Analysis of design parameters influence on the characteristics of optical microelectromechanical angular velocity transducer
Аuthors1*, 2**, 2***
2. Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia
Optical microelectromechanical (MOEM) angular velocity transducer may be constructed on the basis of optical tunneling effect (OTE). Characteristics and measuring range of such a transducer are determined by design parameters of its units. The influence of destabilizing factors on the angular velocity transducer are calculated.
This paper describes the created refined mathematical model of the MOEM angular velocity transducer based on optical tunneling effect that provides high sensitivity with low-rate measurement error and defines conversion function of the refined mathematical model. The described method of determination of optical output power Pout by using refined mathematical model performed to take into account the variability of the initial gap for different contact points of optical radiation on modulated boundary of the prism. Thus, the optical output power is defined as the integral dependence of all points, which are located in the obtained elliptical region by taking into account the variability of the gap d.
The modeling of characteristics of the transducer and the definition of relative errors of the optical output power POUT_ref with refined mathematical model are calculated and compared with result that has been received when used approximate model POUT_app. It is shown that the measuring error decreases when using the refined model instead of approximate model.
The influence of design parameters of the sensitive piezoelectric element (SPE) on the characteristics of the refined mathematical model of angular velocity transducer based on optical tunneling effect is described. To ensure the margin of error (less than 1% on the entire range of measurement) it is needed to use technologies which allow to manufacture SPE with deviation of thickness not more than ± 0,5µm and of length not more than ± 0,25mm.Additional temperature errors of the MOEM angular velocity transducer on the entire operating range of measurement are calculated. It is taken into account the temperature influence on all parameters. Analysis carried out that the impact of temperature in the range of measuring had little influence on the characteristics of the transducer (values of additional temperature error on the borders of the working temperature range are 0.11% (at T = - 500С) and 0.18% (at T = 1500С) at the maximum angular velocity ±4 rad/s). Using two channels of output signals decrease the temperature dependence by 8 times compared with single channel and improve the linearity of the conversion function.
Keywords:transducer, angular velocity, optical tunneling, reflectivity, errors, temperature
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