Research On Design And Experiment Of A XY-Decoupled Compliant Mechanism With High Modal Damping Using Embedded Local Resonance Metastructure

As high speed and high precision manufacturing technology is widely used in various fields,the requirements of the performance of nano-manufacturing systems are becoming higher and higher.The most important indexes of nano-manufacturing systems including speed of operating,range of stroke and accuracy of positioning depend on their core component which are nano-positioning platforms.Generally speaking,the main body of the nano-positioning platform is a compliant mechanism,which has the advantages of fast response speed and high positioning accuracy.However,the first-order natural frequency and low modal damping of compliant mechanism greatly limit the usable frequency bandwidth of the platform.Therefore,in order to solve the problem of low modal damping of traditional compliant guidance mechanism,this paper proposes a method of embedding local resonance matastructure to enhance the first-order modal damping of compliant mechanism,so as to improve the motion control bandwidth of the platform.The main research contents are as follows.1)Study on modal damping enhancement mechanism of embedded local resonance metastructure.Using discrete dynamics theory,an equivalent theoretical dynamics model of a compliant guided structure with local resonant metastructure is established.According to the characteristics of motion and restraints from the rigid members of typical mechanisms,the influence of the characteristic parameters of the embedded matastructure on the absorbing ability of the modal vibration and the corresponding equivalent modal damping are studied.Finally,the theoretical optimization parameters and optimization results are given.2)Structure design of a XY decoupling compliant guide mechanism and research on its dynamic characteristics.A two-degree-of-freedom decoupling compliant steering mechanism was designed by using the traditional compliant mechanism design method and theory.Combining Bernoulli beam theory,Castigliano's second theorem and Lagrange's equation,the corresponding dynamic model is derived.Based on this model,the compliant guide mechanism was optimized to maximize the range of stroke and bandwidth.3)Design and optimization of metastructure embedded in the compliant mechanism.The configuration of a local resonance metastructure unit is proposed,and the first-order natural frequency and frequency response result of a single metatructure unit are obtained by using finite element simulation.While maintaining the equivalent modal mass and modal stiffness of the compliant guide mechanism,several meatstructure units are combined with a pre-designed frame to be embedded in the stage.The finite element optimization method is used to optimize the characteristic parameters of the each metastructure unit.The optimized modal damping and control bandwidth of the stage with metastructure were evaluated.4)Research on the control bandwidth of the strong modal damping compliant guide mechanism.The compliant guide mechanism with and without embedded local resonance metastructure were analyzed experimentally by respectively using proportional-integral control algorithm(PI)and integral resonance control algorithm(IRC)to verify the method of enhancing modal damping by embedding local resonance metastructure can greatly improve the control bandwidth of the compliant mechanism.