• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.2
• /
• pp.173-178
• /
• 2017

As research on the practical use of robots has continued since the past, advancements into each field of society are being continuously tried in modern society, breaking bounds from the previous experimental environment. However, in order for robots to be applied to the real environment, the production cost, which is considered to be the biggest disadvantage of commercializing the existing robot platform, and the adaptability issue in working environments in terms of human standards must be considered. This paper proposes a robot of biped walking form, which conforms to the degree of freedom and the size of human beings. By replacing the encoder with a combined module of potentiometer, the high cost of production is reduced, and by adopting a modular design that is easy to replace parts, the maintenance cost of robots is reduced. Finally, stability was verified by applying a walking pattern to two dummy robots of different sizes and motor arrangements. In this paper, after developing the real biped walking robots, the performance and usability were verified through walking experiments and applying the walking pattern using the developed robots.

• PNF and Movement
• /
• v.17 no.1
• /
• pp.47-56
• /
• 2019

Purpose: This study investigated the effects of neck pattern of proprioceptive neuromuscular facilitation (PNF) on balance and walking ability in patients with chronic stroke. Methods: Fourteen participants with chronic stroke were randomly assigned to vestibular rehabilitation and then divided into two groups: the neck pattern group or treadmill group. Each group underwent 20 sessions (20 minutes/day, five days/week, for four weeks). Patients were assessed with the Berg balance scale (BBS) and gait parameters (gait speed, cadence, step length, and double-limb support period) using a GAITRite system. Results: Vestibular rehabilitation for the neck pattern group and the treadmill group showed significant intragroup improvement on the BBS and in terms of gait speed, cadence, step length, and double-limb support period (p < 0.05). Vestibular rehabilitation was more effective for the neck pattern group than for the treadmill group in terms of the BBS (p = 0.00; 95% CI, 1.49-5.94), gait speed (p = 0.01; 95% CI, 0.05-0.16), cadence (p = 0.02; 95% CI, 0.54-4.99), and step length (p = 0.00, 95% CI, 1.55-4.62). Conclusion: This study used the neck pattern of PNF for vestibular rehabilitation in patients with chronic stroke. The results showed significant improvement in the patients' balance and walking ability. Therefore, the neck pattern of PNF for vestibular stimulation may be more effective than treadmill training to improve balance and walking ability in patients with chronic stroke.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.7
• /
• 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.

• Korean Journal of Applied Biomechanics
• /
• v.17 no.2
• /
• pp.1-9
• /
• 2007

Walking is not only an essential component of the human mobility, but also is a good exercise. Inability to walk freely can reduce an individual's quality of life and independence substantially. Being a relatively low impact activity, walking is particularly good for the elderly and research has shown that regular walking in the elderly reduces the chance of fall-related injuries and mental diseases as well. In spite of the documented benefits of regular walking, it is still difficult to walk without the aid of assistive devices for the frail elderly who have lower extremity problems. Assistive walking devices(AWD), such as crutches, canes, hiking-poles, T-Poles and walkers, are often prescribed to the elderly to make their walking be safe and efficient. Many researchers have demonstrated the effects of AWDs such as reducing lower extremity loading, improved dynamic/gait stability, yet, no study has been done for gait pattern when the elderly gait with AWDs. Therefore, the purpose of this study was to examine whether T-Poles, one of the AWDs, change the elderly gait pattern. Eight community-dwelling female elderly participated in this study. Laboratory kinematics during walking with T-Poles(PW) and with out T-Poles(NPW) was assessed. PW showed significant increase in step width, stride length, gait velocity and decrease in swing time. No significances were found in lower body joint angles but meaningful trend and pattern were found. Maybe the reason was due to the participants. Our participants were healthy enough so that the effect of T-Poles was minimum. PW also showed typical gait phases which are no single support phase during a gait cycle. It indicates that walking with T-Poles may guarantee safe and confident walking to the frail elderly.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.169-170
• /
• 2006

The purpose of this study was to evaluate the smoothness of the gait pattern according to shoe, walking speed, and slope. Eleven male university students used three types(running shoes, mounting climbing boots, elevated forefoot walking shoes) of shoes at various walking speeds(1.19, 1.25, 1.33, 1.56, 1.78, 1.9, 2.0, 2.11, 2.33m/s) and gradients (0, 3, 6, 10%) on a treadmill. Three-dimensional motion analysis (Motion Analysis Corp, Santa Rosa, CA, USA) was conducted with 4 Falcon high speed cameras. The results showed that elevated forefoot walking shoes had the lowest value of normalized jerk at the heel, which means that elevated forefoot walking shoes had the smoothest walking pattern at the heel. In contrast, elevated forefoot walking shoes had greater normalized jerk at the center of mass (COM) at most walking speeds, which means that the smoothness of gait pattern at the center of mass is the lowest for the elevated forefoot walking shoes. This movement at the COM might even have a beneficial effect of activating muscles in the back and abdomen more than other shoes.

