• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3101-3104
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• 2013

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.536-543
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• 2013

In this paper, we propose a new type of hexapod robot that can walk fast. Most of the conventional hexapod robots are either rectangular type of hexagonal type. Those robots have drawbacks in the speed and stability of walking. The proposed robot has six legs, one fore leg, one hind leg, two left legs and two right legs. The proposed robot forms relatively wide supporting polygons along the walking direction, so it can walk very fast stably. We implemented the proposed hexapod robot and showed the feasibility of the robot by 3+3 walking experiment and 2+4 walking experiment.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.12
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• pp.689-695
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• 2003

Fault-tolerance is an important design criterion for robotic systems operating in hazardous or remote environments. This paper addresses the issue of tolerating a locked joint failure in gait planning for hexapod walking machines which have symmetric structures and legs in the form of an articulated arm with three revolute joints. A locked joint failure is one for which a joint cannot move and is locked in place. If a failed joint is locked, the workspace of the resulting leg is constrained, but hexapod walking machines have the ability to continue static walking. A strategy of fault-tolerant tripod gait is proposed and, as a specific form, a periodic tripod gait is presented in which hexapod walking machines have the maximum stride length after a locked failure. The adjustment procedure from a normal gait to the proposed fault-tolerant gait is shown to demonstrate the applicability of the proposed scheme.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.36-48
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• 2010

This paper is concerned with stereo vision-based approach to detect obstacles and to generate the path of destination from the start. The hexapod robot in the experiment is cable of walking by legs and driving by wheels simultaneously. The hexapod robot operates under the driving mode normally, and it changes driving mode to walking mode to overcome obstacles using its legs. Disparity map, which is the correlation between two images taken by stereo camera, is employed for calculation of the distance between the robot and obstacles. When the obstacles information is extracted from the disparity map, the potential field algorithm is applied to create the obstacle-avoidance path. Simulator, based on OpenGL, is developed to generate the graphical path, and the experimental results are shown for the verification of the proposed algorithm.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.3
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• pp.131-140
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• 2005

Fault-tolerant gait generation of a hexapod robot with crab walking is proposed. The considered fault is a locked joint failure, which prevents a joint of a leg from moving and makes it locked in a known position. Due to the reduced workspace of a failed leg, fault-tolerant crab walking has a limitation in the range of heading direction. In this paper, an accessible range of the crab angle is derived for a given configuration of the failed leg and, based on the principles of fault-tolerant gait planning, periodic crab gaits are proposed in which a hexapod robot realizes crab walking after a locked joint failure, having a reasonable stride length and stability margin. The proposed crab walking is then applied to path planning on uneven terrain with positive obstacles. i.e., protruded obstacles which legged robots cannot cross over but have to take a roundabout route to avoid. The robot trajectory should be generated such that the crab angle does not exceed the restricted range caused by a locked joint failure.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.8
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• pp.585-593
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• 2004

Fault-tolerant gait planning in legged locomotion is to design gaits with which legged robots can maintain static stability and motion continuity against a failure in a leg. For planning a robust and deadlock-free fault-tolerant gait, kinematic constraints caused by a failed leg should be closely examined with respect to remaining mobility of the leg. In this paper, based on the authors's previous results, deadlock avoidance scheme for fault-tolerant gait planning is proposed for a hexapod robot walking over even terrain. The considered fault is a locked joint failure, which prevents a joint of a leg from moving and makes it locked in a known position. It is shown that for guaranteeing the existence of the previously proposed fault-tolerant tripod gait of a hexapod robot, the configuration of the failed leg must be within a range of kinematic constraints. Then, for coping with failure situations where the existence condition is not satisfied, the previous fault-tolerant tripod gait is improved by including the adjustment of the foot trajectory. The foot trajectory adjustment procedure is analytically derived to show that it can help the fault-tolerant gait avoid deadlock resulting from the kinematic constraint and does not make any harmful effect on gait mobility. The post-failure walking problem of a hexapod robot with the normal tripod gait is addressed as a case study to show the effectiveness of the proposed scheme.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.2
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• pp.124-129
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• 2013

Hexapod walking robots are superior to biped or quadruped ones in terms of walking stability. Therefore hexapod robots have the advantage in performing intelligent tasks based on walking stability. In this paper, we propose a hexapod robot that has one fore leg, one hind leg, two left legs, and two right legs and can perform various intelligent tasks. We build the robot by using 26 motors and implement a controller which consists of a host PC, a DSP main controller, an AVR auxiliary controller, and smart phone/pad. We show by several experiments that the implemented robot can perform various intelligent tasks such as uneven surface walking, tracking and kicking a ball, remote control and 3D monitoring by using data obtained from stereo camera, infrared sensors, ultra sound sensors, and contact sensors.

• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.916-919
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• 2004

In this paper, we proposed a new method of pre-operative planning for tibial deformity correction using double hexapod external fixator in pseudoacondroplasia. The 3-D computer graphic model of deformed tibia was reconstructed from 3 mm sliced CT data, and CAD model of double hexapod external fixator was developed. The fixator was composed of 170 mm diameter of three rings and 90 mm of twelve struts. The bone deformities and the osteotomy lines for double osteotomy were measured using X-rays, and the necessary joint values to correct the given deformities were obtained by inverse kinematics analysis. The computer graphic simulation was performed to visualize the deformity correction process and evaluate the analysis result. By examining the pre-op and post-op X-rays, the simulation result was in good agreement with the clinical outcomes.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.202-204
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• 2006

In this paper, the detection scheme of the spatial coordinates based on stereo camera for a Transformation algorithm of an Leg-wheel Hexapod Robot is proposed. Robot designed as can have advantages that do transfer possibility fast mobility in flat topography and uneven topography through walk that use wheel drive. In the proposed system, using the disparity data obtained from the left and right images captured by the stereo camera system and the perspective transformation between a 3-D scene and an image plane, depth information can be detected. Robot uses construed environmental data and transformation algorithm, decide wheel drive and leg waik, and can calculate width of street and regulate width of robot.