• Title/Summary/Keyword: 6 dof mechanism

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Design and Modeling of a 6-dof Stage for Ultra-Precision Positioning (초정밀 구동을 위한 6 자유도 스테이지의 설계와 모델링)

  • Moon, Jun-Hee;Park, Jong-Ho;Pahk, Heui-Jae
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.6
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    • pp.106-113
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    • 2009
  • A 6-DOF precision stage was developed based on parallel kinematics structure with flexure hinges to eliminate backlash, stick-slip and friction and to minimize parasitic motion coupled with motions in the other-axis directions. For the stage, lever linkage mechanism was devised to reduce the height of system for the enhancement of horizontal stiffness. Frequency response comparison between experimental results and mathematical model extracted from dynamics of the stage was performed to identify the system parameters such as spring constants and damping coefficients of actuation modules, which cannot be calculated accurately by analytic methods owing to their complicated structures. This newly developed precision stage and its identified model will be very useful for precision positioning and control because of its high accuracy and non-coupled movement.

Kinematic Analysis of a 6-DOF Ultra-Precision Positioning Stage Based on Flexure Hinge (플렉셔 힌지 기반 6-자유도 초정밀 위치 결정 스테이지의 기구학 해석)

  • Shin, Hyun-Pyo;Moon, Jun-Hee
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.7
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    • pp.579-586
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    • 2016
  • This paper describes kinematic analysis of a 6-degrees-of-freedom (DOF) ultra-precision positioning stage based on a flexure hinge. The stage is designed for processes which require ultra-precision and high load capacities, e.g. wafer-level precision bonding/assembly. During the initial design process, inverse and forward kinematic analyses were performed to actuate the precision positioning stage and to calculate workspace. A two-step procedure was used for inverse kinematic analysis. The first step involved calculating the amount of actuation of the horizontal actuation units. The second step involved calculating the amount of actuation of the vertical actuation unit, given the the results of the first step, by including a lever hinge mechanism adopted for motion amplification. Forward kinematic analysis was performed by defining six distance relationships between hinge positions for in-plane and out-of-plane motion. Finally, the result of a circular path actuation test with respect to the x-y, y-z, and x-z planes is presented.

Calibration of 6-DOF Parallel Mechanism Through the Measurement of Volumetric Error (공간오차 측정을 통한 6자유도 병렬기구의 보정)

  • Oh, Yong-Taek;Saragih, Agung S.;Kim, Jeong-Hyun;Ko, Tae-Jo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.3
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    • pp.48-54
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    • 2012
  • This paper introduces the kinematic calibration method to improve the positioning accuracy of a parallel mechanism. Since all the actuators in the parallel mechanism are controlled simultaneously toward the target position, the volumetric errors originated from each motion element are too complicated. Therefore, the exact evaluation of the error sources of each motion element and its calibration is very important in terms of volumetric errors. In the calibration processes, the measurement of the errors between commands and trajectories is necessary in advance. To do this, a digitizer was used for the data acquisition in 3 dimensional space rather than arbitrary planar error data. After that, the optimization process that was used for reducing the motion errors were followed. Consequently, Levenberg-Marquart algorithm as well as the error data acquisition method turned out effective for the purpose of the calibration of the parallel mechanism.

Analysis and Design of a New 6-DOF Haptic Device Using a Parallel Mechanism (병렬구조를 이용한 새로운 6 자유도 역감제시장치의 설계 및 해석)

  • Yoon, Jung-son;Ryu, Je-Ha
    • Journal of Institute of Control, Robotics and Systems
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    • v.7 no.1
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    • pp.1178-1186
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    • 2001
  • This paper presents design and analysis of a 6 degree-of-freedom new haptic device using a par-allel mechanism for interfacing with virtual reality. The mechanism is composed of three pantograph mecha-misms that, driven by ground-fixed servomotors. stand perpendicularly to the base plate. Three spherical joints connect the top of the pantograph with connecting bars, and three revolute joint connect connecting bars with a mobile joystick handle. Forward and inverse kinematic analyses have been performed and the Jacobian matrix is derived by using the screw theroy. Performance indices such as GPI(Global Payload Index), GCI(Global Conditioning index), Traslation and Orientation workspaces, and Sensitivity are evaluated to find optimal pa-rameters in the design stage. The proposed haptic mechanism has better load capability than those of the ex-isting haptic mechanisms due to the fact that motors are fixed at the base. It has also wider orientation work-space mainly due to RRR type spherical joints.

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Design of a 6-DOF Stage for Precision Positioning and Large Force Generation (정밀 위치 결정 및 고하중 부담 능력을 지닌 6-자유도 스테이지의 설계)

  • Shin, Hyun-Pyo
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.1
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    • pp.105-112
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    • 2013
  • This paper presents the structural design and finite element analysis of precision stage based on a double triangular parallel mechanism for precision positioning and large force generation. Recently, with the acceleration of miniaturization in mobile appliances, the demand for precision aligning and bonding has been increasing. Such processes require both high precision and large force generation, which are difficult to obtain simultaneously. This study aimed at constructing a precision stage that has high precision, long stroke, and large force generation. Actuators were tactically placed and flexure hinges were carefully designed by optimization process to constitute a parallel mechanism with a double triangular configuration. The three actuators in the inner triangle function as an in-plane positioner, whereas the three actuators in the outer triangle as an out-of-plane positioner. Finite element analysis is performed to validate load carrying performances of the developed precision stage.