• PNF and Movement
• /
• v.14 no.2
• /
• pp.67-74
• /
• 2016

Purpose: The purpose of this study was to prove the effects of coordinative locomotion training (CLT) on walking speed, walking endurance, and balance for incomplete spinal cord injury patients. Methods: Ten subjects were randomly assigned to the CLT group (n = 5) and the treadmill (TM) group (n = 5). The CLT group performed PNF pattern exercise using the motions of the sprinter and skater for 30 minutes, while the TM group performed using a treadmill for 30 minutes. Both groups performed these therapeutic interventions for five days per week, for a period of four weeks. A 10 meter walking test, Berg Balance Scale (BBS), and 6 meter walking test were used for the assessment of gait speed, balance, and gait endurance. The SPSS Ver. 18.0 statistical program was used for data processing. A Wilcoxon signed rank test was used for the comparison of pre- and post-intervention performance and a Mann-Whitney test was used for comparison between the groups. The significance level for the statistical inspection was set at 0.05. Results: Both groups showed significant improvements in the 10 meter walking test, Berg Balance Scale, and 6 meter walking test (P < 0.05). Conclusion: CLT had an effect on the improvement of walking speed, walking endurance, and the balance of incomplete spinal cord injury patients. Thus, we suggest that CLT is a therapeutic intervention for incomplete spinal cord injury patients.

• Journal of Advanced Navigation Technology
• /
• v.21 no.1
• /
• pp.132-137
• /
• 2017

This paper proposes a transformation method of the zero moment point (ZMP) and the center of mass (CoM) from one walking pattern to other patterns by considering the structure of a robot or walking situations in real time. In general, a humanoid robot has own structure characteristics like height and mass. The structure characteristics make the given CoM/ZMP walking pattern of one human or one humanoid robot to be difficult to apply to other robot directly. For this purpose, we analyze the characteristics of walking patterns according to the step length, duration of walking support phase and the CoM height by using the cart-table model as the simple humanoid robot model. A transformation equation is derived from the analyzation and it is verified with simulation.

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

• PNF and Movement
• /
• v.22 no.1
• /
• pp.31-41
• /
• 2024

Purpose: The purpose of this study is to compare lower extremity muscle activities and ankle joint angles between different foot strike patterns (forefoot strike, heelfoot strike) during stair ascent walking. Methods: The subjects of this study were 22 males who walked in each foot strike pattern on ascent stairs at a speed of 85 beats/min. During stair walking with the two types of foot strike patterns, the muscle activities of the rectus femoris, tibialis anterior, medial gastrocnemius, hamstring, and gluteus medius were measured. Additionally, ankle joint angles for inversion, eversion, dorsi flexion, and plantar flexion were recorded. Each participant underwent the experiment three times, with the foot strike pattern randomized. Results were averaged according to the foot strike pattern. Results: Significant differences in ankle angles were observed across all phases according to foot strike pattern. Muscle activities in the lower extremities showed significant differences in all phases except the swing 1 phase. Moreover, differences in foot movement trajectory were noted depending on the foot strike pattern. Conclusion: Walking on ascent stairs elicited differences in lower extremity muscle activities and ankle joint angles based on foot strike pattern. These findings can serve as foundational data for selecting a suitable foot strike pattern tailored to individual patient conditions when training patients in walking on ascent stairs.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.1
• /
• pp.396-401
• /
• 2017

In this paper, a device to analyze gait pattern was developed by using a 2-axis acceleration sensor attached to the foot. The 1st low-pass filter was adapted to limit the frequency band up to 5 Hz. An algorithm to detect the peak value exceeding the threshold voltage of an X-axis acceleration sensor and a Z-axis acceleration sensor was developed and normal and abnormal walking patterns were thus differentiated. Also, MCU and Bluetooth were combined to transfer the data to other MCUs to display on an LCD; the size of the device could then be reduced. The new algorithm and the device allowed the individual walking patterns to be easily measured at a low cost and with less restriction on activities compared to conventional multiple pressure sensors or motion camera system.