Research On Design Method Of A Novel Compliant Linear-Motion And Buffer Mechanisms

Concerning the development of Automatic Weapons Station (AWS) with lightweight and miniaturization, this objective of this paper is to develop a integrated compliant buffer mechanisms with high dynamic performance, high precision, high efficiency and to research the design problem of compliant linear motion and buffer mechanisms, this thesis is composed of the following content:The kinematic model and working principle are the research base of this paper, the composition and structure function of AWS and its working principle are analyzed. Based on homogeneous transformation principle,the kinematic mode of opto-electrical acquisition, tracking system and weapon servo system is established .The pointing error of AWS including the cause of formation are analyzed, relational models between three squareness errors and pointing error of AWS are completed based on rotation matrix theory, and accuracy requirements are presented for the structure optimization design,manufacturing and assembly of the AWS,those are to provide a basement for the compliant buffer mechanism design.Based on the dynamic model of shock damper system, the transient response and maximum energy storage of several buffers under speed step excitation are analyzed. According to shock response limit, three performance indexes of shock damper system are presented: peak acceleration, peak displacement, steady state amplitude. The mathematical expressions of three performance indexes are developed and response characteristics in different damping ratio range are analyzed, the optimization mathematical model for shock damper system is built, the optimum stiffness, damper parameter suitable for three performance indexes at same time are obtained, those are to provide a optimization object for the compliant buffer mechanism.Based on the performance analysis of different compliant beam element, topological structure of compliant beam and compliant linear-motion are designed by using the modular method, making sure that the maximum guiding stroke and highest guiding precision are obtained in the specified area of compliant mechanism, design constraints and design principles of large stroke compliant buffer mechanism are analyzed , modified Roberts compliant buffer mechanism and multi-folded flexible beam compliant buffer mechanism are designed with guiding function and shock damper function, these mechanisms have advantages of the structure axially symmetric, large stroke , high linear motion precision. This method is to provide a design means to design the structure configuration of the compliant buffer mechanisms directly, quickly, and effectively, and to solve the problem of depending on the experience of designers in design processing of compliant mechanism.According to the structural symmetry, the theoretical model of guiding and buffering stiffness is completed by using the method of half model. The effect of elastic deformations of side beam and shear stresses on the guiding and buffering stiffness is analyzed. Force-displacement characteristic of straight compliant beam and arc compliant beam are analyzed also based on the energy method. Accurate theoretical calculation formulations of guiding and buffering stiffness are derived based on the principle of iterative displacement; it can be used for dynamical modeling and analysis. For the accuracy of dynamics modeling, kinetic energy of compliant beam mass is included in the system total kinetic energy. The calculation formulations for lumped mass parameter of cantilever beam, fixed-guided beam, arc compliant beam, side beam are derived based the method of Rayleigh energy. The multi-degree lumped parameter dynamical model of compliant linear-motion and buffer mechanism with the compliant straight beam are built, and the relationship between first order natural frequency and structure parameter are analyzed, it can be used for improving natural frequency, motion precision and performance.The composition of experiment setup is introduced, and force-displacement testing, modal testing, non-linear stiffness testing and damper identification of metal-rubber are completed. Shooting test for the composed shock damper system with compliant buffer mechanism and metal-rubber are accomplished, the accuracy and effective of research method and results are validated.