Study Of Multi-dimensional Vibration Isolation Based On Limited-DOF Parallel Mechanism

With the increasing demand of precision and service life of equipments and the comfort of travelling in vehicle, it becomes an important problem of engineering how to control and prevent harm caused by dimensional vibration effectively. Traditional method of multidimensional vibration isolation cannot meet the requires of vibration control, in recent years, some scholars applicate parallel mechanisms to the multidimensional vibration isolation platform, and made some breakthrough, but due to actual application in many situations, we don’t needs completely achieved six DOF of vibration isolation, and limited-DOF parallel mechanism can both meet the needs of freedom number, and make mechanisms simplified, economic, easy-controlled, so research on related theory is necessary.This paper is funded by the National Natural Science Foundation of "precision equipment based on flexible metamorphic mechanism study on active multidimensional vibration control(51275275)" and the Fund for outstanding young scientists research award in Shandong Province "research on the active vibration control of precision equipment based on flexible metamorphic mechanism (BS2010ZZ006)",and research on the limited-DOF parallel mechanism theory and its application study of multi-dimensional vibration isolation.Based on the limited-DOF parallel mechanism theories, the thesis designed a3-DOF parallel mechanism and4-DOF parallel mechanism, these two parallel mechanisms have simple structure, compact models, high precision, easier to control and so on, and similar structure make it easier to convert each other, they can build multi-dimensional vibration isolation platform as the main body, achieving three and four dimensional vibration isolation.Firstly, the limited-DOF parallel mechanism applied to multidimensional vibration area,we made an analysis of limited-DOF parallel mechanism with integrated and then designed limited-DOF parallel mechanism according to the dimensional vibration characteristics, verified binding screw theory on the mechanism of freedom analysis. Secondly, the design for kinematics and mechanics analysis of limited-DOF parallel mechanism on its inverse kinematics, speed, velocity, mechanics equation solving, the result of analysis proves these two bodies of kinematics and mechanics equation is relatively simple, body has good decoupling, suitable for use as a main mechanism for vibration isolation platform.Thirdly, put the limited-DOF parallel mechanism as the main body of multi-dimensional vibration isolation platform respectively and find out the location of the active pairs and add spring-damper system for constructing a multidimensional vibration isolation platform model, then establish the dynamic equations and analyze the natural frequencies and the effect of structure parameter variation on natural frequency of the system.The last, we use dynamic simulation software Adams for simulating the vibration isolation platform on kinematics and dynamics, compared and validated of the results of the analysis with Matlab software computing, it proves that the platform has good dimensional vibration isolation effect.Our studies of multi-dimensional vibration isolation based on two limited-DOF parallel mechanisms show that: the two parallel mechanisms are able to achieve three-and four-dimensional vibration isolation, it’s suitable as the main body of multi-dimensional isolation platform vibration for its excellent performance in isolation. At the same time, two mechanisms are similar, and can converse by changing one of the kinematic pairs, it’s the foundation for further metamorphic studies.