Research On Some Key Technologies Of Moment Of Inertial Measurement

Large-sized rockets are the product of modern warfare and of high technology, so in order to achieve the precise attitude control and to improve system performance; the characteristic parameters of the rocket which include the precise measurement of moment of inertia must be obtained. The thesis analyzed the drawbacks of existing moment of inertia measurement equipment and its measurement methods, and depending on it, a new method was proposed in this thesis.Based on the torsion pendulum method and measurement of the moment of inertia methods, torsion pendulum motion equations which considering moment of friction and the aerodynamic drag was established. The Difference of these equations from the linear equations existed is that they are non-linear equations taking damping coefficient and symbolic functions into consideration. Torsion pendulum curves of equations were achieved and linear fitted by Maple software. These equations describe the whole movement of the torsion pendulum completely, therefore rationality of equations are verified.Considering the energy dissipation caused by moment of friction with the aerodynamic drag in the process of the measuring moment of inertia, relationship between the torsion pendulum angle and time was derived. Depending on these, equations that derived by phase plane analysis method were numerically solved by using numerical methods. The influences of both friction and air resistance on the compound are already taken into consideration without estimating measuring the resistances in advance. Moreover, detailed error analysis is conducted, which reveals the relationship between the optimal sampling rate and the error of angle sensor, and the optimal sampling rate strategy is deduced.In the end, with the concept of tensor as tool, measurement error of the moment inertia which is caused by the ideal position of the objects on rotating platform was discussed, and found reason of these errors such as processing errors and deformation of the platform. And the description of these errors was obtained.