Fabrication of frequency scaling circuit using Phase Locked Loop Synthesizer IC for a quartz-crystal tuning-fork tactile sensor

The resonant frequency of the quartz-crystal tuning-fork tactile sensor increases when the base of the tactile sensor comes into contact with the objects. When the base of the tactile sensor is fixed on the top of the acrylic resin vessel with epoxy resin adhesives, the decrease in frequency of the tactile sensor is observed as the liquid level in the acrylic resin vessel increases. We investigated the relationship between the frequency change of the tactile sensor and the liquid level, and the effect of liquid density in the acrylic resin vessel on the frequency decrease. We fabricated the frequency scaling circuit using PLL synthesizer IC to scale the resonant frequency of the tactile sensor and measured the stability of the frequency scaling circuit.