Optimal Design of a 6-DOF Parallel Mechanism using a Genetic Algorithm (유전 알고리즘을 이용한 6자유도 병렬기구의 최적화 설계)

  • Hwang, Youn-Kwon;Yoon, Jung-Won
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.6
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    • pp.560-567
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    • 2007
  • The objective of this research is to optimize the designing parameters of the parallel manipulator with large orientation workspace at the boundary position of the constant orientation workspace (COW). The method uses a simple genetic algorithm(SGA) while considering three different kinematic performance indices: COW and the global conditioning index(GCI) to evaluate the mechanism's dexterity for translational motion of an end-effector, and orientation workspace of two angle of Euler angles to obtain the large rotation angle of an end-effector at the boundary position of COW. Total fifteen cases divided according to the combination of the sphere radius of COW and rotation angle of orientation workspace are studied, and to decide the best model in the total optimized cases, the fuzzy inference system is used for each case's results. An optimized model is selected as a best model, which shows better kinematic performances compared to the basis of the pre-existing model.

A Test Bench with Six Degrees of Freedom of Motion For Development of Small Quadrotor Drones (소형 쿼드로터 드론 개발을 위한 6 자유도 운동 실험 장치)

  • Jin, Jaehyun;Jo, Jin-Hee
    • Journal of Aerospace System Engineering
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    • v.11 no.1
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    • pp.41-46
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    • 2017
  • A new test bench for small multi-rotor type drones has been developed. Six degrees of freedom (DOF) motion is possible due to a ball bushing, wheels, and rotating plates. An FPGA (field programmable gate array) based controller, that supports realtime parallel processing, is used to measure attitude with an accelerometer and a gyro to adjust motor speed. Several tests were performed to check the operational properties of the test bench and the controller. The results show that this test bench is proper for verifying controllers and the control methods of small multi-rotor drones.

Lost Motion Analysis for Nonlinearity Identification of a 6-DOF Ultra-Precision Positioning Stage (6-자유도 초정밀 위치 결정 스테이지의 비선형성 식별을 위한 로스트 모션 해석)

  • Shin, Hyun-Pyo;Moon, Jun-Hee
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.3
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    • pp.263-268
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    • 2015
  • This paper describes lost motion analysis for a novel 6-DOF ultra-precision positioning stage. In the case of flexure hinge based precision positioning stage, lost motion is generated when the displacement of actuator is not delivered completely to the end-effector because of the elasticity of flexure hinge. Consequently, it is need to compute amount of lost motion to compensate the motion or to decide appropriate control method for precision positioning. Lost motion analysis for the vertical actuation unit is presented. The analysis results are presented in two ways: analytic and numerical analyses. It is found that they closely coincide with each other by 1% error. In finite element analysis result, the amount of lost motion is turned out to be about 3%. Although, the amount is not so large, it is necessary procedure to check the lost motion to establish the control method.

Development of a parallel link typed wrist for robotic precision assembly (정밀조립을 위한 병렬다관절 구조를 가진 로봇손목기구의 개발)

  • 문창렬;조형석
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.281-286
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    • 1993
  • In this paper, a parallel link typed wrist is developed for robotic precision assembly. The developed wrist can make the corrective motion required for compensating lateral and tilting errors. The mechanism of this wrist is one example of a motion simulator generating 6 DOF motion in space by 6 actuators connected in paralle. To make the wrist more compact, miniature DC motors containing reduction gears and servo system were used. The parallel link architecture enables a high positioning accuracy and high nominal load capacity. In this study, inverse kinematic problem is solved by using a Denavet-Hartenberg method and a simulational result about workspace of the proposed parallel mechanism is obtained.

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Development of Master-Slave Type Tele-Operation Control Robotic System for Arrhythmia Ablation (부정맥 시술을 위한 마스터-슬레이브 원격제어·로봇 시스템 개발)

  • Moon, Youngjin;Park, Sang Hoon;Hu, Zhenkai;Choi, Jaesoon
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.8
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    • pp.585-589
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    • 2016
  • Recently, the robotic assist system for cardiovascular intervention gets continuously growing interest. The robotic cardiovascular intervention systems are largely two folds, systems for cardiac ablation procedure assist and systems for vascular intervention assist. For the systems, the clinician controls the catheter inserted through blood vessel to the heart via a master console or master manipulator. Most of the current master manipulators have structure of joystick-like pivoting 2 degree of freedom (DOF) handle in the core, which is used in parallel with other sliding switches and input devices. It however is desirable to have customized and optimized design manipulator that can provide clinician with intuitive control of the catheter motion fully utilizing the advantage of the use of robotic structure. A 6 DOF kinematic mechanism that can capture the motion control intention of the clinician in translational 3 DOF and rotational 3 DOF is proposed in this paper. Also, a master-slave motion relationship specially designed for the cardiac catheter manipulation motion is proposed and implemented in an experimental prototype. Design revision for implementation of more efficient motion and experiment in combination with an experimental slave robot system for catheter manipulation are underway.