Study On Design And Control Of The Fast Tool Servo For Fabricating Microlens Arrays

The microlens array that is a kind of optical elements which are composed by a series of microlens what are arranged in a certain order. The fast tool servo technology that has advantage of high precision and high efficiency has developed in recent years. This technology can fabricate not only the microlens array, but also the mould of the microlens array. This technology has p layed a key role in fabricating the microlens array.In this dissertation, take the concave spherical microlens arrays fabricated by FTS as research object. Design the FTS platform driven by voice coil motor. Generate the tool path of the FTS. Design the control system of FTS, Design the discrete time sliding mode controller based on disturbance observer with the high stability and position tracking precision advantage. The main contents are listed as follows:(1) Design the overall structure of FTS and sel ection parts type of the fast tool servo. Design the fast tool servo plat and vibration isolation system. Design the “linear motor + air guide” form and “linear motor + air guide” form as the spindle and X/Z axis motion form. Adopt long stroke and high pre cision voice coil motor as the actuator of the FTS. Design the “voice coil motor + air guide” form as the high frequency response, high speed motion form.(2) Generate and optimize the tool path of FTS for fabricating microlens array. The mechanism of the fast tool servo machining process is introduced. Generate the tool path. Analyze the distribution law and influence of dimensional precision of tool path in the transitional zone of tool path. An optimized method is proposed in transitional zone. The form of the microlens array is simulated with MATLAB.(3) Design control system of the FTS and select parts type. Take the upper-lower(motion controller and IPC) computer as the structure of the control sy stem. Adopt the UMAC multi-axis motion controller as control core. Design the close-loop control system. Use MFC to design the software for fabricating microlens array of upper computer that has the function of human-computer interface, tool path generatio n and on-line instruction. etc.(4) Design the controller and mathematical model of fast tool servo. Based on the research of balance of the voltage and force, establish the mathematical model of the FTS. Design the controller of FTS with discrete time sli ding mode algorithm based on disturbance observer. The discrete PID controller and discrete sliding mode controller are designed by MATLAB. Analyze the difference of position error, over-shoot, under-shoot, oscillation between the discrete PID controller w ith discrete sliding mode controller in no-load and different load status. The results show that the discrete time sliding mode controller based on disturbance observer is better for tracking performance and anti-jamming performance, more suitable for cont rol system of FTS.