• Korean Journal of Applied Biomechanics
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• 제25권4호
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• pp.483-488
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• 2015

Objective : The purposes of this study was to analyze the locomotive movement of forelimbs according to changes in velocities in the quadruped cadence of horses. Methods : Horses selected as subjects consisted of Jeju pony horses (heights of withers: $1.23{\pm}0.51$). Two camcorders (HDR-HC7/HDV 1080i, Sony Corp, Japan) were used to capture the movement of the horses' forelimbs at a rate of 60 frames/sec. Additionally, raw data was collected from Kwon3D XP motion analysis package ver 4.0 program (Visol, Korea) with DARTFISH (DFKREA., Korea) video software solution. The variables analyzed consisted of 1 step lengths, 1 stride lengths, stance time, swing time, 1 stride time, velocity while walking, and trot of the horses. A two-way ANOVA and paired t-test of the variables by velocity and phase were treated at .05 level of significant difference, statistically. Results : The time elapsed of walk(stance: 0.63 sec[63.86%], swing: 0.35 sec[36.14%], 1 stride time: 0.99 sec respectively) showed significant difference with more delay than that of trot(stance: 0.29 sec[45.73%], swing: 0.34 sec[54.27% ], 1 stride time: 0.63 sec respectively), and also showed significant difference at trot in interaction (stance time>tort swing>walk swing>walk stance). The 1 step lengths and stride lengths in trot showed significant difference with longer than that of walk. Velocity of Trot showed significant difference statistically with higher than that of walk Conclusion : The horses' velocity during 1 step lengths and 1 stride lengths showed a proportional relationship, but the correlation between the horses' velocity and stance time showed a negative relationship during the quadruped cadence.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1926-1930
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• 2004

We suggest a turning gait planning of a quadruped walking robot with an articulated spine. Robot developer has tried to implement a gait more similar to that of natural animals with high stability margin. Therefore, so many types of walking robot with reasonable gait have been developed. But there is a big difference with a natural animal walking motion. A key point is the fact that natural animals use their waist-oint(articulated spine) to walk. For example, a crocodile which has short legs relative to a long body uses their waist to walk more quickly and to turn more effectively. The other animals such as tiger, dog and so forth, also use their waist. Therefore, this paper proposes discontinuous turning gait planning for a newly modeled quadruped walking robot with an articulated spine which connects the front and rear parts of the body. Turning gait is very important as same as straight gait. All animals need a turning gait to avoid obstacle or to change walking direction. Turning gait has mainly two types of gaits; circular gait and spinning gait. We apply articulated spine to above two gaits, which shows the majority of an articulated spine more effectively. Firstly, we describe a kinematic relation of a waist-joint, the hip, and the center of gravity of body, and then apply a spinning gait. Next, we apply a waist-joint to a circular gait. We compare a gait stability margin with that of a conventional single rigid body walking robot. Finally, we show the validity of a proposed gait with simulation.

• The Journal of Korean Physical Therapy
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• 제28권2호
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• pp.112-118
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• 2016

Purpose: This study examined thickness changes in abdominal muscles according to difficulty level of core stabilization exercise in healthy subjects. Methods: Thirty healthy subjects (age range: 21-30 years) volunteered under three conditions. In the first condition, the subjects performed an abdominal draw-in maneuver (ADIM). In the second condition, they performed the ADIM during quadruped exercise using a suspension device without extending their lower limbs. In the third condition, the subjects performed the ADIM during quadruped exercise using a suspension device while extending both lower limbs. The changes in thickness of transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles were measured by ultrasonography (US) imaging during the three experimental conditions, and US was used to measure the improvement ratio of muscle thickness at rest. The interventions were conducted over three trials in each condition, and measurements were performed on each subject by one examiner. Results: Our results showed a significantly greater increase in the muscle thickness of TrA and IO muscles after performance of quadruped exercise using a suspension device without knee extension (p<0.05) compared to the other conditions. The results also showed a significantly greater increase in the thickness changes of EO muscle in those who performed the ADIM during quadruped exercise using a suspension device with knee extension (p<0.05) compared with the ADIM only. Conclusion: These findings demonstrated positive evidence that a low-level core stabilization exercise could improve thickness of abdominal muscles.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제16권6호
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• pp.1235-1241
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• 2012

In this paper, each driving motor for leg joints on a robot is controlled by estimating the direction of the legs measuring each joint angle and attitude angle of robot. We used quadruped working robot named TITAN-VIII in order to carry out this experimental study. 4 load cells are installed under the bottom of 4 legs to measure the pressed force on each leg while it's walking. The walking experiments of the robot were performed in 8 different conditions combined with duty factor, the length of a stride, the trajectory height of the foot and walking period of robot. The validity of attitude control for quadruped walking robot is evaluated by comparing the pressed force on a leg and the power consumption of joint driving motor. As a result, it was confirmed that the slip-condition of which the foot leave the ground late at the beginning of new period of the robot during walking process, which means the attitude control of the robot during walking process wasn't perfect only by measuring joint and attitude angle for estimating the direction of the foot.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.551-554
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• 2001

