Semi-empirical estimation and experimental validation of the mass and the center of gravity location of the unmanned aerial system — UAS-S4 of hydra technologies

Abstract

This article presents a structural analysis of the Unmanned Aerial System UAS-S4 ETHECATL. The mass and the center of gravity position are numerically determined and further experimentally verified using the “pendulum method”. The numerical estimations are computed through Raymer statistical-empirical method coupled with mechanical calculations. The mass of the UAS-S4 component are estimated according to their sizes and the UAS-S4 class, by the means of Raymer statistical equations. The UAS-S4 geometry is also decomposed in several geometrical figures, which centers of gravity are individually computed, weighted, and then arithmetically averaged to find the whole UAS-S4 center of gravity. The mass of the UAS-S4 is experimentally determined using two scales. Its center of gravity coordinates are found using the pendulum method. The equilibrium of the pendulum is studied, by including the UAS-S4, the table used to support it and the additional mass used to unbalance it. To determine the accuracy of the pendulum method relatively to the Raymer statistical-empirical estimation, the results obtained by using the two methods are compared and the relative error appears to be less than 6% for the X-coordinate of the gravity center of the UAS-S4, and less than 2% for Y and Z coordinates. For the UAS-S4 mass estimation, the relative error between the Raymer estimation and the actual weighed mass (with scales) is about 5.7%.