• Title, Summary, Keyword: zero moment point

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Stability Analysis of a Biped Robot using Wrench System (렌치 시스템을 이용한 이족보행 로봇의 안정도 해석)

  • 임헌영;심재경;황규혁
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.648-651
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    • 2004
  • Biped robot has better mobility than other mobile robot, but it is hard to maintain balance during walking. In order to maintain balance, stability analysis is a key point for a biped robot. The zero moment point analysis has been used most in stability analysis. In this paper, we propose different method of stability analysis using wrench system. It is possible to generate a wrench system by applying a force along an axis in space and simultaneously applying a moment about the same axis. Wrench system is equivalent to a force and moment applied along the same axis. We compare the result of wrench system analysis with that of zero moment analysis in biped robot stability using simulation program.

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A Study on Reversal Stability of Hydraulic Excavator for Crane Work (유압 굴삭기의 크레인 작업시 전도 안정성에 관한 연구)

  • Um, Hyuk;Choi, Jong-Hwan;Kim, Seung-Soo;Yang, Soon-Yong;Lee, Jin-Gul
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.4
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    • pp.64-72
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    • 2004
  • In this paper, the dynamic stability of a hydraulic excavator using ZMP concept is considered. When a load is moved in an excavator based on automation, an excavator often loses the stability and falls over. This is because a dynamic element is not included in the moment equilibrium equation that is used in order to judge a reversal. Consequently, reversal distinction algorithm including all a static and a dynamic element along a load movement in crane work is necessary. Zero Moment Point(ZMP) is a point on the floor where the resultant moment of the gravity, the inertial force of the manipulator and the external force is zero. This study is going to interpret the reversal stability of the excavator to which is applied ZMP concept through simulation.

Dynamic Gait embody using angular acceleration for a Walking Robot (각가속도를 이용한 이족 로봇의 동적 걸음새 구현)

  • Park, Jae-Mun;Park, Seung-Yub;Ko, Bong-Jin
    • Journal of Advanced Navigation Technology
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    • v.11 no.2
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    • pp.209-216
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    • 2007
  • In this paper, we embodied posture-stabilization and dynamic gait in a walking robot. 10 RC servo motors are used to operate joints. And the joints have enough moving ranges suitable in any walking pattern. Each joint trajectory is generated by cubic spline interpolation method and the stability of the trajectory is verified by using Zero Moment Point from the robot modeling. To avoid complex structure and expression, Zero Moment Point of the biped robot used angular acceleration is suggested. To measure the stability of the biped robot, Tilt sensor and gyro sensor are used. Finally, Personal Computer is used computer monitoring and data processing. Most of computation, such as 10 RC servo motor control, joint trajectory generating, ZMP compensation, sense measuring, etc, was used Digital Signal Processor.

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Stretch Walking Algorithm for Biped Robot Using Zero Moment Point (Zero Moment Point를 이용한 이족보행 로봇의 Stretch Walking 알고리즘)

  • Chu, Jung-Hyun;Lim, Mee-Seub;Lim, Joon-Hong
    • Proceedings of the KIEE Conference
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    • pp.2812-2814
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    • 2005
  • 본 논문에서는 이족보행 로붓의 보행패턴의 한 가지 방법으로 무릎을 피고 걷는 stretch 보행 알고리즘을 제안한다. 이전의 보행 알고리즘은 무릎을 구부리고 걷는 것이 대부분이다. 일반적으로 사람들이 걸을 때는 무릎을 거의 피고 걷기 때문에 사람과 비슷한 보행을 위해서 자세보정 시 Zero Moment Point(ZMP)를 이용한 무릎관절을 피고 걷는 보행 알고리즘을 제안하고 이의 구현을 위한 실험 수행을 통해 그 성능을 평가한다. 로봇은 보행상태에서 몸이나 발의 위치, 각도 등에 대한 보정작업이 없다면, 이로 인해 로봇의 궤적에 오차가 발생하게 되고, 그 결과 불안정하고 부자연스러운 보행을 하게 된다. 이러한 불안정성을 ZMP를 이용하여 보정 할 수 있다.

