• 한국해양공학회지
• /
• 제29권5호
• /
• pp.398-403
• /
• 2015

This paper introduces a method to estimate the contact-force of the leg of a walking robot and proposes a solution to a shortcoming of the previous study. This shortcoming was the deteriorating performance when estimating the contact-force whenever the rotation of each joint was reversed. It occurred because the friction-torque of each joint was not considered. In order to solve this problem, a friction-torque model for a robot leg was developed based on repetitive experimentation and used to improve the contact-force estimation performance. We verified the performance of the proposed method experimentally.

• Journal of Biosystems Engineering
• /
• 제39권1호
• /
• pp.1-10
• /
• 2014

Purpose: This research was conducted to evaluate feasibility of a crank-type walking cultivators for weeding in furrowed upland. Methods: A walking cultivator developed by RDA was selected and evaluated with its working speed (S), cultivation depth (CD) and weeding performance (WP). The evaluation was performed in upland field on July and August, 2012. Also kinematic analysis of the machine was performed to draw out design improvements. Results: S in flat, uphill and downhill were about 0.11 m $s^{-1}$, 0.11 m $s^{-1}$, and 0.13 m $s^{-1}$ respectively. It was found that S had a low relevance with user conditions. The CD was 35 ~ 40 mm which was satisfied with the RDA guide for weeding machine. A wide variation was observed in values of WP depending on the growth stages of weeds and field conditions. The cultivator showed low performance in eliminating the well-grown weeds. Kinematic simulation revealed that high forward speed caused a high ratio of un-weeded area. Conclusions: The weeding performance of the cultivator was satisfactory for weeds in early growth stage but it showed difficulties in handling on up-slope and in entering up-land. Specifically, the weight of the cultivator was judged as overweight for female workers. The crank-hoe type cultivator was judged as unsuitable for small walking type machine due to weight of the four-bar linkage system. Kinematic analysis revealed that the ratio of crank speed to the ground speed must be 850 rpm s $m^{-1}$ (255 rpm based on 0.3 m $s^{-1}$) or greater to avoid uncultivated area. Selection of forward speed is a decisive factor in designing the weeding cultivator.

• 대한정형도수물리치료학회지
• /
• 제18권2호
• /
• pp.67-75
• /
• 2012

Background: Hemiplegic patients have the problems of the balance and weight shifting to the affected leg in walking. The aim of this study was to investigate the effect of unilateral stepping exercise combined with auditory feedback on balance and walking ability of the hemiplegic patients. Methods: Thirty hemiplegic patients were allocated in study group (n=15) or control group (n=15). General exercise and weight supporting exercise were conducted for the control group, and general exercises and unilateral stepping exercise combined with auditory feedback were conducted for the study group. Exercise were conducted three times a week for six weeks. Balance ability was measured by Berg Balance Scale (BBS), postural assessment scale for stroke (PASS), and performance-oriented mobility assessment (POMA). Walking ability was measured by time up and go test (TUG), 10m walk test (10mWT), and six minutes walk test (6MWT). Results: Balance and walking ability were significant increased in both group (p<.05). Balance and walking ability of the study group were more increased than that of the control group (p<.05). Conclusions: Unilateral stepping exercise combined with auditory feedback is more effective than weight supporting exercise to increase on balance and walking ability for the hemiplegic patients.

• 전기학회논문지
• /
• 제64권8호
• /
• pp.1231-1239
• /
• 2015

We developed a robot that has four limbs, each of which has the same kinematic structure and has 6 degrees of freedom. The robot is 600mm high and weighs 4.3kg. The robot can perform walking and manipulating task by using the four limbs selectively. The robot has three walking patterns. The first one is biped walking, which uses two rear limbs as legs and two front limbs as arms. The second one is biped walking with supporting arms, which is basically biped walking but uses two arms as supporting legs for increasing stability of the robot. The last one is quadruped walking, which uses all the four limbs as legs. When a task for the robot is given, the robot approaches the task point by selecting an appropriate walking pattern among three walking patterns and performs the task. The robot has many degrees of freedom and is a redundant system for a three dimensional task. We propose a redundancy resolution method, in which the robot’s translational move to the task point is modeled as a prismatic joint and optimal solutions are obtained by optimizing some performance criteria. Several simulations are performed for the validity of the proposed method.

