Dynamical analysis and experimental verification of deviation angles caused by rubber dampers deformation in high precision mechanically dithered RLG dual-axis RINS

Deviation angles between inertial measurement unit (IMU) and turntable in dual-axis rotational inertial navigation system (RINS) degrade the navigation attitude precision seriously. And rubber dampers deformation is an unavoidable and crucial factor in deviation angles when turntable rotates for high precision mechanically dithered ring laser gyroscope (RLG) dual-axis RINS. In this paper, in order to accurately analyze the deviation angles caused by rubber dampers deformation, a novel dynamic analysis and experimental verification method for these deviation angles in dual-axis RINS is proposed. Firstly, a 3-D Voigt model for rubber damper was proposed, and then a 6-DOF dynamic model of mechanically dithered RLG dual-axis RINS was built based on the proposed 3-D Voigt model. Secondly, dynamic equations were derived based on the proposed model for inner gimbal rotation and outer gimbal rotation respectively. Then dynamic equations were solved analytically by decoupling method and the decoupling method was validated by comparing analytic solutions against numerical solutions got by Runge-Kutta method. Afterwards, rotation experiments for turntable were conducted to obtain actual deviation angles caused by rubber dampers deformation. Finally the proposed model and dynamic analysis method were validated by comparing it against the real deviation angles measured by rotation experiments for turntable.