• Title, Summary, Keyword: Kinematic Constraints

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An IMM Approach for Tracking a Maneuvering Target with Kinematic Constraints Based on the Square Root Information Filter

  • Kim, Kyung-Youn;Kim, Joong-Soo
    • Journal of Electrical Engineering and information Science
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    • v.1 no.2
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    • pp.39-44
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    • 1996
  • An efficient interacting multiple mode(IMM) approach for tracking a maneuvering target with kinematic constraints is described based on the square root information filter(SRIF). The SRIF is employed instead of the conventional Kalman filter since it exhibits more efficient features in handling the kinematic constraints and improved numerical characteristics. The kinematic constraints are considered in the filtering process as pseudomeasurements where the degree of uncertainty is represented by the magnitude of the pseudomeasurement noise variance. The Monte Carlo simulations for the constant speed, maneuvering target are provided to demonstrate the improved tracking performance of the proposed algorithm.

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Real-time Obstacle Avoidance of Non-holonomic Mobile Robots Using Expanded Guide Circle Method (확장 가이드 서클 방법을 이용한 비홀로노믹 이동로봇의 실시간 장애물 회피)

  • Shim, Young-Bo;Kim, Gon-Woo
    • The Journal of Korea Robotics Society
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    • v.12 no.1
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    • pp.86-93
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    • 2017
  • The Expanded Guide Circle (EGC) method has been originally proposed as the guidance navigation method for improving the efficiency of the remote operation using the sensory information. The previous algorithm is, however, concerned only for the omni-directional mobile robot, so it needs to suggest a suitable one for a mobile robot with non-holonomic constraints. The ego-kinematic transform is a method to map points of $R^2$ into the ego-kinematic space which implicitly represents non-holonomic constraints for admissible paths. Thus, robots with non-holonomic constraints in the ego-kinematic space can be considered as "free-flying object". In this paper, we propose an effective obstacle avoidance method for mobile robots with non-holonomic constraints by applying EGC method in the ego-kinematic space using the ego-kinematic transformation. This proposed method shows that it works better for non-holonomic mobile robots such as differential-drive robot than the original one. The simulation results show its effectiveness of performance.

Resolution of kinematic redundancy using contrained optimization techniques under kinematic inequality contraints

  • Park, Ki-Cheol;Chang, Pyung-Hun
    • 제어로봇시스템학회:학술대회논문집
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    • pp.69-72
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    • 1996
  • This paper considers a global resolution of kinematic redundancy under inequality constraints as a constrained optimal control. In this formulation, joint limits and obstacles are regarded as state variable inequality constraints, and joint velocity limits as control variable inequality constraints. Necessary and sufficient conditions are derived by using Pontryagin's minimum principle and penalty function method. These conditions leads to a two-point boundary-value problem (TPBVP) with natural, periodic and inequality boundary conditions. In order to solve the TPBVP and to find a global minimum, a numerical algorithm, named two-stage algorithm, is presented. Given initial joint pose, the first stage finds the optimal joint trajectory and its corresponding minimum performance cost. The second stage searches for the optimal initial joint pose with globally minimum cost in the self-motion manifold. The effectiveness of the proposed algorithm is demonstrated through a simulation with a 3-dof planar redundant manipulator.

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Power-flow Independent Modeling of Vehicle Powertrain (Power-flow에 독립적인 파워트레인 모델링)

  • 최기영;이승종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.267-270
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    • 2001
  • A lot of efforts have been made to analyze the performance of the vehicle equipped with automatic transmission through simulation. It might be necessary to understand the different types of transmissions, i.e., different power flows, for different models. If there is a module that can be applied to different types of automatic transmission, it could be helpful to transmission-related engineers. This study has started up from this idea. The common bond graph has been obtained from several types of the automatic transmission. The overall generalized equations and kinematic constraint equations have been derived using virtual power sources on common bond graph. They are used to derive state equations and constraints. These equations have been applied as an application to the vehicle equipped with two simple planetary gear set type of Ravigneaux gear type automatic transmission. The state equation, kinematic constraints, and dynamic constraints have been derived in every gear and shift operation using overall generalized equations and kinematic constraint equations. Simulations for constraint speed running, standing-start running, rolling-start running, and LA-4 mode have been conducted to analyze the performance of the vehicle powertrain using GVPS(Generalized Vehicle Powertrain Simulation) program wit pull down menus.

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Kinematic Correction of n Differential Drive Mobile Robot and a Design for the Reference-Velocity Trajectory with Acceleration-Resolution Constraint on Motor Controllers (차동 구륜이동로봇의 기구학적 보정과 모터제어기의 가속도 해상도 제약을 고려한 기준속도궤적의 설계)

  • 문종우;김종수;박세승
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.6
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    • pp.498-505
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    • 2002
  • Reducing odometer errors caused by kinematic imperfections in wheeled mobile robots is imestigated. Wheel diameters and wheelbase are corrected by using encoders without landmarks. A new velocity trajectory is proposed that compensates for an orientation error due to acceleration- resolution constraints on motor controllers. Based on this velocity trajectory, the wheel velocity of one out of two driven wheels may be changed by the traveled distance of the mobile robot. It is shown that a wheeled mobile robot can't move along a straight line exactly, even if kinematic correction are achieved perfectly, and this phenomenon is attributable to acceleration-resolution constraints on motor controllers. We experiment on a wheeled mobile robot with 2 d.o.f. are used in the experiment to verify the proposed scheme.

