Design And Control Of Single Degree Of Freeform Fast Tool Servo Apparatus Based On NI Controller

Optical free surface and microstructure functional surface has a wide range of application requirements in the field of civil,military and aerospace.The single point diamond turning technology based on Fast Tool Servo(FTS)has become one of the most effective processing methods for machining optical free surface and microstructure function surface because of its high frequency response and high positioning accuracy.At present,there are mature FTS products sold abroad,but the country is still in the laboratory research stage,and no industrial FTS device.This paper summarizes the driving method,control method and strategy of FTS device.A single-degree-of-freedom FTS device was designed to drive a tool with a high degree of adjustment in the Y-axis direction.Aiming at the characteristics of the designed device,the FTS fuzzy PID control system based on NI controller is studied,and the fuzzy PID control algorithm is designed to control the developed FTS.Fuzzy PID control algorithm can set the ratioquickly and dynamically,differential and integral three coefficients,and it is excellent for periodic excitation signals and uncertain external disturbance control,and is suitable for most FTS devices.This paper will study from the following aspects:(1)Design a single-degree-of-freedom piezo-driven FTS device that can fine tune the height of the diamond tool.The stiffness model of the flexible hinge bracket is established by using the Lagrangian equation,and the key components are analyzed by static analysis and modal analysis.The size of the hinge piece was optimized.The stiffness model of the flexible hinge is established,and the natural frequency of the device is calculated by the stiffness model.Using the specific parameters of the design device,the finite element analysis of the key components of the device is carried out including static analysis and modal analysis.By comparing the analysis results and design requirements,and gradually optimize the design parameters to achieve the best design performance of the device.Perform a performance test on the designed FTS device including Stiffness test,maximum displacement test,step response test to verify the system performance of the designed device.(2)The fuzzy PID control strategy is chosen as the control algorithm of FTS device and compare simple PID control algorithm and fuzzy control algorithm.In the tracking error,fuzzy PID control tracking error amplitude is 0.07?m,while the simple tracking error amplitude is 0.68?m,the tracking control accuracy improves 9.714 times.(3)Constructing the FTS cutting experimental platform.The FTS device designed in this paper is mounted on the Nanoform 250 machine guide rail and using fuzzy PID controller controls FTS system.By machining the end face of the aluminum alloy part and using the ZYGO white light interferometer to detect the machined surface of the workpiece,the machining performance of the FTS device designed in this paper is analyzed from the machined surface type.