• 전기학회논문지
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• 제58권2호
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• pp.382-390
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• 2009

This paper newly proposes a modular type dynamic encoding algorithm for searches (DEAS) which partitions the whole parameters into several modules and carries out exhaustive DEAS for each module. uDEAS is used to measure parameter sensitivities to the cost function, and the variables whose sensitivities are similar are grouped to make a module. The proposed optimization method is applied to optimal trajectory generation for biped walking of a humanoid. and the optimization result is compared with those of the former versions of DEAS.

• 전기학회논문지
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• 제63권5호
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• pp.683-689
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• 2014

The paper introduces dynamic generation technique of foot trajectories for humanoid robots using CPG(Central Pattern Generator) and proposes adaptive walking method for slope terrains combining a feedback network. The proposed CPG based technique generates the trajectory of foot in the Cartesian coordinates system and it can change the step length adaptively according to the feedback information. To cope with variable slope terrains, the sensory feedback network in the CPG are designed using the geometry relationship between foot position and body center position such that humanoid robot can maintain its stability. To demonstrate the effectiveness of the proposed approach, the experiments on humanoid robot Nao are executed in the Webot simulation. The performance and motion features of the CPG based approach are compared and analyzed focusing on the adaptability in slope terrains.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.513-515
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• 2016

There are various walking devices based on Theo Jansen mechanism. And these systems controlled by complicate equations. So we decided to optimize the design of walking device with two points of view. The device is required to ensure stability while maintaining the high speed. To simplify the control system, we applied trigonometric ratio with ideal Jansen trajectory. As a result, we were able to draw the connection between height of barrier and Ground Length (GL). Also we could change traveling distance and Ground Angle Coefficient (GAC) by shifting the position of the joints. Through controlling these parameter, we can analyze stability and speed of the device. Ultimately, we develop the device that can walk more efficiently by the optimization process.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2405-2407
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• 2003

This study deals with the gait optimization of via points on biped robot. ZMP(Zero Moment Point) is most important index in a biped robot's dynamic walking stability. To stable walking of a biped robot, legs's trajectory and a desired ZMP trajectory is required, balancing weight's movement is solved by FDM(Finite Difference Method). In this study, optimal index is defined to dynamically static walking of a biped robot, and optimization of via points is applied by GA(Genetic Algorithm).

• 대한임베디드공학회논문지
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• 제3권2호
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• pp.82-90
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• 2008

In this paper, we introduce a biped walking robot which can do static walking with 22 degree-of-freedoms. The developed biped walking robot is 480mm tall and 2500g, and is constructed by 22 RC servo motors. Before making an active algorithm, we generate the motions of robot with a motion simulator developed using C language. The two dimensional simulator is based on the inverse kinematics and D-H transform. The simulator implements various motions as we input the ankle's trajectory. Also the simulator is developed by applying the principle of inverted pendulum to acquisite the center of gravity. As we use this simulator, we can get the best appropriate angle of ankle or pelvic when the robot lifts up its one side leg during the walking. We implement the walking motions which is based on the data(angle) getting from both of simulators. The robot can be controlled by text shaped command through RF signal of wireless modem which is connected with laptop computer by serial cable.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.552-554
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• 1998

This paper deals with the gait generation of IWR-III using a kick action to have a walking pattern like human. For this, trajectory planning with the consideration of kick action is done in each walking step, and the coordinate transformation is done for simplifying the kinematics. Balancing motion is analyzed by FDM during the walking, By combining 4-types of pre-defined steps, multi-step walking is done. Using numerical simulator, dynamic analysis, ZMP analysis and system stability is confirmed. Walking motion is visualized by 3D- graphic simulator. As a result, trunk ahead motion effect and impactless smooth walking is implemented by experiment. Finally walking with kick action is implemented the IWR-III system.

