Study On The Coupling Whirling Motion Behavior And Control Method In System Of BTA Drill Pipe And Workpiece

As rapid development of production technology nowadays,deep hole processing technology have been more used in aerospace,weapons,high-speed rail and other important areas of manufacturing.However,because of the large length to diameter ratio in deep hole processing,in the process,the drill pipe has active vibration and whirling,these phenomena damage the surface quality of the hole,such as surface finishments,dimensions and tolerances.Deep hole processing is the most complex drilling process in the machinery manufacturing industry,so the price is the most expensive.In this paper,the following work is carried out on the whirling phenomenon of the drill pipe-workpiece in the deep hole machining process of BTA.Based on the hydrodynamic lubrication theory and the inherent vibration equation of the beam,the transverse vibration equation of the drill pipe-workpiece system is established,and considering the disturbance of the high-pressure cutting fluid to the drill pipe processing section,the differential equation of transverse vibration of the drill pipe-workpiece system is improved.Finally,the dynamic differential equation is solved according to the vibration theory,and the differential equation contains a pair of control excitation.Based on the strain sensor,the horizontal displacement detection device of the drill pipe is designed,and three experiments are designed: Experiment 1,the horizontal displacement of the drill pipe is measured when the drill pipe is free to rotate.Experiment 2,the transverse displacement of the drill pipe is measured at the initial stage of the drilling,and the center trajectory of the drill pipe at different speeds is drawn.Experiment 3,different cutting parameters for drilling are set,and the straightness,surface roughness of the processed deep hole workpieces are measured.Based on the straightness and surface roughness measured by experiment 3 to error calculation,the off-line operation model with fuzzy logic model is proposed,which is used to measure the results obtained in the experiment and predict the cutting parameter combination for best surface quality.According to the motion differential equation,the simulation control model is established by using MATLAB/Simulink software,and the whirling characteristics of the drill pipe under different control positions and different control excitation are given.The results show that influenced by different aspects,the drill pipe in BTA deep hole processing has whirling and lateral vibration,and the lateral displacement measuring device based on strain displacement sensor can accurately measure the lateral displacement of the drill pipe.The drill pipe center trajectory diagram can reflect the correctness of the mathematical model.The off-line operation model based on fuzzy logic can well predict the combination of cutting parameters for the best surface quality.At a certain speed,the different position of the external control excitation and different excitation type will have different influence on the whirling suppression effect of the drill pipe.In this paper,the whirling phenomenon of the drill pipe is elaborated in detail,and the corresponding control method is put forward,which is of practical significance.