中文摘要：

提出一种新型的过约束2RPU＋UPU机构,该机构的两个RPU分支一共提供了4个约束,但由于机构运动副的特殊布置,其中的两个约束为过约束。机构中的UPU分支为机构提供了一个约束力。建立该机构的速度约束方程,并基于此分析了该机构的自由度。建立该机构的几何约束方程,确立表达机构末端位姿的独立运动参数。导出机构上平台的位姿、速度和加速度耦合关系。求解该机构的运动学反解、速度、加速度,建立机构RPU分支和UPU分支详尽的运动学模型。基于虚功原理和该机构的运动学模型建立该机构的动力学模型,并采用Matlab软件对该机构动力学进行模拟仿真,模拟结果表明理论结果完全正确。所用的方法同样适合于其他过约束并联机构。

英文摘要：

A novel 2UPR＋SPR parallel manipulator（PM） is proposed.The two RPU legs of this PM provide four constraints whereas two of them are overconstraints due to the particular arrangement of the joints in RPU legs.The UPU leg provides one constrained force for this PM.The velocity constraint equation of this PM is established,and based on this,the degree of freedom of this PM is analyzed.The geometric constraint equations of this PM are established,the independent motion parameters which express the pose of mechanism end are determined,and the coupling relations of the pose,velocity and acceleration of the platform on the mechanism are derived.The inverse kinematics,velocity and acceleration of this PM are solved,and the detailed kinematics model of RPU and UPU type leg is established.The dynamics model is established on the basis of the principle of virtual work and the kinematics model of this PM,and the simulation of mechanism dynamics is implemented by using Matlab software.The simulation results testify the validity of the analytic model.The analytic method for this PM is fit for other over-constrained PMs.