Highly sensitive resonant sensor using quartz resonator cluster for inclination measurement

Quartz crystal resonators are suitable for digital output sensors due to their sensitivity to force. This paper presents a highly sensitive inclinometer sensor with a quartz resonator cluster. The force sensitive resonator cluster is designed on the quartz substrate to eliminate common-mode disturbances, such as temperature, as well as to improve sensitivity to force. The inclinometer sensor comprises two quartz resonator clusters that form a push-pull structure. The difference in inclination causes gravitational acceleration to produce an axial force along the input axis, with the resonance frequency shifting in proportion to the axial force. A signal processing and fusion scheme for the inclinometer sensor is presented and then tested. The results show that the scale factor of the sensor prototype is 3.5102 Hz/1' and that nonlinearity is 1.040% full scale in the range of -2°-+2°. The resolution of the inclinometer sensor is better than 0.0055°, making these devices a potentially attractive option for numerous precision inclination measurement applications.