Investigation of the crossed flexure pivot and the dynamics of the momentum management system spacecraft control component and the dynamically tuned gyroscope

The Momentum Management System (MMS) is a novel concept which incorporates the rate sensing capabilities of the Dynamically Tuned Gyro (DTG) and the actuation ability of a gimballed momentum wheel. The mechanical components of the MMS and DTG consist of a rotor, gimbal and shaft which are connected using crossed flexure pivots.; This document presents a static and vibration analysis of the crossed flexure pivot and a kinematic and dynamic analysis of the Dynamically Tuned Gyroscope and the Momentum Management System. Hamilton's principle of minimum energy is used to develop static and vibrational models of the crossed flexure pivot. These models were used to design the pivots used in the MMS. Comparisons are made between the static model results and those found in the literature. A discussion of the effects of large angle deflections and wide pivot strips is also included. In order to provide additional experimental validation of the static equations, a pivot was designed and tested and the results compared to the theoretical model. The static model showed that the torsional stiffness of the crossed flexure pivot is dependent on the applied loads and that the buckling load is lower than previously thought. The vibration analysis was used to find the unforced, fundamental frequencies of the crossed flexure pivots used in the MMS.; A two body stability analysis of the DTG and MMS involving the gimbal and rotor was performed using small angle equations. This included a study of the effect of using bearings instead of the crossed flexure pivots. The DTG and MMS were found to be unstable only in extreme cases. The dynamic equations were derived using Lagrange's Equations and Hamilton's Canonical Equations. The dynamic equations are used in a numerical simulation which allows the MMS to be modelled. The results show that the three body analysis involving the rotor, gimbal and shaft is more accurate than the standard two body analysis seen in the literature, especially when modelling the MMS.