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Energy-Efficient Reference Walking Trajectory Generation Using Allowable ZMP (Zero Moment Point) Region for Biped Robots (2족 보행 로봇을 위한 허용 ZMP (Zero Moment Point) 영역의 활용을 통한 에너지 효율적인 기준 보행 궤적 생성)

  • Shin, Hyeok-Ki;Kim, Byung-Kook
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.10
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    • pp.1029-1036
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    • 2011
  • An energy-efficient reference walking trajectory generation algorithm is suggested utilizing allowable ZMP (Zero-Moment-Point) region, which maxmizes the energy efficiency for cyclic gaits, based on three-dimensional LIPM (Linear Inverted Pendulum Model) for biped robots. As observed in natural human walking, variable ZMP manipulation is suggested, in which ZMP moves within the allowable region to reduce the joint stress (i.e., rapid acceleration and deceleration of body), and hence to reduce the consumed energy. In addition, opimization of footstep planning is conducted to decide the optimal step-length and body height for a given forward mean velocity to minimize a suitable energy performance - amount of energy required to carry a unit weight a unit distance. In this planning, in order to ensure physically realizable walking trajectory, we also considered geometrical constraints, ZMP stability condition, friction constraint, and yawing moment constraint. Simulations are performed with a 12-DOF 3D biped robot model to verify the effectiveness of the proposed method.

Tests for the Change-Point in the Zero-Inflated Poisson Distribution

  • Kim, Kyung-Moo
    • Journal of the Korean Data and Information Science Society
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    • v.15 no.2
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    • pp.387-394
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    • 2004
  • Zero-Inflated Poisson distribution is Poisson distribution with excess zeros. Recently defects of product hardley happen in the manufacturing process. In this case it is desirable to apply to the Zero-Inflated Poisson distribution rather than Poisson. Our target of this paper is to study the tests for changes of rate of defects after the unknown change-point. We are going to compare the powers of the two proposed tests with likelihood tests by the simulations.

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Real-Time CoM/ZMP Trajectory Transformation Method for Humanoid Robots Considering Structure Characteristics (구조 특성을 반영한 인간형 로봇을 위한 실시간 CoM/ZMP 궤적 변환 방법)

  • Hong, Seok-Min
    • Journal of Advanced Navigation Technology
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    • v.21 no.1
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    • pp.132-137
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    • 2017
  • This paper proposes a transformation method of the zero moment point (ZMP) and the center of mass (CoM) from one walking pattern to other patterns by considering the structure of a robot or walking situations in real time. In general, a humanoid robot has own structure characteristics like height and mass. The structure characteristics make the given CoM/ZMP walking pattern of one human or one humanoid robot to be difficult to apply to other robot directly. For this purpose, we analyze the characteristics of walking patterns according to the step length, duration of walking support phase and the CoM height by using the cart-table model as the simple humanoid robot model. A transformation equation is derived from the analyzation and it is verified with simulation.

Stability Analysis of a Biped Robot using FRI (FRI를 이용한 이족 보행 로봇의 안정도 해석)

  • 김상범;최상호;김종태;박인규;김진걸
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.574-577
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    • 2001
  • This paper presents the comparison of FRI(Foot Rotation Indicator) point and ZMP(Zero Moment Point) in biped robot stability. We showed FRI may be employed as a useful tool in stability analysis in biped robot. Also, we proposed the balancing joint trajectory derived from FRI point equation for stable gait. The numerical calculation routines and walking algorithms for simulation are performed by MATLAB. The procedure is composed of the leg trajectory planning, the generation of balancing trajectory, and the verification of dynamic stability.

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A study on the motion trajectory planning and dynamic simulation of biped walking robot (이족 보행 로보트의 운동 궤적 계획 및 동적 시뮬레이션에 관한 연구)

  • 김창부;김웅태
    • 제어로봇시스템학회:학술대회논문집
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    • pp.959-964
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    • 1992
  • This study treats the method for kinematic modeling of the biped walking robot, for synthesizing various gait trajectories, and for calculating adequate values of the joint torque inside the stable region. To synthesize various and anthropomorphic walking easily, the gait trajectory is specified by a set of ten walking prameters, and the trunk motion equation is derived by the zero moment point and the gait trajectory. By distributing ground reaction force and moment reduced at the zero moment point to the both feet, the joint torque equation can be derived readily, and according to this equation, the joint torque to stable walking can be computed.

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A Study on the Improvement of rotor axes arrangement method through the stress anaylsis (응력해석을 통한 회전체의 축정렬 방법 개선에 관한 연구)

  • 김경석;정현철;이시연;윤주호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.355-360
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    • 1995
  • In order to align the shaft, the dialgauge method has used as a means of solution until now. The method using a dialgauge require a great deal of labour and money due to making by hand, the accurate alignmentis not up to the expectation. For aligning the shaft, all the rotor must come to accord. It means that the moment of the point of coupling must keep being "Zero". The ideal measurement method as to material on the zero is used by straingauge which can gauge the moment at any point of the shaft. Also, the dialgauge method cannot be compared with straingauge measurement method, form the viewpoint, which can gauge in short time.hort time.

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