UAV

Components:

• NVIDIA Jetson Nano

• Pixhawk 6C Flight Controller

• Pozyx transducer, 

• Radiolink R12DS RC Receiver

Overview:

The GNC box contains a Jetson Nano, a Pixhawk 6C, a Pozyx transducer, and an RC receiver. The Jetson Nano runs the high level control software through ROS/C++. The Pixhawk is the flight controller, handling the mid- and low-level control through PX4, using the built-in IMU and enabled GPS antenna. The Nano and Pixhawk communicate via MAVROS. Finally, the Pozyx transducer, which is a shield on an Arduino Uno, reads the transmissions for the LaRP on the WAM-V. The Uno runs a constant low-pass filter to remove noise and calculates the location of the UAV with respect to the WAM-V, sending that information to the high-level controller on the Nano, where it is used in the landing control. The GNC box and Software Architecture are shown in the figures below.

Overview:

 For completing Tasks 7 and 8 at RobotX, a novel method of launching and recovering a UAV from the WAM-V was devised using a Pozyx indoor GPS system to create a local coordinate frame over the USV. This frame is used as a reference by the UAV  to land accurately on the WAM-V, independently of  lighting conditions which would render standard vision-based landing impossible. The UAV Launch and Recovery Platform (LaRP) consists of a 1 m2 launch pad raised above the deck of the WAM-V. Further PVC arms extend out from the center of the LaRP, which hold four acoustic transmitters at varying heights. These four transmitters form the local 3D coordinate system with which the UAV to localize with respect to the WAM-V. Finally, safety nets were installed between the arms to catch the UAV if it failed to properly take off or tipped off the edge of the platform when landing. MATLAB Simulations were run to verify that the drone could autonomously land on the USV during autonomy.