Main Body System Upgrade

In this page a brief discussion of main body system upgrade by FDT can be found.

Power Distribution System

For this project, a variety of special payloads were integrated. Each of these had special power. Some of them also needed a control system to manage their functionality. To provide a compact solution satisfying many of these needs, we designed a power distribution board and built two prototypes--one for each of the UAS. These boards each hosted two boards: an Arduino Micro and a Pololu DRV8834 Low-Voltage Stepper Motor Driver. The Arduino was included to fulfill several needs.

• Monitor the temperature of the battery case and the area covered by the Kevlar dome using thermistors.
• Monitor pressure-sensitive resistor inputs for the Payload Delivery System to determine when the grabber plates have applied sufficient pressure to a payload.
• Control the Payload Delivery System's stepper motor via the DRV8834 driver board.

The DRV8834 provided a convenient interface to control the payload delivery system's bipolar stepper motor. This small 0.6" x 0.8" board has several useful features.

• Input to turn on motor
• Input to control direction of motor
• Inputs to control step resolution (Options: full step, half step, 1/4 step, 1/8 step, 1/16 step, and 1/32 step)
• Protection from various types of short-circuit faults

Besides the two special boards, the auxiliary power distribution board also featured a variety of ways to distribute power: two USB power ports, connected to 5 V each, a row of pin headers for a 5 V rail, and another row of pin headers for a 12 V rail. One of the USB ports has been utilized for the Digital Content Delivery System's Raspberry Pi. In the future, this prototype power distribution board could be turned into a cleaner, lower-profile printed circuit board (PCB).

Thermal Modifications

At Frontier Drone Tech, we are testing out these UAVs in the great state of Alaska. Since one of our offices is in Fairbanks, which can have temperatures as low as -40°F or -50°F in certain winters (-40°C and -45.5°C, respectively) , with typical cold weather being around -30°F (-34.4°C), we have to keep parts of the UAS warm. Given this, and that it is unlikely that a flying UAS won't experience wind (added cooling effect of wind?), the battery can be adversely affected with decreased performance. In cold regions, the people can relate to battery problems with their phones: when their phone gets too cold, the percentage reading can drop, or even just have the phone shut off due to chemical reactions in the battery being too slow to keep the device running. Since we don't want our UAS to fall out of the sky due to a cold battery, the main thermal modification is having an insulated case for the battery to keep it around 40°F (4.4°C). This temperature was chosen to allow for higher temperatures for when the motors have to run at full capacity. Additionally, to reduce the cooling effect of the wind, the dome and body side panels were added, thanks to Robert Clark and Clynce Carrillo, respectively. Two temperature sensors were also integrated into the system, for the battery and electronics in the dome.

Kevlar Dome

A weather protective dome was designed to help protect electrical components from rain or snow when flying in inclement weather. The attachment ring is 3d printed and the dome is fabricated out of Kevlar for weight reduction. Molds for fabricating the Kevlar dome are 3d printed. The dome attaches to existing holes in each UAS frame so no custom modification is required. S1000 Dome Left, S900 Dome Right.

Body Side Panels

With openings on the side of the center frames of the drones exposing sensitive drone components to environmental hazards, such as snow or rain, side covers were needed. The side panels are made 3D printed with ABS plastic (can be substituted with PLA plastic) for ease of manufacturing and allows some flexibility to simply be press-fit into the desired openings.