• 로봇학회논문지
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• 제6권4호
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• pp.308-316
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• 2011

This work deals with development of effective redundancy resolution algorithms for the motion control of manipulator. Differently from the typical kinematically redundant robots that are attached to the fixed ground, the ZMP condition should be taken into account in the manipulator motion in order to guarantee the system stability. In this paper, a new motion planning algorithm for redundant manipulator not fixed to the ground is introduced. A sequential redundancy resolution algorithm is proposed, which ensures the ZMP (Zero Moment Point) stability, the planned operational motion, and additional sub-criteria such as joint limit index. A geometric constraint equation derived by reshaping the existing ZMP equation enables one to employ the sequential redundancy algorithm. The feasibility of the proposed algorithm is verified by simulating a redundant manipulator model.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1793-1794
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• 2008

본 연구는 다양한 환경에서의 인간형 로봇의 안정적인 보행을 하기위한 FSR (Force Sensing Resistor) 센서 기반의 보행패턴에 관한 전체 시스템의 설계와 이의 모의실험이다. 인간형 로봇의 안정적인 보행을 구현하기 위해서는 보행 패턴의 ZMP(Zero Moment Point) 궤적이 안정 영역 내에 위치하게 하여야 하고, 실제 보행 중에도 외부의 환경적인 요인과 내부의 제어 오차에 따라 보행패턴의 수정과 보완이 요구된다. 이에 FSR 센서를 적용하여 전체 인간형 로봇의 보행 시스템을 설계하고 안정적인 다양한 보행을 구현하기 위한 보행패턴을 제안한다. 이를 모의실험을 통해 평지, 계단, 경사면에 따른 보행 안정성을 검증한다. 차후 이러한 모의실험 결과를 보완하여 FSR 센서를 실제 인간형 로봇에 장착하고 실험하여 안정적인 보행을 구현할 계획이다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.567-572
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• 2004

In this research, a stable walking pattern generation method for a biped robot is presented. A biped robot is considered as constrained multibody system by several kinematic joints. The proposed method is based on the optimized polynomial approximation of the trunk motion along the moving direction. Foot motions can be designed according to the ground condition and walking speed. To minimize the deviation from the desired ZMP, the trunk motion is generated by the fifth order polynomial approximation. Walking simulation for a virtual biped robot is performed to demonstrate the effectiveness and validity of the proposed method. The method can be applied to the biped robot for stable walking pattern generation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.113-118
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• 1993

This paper represents mechanical compliance & ZMP(Zero Moment Point) control algorithm for IWR(Inha Walking Robot) system. In case of walking in different environments, a biped walking robot must vary its gait(walking period or step length, etc.) according to the environments. However, most of biped walking robots do not have the capability to change their gaits or need more complex control algorithm, because ZMP cannot be defined in their control algorithm. Therefore new linear type with balancing joint is proposed which is used as an aid in balancing & ZMP control itself. In IWR system, ZMP can be defined by solving differential equations and it does not need to be predefined ZMP trajectory. Furthermore we can input the desired ZMP position. In parallel with the development, we also considered a mechanical compliance for reducing the inverse kinematics, dynamics and the control complexity. It will figure out some powerful adaptation with 3D irregular terrains.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.998-1001
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• 2003

In this paper, a entertainment biped robot controlled by R/C servo motors is built using the embedded RTOS (Real Time Operating System). uC/OS-II V2.00 is used for RTOS and control algorithm of R/C servo motors is proposed based on uC/OS-II's preemptive and deterministic property without any extra PWM module. The realized biped robot has 19 DOF, and a board 80C196KC as main CPU. To verify the proper walking process, ZMP(Zero Moment Point) theory is applied and ADAMS is used for simulation.

