• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.103-108
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• 1988

A walking robot must have the ability to change the body direction in order to avoid the obstacles. In this paper, we develop a gait control algorithm that can maintain the stable movement of the robot for three different modes of changing directions. The algorithm makes it possible for the robot to have the larger gait stability margin than the threshold value by the method of changing the body speed.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.5
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• pp.617-623
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• 2012

In this paper, we propose a gait generation method for a quadruped robot to walk efficiently on the slope, which uses the waist joint of a quadruped robot. We derive the kinematic model of a quadruped robot with waist joint using the Denavit-Hartenberg representation method and the algebraic method. In addition, the gaits are generated based on the wave gait. In the proposed gait generation method, first in order to alleviate the mechanical restriction and the reduction of the stride, we determine the appropriate waist joint angle according to the slope degree, and then decide the location of the tiptoe of a quadruped robot by exploring the workspace. Finally, through computer simulations, we verify the effectiveness and applicability of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.11
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• pp.886-896
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• 1991

In this paper a new turning gait is proposed for a quadruped walking robot. The proposed scheme makes it possible to control the translation and orientation of the walking robot simultaneously. At first the feasible leg sequences which can guarantee a positive longitudinal gait stability margin for each direction of movement are found. A method for finding the lifting time of each leg of a feasible leg sequince and selecting an optimal gait among feasible gaits is then suggested. The proposed gait can be appled to control the posture of walking robots and to generate an optimal gait for a desired movement of translation and rotation of the walking robot systematically.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1780-1783
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• 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.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.843-848
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• 2007

Quadruped robot is very useful mechanism for a various area. Recently, home entertainment and military robots adapted quadruped platform and useful function have been introduced. Our goal is the development of quadruped robot locomotion for any type of ground included to sloping one and irregular terrain. This paper, as a first step, deals with design and construction of quadruped robot walking on the flat ground. The most important factor of quadruped robot is stability of locomotion. At first, we introduce the developed quadruped robot based on dynamic simulation and experimental study of general gait algorithm. Finally, propose unique locomotion proper to our mechanism. Future work of this study is the performance test and analysis on the ground of various conditions and proposes the improved mechanism and gait algorithm.

• 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.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.3
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• pp.305-311
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• 2012

In this paper, we propose a gait generation method for quadruped robots using the xz-axis sway of the quadruped robot, which minimizes the shake of the quadruped robot and maximizes the stability margin. In the proposed method, the gait is generated based on wave gaits and the stability analysis uses the body tilt information of the quadruped robot according to the leg's height of leg. In addition, to reduce the impact on the body caused by the z-axis sway while walking, the proposed method generates the smooth walking movement trajectory with less impact by using Fourier series. Finally, to verify the applicability and effectiveness of the proposed method, we carry out the computer simulations and the real walking experiments with the implemented quadruped robot.

• 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.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.131-136
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• 1988

In this paper we describe a motion control algorithm for a 4-legged robot over slopped terrain and steps. The new concept of the mechanically constrained angle has been introduced and the algorithm has been developed based on the relationship between the gait stability margin and the slope angle. The result then has been extended to the case where the robot walks over steps.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.457-463
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• 2009

In this paper, a novel foot force distribution algorithm for hexapod walking robots is presented. The considered hexapod robot has fault-tolerant tripod gaits with a failed leg in locked-joint failure. The principle of the proposed algorithm is to minimize the slippage of the leg that determines the stability margin of the fault-tolerant gaits. The fault-tolerant tripod gait has a drawback that it has less stability margin than normal gaits. Considering this drawback, we use the feature that there are always three supporting legs, and by incorporating the theory of Zero-Interaction Force, we calculate the foot forces analytically without resort to any optimization technique. In a case study, the proposed algorithm is compared with a conventional foot force distribution method and its applicability is demonstrated.