与串并联机构运动等效的新型并联机构综合方法研究

Research on Synthesis Method of Novel Parallel Mechanisms with Equivalent Motion to Serial-parallel Mechanism

为简化串并联机构结构,使该类机构得到更好的应用,提出一类与串并联机构运动等效的并联机构,其特点在于没有中间平台,两个并联机构通过对应分支直接连接或共用部分运动副连接在一起融合为一个整体机构。基于螺旋理论,提出了这类并联机构综合方法,给出了综合条件,制定了综合流程。采用该方法,对与三转动机构和三平移机构构成的串并联机构运动等效的新型6自由度并联机构进行了综合,综合出多种新机构,丰富了并联机构构型。新型6自由度并联机构结构上具有结构简单、紧凑,轻量化的优点。对综合出的机构进行约束力分析表明,球面三转动子机构力学分析中不存在静不定问题。综合的6自由度并联机构以其在结构和分析上的优点,在指向隔振等领域具有良好的应用前景。

In order to simplify the structure of the serial-parallel mechanisms and make this kind of mechanisms better applied, a novel kind of parallel mechanisms with equivalent kinematics to serial-parallel mechanisms are proposed. The difference is that two parallel mechanisms are directly connected through corresponding branches or indirectly connected through the common kinematic pairs of corresponding branches to form an integral mechanism with no intermediate platform. Based on screw theory, a new synthesis method for this kind of novel mechanisms is proposed, the synthesis conditions are given and the synthesis process is formulated. With this metho d, new six degrees of freedom(6-DOF) parallel mechanisms with equivalent kinematics to serial-parallel mechanisms composed of 3-DOF rotational mechanisms and 3-DOF translational mechanisms are synthesized. Some new mechanisms have been synthesized, which enriches the parallel mechanism configurations. The new 6-DOF parallel mechanisms have simple and compact structure. The constraint force analysis indicates that there exists no statically indeterminate problem in the spherical 3-DOF rotational mechanism. The synthesized 6-DOF parallel mechanisms have potential application to pointing and vibration isolation platform for the advantages of structure and analysis.