**2. Drone's mechatronic design**

#### **2.1 Drone electric power units**

The developed octarotor drone has a take-off weight of 40 kg and a 30 min flight time. The drone's frame was designed and fabricated in collaboration with Vulcan UAV©. The authors' input on this aspect is related with both extending the bare-bone design of Vulcan to accommodate for payload carriage, as well as fabricating the final prototype and mounting all the additional modalities mentioned in the sequel. The backbone structure consists of three ø 25 mm, 1200 mm length aluminum tubes in a triangular cross sectional configuration. Four 575 mm length aluminum rectangular arms attached at each end of this structure and carry two motors in a coaxial configuration. The arms are fixed to the main frame using a 5 mm thick carbon plate. The resulting "H-frame" configuration can be visualized in **Figure 1**.

**41**

**Figure 2.**

*Development of a Versatile Modular Platform for Aerial Manipulators*

the octarotor's motors sink 11.7 A each, resulting in a flight

is achieved via the MAVlink protocol command set [12].

provide 24, 19 and 12 V respectively to the end-user.

monitoring and intervention and comply with flying regulations.

*Landing gear detail (left) and payload assembly with battery holder (right).*

**2.2 Flight command unit and related software**

.

Although the lower motor provides 25% less thrust [11] it offers some redundancy against single motor failure. The selected 135 KV KDE© brushless motors coupled with ø71.12 cm custom designed carbon propellers, collectively provide 37.2 kg of thrust at 50% throttle input. The extra thrust can be used for rapid maneuvering of the drone and for exerting forces by the aerial manipulator shown

Power is provided by a 12S 22 Ah LiPo battery pair connected in parallel to the Power Distribution Board (PDB). At 50% thrust with full payload while hovering,

Two carbon rods of ø12 mm are fixed at the underside of the mainframe tubes for payload carriage. The maximum payload weight is 30 kg and can be easily dismantled from the main frame using quick release clamps. Similarly, the retractable landing gear assembly is attached with these clamps to the main frame tubes for enhanced modularity, as shown in **Figure 2**. The gear can retract within a 45 80 °- ° angle window using a Pulse Width Modulation (PWM) signal, provided by the FCU's rail pins, with a 50 Hz switching frequency. The landing gear operation

Additional power for peripherals and sensing modalities can be supplied through

The PixHawk Cube FCU was selected [13] featuring triple redundant dampened Inertial Measurement Units (IMUs), with a modular design and industrial standard I/O connectors. Additional telemetry and R/C circuits are deployed to enable

The *Here* + Global Navigation Satellite System (GNSS) [14] with Real-time kinematic (RTK) capabilities was selected for outdoor navigation and placed on top of a carbon fiber pole at a height of 35 cm from the main frame's top plane. For immunity to electromagnetic interference, the primary magnetometer of the flight controller is selected to be the build-in magnetometer module of the GNSS receiver. A high processing power 8th generation Intel NUC i7-computing unit with 32 GB RAM and 1 TB SSD, shown in **Figure 3**, was mounted symmetrically to

a dedicated 750 W buck converter, mounted on the payload carrier assembly, as shown in **Figure 3**. The converter is contained within a custom 3D printed case and standard Unmanned Aerial Vehicle (UAV) *XT XT* 30, 60 connectors protrude to

*DOI: http://dx.doi.org/10.5772/intechopen.94027*

time of 2 22 60 min 26 min

´ ´ = ´

11.7 8

in Section 5.

**Figure 1.** *Drone's backbone structure.*

#### *Development of a Versatile Modular Platform for Aerial Manipulators DOI: http://dx.doi.org/10.5772/intechopen.94027*

Although the lower motor provides 25% less thrust [11] it offers some redundancy against single motor failure. The selected 135 KV KDE© brushless motors coupled with ø71.12 cm custom designed carbon propellers, collectively provide 37.2 kg of thrust at 50% throttle input. The extra thrust can be used for rapid maneuvering of the drone and for exerting forces by the aerial manipulator shown in Section 5.

Power is provided by a 12S 22 Ah LiPo battery pair connected in parallel to the Power Distribution Board (PDB). At 50% thrust with full payload while hovering, the octarotor's motors sink 11.7 A each, resulting in a flight time of 2 22 60 min 26 min .

11.7 8 ´ ´ = ´

*Service Robotics*

usually sought [9].

attached robot manipulator.

Section 5, followed by Concluding remarks.

**2. Drone's mechatronic design**

**2.1 Drone electric power units**

Multi-rotor drones have been very popular among researchers with their naming typically by the rotor count (tricopters, quadcopters, hexacopters, and octacopters). The drone's thrust increases with the number of rotors allowing the lift of higher payloads at the expense of a reduced flight time, and power tethering systems are

The majority of the off-the-self drones have a 1-2 kg payload capability with very few drones being capable of lifting an order of higher magnitude [10]. This is primarily due to the FCU's necessary tuning, the advanced ESCs and the need to

Pertaining to the described challenges, this chapter presents a drone that based on its mission can be modular in terms of software and hardware while lifting a high payload. The drone can operate either indoors or outdoors and has navigation and mapping capabilities as well as can interact with the environment through an

In Section 2 the mechatronic design of the drone is presented, while in Section 3 the drone's software for localization is explained and evaluated. The drone's ability to perform either in a collaborating or an adversarial environment using computer vision is discussed in Section 4. The aerial manipulation concept is addressed in

The developed octarotor drone has a take-off weight of 40 kg and a 30 min flight time. The drone's frame was designed and fabricated in collaboration with Vulcan UAV©. The authors' input on this aspect is related with both extending the bare-bone design of Vulcan to accommodate for payload carriage, as well as fabricating the final prototype and mounting all the additional modalities mentioned in the sequel. The backbone structure consists of three ø 25 mm, 1200 mm length aluminum tubes in a triangular cross sectional configuration. Four 575 mm length aluminum rectangular arms attached at each end of this structure and carry two motors in a coaxial configuration. The arms are fixed to the main frame using a 5 mm thick carbon plate. The resulting "H-frame" configuration can be visualized

abide to the laws imposed by each country's regulatory authority.

**40**

**Figure 1.**

*Drone's backbone structure.*

in **Figure 1**.

Two carbon rods of ø12 mm are fixed at the underside of the mainframe tubes for payload carriage. The maximum payload weight is 30 kg and can be easily dismantled from the main frame using quick release clamps. Similarly, the retractable landing gear assembly is attached with these clamps to the main frame tubes for enhanced modularity, as shown in **Figure 2**. The gear can retract within a 45 80 °- ° angle window using a Pulse Width Modulation (PWM) signal, provided by the FCU's rail pins, with a 50 Hz switching frequency. The landing gear operation is achieved via the MAVlink protocol command set [12].

Additional power for peripherals and sensing modalities can be supplied through a dedicated 750 W buck converter, mounted on the payload carrier assembly, as shown in **Figure 3**. The converter is contained within a custom 3D printed case and standard Unmanned Aerial Vehicle (UAV) *XT XT* 30, 60 connectors protrude to provide 24, 19 and 12 V respectively to the end-user.
