• 제목/요약/키워드: Initial Trajectory

검색결과 227건 처리시간 0.021초

이족보행로봇의 궤적 추종 오차 감소를 위한 걸음새 분석 (Walking Pattern Analysis for Reducing Trajectory Tracking Error in a Biped Robot)

  • 노경곤;공정식;김진걸
    • 제어로봇시스템학회논문지
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    • 제8권10호
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    • pp.890-897
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    • 2002
  • This paper deals with the reduction of trajectory tracking error by changing the initial postures of a biped robot. Gait of a biped robot depends on the constraints of mechanical kinematics and the initial states including the posture. Also the dynamic walking stability in a biped robot system is analyzed by zero moment point(ZMP) among the stabilization indices. Path trajectory, in which knee joint is bent forward like human's cases, is applied to most cases considered with above conditions. A new initial posture, which is similar to bird's gait, is proposed to decrease trajectory tracking error and it is verified through real experimental results.

추력벡터제어 비행체의 일관된 탄도 성형을 위한 피치각명령 산출 방법 (Pitch Command Generation Method for Consistent Initial Trajectory of Thrust-Vector-Controlled Vehicle)

  • 이용인;최동균;황태원
    • 한국군사과학기술학회지
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    • 제16권6호
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    • pp.739-744
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    • 2013
  • In this paper, we propose a method of generating pitch commands for consistent initial trajectories irrelevant to flight conditions in the initial boosting phase of a thrust-vector-controlled vehicle. After shape assumption of the pitch command profile, parameters of the profile are determined in real time in order for the summit height of the trajectory to be a desired value by deriving the summit height considering thrust performance, gravity, and other flight conditions. Computer simulation results demonstrate good performance of the proposed method.

로보트 매니퓰레이터에 대한 궤적 계획 방법들의 실시간 구현 및 상호 비교 연구 (Real-time Implementation and Comparative Study on Trajectory Planning Methods for Robot Manipulators)

  • 조정호;서일홍;임준홍;양해원;임달호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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    • pp.462-466
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    • 1989
  • This paper describes the methods of spline low-order polynomial trajectory planning using only a few limited look-ahead knots on the desired trajectory for the real-time computing. Specifically presented are the mixed joint trajectory planning methods which apply linear or LSPB method to initial and finial segments, overlapped cubic spline method to the other segments, where the displacements for initial and finial segments are chosen to be relatively smaller than the displacements for the other, equidistant segments. Experimental and simulation results of these methods show smooth motions and improved path tracking performances compared with any other interpolated joint trajectory planning methods.

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위치 오차를 갖는 2관성 공진계에 대한 반복학습 제어의 적용에 관한 연구 (Application of Iterative Learning Control to 2-Mass Resonant System with Initial Position Error)

  • 이학성
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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    • pp.307-310
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    • 2003
  • In this paper, an iterative learning control method is applied to suppress the vibration of a 2-mass system which has a flexible coupling between a load an a motor. More specifically, conditions for the load speed without vibration are derived based on the steady-state condition. And the desired motor position trajectory is synthesized based on the relation between the load and motor speed. Finally, a PD-type learning iterative control law is applied for the desired motor position trajectory. Since the learning law applied for the desired trajectory guarantees the perfect tracking performance, the resulting load speed shows no vibration. In order to handle the initial position error, the PD-type learning law is changed to PID-type and a weight function is added to suppress the residual vibration caused by the initial error. The simulation results show the effectiveness of the proposed learning method.

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시스템 사양을 고려한 컨볼루션 기반 목표궤적 생성 방법 (Convolution-based Desired Trajectory Generation Method Considering System Specifications)

  • 이건;최영진;김진현
    • 제어로봇시스템학회논문지
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    • 제16권10호
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    • pp.997-1005
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    • 2010
  • Most motion control systems consist of a desired trajectory generator, a motion controller such as a conventional PID controller, and a plant to be controlled. The desired trajectory generator as well as the motion controller is very important to achieve a good tracking performance. Especially, if the desired trajectory is generated actively utilizing the maximum velocity, acceleration, jerk and snap as given system specifications, the tracking performance would be better. For this, we make use of the properties of convolution operator in order to generate a smooth (S-curve) trajectory satisfying the system specifications. Also, the proposed trajectory generation method is extended to more general cases with arbitrary initial and terminal conditions. In addition, the suggested trajectory generator can be easily realized for real-time implementation. Finally, the effectiveness of the suggested method is shown through numerical simulations.

다자유도 기계 시스템의 모션 제어를 위한 동기된 온라인 궤적 생성 방법 (Synchronized On-line Trajectory Generation Method for Mechanical System with Multiple Degrees-of-Freedom)

  • 원대희;신은철
    • 전기학회논문지
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    • 제66권9호
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    • pp.1385-1391
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    • 2017
  • This work presents a synchronized on-line trajectory generation algorithm for mechanical system with multiple degrees-of-freedom. Proposed algorithm is designed to generate time-optimized trajectories and synchronized trajectories under the constraints such as maximum speed, acceleration, deceleration, non-zero initial velocity, etc. Also, because of small computation time, therefore this can be applied in real-time and it is easier to change the trajectory when an event occurs. We verified the feasibility through various trajectory generation.

