Design Study of Multidirectional Jet Flow for a Triple-Axis Fluidic Gyroscope

Abstract

In this paper, we report the design study of a fluidic device that produces four microjet flows comprising two perpendicular pairs of flow and the application of these jets for an angular rate sensor. The jets were created in a closed fluidic network without a check valve and they can freely deflect in a confined sensing chamber. The formation of the continuous flow in a confined space has been confirmed by experiment. This allows the study to a triple-axis angular rate sensor whose working principle relies on the deflection of a jet in a rotating frame. In this paper, the formation of the jets is considered such that the jets have an axisymmetric property, which is key to overcoming the apparent decoupling and cross sensitivity. The triple-axis angular rate sensor can be designed with only four thermal sensing elements. The transient flow simulation under an applied angular velocity provides a design with small size and minimum number of hotwires, which is beneficial for singlechip development and also maintains compatibility with bulk microfabrication technology. While the sensing performances of the three axes are in the same order of magnitude, the cross sensitivity is two orders smaller than that in the published results. In addition to the inertial sensing application, this paper can be adapted to help researchers quickly develop a prototype or to integrate an inertial sensing component in their own microfluidic, microbio, or lab-on-a-chip systems.

Fluidic mechanism for dual-axis gyroscope

“…Results depict that the output voltage linearly increases with the increase of angular speed with a scale factor of 0.26 μVs/° until the speed reaches 900 rpm (5400 °/s). A nonlinear increase of the output voltage observed at higher speeds may correlate with the flow deflection restricted by the wall of chamber as stated in [43]. For example, at the angular speed of 1500 rpm, the measured velocity of flow is =3.06 m/s (see section 4.1) and the flow deflection is estimated as (nearly a half of the distance from the jet axis to the wall chamber).…”

“…The principle of a flow chip was reported elsewhere [43], [46] and is summarized here as follows. A disk pump chamber with a diameter of 18 mm and a depth of 0.3 mm, activated by a PZT diaphragm is located at the top center.…”

“…This deflection is detected by hotwires. Based on the 3D simulation of flow inside a rotating device performed in our last publication [43], an analytical expression is presented in this paper for the sake of discussing in the next sections.…”

“…Experimental results shown that although the principle of the fluidic gyroscope and its configuration are relatively simple, there are certain limits in the fundamental design due to the cumbersome and high cost of the device. Several alternative techniques such as using planar overlapping layers are applied to simplify the fabrication process, but difficulties in the theoretical design are still existent [42], [43]. Thus, several ideas, such as the introduction of PZT pumping using microfabrication process to the fluidic gyroscope, were recently published.…”

Angular Rate Sensing by Circulatory Vortex Flow: Design, Simulation and Experiment

“…Vortex-based inertial fluidic systems presented in several recent publications include vortex based inertial fluidic system and fluidic amplifier [1]- [3] and vortex based gyrometer [4]. While fluidic gyroscopes are typically categorized as jet flow gyroscope and thermal gas gyroscope with sufficient literature reports on laminar gas stream, corona discharge or thermal expansion principles [5]- [12], there has not been any adequate technical information disclosed for vortex gyrometer. More recently, some groups studied multi-axis inertial sensor using the vortex movement; nevertheless, the mechanism was not sufficiently described [13], [14].…”