6 자유도 다축 시뮬레이션 테이블의 역 · 순기구학 해석 및 검증

진재현(Jaehyun Jin),전승배(Seung-Bae Jeon) 대한기계학회 2008 大韓機械學會論文集A Vol.32 No.2

A 6 DOF Multi axis simulation table (MAST) is used to perform vibration and fatigue tests for parts or assemblies of automobiles, aircraft, or other systems. It consists of a table and 6 linear actuators. For its attitude control, we have to adjust the lengths of 6 actuators properly. The system is essentially a parallel mechanism. Three actuators are connected to the table directly and other three actuators are connected indirectly. Because of these, the MAST shows also a serial mechanism’s property: the inverse kinematics is more complicated than a pure parallel mechanism and each actuator can operate independently. The authors have performed a kinematics analysis of the 6 DOF MAST. We have presented an analytical and a numerical solution for the inverse and forward kinematics, and we have verified the solutions by a 3D CAD software.

스튜어트 플랫폼 순기구학 해의 실시간 추정기법

정규홍,이교일 대한기계학회 1994 대한기계학회논문집 Vol.18 No.7

The Stewart Platform is a six-degree-of-freedom in-parallel-actuated manipiulator mechanism. The kinematic behavior of parallel mechanisms shows inverse characteristics as compared that of serial mechanisms; i.e, the inverse kinematic problem of Stewart Platform is straightforward, but no closed form solution of the forward kinematic problem has been previously presented. Thus it is difficult to calculate the 6 DOF displacement of the platform from the measured lengths of the six actuators in real time. Here, a real-time estimation algorithm which solves the Stewart Platform kinematic problem is proposed and tested through computer simulations and experiments. The proposed algorithm shows stable convergence characteristics, no estimation errors in steady state and good estimation performance with higher sampling rate. In experiments it is shown that the estimation result is the same as that of simulation even in the presence of measurement noise.

한 개의 선형 여유센서를 갖는 스튜어트 플랫폼의 실시간 순기구학

심재경,이태영,Sim, Jae-Gyeong,Lee, Tae-Yeong 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.9

This paper deals with the forward kinematics of the 6-6 Stewart platform of planar base and moving platform using one extra linear sensor. Based on algebraic elimination method, it first derives an 8th-degree univariate equation and then finds tentative solution sets out of which the actual solution is to be selected. In order to provide more exact solution despite the error between measured sensor value and the theoretic alone, a correction method is also used in this paper. The overall procedure requires so little computation time that it can be efficiently used for real-time applications. In addition, unlike the iterative scheme e.g. Newton-Raphson, the algorithm does not require initial estimates of solution and is free of the problems that it does not converge to actual solution within limited time. The presented method has been implemented in C language and a numerical example is given to confirm the effectiveness and accuracy of the developed algorithm.

스튜어트 플랫폼의 빠른 순기구학 해석

하현표,한명철,Ha, Hyeon-Pyo,Han, Myeong-Cheol 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.3

The inverse kinematics problem of Stewart platform is straightforward, but no closed form solution of the forward kinematic problem has been presented. Since we need the real-time forward kinematic solution in MIMO control and the motion monitoring of the platform, it is important to acquire the 6 DOF displacements of the platform from measured lengths of six cylinders in small sampling period. Newton-Raphson method a simple algorithm and good convergence, but it takes too long calculation time. So we reduce 6 nonlinear kinematic equations to 3 polynomials using Nairs method and 3 polynomials to 2 polynomials. Then Newton-Raphson method is used to solve 3 polynomials and 2 polynomials respectively. We investigate operation counts and performance of three methods which come from the equation reduction and Newton-Raphson method, and choose the best method.

인공지능망을 이용한 스튜어트 플랫폼의 순기구학 연산속도 향상

이태영(Tae Young Lee),박종현(Jong Hyeon Park) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

This paper proposes a method to improved computation speed of forward kinematics solution of Stewart platform using neural network. Solution of the inverse kinematics is easily found by the vectors of the links which is composed of the joint coordinates in base and plate frame, but forward kinematic is not easily solved because of the nonlinearity and complexity of the Stewart platform. Actually we can get the solution of forward kinematics by solving nonlinear simultaneous equation by Newton-Raphson, but this method is too slow computation speed. Because this method has some problem about setting initial condition. Hence we suggest a method to increase the computation speed by setting the initial condition of Newton-Raphson with neural network.

