Study On Structural Optimization Of Key Components And Dynamic Performance Control Of Micro-machine Tool

Micro-machining technology is one of the key technologies for manufacturing high-performance parts.The machining accuracy and surface quality of high-performance parts limit the performance of high-end equipment.At present,China is far from other developed countries in the field of micro-machining.Accelerating the research on micro-machining machine tools and their key technologies is of great significance in improving the international competitiveness of high-end equipment manufacturing in China.This paper aims at optimizing the dynamic performance of Micro-machining machine tools.Based on the dynamic performance analysis of the micro-machining machine tool,the optimization of the key components of the micro-machining machine tool and the active control of the dynamic performance are studied.The main contents of the paper are as follows:1.According to the target of the subject,we developed a vertical micro-machine tool for the machining of flexible joint blade with integral double-balanced rings in the field of inertial navigation.A new Sofa style Machine Bed Structure(SMBS)is designed to lower center of gravity of the machine by more than 40 mm,reduce the total static deformation at the tool tip,and meets the installation requirements for vertical hydrostatic stage.2.Based on the analysis of the dynamic characteristics of the whole machine,the key weak components are identified and the optimization of Weak Component based on Sensitivity Analysis(OWCSA)are proposed.The bolt layout is optimized by analyzing the pressure distribution in interface,which effectively improves the contact pressure of interface and the stiffness of the machine tool.3.Based on the vibration characteristics of the micro-machining machine tool,a series two-degree-of-freedom active vibration reduction platform and a two-stage active vibration isolation platform were developed.The series two-degree-of-freedom active vibration reduction platform solves the kinematic interference between two motion axes existing in the traditional parallel platform,realizes kinematic decoupling,reduces the complexity of the control algorithm,and improves the control accuracy.The designed two-stage active vibration isolation platform takes into account the advantages of active vibration isolation and passive vibration isolation,and focuses on increasing the attenuation of low-frequency vibration.4.Based on the linear matrix inequality(LMI)optimization method,the cutting force is regarded as the external disturbance to the system,and the workpiece vibration is taken as the control target.A constrained multi objective active vibration control algorithm(CMOAVCA)is designed.Based on the filtered least mean square algorithm(Fx-LMS)and actuator characteristics,an improved Fx-LMS active vibration isolation algorithm was designed.the effectiveness of the algorithms is verified through engineering experiments.The optimization method of key components and dynamic performance control method of micro machine tool active vibration control platform has been applied to micro-machining machine tools,achieving an increase in the stability of the machine’s overall structure under ultra-high-speed machining conditions.The machine’s first three natural frequencies are Increased by more than 10%,the maximum resonance displacement of the whole machine in X,Y,and Z directions was reduced by 8.6%,6.4%,and 10.1%,respectively.Vibration control platform and vibration isolation platform under the control of the corresponding algorithm,achieve micro-processing vibration attenuation in the horizontal direction of 20%,in the vertical direction of the vibration attenuation of 30%,which provides a new equipment for high-quality,high-efficiency micro-processing.