Adaptive Active Vibration Control Of Time-Varying Cutting System For Thin-walled Parts

With the rapid development of aerospace,military industry and other fields,the demand for lightweight,high-performance,strong flexibility,structural complex parts is increasing,among which complex thin-walled parts are active in many cutting-edge manufacturing applications.However,due to the weak rigid characteristics of thin-walled parts and the time-varying characteristics in the process of machining,there will be obvious vibration problems in the milling process of thin-walled parts,which will not only greatly reduce the tool life,limit the machining efficiency,make the process parameter design more complicated,but also ultimately greatly affect the surface integrity of the workpiece.Therefore,it is of great significance to study the dynamic response of time-varying milling of thin-walled parts and to propose a suitable and effective adaptive active vibration reduction method.Aiming at the vibration problem of time-varying cutting system of thin-walled parts,based on the analysis of dynamic response in time-varying milling process of thin-walled parts,the dynamic model of controlled machining system is established,the active vibration control strategy is proposed,the adaptive vibration control method is designed,and the vibration control algorithm is optimized.In order to realize the adaptive active vibration control and improve the efficiency of time-varying cutting system of thin-walled parts The theoretical basis and example reference are provided for the machining accuracy of thin-walled parts.Firstly,based on the analysis of milling conditions of thin-walled workpiece,the piezoelectric fiber sheet attached to the workpiece is used as the vibration control driver to simplify the thin-walled workpiece into Kirchhoff plate.The dynamic model of the controlled thin-walled workpiece is established by combining the strain equation of piezoelectric material and Hamilton principle,and the finite element numerical solution is used to solve the dynamic model.The dynamic model is used to analyze the response characteristics of the controlled thin-walled parts in the driven state,which provides theoretical support for the subsequent control algorithm.In order to verify the effectiveness of the piezoelectric fiber sheet as the control driver,the output characteristics of the driven thin-walled parts under the control of the piezoelectric fiber sheet are observed through specific experiments.Then,the control strategy based on acceleration feedback is proposed,and the corresponding equipment selection and system construction are carried out.Considering the time-varying characteristics of thin-walled milling,an adaptive time-space dependent PD control method is proposed,and the corresponding control parameters are selected and the control algorithm based on the Simulink module is implemented.The influence of control system on cutting stability is analyzed by hammering experiment,and the effectiveness of variable PD control method is verified by cutting experiment.Finally,on the basis of variable PD control method,ANFIS system is used to optimize the parameters of the control system.The training data set is collected,the training framework of fuzzy reasoning model is built,and then the fuzzy reasoning model of the controlled thin-walled milling process is obtained.The response prediction and control parameters optimization of the milling process of the controlled thin-walled parts are carried out by using the obtained fuzzy inference model.The reliability of fuzzy reasoning model and the effectiveness of parameter optimization are verified by cutting experiments.