Reliability of balanced multi-level Unmanned Aerial Vehicles

This paper presents reliability modeling and estimation of multi-level balanced Unmanned Aerial Vehicles (UAV). This type of UAVs includes n pairs and m levels of rotors and is modeled as a (k(1),k(2))-out - of-(n, m) Pairs: G balanced system. In many cases, reallocating thrust force or changing rotors' rotational directions when a failure occurs are infeasible in controlling and maintaining stability of the UAV. We present an operational control that forces down and resumes rotors at specific locations according to balance and control requirements. We present two scenarios: (1) forced down rotors are considered as failed and (2) forced down rotors are considered as standbys and are resumed when needed. Reliability estimations for the both scenarios are obtained by enumerating operational states and calculating the probability of their occurrences. Algorithms are provided for efficient calculations. We demonstrate that operational control is a viable alternative to the engineering control and it achieves system's controllability in cases when the engineering approach fails. (C) 2019 Elsevier Ltd. All rights reserved.