Design And Key Technology Research Of Magnetic Levitation Stylus Surface Measuring Sensor

With the continuous development of precision and ultra-precision manufacturing technology,the requirement of surface topography measurement technology is also increasing.The mechanical stylus surface topography measuring instrument is widely applied because of its simple structure,good dynamic performance and high resolution.But the lever structure inevitably introduces nonlinear errors in measurement results,which affects the accuracy of measurement.For this reason,this paper designs a magnetic levitation stylus surface measurement method.The stylus shaft translates in the vertical direction,which is different from lever structure,and can be used for high precision surface topography measurement.The main work of this paper is as follows:1.The theory and method of magnetic levitation stylus measurement are studied,and the measurement system is designed.The kinematic model of the magnetic levitation stylus measuring system is established.The influence of the parameters of the natural frequency,damping ratio and velocity of the system on the dynamic response force is studied.The influence factors of the stylus flight are analyzed,and the static contact force is discussed.The analysis results provide a theoretical basis for the design of magnetic levitation stylus measurement system.2.Based on the split magnetic field method,the magnetic field distribution of the magnetic levitation stylus sensor is analyzed,and the radial bearing capacity equation is deduced,the influence of parameters such as effective magnetizing length,axial displacement and radial offset on the radial bearing capacity is analyzed.3.The feedback control circuit of the stylus shaft position is designed.The structure of the power amplifier and the controller in the control circuit is analyzed in detail.The pulsewidth modulation switched power amplifier is designed.The PID controller is designed based on the PID control algorithm,and the circuit performance is verified experimentally.4.The experimental device of magnetic levitation stylus measurement system was set up.The system accuracy was tested.The standard roughness sample was used to calibrate the measurement system.Finally,the common engineering surface was measured.The results showed that the measurement system could meet the requirements of the engineering surface measurement.