induced by micro-fluidic inertial sensor based on the principle of convection heat transfer
were too weak to be detected easily. Now two methods are applied to drive this kind of gyros and then influence on the character performance. Method : First
the operational principle of these devices were analyzed. A silicon micro-fluidic gyro was comprised of a chamber and along each side of the fluid center axis disposed a thermocouple symmetrically. During zero input angular velocity
the temperature was symmetrical such that both thermocouples sensed the same temperature and therefore provided the same output voltage. While the gyro worked
the Coriolis acceleration,induced by an external angular velocity
caused the deflections of fluid velocity to cool the thermocouples oppositely
then
through Wheatstone bridge circuit the temperature disturbance of thermocouples could be converted to a differential output voltage proportional to the applied angular rate of motion. Secondly
the micro-fluidic inertial sensor might be driven by two methods
DC and AC signals. The AC drive technology included the alternating current driving and the alternating voltage driving. The DC actuated might increase the temperature of chamber
driver resistors and the power similar as the alternating current driving. On the contrary
the alternating voltage drive also increased the temperature of chamber as well as resistors but decreased the power of drive. This might influence the character performance of output signals
such as zero drift. Finally
the methods of corresponding measurement and the block diagram were discussed as well. When DC driving
a DC velocity was induced and amplified directly to extract a DC differential output voltage proportional to the external angular velocityω. On the other hand
if the alternating voltage drive was used
the required signals included in sine wave velocity could be selected out with the use of phase sensitively demodulation (PSD)
then passed through low-pass filters
amplified and at last obtained the DC voltage proportional to the external angular velocityω. Result: Experimental results indicate that the zero drift of output signals rise continuously and the linearity is 1.62% by DC driving while 0.113% with the alternating voltage actuated. Conclusion: It is concluded that the micro-fluidic gyroscope is characterized by stable zero drift and better linearity with the drive of alternating voltage.