Combined MEMS accelerometer and gyroscope

US8464585B2 · kind B2 · utility

Assignees

• MELEXIS TECHNOLOGIES NV · BE
• UNIVERSITEIT GENT · BE

Inventors

• Johan Raman · Knesselare, BE
• Pieter Rombouts · Mariakerke, BE

Key dates

• Filing date: Oct 20, 2008
• Grant date: Jun 18, 2013
• Expiry date: Oct 7, 2029

Classification

• Technology area (CPC G): Physics
• CPC primary: G01P15/18
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A MEMS structure for a combined gyroscope and accelerometer unit (100) based on in-plane vibratory movements comprises a proof mass (101) and comb-drives (102) operable to cause the proof mass (101) to resonate in the x-direction, commonly referred to as the primary mode. Under the influence of a rotation Ωz around the z-axis, a Coriolis force acting in the y-direction results. This excites the secondary (or sense) mode. A set of parallel-plate capacitors 103 are provided to enable position readout along the secondary axis. In addition to the above, the comb-drive capacitors (102) of the primary mode can also be used for readout of position along the primary axis, and the parallel-plate capacitors (103) for actuation along the secondary axis. This can be achieved either by time-multiplexing these capacitors (102, 103) or by providing separate sets of capacitors (102, 103) for sensing and actuation along each axis. The unit can operate in separate ΣΔ force-feedback loops with respect to both axes. This force-feedback approach is already known for readout of the secondary mode of MEMS gyroscopes. It has not previously been applied to the primary mode of a gyroscope for the measuremen…