Research On The PZT Driven Focus Control System Of Laser Cutting Machine

Laser cutting has many advantages such as high quality,high efficiency and high flexibility,and it has became the most important and the most advanced material cutting method.The laser processing technology is the most widely used in the fields of machinery,steel,automobile,shipbuilding,aerospace and other industries.However,because of the development of production and the application of new technology,so the shape of parts becomes more and more complex,and the requirement of laser cutting quality is higher and higher.In this paper,we focus on the control of laser lens,and then changing the relative position of the central axis of the laser beam and the middle axis of the auxiliary gas can improve the quality of laser cutting,The micro positioning platform of PZT driven laser cutting machine is designed,and the control system of micro positioning platform is designed.Firstly,in this paper the overall structure of the PZT driven laser cutting machine focus control micro positioning platform is designed.The orthogonal analysis method is used to design the diamond displacement amplification mechanism,and the size parameters of micro positioning platform in X and Y direction is determined,and the influence of size parameters on the magnification of displacement amplifier is studied.The guide mechanism of micro positioning platform is analyzed,and the symmetrical elastic plate flexible hinge as the guiding mechanism was determined.The static analysis of the micro positioning platform of PZT drive laser cutting machine.The static analysis of the symmetric elastic plate flexure hinge is presented,and the influence of size parameters on the stiffness of symmetric elastic plate is studied.The static analysis of the PZT driven laser cutting machine micro positioning platform for the focal point control was based on the law of conservation of energy,and the influence of size parameters on the magnification of micro positioning platform is analyzed.The maximum displacement output,stress distribution and frequency response performance of the micro positioning platform were analyzed by using the finite element analysis software.Dynamic analysis of the PZT driven laser cutting machine focus control micro positioning platform.The stiffness model of micro positioning platform was established,and the differential dynamic equation of the micro positioning platform is established by using Lagrange dynamics method,and then the transfer function of the micro positioning platform is deduced.Matlab Simulink is used to design the PID controller,In X direction that the P=300,I=350000,D=0.1,and in Y direction that the P=300,I=400000,D=0.1.Finally,the experimental test system of PZT driven laser cutting machine focus control micro positioning platform is built.The maximum output displacement of the micro positioning platform in X direction is 351?m,and maximum output displacement of the micro positioning platform in Y direction is 386?m.In the closed loop PID control,in X direction P=300,I=350000,D=0.1,the response time is 0.35 s,in Y direction P=300,I=400000,D=0.1,the response time is 0.35 s.The minimum displacement resolution of the micro positioning platform in the X direction is about 4?m,and the minimum displacement resolution of the micro positioning platform in the Y direction is about 3?m.The repeat positioning accuracy in X direction is ±2.301?m,and the repeat positioning accuracy in Y direction is ±2.343?m.