A Lever Coupling Mechanism in Dual-Mass Micro-Gyroscopes for Improving the Shock Resistance along the Driving Direction

Abstract

This paper presents the design and application of a lever coupling mechanism to improve the shock resistance of a dual-mass silicon micro-gyroscope with drive mode coupled along the driving direction without sacrificing the mechanical sensitivity. Firstly, the mechanical sensitivity and the shock response of the micro-gyroscope are theoretically analyzed. In the mechanical design, a novel lever coupling mechanism is proposed to change the modal order and to improve the frequency separation. The micro-gyroscope with the lever coupling mechanism optimizes the drive mode order, increasing the in-phase mode frequency to be much larger than the anti-phase one. Shock analysis results show that the micro-gyroscope structure with the designed lever coupling mechanism can notably reduce the magnitudes of the shock response and cut down the stress produced in the shock process compared with the traditional elastic coupled one. Simulations reveal that the shock resistance along the drive direction is greatly increased. Consequently, the lever coupling mechanism can change the gyroscope’s modal order and improve the frequency separation by structurally offering a higher stiffness difference ratio. The shock resistance along the driving direction is tremendously enhanced without loss of the mechanical sensitivity.

Design and Implementation of a Dual-Mass MEMS Gyroscope with High Shock Resistance

“…As was studied in our previous work [1], raising the in-phase frequency can improve the impact resistance, while raising the anti-phase frequency will reduce the mechanical sensitivity. As the in-phase mode frequency is close to the anti-phase mode frequency, the increase of the in-phase mode frequency will also cause the increase of the anti-phase mode frequency, which will influence the mechanical sensitivity.…”

“…As is discussed in detail in [1], the increase of the in-phase mode frequency can reduce the shock sensitivity, but the increase of the anti-phase mode frequency will reduce the mechanical sensitivity. Usually, for the dual-mass gyroscope coupled by elastic beams, the in-phase mode frequency is lower than the anti-phase mode frequency.…”

“…As a result, the anti-phase mode frequency will also increase with the rising of the in-phase mode frequency. In order to avoid excessive loss of mechanical sensitivity, many researchers have done much work on the coupling mechanisms to achieve modal inversion [1,18,19,20,21]. This paper uses the coupling mechanisms in [18,21] as the drive coupling mechanism and the sense coupling mechanism, respectively.…”

“…For the dual-mass gyroscope without the stopper mechanism, the shock response is analyzed in detail in our previous paper and can be expressed in an analytical form [1]. The kinetic equation under the shock load can be expressed as:$\left\{\begin{array}{c}trueleft\ddot{x}+\frac{{\omega }_x}{Q_x}\dot{x}+{{\omega }_x}^2=a,\\ left\ddot{y}+\frac{{\omega }_y}{Q_y}\dot{y}+{{\omega }_y}^2=a,\end{array}\right.$where x , y are the mass displacements in the drive and sense direction; ${\omega }_x$, ${\omega }_y$ are the in-phase mode frequencies along the x -axis and y -axis; $Q_x$, $Q_y$ are the quality factors along the x -axis and y -axis; $m_x$, $m_y$ are the masses along the x -axis and y -axis.…”

“…In the past several decades, with the advancements of the architecture, measuring and controlling technology, micro-gyroscopes have achieved rapid development. At present, they are widely adopted in many fields, including the automotive industry, consumer electronics, robot control systems, aerospace navigation and military weapons [1,2]. …”