Analyse the angular velocity estimation errors of α-β-γ filter based on high sampling rate

Abstract

In order to get angular velocity of stabilization servo mechanism from angular position sensors, α-β-γ filter based on high sampling rate was established, model and error characteristics were analyzed. With the hypothesis of constant acceleration, α-β-γ filter and its angular velocity transfer function were deduced. Combing with optimum parameters, the effects of α and sample rate on the error characteristics were evaluated. According to the requirements of stabilization servo mechanism, the frequency characteristics of angular velocity transfer function are analyzed, and the filter parameters are designed. The experimental which filter tracked and smoothed sinusoidal signal, the results show that when the cutoff frequency of angular velocity loop is 44.9rad/s, sampling period and parameters α are 0.08ms and 0.01279 respectively, the phase leading of angular position is 70°. α-β-γ filter tracked sinusoidal signals with maximum angular velocity(30°/s) and maximum angular acceleration(30°/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), the error of angular velocity estimation was 0.053°/s. In the engineering of electro-optical stabilization servo mechanism, α-β-γ filter can reduce noise effectively, and reached the requirement of platform angular velocity estimation. Also it is one of the effective methods to get angular velocity from angular position sensors.