Research On EDM Adaptive Control System Of EDM Machine Tool

EDM machine tool is a kind of EDM machine tool,which can realize precise drilling,mirror machining and spherical cavity perforation,but its machining effect depends largely on the EDM control system and control algorithm.The FPGA technology emerging in recent years has a good balance among flexibility,performance,power consumption,and cost,and is widely used in many industries.This subject develops the machining discharge control system of the forming machine tool on the basis of FPGA technology,and then in order to overcome the shortcomings of low machining efficiency and high loss in the EDM process,this subject first establishes a complete machining process for the EDM process.Mathematical model,an adaptive controller is designed according to the model,which improves the processing efficiency and reduces the loss of the electrode.First,the EDM control system of the EDM machine is developed.The EDM numerical control system is divided into two parts: the upper computer and the lower computer.The role of the host computer is for the input of numerical control instructions,the real-time observation of the processing state and the transmission of instructions.The lower computer includes an electrical discharge machining control system,whose main function is to decode and classify the operation instructions transmitted from the upper computer,generate discharge pulse signals and transmit them to the main circuit of the pulse power supply,the driving part,etc.on the machine tool,and is also responsible for receiving the voltage between the poles And current signal,real-time feedback to the host computer.On the basis of FPGA technology,this subject puts forward the design ideas and schemes of each module in the machining control system,and on this basis,develops a hardware platform that can realize machining discharge control,and uses Verilog HDL to complete the system software.write.Secondly,because there are various unstable factors in the EDM process,this paper firstly identifies the EDM process systematically,identifies the mathematical model that conforms to the EDM process through Matlab,and determines the order of the model through the least squares method.The number and parameters are compared,and the reliability is verified by comparing the degree of fit;the online computing model identification problem of the controller object is solved by the recursive least squares method based on UD decomposition.Then,based on the identified EDM model,a minimum variance self-calibration controller that can be adjusted in real time according to the EDM state is built,converted into Verilog HDL,and simulated in Modelsim.Finally,the designed machining control system and adaptive controller are used to conduct EDM experiments through electrodes of different diameters.Compared with the machining mode of the machine tool,the adaptive controller can increase the machining efficiency by 27.27%,and the electrode loss is more than 27.27%.It can be reduced by 26.37%.