# Improvement of Hexacopter UAVs Attitude Parameters Employing Control and Decision Support Systems
## 2 Related Work  
### Latest Developments in Hexacopter Drones Design  
[PERSON] et al. [39] present in a complex review many different configurations, flight mechanisms and applications in which drones are currently employed. The UAVs are categorized, and their characteristics, advantages and drawbacks are discussed. This study also presents vertical takeoff and landing (VTOL) hexacopter drones in a flat configuration, used by the last mile delivery drone, the HexH2O seaplane drone, an antidrone hexacopter, which uses a net to capture rogue drones; power tower cleaning hexacopters; and agriculture, inspection, survey and mapping hexacopters. [PERSON] et al. [40] presents a generic methodology that analyses the sizing aspect of the multicopter drones with electric propulsion, which allows configuration optimization for different applications. The study starts from a set of algebraic equations based on scaling laws and models that have resemblances. In the next phase, the optimization of the drone sizing is analysed through a proposed methodology. The obtained results are validated by comparing the characteristics of existing multirotors and performance predictions of these configurations which were performed taking into account different flight types and payload variants. In the case of the classic hexacopter, studies have been carried out on mounting the rotors under certain tilt angles, this modification allowing the hexacopter to be fully actuated in the sense that all six degrees of freedom associated with the three translational and three rotational movements become independently controllable. These types of platforms are still the subject of study, making it difficult to explain which type of structure is suitable for a particular type of application. One of the proposed approaches to obtain a structure close to the one already mentioned is to develop a scheme to optimize the construction design of the drone. Aspects related to the design and optimization of hexacopter drones can be found in several variants proposed by [PERSON] et al. [41], [PERSON] et al. [42], [PERSON] et al. [43], [PERSON] et al. [44], [PERSON] et al. [45] and [PERSON] et al. [46]. Work performed by [PERSON] et al. [47], [PERSON] et al. [48] and [PERSON] et al. [49], respectively, present an analytical characterization of the relationships between the dynamic properties of the drone, the arrangement of the rotors and their pitch angles. The results obtained are then taken into account when formulating the design aspects of the hexacopter and the manoeuvrability of the fully powered drone is analysed after the rotors are placed under a certain tilt angle. The following aspects are addressed: the effect of the rotor placement is analysed using the dynamic model of the hexacopter and the dynamic manipulability measure (DMM)--an index measuring the omnidirectional acceleration. An adapted version of the DMM suitable for a hexacopter is introduced. The DMM evaluates the input-output relationship between the thrust developed by the rotors and the acceleration of the vehicle and the introduction of a new type of structure, namely, symmetric coplanar tilted rotor (SCTR). The DMM method applied to the hexacopter in the new SCTR structure is considered suitable for the evaluation of the integral drive property of the multirotor structure. Finally, issues of optimizing the hexacopter construction design are considered by [PERSON] et al. [50]. [PERSON] et al. [51] presented an interesting approach that combines modelling and simulation for different drone configurations, employing an original software combination between Solidworks-PID Simulink and SPSA (Simultaneous Perturbation Stochastic Approximation) to develop an algorithm for optimizing flight parameters and studying different flight regimes for a certain fixed length of the motor support arms. [PERSON] et al. [52] depict the manoeuvrability of a fully powered hexacopter over all six degrees of freedom by installing all the propellers under the same pitch angle.