A sensor for the on-line inspection of drilled hole dimensional parameters†
提出一种基于陶瓷杆上四个电容传感器的在线孔检测系统，通过测量电容变化获取孔几何参数，适用于生产环境，精度优于10微米。
The on-line hole inspection system consists of a circular rod made of ceramic material, containing four small capacitive sensors at its circumference. When inserted into the hole, the capacitance of each sensor element varies as a function of its distance from the hole wall. Each capacitor is connected to an electronic oscillator/demodulator unit whose output signal is sampled by a microcomputer. In its present version, the hole probe is designed to measure the geometry of holes up to.50 mm long, making measurements every 100 um. The accuracy of the hole diameter measurement is better than l0 um as long as the distance from the probe tip to the hole wall is below Do mm. Because the capacitive probe tips are completely encapsulated by hard ceramic material. the sensor is rugged and suitable for operation in a production environment.