• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.395-402
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• 2015

In this paper, we propose an efficient gait trajectory generation method for the static stair climbing of a quadruped robot with mechanism of insectile legs, which has no collision with staris. First, we derive the kinematic and inverse models of a quadruped robot using the algebraic and geometrical methods, respectively. In the proposed method, we generate the stair locomotion trajectory of a sine wave after lifting a leg from the start position, and then determine the coefficient of the generated trajectory to avoid the collision with stairs. In addition, we make the gait sequence for the stable stair locomotion. Finally, we verify the effectiveness and applicability of the proposed stair locomotion method through computer simulations.

• Journal of Internet of Things and Convergence
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• v.6 no.3
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• pp.59-65
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• 2020

The Internet of Things (IoT) era, in which all items used in daily life are equipped with a network connection function, and they are closely linked to increase the convenience of life and work, has opened wide. Robots also need to develop according to the IoT environment. A use of new type of evolved fuzzy machine (EFM) for generating legged robot trajectory in IoT enviornmentms is discussed in this paper. Fuzzy system has been widely used for describing nonlinear systems. In fuzzy system, determination of antecedent and consequent structures of fuzzy model has been one of the most important problems. EFM is described which carries out evolving antecedent and consequent structure of fuzzy system for legged robot. To generate the robot trajectory, parameters of each structure in the fuzzy system are tuned automatically by the EFM. The results demonstrate the performance of the proposed approach for the legged robot.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.3 s.303
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• pp.1-10
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• 2005

This paper proposes a novel fault-tolerant gait planning of a hexapod robot considering kinematic constraints. 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. It is shown that the conventional fault-tolerant gait of a hexapod robot for forward walking on even terrain may be fallen into deadlock, depending on the configuration of the failed leg. For coping with such deadlock situation, a novel fault-tolerant gait planning is proposed. It can avoid deadlock by adjusting the position of the foot trajectory, and has the same leg sequence and stride length as those of the conventional fault-tolerant gait. To demonstrate the superiority of the proposed scheme, a case study is presented in which a hexapod robot, having walked over even terrain before a locked joint failure, could avoid deadlock and continue its walking by the proposed fault-tolerant gait planning.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.9
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• pp.1039-1048
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• 2015

In this paper, we propose an efficient stair locomotion method for a quadruped robot with mechanism of insectile legs using genetic algorithm(GA). In the proposed method, we first define the factors and the reachable region for the stair locomotion. In addition, we set the gene and the fitness function for GA and generate the gait trajectory by searching the landing position of a quadruped robot, which has the minimun distance of movement and the optimal energy stability margin(ESM). Finally, we verify the effectiveness and superiority of the proposed stair locomotion method through the computer simulations.

• Annual Conference of KIPS
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• 2022.05a
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• pp.233-235
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• 2022

서비스 제공자는 사용자의 위치를 기반으로 용이한 정보를 제공한다. 과거에는 사용자가 질의를 요청하는 순간(snapshot)에 대해 사용자의 위치를 보호하는 기법들이 주를 이루었다면 최근에는 연속적인 질의를 요청할 때 사용자의 위치를 보호하는 기법들이 연구되고 있다. 그러나 연속적인 질의처리는 시간별로 요청되는 질의의 묶음으로서 영역을 보호할 수 있으나 영역을 연결할 경우 사용자의 궤적이 노출되는 문제가 발생할 수 있다. 가장 최근 연속적인 질의에서 이동 궤적을 보호하는 k-ATY가 제안되었지만 사용자와 동일한 이동 속도와 일정한 방향을 기준으로 더미를 생성하기 때문에 장애물(다리, 건물 등)이 있을 경우 더미의 위치가 노출될 수 있다. 본 논문에서는 이러한 문제점을 개선하기 위하여 장애물을 고려한 k-oATY 기법을 제안하고 기존기법과 비교한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.2
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• pp.170-177
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• 2019

