An energy-based trim procedure for multirotor VTOLS

Abstract

The aim of the proposed paper is the development of a general approach capable of determining the set of trim commands, aerodynamic controls surfaces actuation and/or engine thrust regulation, that allow specific steady-state flight conditions of non-conventional VTOLs, under given performance constraints. Specifically, an energy-based trim algorithm is introduced, based on the minimization of a cost function. This approach is particularly interesting in that, in case of multi-rotor system, it allows to determine the control settings such to guarantee the required flight condition while using the redundant controls to optimise selected target functions, as for instance performance or noise emission. The proposed approach will be applied to a quadcopter configuration, for validation purposes, and a hexacopter configuration for which a comparison with a conventional trim procedure will be performed. Three different control strategies are applied: a pure rotor angular velocity control, a pure blade collective pitch control and a combined angular velocity and blade collective pitch control.