Design and analysis of a novel 2-DoF rotational decoupled adjusting parallel mechanism

In recent years, the study on novel type parallel mechanisms with less degrees of freedom (DoFs) has attracted the attention of many scholars at home and abroad. In this field, type synthesis of parallel mechanisms which can realize decoupling is a frontier subject. To this end, based on the rotational conditions (RCs) presented in our pre-paper, this paper introduces the concept of accompanying movement screw and the synthesis rule of limbs for rotational decoupled parallel mechanisms. According to the above-mentioned workings, a family of 2-DoF rotational decoupled adjusting parallel mechanisms (RDAPMs) is performed based on the screw theory. Moreover, taking a parallel mechanism only with revolute pairs and prismatic pairs as an example, the motion feature of which is analyzed with the constraint screw method, and then its mobility is calculated using the Modified Kutzbach-Grübler criterion. Furthermore, the forward and inverse displacement problems of the proposed manipulator are solved. Finally the kinematic simulation is completed using the ADAMS, which can validate the correctness of the calculation of the DoF, the ability of successive rotation and its movement decoupling.