기구학적 전이를 이용한 케이싱 오실레이터의 순기구학 해석

배형섭(Hyung Sub Bae),백재호(Jae Ho Baik),박명관(Myeong Kwan Park) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.11

The Casing Oscillator is a bore file Equipment for the all-casing process. All-casing process is a method of foundation work in construction yard to oscillate steel Casing in the ground. The existing Casing Oscillator has some problem like not boring horizontally with disturbance and not driving Casing other angle except horizon. To solve problem, the new structure Casing Oscillator is presented and studied. The performance of Casing Oscillator is improved by kinematics analysis. The Casing Oscillator is similar to the parallel manipulator in structure. So we obtain Inverse kinematics solution of Casing Oscillator easily. But it is difficult to solve forward kinematics of Casing Oscillator. This paper presents a novel pose description corresponding to the structure characteristics of parallel manipulators. Through analysis on geometry theory, we obtain a new method of the closed-form solution to the forward kinematics using Kinematic Inversion. The closed-form solution contains two different meanings-analytical and real-time. So we reach the goal of practical application and control. Closed-form forward kinematics solution is verified by an inverse kinematics analysis. It shows that the method has a practical value for real-time control and inverse kinematics servo control.

6자유도 조작장치의 설계와 기구학적 특성에 관한 연구

김정태,김문생,Kim, Jeoung-Tae,Kim, Moon-saeng 대한기계학회 1998 大韓機械學會論文集A Vol.22 No.2

The Six Degree-of-Freedom manipulators are generally operated by linear actuators which are hydraulic cylinder, pneumatic cylinder, ball-screw. But these actuators are not adequate to have a wide work-space, and furthermore some of them have a self-locking property. Therfore, we have designed a new manipulator which fully overcomes these demerits. The new manipulating system consists of 6 DC-motors to generate operation forces and 6 position transducers to feedback displacement signals. This paper presents an overview of the design and characteristics of 6 Degree-of-Freedom force feedback manipulators for vitual reality implementation. we can operate Six Degree-of-Freedom manipulator with six motors and six potentiometers.

6-3 스튜워트 플랫폼 운동장치의 새로운 기구학 해석방법

김낙인,이종원,Kim, Nak-In,Lee, Chong-Won 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.8

The kinematic analysis of Stewart platform manipulator(SPM) is carried out in order to reduce the calculation time for its forward kinematic solution when the iterative numerical method is employed. The kinematic equations for three substructures of the 6-3 SPM are newly derived by introducing Denavit-Hartenberg link parameters and using kinematic constraints associated with the SPM and substructure kinematics. It is shown that the forward kinematics can be easily solved from three nonlinear equations with three unknown variables only, leading to a great reduction in calculation time.

스튜어트 플랫폼형 범용 수동조작기의 설계연구

김상범,최용제 대한기계학회 1995 대한기계학회논문집 Vol.19 No.1

The practical design and construction of a Stewart Platform-based unilateral universal hand-controller is presented. It is also presented that such a design concept could be implemented by developing a technical method of determining the forward kinematics of a Stewart Platform in real time. In this work, the forward kinematics of a Stewart Platform has been determined in real time using three additional displacement sensors which eliminate the computational burden of solving the forward kinematics described in nonlinear simultaneous equations. The workspace of the Stewart Platform via inverse kinematics has been analyzed numerically and used as a design guide for the determination of the mechanism dimensions such as the sizes of the upper and base platforms and the minimum and maximum lengths of the legs. The hardware of the hand-controller has been constructed and tested to demonstrate the feasibility of the design concept.

Kinematic Analysis for a Four-Axis Palletizing Robot

I. H. Park(박일환),A. R. Go(고아라),E. J. Ha(하은주),D. S. Hong(홍대선) 유공압건설기계학회 2020 유공압건설기계학회 학술대회논문집 Vol.2020 No.12