A necessity of remote control robots or various searching robots etc. that accomplish works given instead of human under long distance and extreme environment such as volcano, universe, deep-sea exploration and nuclear power plant etc. is increasing, and so the development and the research regarding these mobile robots are actively progressing. The wheel mobile robot or the track mobile robot have a sufficient energy efficiency under this en, but also have a lot of limits to accomplish works given which are caused from the restriction of mobile ability. Therefore, recently many researches for the walking robot with superior mobility and energy efficiency on the terrain, which is uneven or where obstacles, inclination and stairways exist, have been doing. The research for these walking robots is separated into fields of mechanism and control system, gait research, circumference environment and system condition recognition etc. greatly. It is a research field that the gait research among these is the centralist in actual implementation of walking robot unlike different mobile robots. A research field for gait of walking robot is classified into two parts according to the nature of the stability and the walking speed, static gait or dynamic gait. While the speed of a static gait is lower than that of a dynamic gait, a static gait which moves the robot to maintain a static stability guarantees a superior stability relatively. A dynamic gait, which make the robot walk controlling the instability caused by the gravity during the two leg supporting period and so maintaining the stability of the robot body spontaneously, is suitable for high speed walking but has a relatively low stability and a difficulty in implementation compared with a static gait. The quadruped walking robot has a strong point that can embody these gaits together. In this research, we will develope an autonomous quadruped robot with an asaptibility to the environment by selectry appropriate gait, element such as duty factor, stride, trajectory, etc.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제17권4호
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• pp.781-788
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• 2013

In this paper, we introduce a quadruped robot-based alarm system for monitoring the emergency situation due to falling in the elderly. Quadruped robot includes the FPGA Board(Field Programmable Gate Array) applying a red-color tracking algorithm. To detect a falling of the elderly, a sensor node is worn on chest and accelerations and angular velocities measured by the sensor node are transferred to quadruped robot, and then the emergency signal is transmitted to manager if a fall is detected. Manager controls the robot and then he judges the situation by monitoring the real-time images transmitted from the robot. If emergency situation is decided by the manager, he calls 119. When the fall detection system using only sensor nodes is used, sensitivity of 100% and specificity of 98.98% were measured. Using the combination of the fall detection system and portable camera (robot), the emergency situation was detected to 100 %.

• Journal of the Institute of Convergence Signal Processing
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• 제13권2호
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• pp.113-118
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• 2012

Most of the existing multiped walking robots are biomimetic, i.e. they are designed to have the shapes of living things such as animals or insects. Even though those robots are familiar to us, they have some drawbacks in the view point of walking efficiency such as stability and walking speed. In this paper, we introduce a quadruped walking robot that can perform fast and stable walking by virtue of its distinctive leg positions. The proposed quadruped robot has a foreleg, a hindleg, a left leg, and a right leg. In the conventional robots, dynamic walking is needed to increase walking speed. Dynamic walking is difficult to be accomplished and is apt to be unstable. The proposed robot can move its legs in a manner that its center of gravity is always laid in the supporting polygon, so it can perform fast and stable walking without dynamic walking.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.645-650
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• 2003

Legged robots can avoid an obstacle by crawling-over or striding, according to the obstacle’s nature and the current state of the robot. Thus, it can be observed that the mobility efficiency to reach a destination is improved by such action. Moreover, if robots have many legs like 4-legged or 6-legged types, then the robot movement range is affected by the order of swing leg. In this paper, the avoidance action of a quadruped robot is generated by a neural network (NN) whose inputs are information on the position of the destination, the obstacle configuration and the robot's self-state. To realize a free gait in static walking, the order of swing leg is determined using an another NN whose inputs are the amount of movements and the robot’s self-state. The design parameter of the latter NN is adjusted by using genetic algorithm (GA).

• Transactions of the Korean Society of Mechanical Engineers A
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• 제24권1호
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• pp.118-123
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• 2000

Most quadruped walking robots under current research are individually controlling every joint ic make them step or walk according to an integrated strategy. Such methods are characterized by at least one pair of an actuator and a sensor installed per each 'oint so that the robots weigh execssively and move inefficiently in terms of energy expenditure. In addition, the task of controlling all the joints simultaneously is quite complex and prone to destabilize the robot motion. These respects keep the existing walking robots away from realistic applications such as transportation even if they have potentially, outstanding adaptability to swamps or uneven terrains as opposed to wheeled vehicles. So, this paper presents a new conceptual quadruped robot developed to walk and steer only with a minimal number of actuators owing to a closed-chain mechanism. To prove its actual performance including the adaptability to various types of terrains. experiments are done with the mammal-type prototype. And. it is also shown that the same concept can be easily extended to carry out different gait forms. for instance, that of spiders only with minor modifications.

• Journal of the Korean Institute of Intelligent Systems
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• 제25권3호
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• pp.236-241
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• 2015

This paper presents a study on transformable multiple quadruped robots by docking between robots and waist joints. This robot is able to go on a variety of angles because of mecanum wheels. It is also a hybrid design which allows robot use legs to overcome obstacles on complex terrains and wheels to move on flat ground. The robot is applied kinematics of mecanum wheels and walking, and its walking is based on specific patterns. Docking module is located in front and backside of robot, docking algorithm is suggested and fulfilled for docking between 2 robots. A waist joint is at the center of robot body for transformation and after docking and transformation, robot can activate new functions that carry something.