. The GRF profiles under the stance foot of Apkubi movement and walking were directly measured in sample of 20 healthy older persons. In the anterior-posterior and vertical direction, the GRF of the Apkubi movement reached to the peak braking force at 10% of the normalized stance time percent and the peak driving force at 90% of stance time, but that of the walking reached to the peak braking force at 20% of stance time and the peak driving force at 80% of stance time. In vertical force, the GRF of the walking showed two peak values, but that of the Apkubi movement seemed three peak values. Moreover the first peak vertical force was significantly(t=6.085, p<.001) greater in the walking(about 1.8 times of body weight) than the Apkubi(about 1.4 times of body weight). The walking velocity was affected significantly(over p<.05) by the braking impulse, the peak braking force and the first peak vertical force. Futhermore the peak braking force in the Apkubi showed a significant effect on the Apkubi's stride length(p<.01). So, we concluded that the braking force after the right touch down, the stance foot on the ground contributed to move the leg forward.

• 대한물리치료과학회지
• /
• 제25권2호
• /
• pp.55-61
• /
• 2018

Purpose: This study is to compare muscle activation of leg muscles with forward and backward gait and treadmill speed. Method: The experimenter is a healthy ten male and female. They practice walking on the treadmill for 2 minutes and then walk 2km/h and 4km/h in front and back for 3 minutes. Muscle activities were recorded from the lower limb muscles (rectus femoris [RF], biceps femoris [BF], gastrucnemius [GCM]). Results: According to the study, lower extremity muscles have higher backward gait than forward gait. Conclusion: Muscle activity at the speed indicated that the muscular activity of the lower limbs was 4.0km/h, which is higher than 2.0km/h.

• 한국HCI학회:학술대회논문집
• /
• 한국HCI학회 2008년도 학술대회 1부
• /
• pp.534-539
• /
• 2008

본 논문은 시력이 떨어지고 보행이 불편한 고령자의 이동을 지원하는 지능형 6족 이동 로봇에 대한 연구이다. 센서 및 소형카메라를 장착한 6족 지능형 이동 로봇은 다양한 보행 및 회전, 이동 속도 조절 등의 이동 능력과 다양한 센서를 이용한 장애물 회피, 위협 상황 인식, 경사보행, 물체영역의 인식 및 추적 등의 기능을 가지며, 로봇에 연결된 선을 이용해 고령자의 보행을 유도한다. 로봇의 안정된 보행을 위한 모터의 제어방법, 센서 및 영상인식을 통한 로봇의 환경인식, 그에 따른 로봇의 지능적이고 능동적인 대응, 감지된 환경정보를 신속하게 무선통신을 통해 필요한 고령자 또는 보호자에게 전송하는 방법 등을 구현하였다. 한 다리에 3자유도를 가진 18관절 6족 로봇으로 구현되어 비평탄 지형에서도 안정된 보행구현은 물론 다양하고 부드러운 동작을 취할 수 있으며 강력한 구동 능력을 위해 디지털 슈퍼토크 서보모터를 사용하였고, 위험 상황 인식을 위해 3축 가속도 센서, PIR(초전)센서, 불꽃센서, 연기센서, 적외선, 초음파 거리감지 센서, 조도센서, 터치센서, 온도/습도 센서, 음성인식센서와 카메라를 통한 영상인식 등을 센서 융합에 의해 구현함으로써 상황인식의 정확도를 높이고 고령자들의 길안내 시 위험을 조기에 예측하여 전달하는 에이전트 역할을 수행하도록 설계되었다.

• 제어로봇시스템학회논문지
• /
• 제7권5호
• /
• pp.420-426
• /
• 2001

In this paper, we introduce a case study of developing a miniature humanoid robot that has 16 degrees of freedom and is able to perform statically stable walking. The developed humanoid robot is 37cm tall and weighs 1,200g. RC servo motors are used as actuators. The robot can walk forward and turn to any direction on an even surface. It equipped with a small digital camera, so it can transmit vision data to a remote host computer via wireless modem. The robot can be operated in two modes: One is a remote-controlled mode, in which the robot behaves according to the command given by a human operator through the user-interface program running on a remote host computer, the other is a stand-alone mode, in which the robot behaves autonomously according the pre-programmed strategy. The user-interface program also contains a robot graphic simulator that is used to produce and verify the robot\`s gait motion. In our walking algorithm, the ankle joint is mainly used for balancing the robot. The experimental results shows that the developed robot can perform statically stable walking on an even surface.