• 전기학회논문지
• /
• 제67권5호
• /
• pp.663-668
• /
• 2018

A combined CPG (Central Pattern Generator) based foot trajectory and GA (Genetic Algorithm) based joint compensation method is presented for adaptive humanoid walking. In order to increase an adaptability of humanoid walking for rough terrains, the experiment for rolling terrains are introduced. The CPG based foot trajectory method has been successfully applied to basic slops and variable slops, but has a limitation for the rolling terrains. The experiments are conducted in an ODE based Webots simulation environment using humanoid robot Nao to verify a stability of walking for various rolling terrains. The proposed method is compared to the previous CPG foot trajectory technique and shows better performance especially for the cascade rolling terrains.

• EDISON SW 활용 경진대회 논문집
• /
• 제5회(2016년)
• /
• pp.424-428
• /
• 2016

This paper presents the kinematics of a walking robot leg based on Jansen mechanism. By using simple mathematics, all trajectories of walking robot leg links can be calculated. A foot point trajectory is used to evaluate the performance of a walking robot leg. Trial and Error method is used to find a best combination of link lengths under certain restrictions. All simulations are performed by Matlab. Ground score, drag score, step size, foot lift, instant speed, and average speed of foot point trajectories are used for selecting the best one.

• 농촌의학ㆍ지역보건
• /
• 제46권2호
• /
• pp.98-108
• /
• 2021

본 연구는 지역사회 걷기와 관련된 공공사업의 현황을 확인하고 정책적 시사점을 모색하기 위해 한국의 법령, 중앙정부부처의 백서, 그리고 우수사례로서 서울시 사업을 고찰하였다. 지역사회 걷기와 관련된 법령에는 물리적 환경 개선을 중심으로 제도적 근거가 마련되어 있고, 관련 법령을 소관하는 중앙정부부처에서만 걷기를 목적으로 한 다수의 사업을 장기적으로 추진하고 있어 지역사회 걷기증진을 위한 포괄적인 법적 토대를 구축해야 한다. 서울시는 지역사회 걷기와 관련된 유관부서의 개입이 다각적으로 이루어지고 있지만, 부서를 아우르고 연계, 조정할 수 있는 거버넌스 체계의 개발과 걷기 친숙한 사회문화적 여건을 조성하기 위한 보다 구체적이고 체계화된 노력이 요구된다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.1780-1783
• /
• 2005

In this paper ZMP was considered in order to get a walking stability, so the gait in the stable domain was realized through putting the stability margin in the sole domain of a foot. It is assumed that the robot's legs have 12 joints to operate a open-loop drive and there was no external disturbance under walking phases, additionally, the robot is walking on the flat plane. It was observed that the robot's walking trajectory, locus of COM and ZMP after imposing the motion to each joint. For realizing the simulation considering ZMP and movement of mass center, it was checked if it is stable for the constraint robot model to walk in stability and the feasibility was estimated about its dynamic gait. Eventually it was shown that a constraint gait algorithm is able to realize. To verify the proper walking process, ZMP(Zero Moment Point) theory is applied and the simulation has been done by ADAMS.

• PNF and Movement
• /
• 제14권2호
• /
• 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.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.15-18
• /
• 2000

We developed a human-sized BWR(biped walking robot) driven by a new actuator based on the ball screw which has high strength and high gear ratio. The robot overcomes the limit of the driving torque of conventional BWRs. Each leg of the robot is composed of three pitch joints and one roll joint. In all, a 10 degree-of-freedom robot with two balancing joints was developed. The BWR was developed to walk autonomously such that it is actuated by small torque motors and is boarded with DC battery and controllers. In the performance test, the BWR performed nice motions of sitting-up and sitting-down. Through the test, we could find capability of high performance in biped-walking.