In this paper, the dynamic and static contact characteristics of the aerostatic bearing stylus displacement sensor are analyzed, including static contact damage and dynamic response. The dynamic response at frequency and different speeds is studied and obtained the relationship between the measured force and frequency and velocity. The stylus does not contact well from the surface when the measuring force is less than 0. In this case, the traceability of the tip can be analyzed based on the characteristics of the amplitude. Finally, the experimental verification of the relevant theory is obtained by measuring the aluminum turning sample at different speeds.
During the measurement,The traditional lever type measuring instrument will introduce a nonlinear error due to the rotation of the lever, which will affect the measurement result.A magnetic levitation stylus measuring instrument was designed based on it. It changed the lever supporting mode from the stylus shaft to the vertical direction linear translation which can eliminate the nonlinear error and improve the measurement accuracy.This paper introduces the measuring principle based on the magnetic levitation bearing stylus surface topography sensor, designs the electronic control system of the magnetic levitation contact measuring instrument, and finally conducts the surface topography measurement test.The experimental results show that the designed electronic control system can meet the design requirements of the magnetic levitation system.
Due to the high measurement accuracy and wide range of applications, lever-type stylus profilometry is commonly used in industrial research areas. However, the error caused by the lever structure has a great influence on the profile measurement, thus this paper analyzes the error of high-precision large-range lever-type stylus profilometry. The errors are corrected by the Nelder-Mead Simplex method, and the results are verified by the spherical surface calibration. It can be seen that this method can effectively reduce the measurement error and improve the accuracy of the stylus profilometry in large-scale measurement.
This paper discusses electromagnetic force actuator and configuration design of the aerostatic bearing stylus displacement sensor for the surface topography measurement. This stylus displacement sensor is designed based on the structure of direct metrology of stylus displacement, and aerostatic bearing is utilized to achieve the precise linear movement of stylus, with which the profiler measurement system has high precision without non-linear error. During the measurement process, the attitude of the stylus is adjusted by electromagnetic force to control the contact force between stylus and surface, thus the electromagnetic force analysis and implement is the key component to support the constant measurement force. The electromagnetic actuator combined permanent magnet with coils is designed to achieve the electromagnetic force precisely. The results of the numerical analysis and experiments indicate that the electromagnetic actuator can balance the gravity of stylus and keep a constant contacting force during the measurement. The surface topography measurement system based on aerostatic bearing stylus displacement sensor is constructed and the primarily experiment result is also given.