Fulfilled R&D projects

Finite element analysis of the rotary micromechanical gyroscope vibrations

Keywords micro-electromechanical systems, micromechanical gyroscope, eigenfrequencies and mode shapes
Programs in use ANSYS

Natural oscillations of the rotary micro-mechanical hyroscope utilized in modern navigation systems for angle velocity measurements are analyzed.

Sensitive element (oscillator) of the rotary micro-mechanical hyroscope is presented at Fig. 1. Zone of oscillator fastening to the glass basement is marked with white. Oscillator is made of monocrystalline silicon. Its elastic properties is local coordinate system is described by three independent moduli. 3D FE model containing 3328 20-node elements (88416 DOF) was created based on solid model.

 

 

Finite element analysis of the rotary micromechanical gyroscope vibrationsFinite element analysis of the rotary micromechanical gyroscope vibrations
Finite element analysis of the rotary micromechanical gyroscope vibrationsFinite element analysis of the rotary micromechanical gyroscope vibrations
 
Copmutation of natural frequenies and mode shapes of the sensitive element was done to determine possible operating frequencies of the hyroscope. Two lower mode shapes of the sensitive element are shown at Fig. 2, 3.

Effect of temperature-induced stresses on the spectrum of natural frequencies is analyzed. FE model created allows to take into consideration technological (manufacturing tolerance loss) and temperature factors. Fig. 4 illustrates relative displacement vector modulus Usum/R (R – radius of the silicon plate, R ~ 103 microns), originated due to welding of the silicon and glass parts and subsequent cooling till Т = 20°С.
First (torsional) natural mode shape of the rotor-type microgyroscope 

First (torsional) natural mode shape of the rotor-type microgyroscope
Second (bending) natural mode shape of the rotor-type microgyroscope 

Second (bending) natural mode shape of the rotor-type microgyroscope




Materials to download (in Russian):
 

Description
Video (avi, 5.16 Mb) 
Presentation (MSPowerPoint, 846 Kb - no video) 
Presentation (zip-archive, 1.96 Mb - including video)