Design on electromagnetic actuator of aerostatic bearing stylus displacement sensor

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.