하중 적분 PDC와 T-S 퍼지 외란 관측기를 이용한 이동 로봇의 강인 궤도 추적 제어 (Robust Trajectory Tracking Control of a Mobile Robot Based on Weighted Integral PDC and T-S Fuzzy Disturbance Observer)

  • 백두산;윤태성
    • 한국정보통신학회논문지
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    • 제21권2호
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    • pp.265-276
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    • 2017
  • 본 논문에서는 하중 적분 PDC 제어 기법과 T-S 퍼지 외란 관측기를 이용한 강인하면서도 보다 정확한 이동 로봇의 궤도 추적 제어 방법을 제안한다. 하중 적분 PDC 제어 기법은 PDC 제어 기법에 하중 적분 항을 추가함으로써 정상상태 오차를 감소시켜 준다. T-S 퍼지 외란 관측기는 T-S 퍼지 모델로 표현된 비선형 시스템에 대해 외란을 추정하고 상쇄시킬 수 있도록 한다. 따라서, T-S 퍼지 외란 관측기에 기반한 궤도 추적 제어기는 강인한 궤도 추적 성능을 보여준다. 또한, 본 연구에서는 $B\acute{e}zier$ 곡선에 의한 가속도 제한을 갖는 경로 설계 방법에 의해 초기 접근 경로를 설계함으로써, 이동 로봇의 초기 위치가 기준 궤도의 초기 위치와 다를 때 제어 입력이 매우 커지게 되어 실제적으로 사용할 수 없게 되는 문제를 해결한다. 제안된 궤도 추적 제어기의 성능을 시뮬레이션을 통해서 입증하였다.

이족 보행 로봇의 초기 자세에 따른 걸음새 해석에 관한 연구 (A Study on the Gait Analysis for Initial Posture of a Biped Robot)

  • 노경곤;정진걸
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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    • pp.301-303
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    • 2001
  • This paper deals with the biped robot gait on changing the initial postures. Gait of a biped robot depends on the constraints of mechanical kinematics and initial posture. Also biped robot's dynamic walking stability is investigated by ZMP(Zero Moment Point). The path trajectory. with the knee joint bent like a human, is generated and applied with the above considerations. To decrease trajectory tracking error, in this paper, a new initial posture similar to bird's case is proposed and realized with the real robot.

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Trajectory Optimization for a Supersonic Air-Breathing Missile System Using Pseudo-Spectral Method

  • Park, Jung-Woo;Tahk, Min-Jea;Sung, Hong-Gye
    • International Journal of Aeronautical and Space Sciences
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    • 제10권1호
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    • pp.112-121
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    • 2009
  • This paper deals with supersonic air-breathing missile system. A supersonic air-breathing missile system has very complicated and incoherent thrust characteristics with respect to outer and inner environment during operation. For this reason, the missile system has many maneuver constraints and is allowed to operate within narrow flight envelope. In this paper, trajectory optimization of the missile is accomplished. The trajectory optimization problem is formulated as a discrete parameter optimization problem. For this formulation, Legendre Pseudo-Spectral method is introduced. This method is based on calculating the state and control variables on Legendre-Gauss-Lobatto (LGL) points. This approach helps to find approximated derivative and integration quantities simply. It is shown that, for this trajectory optimization, trend analysis is performed from thrust characteristics on various conditions so that the trajectory optimization is accomplished with fine initial guess with these results.

Anomalous Propagation Characteristics of an Airy Beam in Nonlocal Nonlinear Medium

  • Wu, Yun-Long;Ye, Qin;Shao, Li
    • Current Optics and Photonics
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    • 제5권2호
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    • pp.191-197
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    • 2021
  • The anomalous propagation characteristics of a single Airy beam in nonlocal nonlinear medium are investigated by utilizing the split-step Fourier-transform method. We show that besides the normal straight propagation trajectory, the breathing solitons formed by the interaction between Airy beam and nonlocal nonlinear medium can propagate along the sinusoidal trajectory, and the anomalous trajectory can be modulated arbitrarily by altering the initial amplitude and the nonlocal nonlinear coefficient. In addition, the initial amplitude and the nonlocal nonlinear coefficient can have inverse impacts on the formation and transformation of the equilibrium state of spatial solitons, when the two parameters are larger than certain values. Therefore, the reversible transformation of the evolution dynamics of two soliton states can be realized by adjusting those two parameters properly. Finally, it is shown that the propagation properties of the solitons formed by the interaction between Airy beam and nonlocal nonlinear medium can be controlled arbitrarily, by adjusting the distribution factor and nonlocal coefficient.