In this paper, three theories for improving the stability of quadruped robot are presented. First, the Minimum-Jerk Trajectory is used to optimize the leg trajectory. Second, we compare the newly proposed sine wave and the conventional LSM in this paper based on the Jerk value. Third, we calculate the optimum stride of the sway through repetitive robot simulation using ADAMS-MATLAB cosimulation. Through the above process, the improvement of the robot walking is compared with the existing theory. First, the average gradient of the point where the leg trajectory changes rapidly was reduced from at least 1.2 to 2.9 by using the Minimum-Jerk targetory for the movement of the body and the end of the leg during the first walk, thereby increasing the walking stability. Second, the average Jerk was reduced by 0.019 on the Z-axis, 0.457 on the X-axis, and 0.02, 3D on the Y-axis by 0.479 using the Sin wave type sways presented in this paper, rather than the LSM(Longitude Stability Margin) method. Third, the length of the optimal stride for walking at least the Jerk value was derived from the above analysis, and the 20cm width length was the most stable.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.319-327
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• 2019

The muscle activity and balance ability of the acute stroke patient has been checked by the functional electrical stimulation using biofeedback fusion postural control training in this study. Functional electrical stimulation using biofeedback fusion postural control training have been implemented on 15 trainees and general biofeedback fusion postural control training have been implemented on another 15 trainees for 30 minutes at 5 times per week during 8 weeks, and vastus lateralis, vastus medialis, rectus femoris and biceps femoris have been measured using the biceps femoris to evaluate the muscle activity of the lower extremity. The moving surface area, whole path length and limited of stability have been measured using biorecue to measure the balance ability. There was statistically meaningful difference on the vastus lateralis, vastus medialis, rectus femoris and biceps femoris in the muscle activity of the lower extremity and there was statistically meaningful difference on surface area, whole path length and limited of stability in the balancing ability. Based on above, it is realized that the functional electrical stimulation using biofeedback fusion postural control training is more effective than the general biofeedback fusion postural control training on the improvement of the muscle activity of the lower extremity and the balance ability.

• Journal of Internet of Things and Convergence
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• v.4 no.2
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• pp.7-11
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• 2018

In this paper, kinematic based walking pattern generation of biped walking robot is reviewed. Biped walking robot should be consisted of 6 Degree of Freedom(DOF) for each leg to walk properly in 3 dimensional circumstance. In this paper, simple structure of biped robot is depicted for walking pattern firstly. After fixing path of ankle of the robot, angle joints are coming from kinematic equatioins. Coordination of joints of a robot was set for dynamic analysis also. So walking pattern of a robot will be designed using dynamic equations of coordination of joint angles. Finally, setting of ankle of robot and pattern generation are key procedures of the robot walking.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.135-143
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• 2003

This paper presents the impact minimization of a biped robot by using genetic algorithm. In case we want to accomplish the designed plan under the special environments, a robot will be required to have walking capability and patterns with legs, which are in a similar manner as the gaits of insects, dogs and human beings. In order to walk more effectively, studies of mobile robot movement are needed. To generate optimal motion for a biped robot, we employ genetic algorithm. Genetic algorithm is searching for technology that can look for solution from the whole district, and it is possible to search optimal solution from a fitness function that needs not to solve differential equation. In this paper, we generate trajectories of gait and trunk motion by using genetic algorithm. Using genetic algorithm not only on gait trajectory but also on trunk motion trajectory, we can obtain the smoothly stable motion of robot that has the least impact during the walk. All of the suggested motions of biped robot are investigated by simulations and verified through the real implementation.

• Journal of Advanced Navigation Technology
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• v.24 no.5
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• pp.444-449
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• 2020

I proposed small ambulatory robot actuators using piezoelectric benders. In order to make the motion of the biomimetic robot legs similar to the movements of the cockroaches or similar insects, two pairs of legs in the diagonal direction in the four leg structures are required to make the same movement. And elliptical displacement is realized by taking into account horizontal and vertical displacement of multimode oscillations and driving them by electrical signals with differences step by step, for example of 90° the T-shaped robot actuator showed wide range of speed (From 2 mm/sec. up to 266 mm/sec.) and ability of transportation (up to 10 g with 50 mm/s). Locomotive performance of the robot was competitive to the preceding robots, and moreover, the modular type actuators of a segmented myriapods robot could be added and removed for different tasks or performances.