Kinematic Analysis of the Multi-Link Five-Point Suspension System in Point Coordinates

  • Attia, Hazem-Ali
    • Journal of Mechanical Science and Technology
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    • v.17 no.8
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    • pp.1133-1139
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    • 2003
  • In this paper, a numerical algorithm for the kinematic analysis of a multi-link five-point suspension system is presented. The kinematic analysis is carried out in terms of the rectangular Cartesian coordinates of some defined points in the links and at the joints. Geometric constraints are introduced to fix the relative positions between the points belonging to the same rigid body. Position, velocity and acceleration analyses are carried out. The presented formulation in terms or this system of coordinates is simple and involves only elementary mathematics. The results of the kinematic analysis are presented and discussed.

A Unified Framework for Overcoming Motion Constraints of Robots Using Task Transition Algorithm (작업 전이 알고리즘 기반 로봇 동작 제한 극복 프레임워크)

  • Jang, Keunwoo;Kim, Sanghyun;Park, Suhan;Park, Jaeheung
    • The Journal of Korea Robotics Society
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    • v.13 no.2
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    • pp.129-141
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    • 2018
  • This paper proposes a unified framework that overcomes four motion constraints including joint limit, kinematic singularity, algorithmic singularity and obstacles. The proposed framework is based on our previous works which can insert or remove tasks continuously using activation parameters and be applied to avoid joint limit and singularity. Additionally, we develop a method for avoiding obstacles and combine it into the framework to consider four motion constraints simultaneously. The performance of the proposed framework was demonstrated by simulation tests with considering four motion constraints. Results of the simulations verified the framework's effectiveness near joint limit, kinematic singularity, algorithmic singularity and obstacles. We also analyzed sensitivity of our algorithm near singularity when using closed loop inverse kinematics depending on magnitude of gain matrix.

A new kinematic formulation of closed-chain mechanisms with redundancy and its applications to kinematic analysis

  • Kim, Sungbok
    • 제어로봇시스템학회:학술대회논문집
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    • pp.396-399
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    • 1995
  • This paper presents a new formulation of the kinematics of closed-chain mechanisms and its applications to obtaining the kinematic solutions and analyzing the singularities. Closed-chain mechanisms under consideration may have the redundancy in the number of joints. A closed-chain mechanism can be treated as the parallel connection of two open-chains with respect to a point of interest. The kinematics of a closed-chain mechanism is then obtained by imposing the kinematic constraints of the closed-chain on the kinematics of the two open-chains. First, we formulate the kinematics of a closed-chain mechanism using the kinematic constraint between the controllable active joints and the rest of joints, instead of the kinematic constraint between the two open-chains. The kinematic formulation presented in this paper is valid for closed-chain mechanisms with and without the redundancy. Next, based on the derived kinematics of a closed-chain mechanism, we provide the kinematic solutions which are more physically meaningful and less sensitive to numerical instability, and also suggest an effective way to analyze the singularities. Finally, the computational cost associated with the kinematic formulation is analyzed.

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A Gemetric Kinematic Analysis of Constrained Multibody System (구속된 다물체 시스템을 위한 기하학적 운동구속론)

  • 김재용;배대성;한창수;이상호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.4
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    • pp.80-90
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    • 1994
  • Basic constraint equations derived from orthogonality conditions between a pair of body-fixed vectors and a body-fixed vector or a vector between two bodies are reformulated by using relative coordinate kinematics between two adjacent reference frames. Arithmetic numbers of operations required to compute derivatives of the constraint equations are drastically reduced. A mixed formulation of relative and cartesian coordinates is developed to further simplify derivatives of the constraints. Advantages and disadvantages of the new formulation are discussed. Possible singularity problem of para llelism constraints is resolved by introducing an extra generalized coordinate. Kinematic analysis of a McPherson strut suspension system are carried out to illustrate use and efficiency of the new formulation.

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Tracking Control for Mobile Robot Based on Fuzzy Systems (퍼지 시스템을 이용한 이동로봇의 궤적제어)

  • 박재훼;이만형
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.6
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    • pp.466-472
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    • 2003
  • This paper describes a tracking control for the mobile robot based on fuzzy systems. Since the mobile robot has the nonholonomic constraints, these constraints should be considered to design a tracking controller for the mobile robot. One of the well-known tracking controllers for the mobile robot is the back-stepping controller. The conventional back-stepping controller includes the dynamics and kinematics of the mobile robot. The conventional back-stepping controller is affected by the derived velocity reference by a kinematic controller. To improve the performance of the conventional back-stepping controller, this paper uses the fuzzy systems known as the nonlinear controller. The new velocity reference for the back-stepping controller is derived through the fuzzy inference. Fuzzy rules are selected for gains of the kinematic controller. The produced velocity reference has properly considered the varying reference trajectories. Simulation results show that the proposed controller is more robust than the conventional back-stepping controller.