Configuration Synthesis And Design Of Elastic Micro Deformation Parallel Mechanism Based On Statics/Dynamics Multi-objective Topology Optimization Theory

The mechanism of micro elastic deformation is a novel mechanism,it is combined with the structural characteristic of micro elastic deformation mechanism and parallel mechanism,it contains the advantage of micro elastic deformation mechanism such as friction-free,non-wear,no moving clearance and free assembly etc and also has the advantage of parallel mechanism such as high kinematic accuracy,high bearing capacity,strong stability and multi-degree of freedom motion etc.Due to the material characteristic of high flexibility,micro elastic deformation mechanism shows high flexibility and can easily generates obvious derivative movement during operation,it also can easily cause vibration disturbance from external dynamic excitation in the complex operating environment.In order to eliminate this disadvantage of micro elastic deformation and improve its accuracy during its working process,it is necessary to introduce a practical design method to design the configuration of micro elastic deformation mechanism.Topology optimization of continuum structure is one of the most frontier research topic in structure optimization design field,it is also a hot research recently.This paper mainly researched the relative theory research and example application of Solid Isotropic Microstructures with Penalization(SIMP)for continuum structure,optimization algorithms and the methods of overcoming the instability of topology optimization results etc.Optimization solution algorithm is the core and difficulty in structural optimization design problem,this paper systematically analyzed the optimization algorithm of continuum structure that focused on Optimality Criteria Method(OC Method)and Moving Asymptote Algorithm(MMA Method),and the characteristics of different algorithm and their own application is analyzed and compared.In addition,the key to solve the optimal configuration is to build a correct optimization model,this paper mainly systematically expounded the SIMP material interpolation model and level-set optimization model,some related case analysis is followed.This topic designs the optimal structure of micro elastic deformation mechanism that accord with product performance.The main content is :1)?Firstly,establishing the differential Jacobian matrix equation of parallel prototypical mechanism,the vector isomorphic mapping between micro elastic deformation mechanism before optimization and parallel prototypical mechanism is realized.According to this relationship,the SIMP material interpolation model of micro elastic deformation parallel mechanism which has been built,solving this optimization model used optimality criteria.Meanwhile,modal analysis used to solve the low-order natural frequencies micro elastic deformation mechanism.2)?Then,Based on compromise programming method of static stiffness and average frequency method of vibration natural frequency,the multi-objective optimization function is defined,and volume fraction is adopted as constraint condition to establish SIMP multi-objective topology optimization model of micro elastic deformation parallel mechanism.The analytical hierarchy process method(AHP)is applied to construct decision matrix and solve the matrix's eigenvalue and eigenvector,in order to determine the weight coefficient of sub-objectives in the actual engineering problem.AHP method is to divide elements related to decision-making into objective,criteria and scheme etc hierarchy,and precede the decision-making method based on qualitative and quantitative analysis.3)?Finally,by comparing its simulation of stress distribution and first four vibration natural frequencies before and after optimization,it shows that this optimal configuration can not only reduce the flexibility but improve the low-order natural frequencies greatly,meanwhile,the simulation of differential kinematical characteristics shows differential kinematics of isomorphism between the optimal configuration after optimization and traditional parallel prototypical mechanism.Above all,based on multi-objective topology optimization,the optimal micro elastic deformation mechanism of 2R1 P kinetic characteristic not only effectively improves its static stiffness,but also greatly improves its low-order natural frequencies of vibration.Besides,the crossover oscillation of the frequency weakened and convergence obviously during the optimization process.This research provides the theoretical basis and method for optimization design of engineering mechanism and architectural engineering structure in actual engineering application,establishes the theoretical foundation for the development of multi-objective topology optimization theory,offers an efficient and novel optimal design method for the configuration optimization of micro elastic deformation mechanism and traditional parallel mechanism.