2461. A New Method for RBP Estimation – The Dynamic Inertia Method

Paper

Abstract

A new method for rigid body inertia property estimation is being developed at the University of Cincinnati in conjunction with NASA Dryden, which may have advantages over traditional methods. With the Dynamic Inertia Method (DIM), dynamic forces are applied to an object and its resulting rigid body acceleration is measured. Advances in force sensing technology make this method possible with the advent of a 6 degree of freedom (DOF) load cell. The 6 DOF load cell is used in order to completely measure all forces applied to the test article, including support forces and moments. An array of linear accelerometers is also used to measure the 6 DOF acceleration of the test article. From these measurements, the mass, CG and inertia tenser are estimated. Other dynamic techniques, utilizing the massline of inertance functions to extract RB properties, have been presented in the past with limited success outside the laboratory. What makes this technique different is the ability to measure the 6 DOF support forces. Several examples of the method will be presented, from small automotive components (brake rotor) through large aerospace vehicles (NASA X-38), with independent verification when possible. The DIM shows promise and with adequate development could be an alternative to traditional bifilar and trifilar measurement techniques when vibration testing equipment is available.