• International Journal of Precision Engineering and Manufacturing
• /
• 제2권1호
• /
• pp.5-10
• /
• 2001

A method is proposed to obtain the Jacobian matrix of the 5 -bar parallel manipulator by employing the orthogonality between position and velocity vectors of rotating rigid-body around a fixed point. The dynamics of the 5-bar parallel manipulator is analyzed and utilized to design the computed-torque controller by developing a transformation matrix of the passive joints with respect to the active ones. In experimental demonstration, it shows that high-speed and accuracy tasks are performed by the proposed computed-torque control.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.224-228
• /
• 2000

In this paper, the kinematics of the new type of parallel manipulator is studied, and neural network is applied to solve the forward kinematics problem. The parallel manipulator, called a Stewart platform, has an easy and unique solution about the inverse kinematics, however the forward kinematics is difficult to get the solution because of the lack of an efficient algorithm due to its highly nonlinearity. This paper proposes the neural network scheme as an alternative Newton-Raphson method. The neural network is found to improve its accuracy by adjusting the offset of the result obtained.

• 한국공작기계학회논문집
• /
• 제17권3호
• /
• pp.1-7
• /
• 2008

This paper describes the kinematics which is a new type of parallel manipulator, and the neural network is applied to solving the forward kinematics problem. The parallel manipulator called it as a Stewart platform has an easy and unique solution about the inverse kinematics. However, the forward kinematics is difficult to get a solution because of the lack of an efficient algorithm caused by its highly nonlinearity. This paper proposes the neural network scheme of an Newton-Raphson method alternatively. It is found that the neural network can be improved its accuracy by adjusting the offset of the obtained result.

• 대한기계학회논문집A
• /
• 제29권11호
• /
• pp.1509-1517
• /
• 2005

This paper presents the two degree-of-freedom(DOF) planar parallel mechanism called 2R$\underline{P}$R-RP manipulator, whose degree-of freedom is dependent on a passive constraining leg connecting the base and the platform. First, the kinematic analysis of the mechanism is performed analytically: the inverse and forward kinematic problems are solved in the closed font the practical workspace is systematically derived, and all of the singular configurations are examined. Then, in order to determine the geometric parameters and the operating limits of the actuators, the optimization of the mechanism is performed considering its dexterity and stiffness. Finally, the kinematic performances of the optimized mechanism are evaluated through comparing to the 5-bar parallel manipulator.

• 대한기계학회논문집A
• /
• 제28권5호
• /
• pp.495-502
• /
• 2004

In this paper, kinematic structure of parallel manipulator having 6-DOF is determined to follow the specific trajectory represented by several curves expressed by the parametric variable functions. In addition, the parallel manipulator is designed to have a high dexterity by considering a kinematic isotropy which can stabilize the motion of the moving platform in the restricted workspace.

• 한국정밀공학회지
• /
• 제13권4호
• /
• pp.109-121
• /
• 1996

This paper presents how the input forces along the prismatic joints of a parallel manipulator are transmitted to the upper platform. In order to consider force transmission and moment transmission seperately the Jacobian matrix for parallel manipulators is splitted into two parts. Magnitudes of input forces on the six actuators at a given manipulator configuration which generate maximum/minimum output force with no moment generated on the platform are obtained through the singular value decomposition of a matrix involving the Jacobian. Similarly the directions of the input forces to obtain only the rotation of the platform have been analyzed. Using the singular values a simple equation for the volume of ellipsoid which is a good tool for manipulability measure is provided. Obtained results could be useful in determinimg design parameters like radius of plaform, angles between joints, etc. Simulations are porvided.

• 대한기계학회논문집A
• /
• 제31권4호
• /
• pp.441-450
• /
• 2007

In this study, a 3-DOF XYZ micro parallel manipulator utilizing compliance mechanism is developed and analyzed. In so doing, a matrix method is used to rapidly solve displacements of the designed kinematic structure, and then kinematic characteristics of the developed manipulator are analyzed. Finally, the design analysis of the kinematic characteristics by changing hinge thickness and structure to improve workspace and translation motion is performed to show that the performance of the developed manipulator is relatively superior to the other similar kind of manipulators.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 춘계학술대회 논문집
• /
• pp.557-560
• /
• 2000

The Purpose of this study is analysis of kinematic for a modified manipulator and experimental test to certify auto-balancing operation. The test is carried out as follows. First, we solve the inverse kinematics and then do a closed loop control. Second we confirm translation displacement and rotation angle of a manipulator.

• 한국생산제조학회지
• /
• 제23권2호
• /
• pp.164-172
• /
• 2014

This paper presents a method for analyzing the stiffness of full and low DOF (degree of freedom) planar parallel manipulators with serially connected legs. The individual stiffness of each leg is obtained by applying reciprocal screws to the leg twist using passive joints and elastic elements consisting of actuators and links. Because the legs are connected in parallel, the manipulator stiffness is determined by summing the individual leg stiffness values. This method does not require the assumption that springs should be located along reciprocal screws and is applicable to a planar parallel manipulator with a generic or singular configuration. The stiffness values of three planar parallel manipulators with different DOFs are analyzed. The numerical results are confirmed using ADAMS S/W.

• 동력기계공학회지
• /
• 제19권6호
• /
• pp.5-11
• /
• 2015

The 6DOF (degrees of freedom) Parallel Manipulators have some advantages that are high power, high rigidity, high precision for positioning and compact mechanism compared with conventional serial link manipulators. For these Parallel Manipulators, it can be expected to work in the new fields such that the medical operation, high-precision processing technology and so on. For this expectation, it is necessary to control the action reaction pair of forces which act between the Parallel Manipulator and the operated object. In this paper, we analyze the dynamics of the 6DOF Parallel Manipulator and present numerical simulation results.