十字形薄板ばねの振動を利用した加振式タッチプローブの試作検討

抄録

In this study, a resonance based touch trigger probe that detects a contact with lower measuring force is developed. The touch trigger probe is consisted of 2 parallel thin cross-shaped leaf springs and a piezoelectric actuator. The fundamental concepts and analysis by FEM are described. From the analysis, when the probe vibrates at the frequency of the 5th natural mode, the probe is considered to oscillate like an inverted pendulum with the center of oscillation being near the tip of the stylus. If a contact has been made when the probe is in the condition of natural vibration, the waveform is changed. Thus a contact can be detected by catching the change of waveform. A prototype is constructed and tested. According to the results of experiments, the measuring force is smaller than 50μN, and the repeatability could be smaller than 500 nm. Meanwhile, because the trajectory of the tip of the stylus remains still unknown, further analytic investigation is needed and it will lead to the optimum design.