• 제어로봇시스템학회논문지
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• 제14권7호
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• pp.672-678
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• 2008

This paper proposes a new rehabilitation robot with upper and lower limb connections for gait training. As humans change a walking speed, their nervous systems adapt muscle activation patterns to modify arm swing for the appropriate frequency. By analyzing this property, we can find a relation between arm swinging and lower limb motions. Thus, the lower limb motion can be controlled by the arm swing for walking speed adaptation according to a patent's intension. This paper deals with the design aspects of the suggested gait rehabilitation robot, including a trajectory planning and a control strategy. The suggested robot is mainly composed of upper limb and lower limb devices, a body support system. The lower limb device consists of a slider device and two 2-dof footpads to allow walking training at uneven and various terrains. The upper limb device consists of an arm swing handle and switches to use as a user input device for walking. The body support system will partially support a patient's weight to allow the upper limb motions. Finally, we showed simulation results for the designed trajectory and controller using a dynamic simulation tool.

• 제어로봇시스템학회논문지
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• 제20권9호
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• pp.936-941
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• 2014

Walking mechanisms are very important for legged robots to ensure their stable locomotion. In this research, Klann-linkage is suggested as a walking mechanism for a water-running robot and is optimized using level average analysis. The structure of the Klann-linkage is introduced first and design variables for the Klann-linkage are identified considering the kinematic task of the walking mechanism. Next, the design problem is formulated as a path generation optimization problem. Specifically, the desired path for the foot-pad is defined and the objective function is defined as the structural error between the desired and the generated paths. A process for solving the optimization problem is suggested utilizing the sensitivity analysis of the design variables. As a result, optimized lengths of Klann-linkage are obtained and the optimum trajectory is obtained. It is found that the optimized trajectory improves the cost function by about 62% from the initial one. It is expected that the results from this research can be used as a good example for designing legged robots.

• 한국정보통신학회논문지
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• 제9권8호
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• pp.1722-1729
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• 2005

본 연구에서는 OpenGL 프로그램으로 4족 보행로봇인 TITAN-VIII의 가상로봇을 설계한 후, 실제로봇의 관절각도, 본체 자세각을 가상로봇에 입력하고 벡터 회전과 평행이동을 이용하여 보행 중 본체를 수평으로 유지하는 제어를 10[ms]마다 행하였다. 디딤율 $\beta$를 0,5로 일정하게 하고, 주기가 1.5, 2.0, 3.0[sec]일 때 한주기당 이동거리를 0.2, 0.3[m]로 변경하여 좌우요동보행을 시키면서 가상로봇의 ZMP, 실제로봇의 ZMP 무게중심의 이동경로를 구하고 발바닥 좌표 변화와의 관계를 비교 분석하였다.

• 대한기계학회논문집A
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• 제24권4호
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• pp.1007-1015
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• 2000

This paper proposes an adaptive trajectory generation strategy of using on-line ZMP information and an impedance control method for biped robots. Since robots experience various disturbances during their locomotion, their walking mechanism should have the robustness against those disturbances, which requires an on-line adaptation capability. In this context, an on-line trajectory planner is proposed to compensate the required moment for recovering stability. The ZMP equation and sensed ZMP information are used in this trajectory generation strategy. In order to control a biped robot to be able to walk stably, its controller should guarantee stable footing at the moment of feet contacts with the ground as well as maintaining good trajectory tracking performance. Otherwise, the stability of robot will be significantly compromised. To reduce the magnitude of an impact and guarantee a stable footing when a foot contacts with the ground, this paper. proposes to increase the damping of the leg drastically and to modify the reference trajectory of the leg. In the proposed control scheme, the constrained leg is controlled by impedance control using the impedance model with respect to the base link. Computer simulations performed with a 3-dof environment model that consists of combination of a nonlinear and linear compliant contact model show that the proposed controller performs well and that it has robustness against unknown uneven surface. Moreover, the biped robot with the proposed trajectory generator can walk even when it is pushed with a certain amount of external force.