完全解耦3T2R并联机器人构型综合方法

Structural synthesis method of fully decoupled 3T2R parallel robotic manipulators

针对并联机构内部耦合性带来运动学和动力学分析困难的问题,基于GF集理论提出一种简单而有效的三移动两转动(3T2R)完全解耦构型综合方法。首先,阐述GF集并联机器人构型理论;其次,根据GF集的求和运算和转动轴线迁移定理,给出了机构输入运动副选择原则以及解耦支链设计准则;按照完全解耦并联机构设计步骤,列举出了3T2R并联机构各解耦分支运动链,综合出了含有单、双驱动支链的3T2R五自由度完全解耦并联机构,得到了大量新构型;通过所综合出的一种新型并联机构,运用约束螺旋法对机构的自由度数目和运动特性进行分析,根据机构输入与输出参数间关系式,求解得到机构雅可比矩阵,验证了机构的解耦特性,进一步证明了该构型方法的有效性。研究对解耦并联机构的构型设计具有理论指导意义。

To avoid the difficulties in the kinematics and dynamic analysis brought by the existence of coupling in the parallel mechanism,a very simple yet effective structural design is proposed about three-translational and two-rotational（3T2R）parallel robotic manipulators based on GFset.The GFset theory for type synthesis of parallel mechanisms is firstly introduced.Secondly,according to union arithmetic of GFset and rotational motion planet theorem,the selection criterion of the input pair and type synthesis principle of decoupled branches are given.Following the type synthesis step,the structural synthesis of each kinematic chain for fully decoupled 3T2 Rparallel mechanism is performed,and specific process for structural synthesis of 3T2 Rfive degrees of freedom decoupled parallel mechanism which include sole and double motivation kinematic chain is finished.Simultaneously,a lot of new mechanisms are attained.Finally,constraint screw is applied to analyzing kinematic characteristic of a parallel mechanism synthesized above.The expression of the Jacobian matrix is deduced which validates the decoupling feature of the mechanism.In addition it demonstrates the effectiveness of the novel method of structural synthesis for parallel mechanisms.The research provides a reference and possesses significant theoretical meanings for the synthesis and development of the novel decoupled parallel mechanisms.