Research On Dynamics And Simulation Of Compliant Mechanisms Based Two Types Of Compliant Units

With the development of modern mechanisms, the application of compliantmechanisms becomes more and more widespread. It has a wide range of applications inminimally invasive surgery, micro-switch technology, precision positioning, precision andultra-precision manufacturing, precision operation, and micro-electromechanical systems(MEMS). Presently, the researches of compliant mechanism are focus on: static andkinematics analysis; kinetic analysis; topology optimization design. Among them, thedynamics of compliant mechanism is relatively less studied. The design and research ofcompliant mechanisms is usually very complex. The application of compliant mechanismsis very wide, but the design of compliant mechanisms is usually just to satisfy the missionrequirements. It did not do in-depth research on the dynamics characteristics of compliantmechanism.The research of flexible hinge and flexible beam is the basic theory. The main study isthe dynamics of compliant mechanisms constituted by the two units.Firstly, the calculation method of bending stiffness and tensile (compression) stiffnessof three types of flexible hinges are studied. And the finite element simulation experimentsare finished. Through the compare of simulation data and theoretical results, it is provedcorrect. So, it also can be used in the research of dynamics of compliant mechanism.Subsequently, the distribution of normal stress and shear stress of three types of flexiblehinges are obtained by the theory of pure bending beam. The positions of the maximum ofnormal stress and shear stress are found and it can provide theoretical support for the designof flexible hinge.Secondly, the pseudo-rigid body models of two types of flexible beams are built by the method of pseudo-rigid body. The kinetic energy and potential energy of the two types offlexible beams are studied. The derivation of kinetic energy formula and the data fitting ofcoefficients of kinetic energy equivalent are finished mainly. It can help simplify theformula and provide the basis for the dynamics studies of compliant mechanism basedflexible beam.By the research of two units, the studies of dynamics of three types of compliantmechanisms based on the two units are finished. A type of five-bar slider compliantmechanism is studied in the paper. The statics, kinematics and dynamics of the compliantmechanism are mainly discussed by the method of pseudo-rigid-body model. Dynamicsimulation is finished by the dynamics simulation software, and the simulation results ofhinge points and torsion springs are obtained. Simulation data can provide theoreticalsupport for optimization of compliant mechanism; the dynamics analysis of compliantmechanism based on flexible beam is usually very complex. The dynamics analysis of aparallel-oriented compliant mechanism is finished by the method of pseudo-rigid-bodymodel in the paper. But for the large deformation of compliant mechanism in which all theunits are flexible beams, ANSYS finite element nonlinear technique is introduced and thesimulation experiment is enumerated. For this type of compliant mechanism, a new designmethod is raised and it can improve the design efficiency; at last, the dynamics analysis of atype of five-bar compliant mechanism based flexible hinges and flexible beam is finishedby the method of pseudo-rigid-body model. The dynamics characteristic is studied, and theinfluence of various parameters on the natural frequency of the system is discussed. Thefinite element simulation is finished. Then, the modal graphs and stress distribution areobtained. It can provide theoretical support for the design this kind of compliantmechanism.