http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Qinchuan Li (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
Tex3: An 2R1T Parallel Manipulator with Minimum DOF of Joints and Fixed Linear Actuators
Lingmin Xu,Qinchuan Li,Junhua Tong,Qiaohong Chen 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.2
A new 2R1T (R: rotation, T: translation) parallel manipulator (PM), called Tex3, is proposed. The Tex3 PM is a 2PUR-PRU PM consisting of 9 joints with 12 DOFs (degrees of freedom), and can be actuated by fixed linear actuators. Mobility analysis shows that it is an RPR-equivalent PM whose finite motion is the product of a rotation (R) followed by a translation (P) and another rotation (R). Inverse position and velocity analyses are discussed. Furthermore, the local transmission index and good transmission workspace are used to evaluate the motion/force transmissibility of the proposed PM. The singularity loci of the proposed PM are obtained according to the motion/force transmissibility, corresponding to the inverse, forward and combined kinematic singularity. The constraint singularity is also discussed. Finally, link parameters are optimized to obtain an improved good transmission workspace. Because of its minimum DOF of joints and fixed linear actuators, the Tex3 PM has good kinematic performance and is suited to the high-speed machining of workpieces with curved surfaces.
-
Elastostatic Stiffness Analysis of a 2PUR-PSR Overconstrained Parallel Mechanism
Chao Yang,Qiaohong Chen,Junhua Tong,Qinchuan Li 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.4
The elastostatic stiffness performance of a 2PUR-PSR (S: spherical joint; U: universal joint; R: revolute joint; P: prismatic pair) overconstrained parallel mechanism with two rotational and one translational (2R1T) degrees of freedom was studied based on screw theory and strain energy. First, the actuator and constraint wrenches of the mechanism were obtained based on screw theory. Second, by considering the space composite elastic deformation of the rod (including axial tension, and shear, torsional and bending deformation), compact limb stiffness matrixes were obtained in terms of strain energy and Castigliano’s second theorem. Finally, analytic expressions for the overall stiffness matrix of the mechanism and the amplitudes of the actuator and constrained wrenches were obtained based on the virtual-work principle and the balance equation for a moving platform. The relative error between results from the analytical model and the Workbench finite element model is approximately 1.3%, which validates the effectiveness of the proposed elastostatic stiffness model. Unlike traditional stiffness evaluation index, a regional stiffness index was proposed to measure the mechanism’s stiffness performance at various working heights. Using the index, it is possible to determine the optimum stiffness region of a moving platform with known external wrenches.
-
Yekai Tu,Qiaohong Chen,Wei Ye,Qinchuan Li 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.6
Parallel manipulators (PMs) with 3T1R (three translational and one rotational degrees of freedom) or Schönflies motion are very useful in industry. However, most 3T1R PMs have a limited range of rotation less than 90° while many practical tasks require a large range of rotation over 180°. Furthermore, there are no 3T1R PMs with full rotational capability that has small number of single-DOF joints and fixed actuators. A novel 2-(RRR) 2 RH PM with full rotational capability is proposed, where R and H denote a revolute joint and a helical joint, respectively. The moving platform is connected to the fixed base by two identical (RRR) 2 RH chains, where (RRR) 2 denotes a 2-RRR closed chain. First, kinematic analysis of the proposed 2-(RRR) 2 RH PM, including mobility analysis, inverse and direct kinematics, singularity analysis, and workspace is presented. Second, the local conditioning index is used to evaluate the kinematic performance of the PM. Finally, optimal kinematic design of the 2-(RRR) 2 RH PM is investigated. The 2-(RRR) 2 RH PM has only 16 single-DOF joints and can be actuated by four fixed revolute joints. These features make it a good candidate in many applications.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
