Dimensional Synthesis of a 3-DOF Parallel Manipulator with Full Circle Rotation

• Published in: Chinese journal of mechanical engineering 2015-07, Vol.28 (4), p.830-840
• Main Authors: Ni, Yanbing, Wu, Nan, Zhong, Xueyong, Zhang, Biao
• Format: Article
• Language: English
• Subjects: Algorithms; Angles (geometry); Electrical Machines and Networks; Electronics and Microelectronics; Engineering; Engineering Thermodynamics; Heat and Mass Transfer; Instrumentation; Jacobi matrix method; Jacobian matrix; Kinematic equations; Kinematics; Machines; Manipulators; Manufacturing; Mapping; Mechanical Engineering; Optimization; Parallel degrees of freedom; Parameters; Performance indices; Perturbation; Position errors; Power Electronics; Processes; Robot arms; Robots; Rotation; Synthesis; Theoretical and Applied Mechanics; Translations; Vector analysis; 位置误差; 并联机器人; 旋转自由度; 末端执行器; 机构尺度综合; 研究成果; 综合性能指标; 运动学分析
• ISSN: 1000-9345; 2192-8258
• DOI: 10.3901/CJME.2015.0122.051

Parallel robots are widely used in the academic and industrial fields. In spite of the numerous achievements in the design and dimensional synthesis of the low-mobility parallel robots, few research efforts are directed towards the asymmetric 3-DOF parallel robots whose end-effector can realize 2 translational and 1 rotational（2T1R） motion. In order to develop a manipulator with the capability of full circle rotation to enlarge the workspace, a new 2T1 R parallel mechanism is proposed. The modeling approach and kinematic analysis of this proposed mechanism are investigated. Using the method of vector analysis, the inverse kinematic equations are established. This is followed by a vigorous proof that this mechanism attains an annular workspace through its circular rotation and 2 dimensional translations. Taking the first order perturbation of the kinematic equations, the error Jacobian matrix which represents the mapping relationship between the error sources of geometric parameters and the end-effector position errors is derived. With consideration of the constraint conditions of pressure angles and feasible workspace, the dimensional synthesis is conducted with a goal to minimize the global comprehensive performance index. The dimension parameters making the mechanism to have optimal error mapping and kinematic performance are obtained through the optimization algorithm. All these research achievements lay the foundation for the prototype building of such kind of parallel robots.