This paper presents the comparison between serial and parallel manipulators. Day by day, the applications of the parallel manipulator in various field is become apparent and with a rapid rate utilized in precise manuf...This paper presents the comparison between serial and parallel manipulators. Day by day, the applications of the parallel manipulator in various field is become apparent and with a rapid rate utilized in precise manufacturing, medical science and in space exploration equipments. A parallel manipulator can be defined as a closed loop kinematic chain mechanism whose end effector is linked to the base by several independent kinematic chains. The classification of various parallel manipulators is presented herewith. The prime focus of the paper is to realize the parallel manipulators applications for industry, space, medical science or commercial usage by orienting manipulator in the space at the high speed with a desired accuracy.展开更多
A novel high-speed parallel kinematic machine （PKM） named Delta-S parallel manipulator is proposed, which consists of a fixed base connected to a moving platform through three limbs with identical topology. Each lim...A novel high-speed parallel kinematic machine （PKM） named Delta-S parallel manipulator is proposed, which consists of a fixed base connected to a moving platform through three limbs with identical topology. Each limb is composed of one driving ann and one follower arm, herein, the latter includes two strings and one middle rod, all located in a same plane. Compared with similar manipulators with uniform parameters, the novel and unique topology as well as the addition of two strings of Delta-S manipulator can remove the clearance of the spherical joints, reduce the inertial load of components further, improve the positioning accuracy and dynamic performance, and so on. In order to formulate the kineto-static model of Delta-S manipulator, the kineto-static analyses and models of the driving arm, the generalized follower and the moving platform can be carried out by the D＇ALEMBERT principle. For the sake of obtaining the force analytic results of strings, the deformation compatibility condition of strings and the middle rod are determined. Furthermore, in virtue of the assumption of small deformation and the linear superposition principle, the minimal pre-tightening force of the strings is calculated. The main results include that the loads of the strings and the middle rod must be larger than ＂zero＂ and the pre-tightening force over the workspace must be larger than the minimal pre-tightening force at any time within the workspace, which lay the foundation for the dynamic analysis and the prototype manufacture of the Delta-S manipulator.展开更多
针对DELTA并联机械手的振动与冲击问题,提出一种适用于DELTA并联机械手P-A-P(pick and place)拾取轨迹的梯形加速度算法。该算法采用高次多项式为过渡曲线并考虑端点处的边界条件,与电机控制中常用的修正梯形、正弦和多项式加减速算法相...针对DELTA并联机械手的振动与冲击问题,提出一种适用于DELTA并联机械手P-A-P(pick and place)拾取轨迹的梯形加速度算法。该算法采用高次多项式为过渡曲线并考虑端点处的边界条件,与电机控制中常用的修正梯形、正弦和多项式加减速算法相比,能在满足并联机械手高速运行的情况下,尽可能地减小末端执行器的振动和电机轴的冲击。通过虚拟样机仿真,测得末端加速度和电机轴扭矩曲线,并与修正梯形加减速算法的结果进行比较,证明该算法在减小末端冲击和振动方面具有更大的优越性,满足机械手的要求。展开更多
文摘This paper presents the comparison between serial and parallel manipulators. Day by day, the applications of the parallel manipulator in various field is become apparent and with a rapid rate utilized in precise manufacturing, medical science and in space exploration equipments. A parallel manipulator can be defined as a closed loop kinematic chain mechanism whose end effector is linked to the base by several independent kinematic chains. The classification of various parallel manipulators is presented herewith. The prime focus of the paper is to realize the parallel manipulators applications for industry, space, medical science or commercial usage by orienting manipulator in the space at the high speed with a desired accuracy.
基金Projects(50175295,50675151) supported by the National Natural Science Foundation of ChinaProject(11JCZDJC22700) supported by Tianjin Science and Technology Program,ChinaProject(2007AA042001) supported by the National High Technology Research and Development Program of China
文摘A novel high-speed parallel kinematic machine （PKM） named Delta-S parallel manipulator is proposed, which consists of a fixed base connected to a moving platform through three limbs with identical topology. Each limb is composed of one driving ann and one follower arm, herein, the latter includes two strings and one middle rod, all located in a same plane. Compared with similar manipulators with uniform parameters, the novel and unique topology as well as the addition of two strings of Delta-S manipulator can remove the clearance of the spherical joints, reduce the inertial load of components further, improve the positioning accuracy and dynamic performance, and so on. In order to formulate the kineto-static model of Delta-S manipulator, the kineto-static analyses and models of the driving arm, the generalized follower and the moving platform can be carried out by the D＇ALEMBERT principle. For the sake of obtaining the force analytic results of strings, the deformation compatibility condition of strings and the middle rod are determined. Furthermore, in virtue of the assumption of small deformation and the linear superposition principle, the minimal pre-tightening force of the strings is calculated. The main results include that the loads of the strings and the middle rod must be larger than ＂zero＂ and the pre-tightening force over the workspace must be larger than the minimal pre-tightening force at any time within the workspace, which lay the foundation for the dynamic analysis and the prototype manufacture of the Delta-S manipulator.
文摘针对DELTA并联机械手的振动与冲击问题,提出一种适用于DELTA并联机械手P-A-P(pick and place)拾取轨迹的梯形加速度算法。该算法采用高次多项式为过渡曲线并考虑端点处的边界条件,与电机控制中常用的修正梯形、正弦和多项式加减速算法相比,能在满足并联机械手高速运行的情况下,尽可能地减小末端执行器的振动和电机轴的冲击。通过虚拟样机仿真,测得末端加速度和电机轴扭矩曲线,并与修正梯形加减速算法的结果进行比较,证明该算法在减小末端冲击和振动方面具有更大的优越性,满足机械手的要求。
