An Adaptive Adjustment Method Of Floating Clamping For Large Complex Structural Parts NC Machining

Supported by the National S&T Major Project and the National Natural Science Foundation of China,considering the demands of aviation and aerospace industry,in the view of problems that the deformation of complex stuctural parts NC machining is intricate,problems existing in floating clamping processing method to reduce deformation,the adaptive adjustment method of floating clamping for the large complex structures NC machining was deeply studied.The main achievements of this paper are as follows:(1)The triggering method of floating clamping adaptive adjustment based on the clamping force monitoring is proposed.Analysis of the main factors influencing the deformation of aluminium alloy structural parts was conducted.The deformation pattern of aluminium alloy structural parts NC machining was analyzed.Discrete intermediate processing state of the workpiece was established prior.Calculating deformation of processing intermediate state based on real-time monitoring clamping force using simulation tools.The strategy for floating clamping adaptive adjustmentd triggering was realized.According to real-time monitoring clamping force adaptively trigger floating clamp open,thus free deformation.(2)The adjust method of workpiece position and posture based on detecting data is proposed.The detection of deformation is triggered by deformation monitoring data.Detecting point was automaticly planned based on machining features.Machining allowance was calculated based on detecting data and theoretical models of the workpiece.Uniformity of machining allowance is the optimizing purpose.Theoretical end model enveloped by intermediate processing state of the workpiece is the constraints.Workpiece position and orientation was optimized based on genetic algorithm.Workpiece position and orientation was adjusted through the float fixture.(3)The cooperative control method of floating fixture and CNC machine tool is proposed.Some key technologies of the method was researched,Floating fixture adaptive control system communication based on CAN bus,force real-time monitoring and deformation detection on the workpieces by the sensors,monitoring NC machine state based on OPC.According to monitoring and detection information,the floating fixture system realizes interactive control of with NC machine tool.(4)According to the above research,Control system based on cooperative control of floating fixture and NC machine tool is designed.The stability and reliability of control system is verified during machining aircraft structural parts in aviation manufacturing enterprises.