Capacitive silicon micromachined gyro with mechanical coupling for sensitive signal reading 5

3、 Sampling method design

Based on the above analysis, sensitive signals should be collected when the mechanical coupling is at its minimum. Due to the possible inconsistency of mechanical coupling between forward and reverse vibrations, the minimum moments of mechanical coupling should be selected separately. By utilizing the inertia of mechanical motion during vibration, the driving voltage signal is turned off during sampling to eliminate electrical coupling interference.

Figure 5 Collection and Drive Block Diagram  diode

G micro gyroscope mechanical vibration block; C1 and C2 sensitive capacitors; C3 and C4 drive capacitors; A1 differential capacitor conditioning circuit; A2 differential amplifier; S/H1, S/H2 sampling and holding devices; U1 acquisition and control microcontroller

Figure 5 shows the acquisition and driving diagram. The control timing is completed by U1. In order to accurately control the timing, a DSP device with a higher clock frequency was used in this experiment TMS320F2810.html" target="_blank" title="TMS320F2810">TMS320F2810。 The control timing is shown in Figure 6, and the sampling timing pulse occurs at the static equilibrium point of the vibrating mass block. Experimental process: Determine the resonant frequency range through microscopic observation; Under zero rotational speed conditions, the maximum mechanical coupling frequency is found by changing the driving frequency, and under rotational speed conditions, the maximum driving frequency of the signal output is searched, and the mechanical resonance frequency is verified from both aspects; Search for the synchronous sampling time with the minimum mechanical coupling under zero speed conditions. At this moment, the sensitive signal is usually close to the maximum value when there is a rotational speed. Preliminary test results: Drive cycle of 3017Hz, turntable speed of 0.1Hz, average of 10 times, digital output signal jumping of 1%.  diode