Development of a Dual-Axis Convective Gyroscope With Low Thermal-Induced Stress Sensing Element

This paper describes the design, simulation, and fabrication of a dual-axis gyroscope, whose working principle is based on the thermal convective and thermoresistive effects in lightly doped p-type silicon. The sensor configuration consists of a piezoelectric pump and a microthermal sensing element that is packaged in an aluminum case with a diameter of 14 mm and a length of 25 mm. The novel structure of the sensing element reduces the thermal-induced stress up to 89% as compared with the previous design. The sensor has been fabricated by micro- electromechanical systems technology, and completely packaged and characterized. The measured sensitivities of the gyroscope for the X-axis and Y-axis were 0.082 and 0.078 mV/deg/s, respectively. The cross sensitivities between the two input axes were less than 0.26%, and the nonlinearity was smaller than 0.5% full scale in the range of plusmn200deg/s. The resolution was 0.2deg/s at a measurement frequency of 1 Hz. The noise equivalent rate was 0.18deg/s/radicHz, which is equivalent to an angle random walk of 10.8deg/radich in a 65-Hz bandwidth. The offset drift was 360deg/h in 12-h measurement.