• 한국정밀공학회지
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• 제22권3호
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• pp.38-45
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• 2005

In this paper, a bird type biped robot for entertainment controlled by R/C servo motors, is built using the embedded RTOS (Real Time Operating System). ${\mu}C/OS-II$ V2.00 is used fur RTOS and the board 80C196KC for main CPU. A control algorithm of R/C servo motors is proposed on ${\mu}C/OS-II's$ preemptive and deterministic property without any extra PWM module. The realized biped robot has 19DOF, that is, 12DOF for both legs, 6DOF for both arms and 1DOF for neck. To verify the proper walking process, ZMP(Zero Moment Point) theory is applied and the simulation has been done by ADAMS.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제26권2호
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• pp.108-120
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• 2022

We considered qualitative behaviour of the generalization of Einstein's model of Brownian motion when the key parameter of the time interval of free jump degenerates. Fluids will be characterised by number of particles per unit volume (density of fluid) at point of observation. Degeneration of the phenomenon manifests in two scenarios: a) flow of the fluid, which is highly dispersing like a non-dense gas and b) flow of fluid far away from the source of flow, when the velocity of the flow is incomparably smaller than the gradient of the density. First, we will show that both types of flows can be modeled using the Einstein paradigm. We will investigate the question: What features will particle flow exhibit if the time interval of the free jump is inverse proportional to the density and its gradient ? We will show that in this scenario, the flow exhibits localization property, namely: if at some moment of time t₀ in the region, the gradient of the density or density itself is equal to zero, then for some T during time interval [t₀, t₀ + T] there is no flow in the region. This directly links to Barenblatt's finite speed of propagation property for the degenerate equation. The method of the proof is very different from Barenblatt's method and based on the application of Ladyzhenskaya - De Giorgi iterative scheme and Vespri - Tedeev technique. From PDE point of view it assumed that solution exists in appropriate Sobolev type of space.

• 한국정밀공학회지
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• 제13권2호
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• pp.76-83
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• 1996

We have developed the unconventional robot arm which is composed of the two main parts, one is a ball screw and the other is a robot arm. The dynamic systems of the robot arm and ball screw are unstable systems coupled with each other. The ball screw mechanism is unstable system but controllable system. The robot arm's dynamics is quasi stable system when ball screw's angular position is zero, else, unstable system. Our system has the duality between stability and controllability at the view point of control. This duality causes difficulty to control of the robot arm using normal control law. We have investigated the location of the characteristic roots of the dynamic equation. And we have found out that the best condition for the control of the arm is quasi stable state. In this paper, we have proposed multiple control laws which are consist of three components to guarantee the stability and controllability simultaneously. The computer simulations were carried out based on VSC about the angular position control of the robot arm, and it is confirmed that the good performances could be obtained by using new controller.

• 한국소음진동공학회논문집
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• 제13권1호
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• pp.10-18
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• 2003

This paper presented a design and control of a biped walking RGO(robotic gait orthosis) and its simulation. The biped walking RGO was distinguished from the other one by which had a very light-weight and a new RGO system will be made of 12-servo motors and 12-controllers. The vibration evaluation of the dynamic PLS(posterior leaf splint) on the biped walking RGO was used to access by the 3-axis accelerometer with a low frequency vibration of less than 30 Hz. The galt of the biped walking RGO depends on the constrains of mechanical kinematics and the initial posture. The stability of dynamic walking was investigated by analyzing the ZMP (zero moment point) of the biped walking RGO. It was designed according to the human wear type and was able to accomodate itself to the environments of S.C.I. Patients. The Joints of each leg were adopted with a good kinematic characteristics. To analyse joint kinematic properties. we made the strain stress analysis of the dynamic PLS and the analysis study of FEM with a dynamic PLS.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.752-759
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• 2002

This paper presented a design and a control of a biped walking RGO and walking simulation by this system. The biped walking RGO was distinguished from the other one by which had a very light-weight and a new RGO type with 12-servo motors. The vibration evaluation of the dynamic PLS on the biped walking RGO was used to access by the 3-axis accelerometer with a low frequency vibration for the spinal cord injuries. The gait of a biped walking RGO depended on the constrains of mechanical kinematics and the initial posture. The stability of dynamic walking was investigated by a ZMP (Zero Moment Point) of the biped walking RGO. It was designed according to a human wear type and was able to accomodate itself to a human environments. The joints of each leg were adopted with a good kinematic characteristics. To test of the analysis of joint kinematic properties, we did the strain stress analysis of the dynamic PLS and the analysis study of FEM with a dynamic PLS. It will be expect that the spinal cord injury patients are able to recover effectively with a biped walking RGO.