The main focus of the project was to obtain a robust and stable control system for the heavy load UAV platforms being developed by Drone Hopper for firefighting operations.
The dynamic model of the project UAV has been changed many times to be customized as per the main objective. Firstly, the UAV was supposed to be with Electrical Ducted Fans (EDFs); this design, however, fails in harsh situations, when the fire is blaming catastrophically, several maneuvers will be needed and if an engine burns, this would be hard to control landing in addition to an architecture to be immune to one engine fails, flaps are provided to compensate for the stability.
The fuselage is made with a semi-rectangular geometry and a quite aerodynamic customization simulated in ANSYS FLUENT software. Propellers are designed to generate maximum thrust.
To continue, about the ducts which are magnificent novelties for the UAV during the designation. “Fig. 1” Modified to be short adequate for flap installment.
Figure 1 Flaps arrangement below the coaxial propellers, outside of the duct to influence maximum.
Figure 2 The Real Flap after finishing design and testing.
EDFs manufactured by Schuebeler and design are optimized for saving energy.
“Fig. 3” shows Various views of the UAV are revealed in this figure, including the vertical and horizontal dimensions (a); flap position, the center of mass (CoM), payload tank, and duct size (b); EDFs and four coaxial pairs of propellers (c); EDF angle of incidence, EDF wall, and Body frame (d).
Figure 3 Schematic of dynamical coordinate systems.
Figure 4 The real EDF.
Results and potential impacts:
The new control system developed contributed to the augmentation of the designed aircraft by supporting the desired payload from 150L to 600L.
Through the researcher work, the UAV stability and state was measured regarding to the positions and attitude with different parameters as shown in Fig.5 6, and 7.
Figure 5 Comparison of the drone state and reference positions and attitude angles, when X_"ref " =6" " m,Y_"ref " =6" " m, and Z_"ref " =5" " m and both flaps and EDFs are utilized.
Figure 6 Comparison of the drone state and reference positions and attitude angles, when X_"ref " =6" " m,Y_"ref " =6" " m, and Z_ref=5" " m and only EDFs are utilized.
Figure 7 Comparison of the drone state and reference positions and attitude angles, when X_"ref " =6" " m,Y_"ref " =6" " m, and Z_"ref " =5" " m and only flaps are utilized.
Through Fig. 8, it is cleared that the position and attitude variables are dependent, since the position values are issued by the reference block, and then through the guidance loop, attitude desired values are computed.
Figure 8 A full schematic diagram of the guidance and controller loop.
Once the system was designated to be controlled only by flaps, then only by EDFs, and finally, equipping both, concurrently. The benefit of using such a system is controlling the attitude, using flaps and EDFs, and increasing the flight time endurance by using gas engines; all these points are converted to a huge benefit, which is the ability to increase the capacity payload of the system from 150L to 600L.
