1.4.2) AERPAW UAVs

Large AERPAW Multirotor (LAM) 6 Overview

The Large AERPAW Multirotor is the platform that has been developed at NC State University under the AERPAW Project for use as a standardized aerial platform for carrying large modular payloads. This UAS was designed to give the best combination of performance, flexibility, and in house manufacturability + repair. This page provides an overview of what the platform is and it’s basic capabilities. The manufacturing information and user manual will be provided in the future.

Standard Configuration and Specifications:

Max All Up Weight: 30 Kg (25 Kg - Part 107)
Battery Capacity: 2 x 25 Ah 6S LiHV (1,140 Wh)
Payload With Standard Battery: 16Kg (11 Kg - Part 107)
Dry Weight (No Battery): 7.8 kg
No Payload Flight Time: 47 min
Flight Time With 3kg Payload: >35 min
Propellers: 6 x 23”
Triple Redundant Heated IMUs
Dual GPS With RTK Support
Redundant Flight Controller Power Supplies
Quick Attach System for Payload and Batteries
20 Km Standard Control / Telem Range
Independent 900 MHz and 2.4Ghz Telemetry Systems
10 - 28 VDC Power Supply for Payloads (up to 300W)
Aux Battery Voltage Connections 3 x 20A
Arms and Legs Fold for Storage
Navigation and Beacon Lights

LAM6 Standard Configuration (With Folding Arms & Legs)

Avionics Systems

Flight Controller:

The LAM6 runs the well tested and highly featured ArduCopter firmware on it’s flight controller. This fully open source firmware provides excellent vehicle control and allows extensive customizations while still being easy to use for the pilot and lacks any sort of artificial limitations other commercial solutions may have. The project has many industry partners and receives regular updates and enhancements through official developers and the community.

The Cube Autopilot:

The ArduCopter Firmware runs on The Cube autopilot module, one of the most fully featured and well tested autopilots available today. It was developed in collaboration with the industry specifically to run ArduCopter (and other open) firmware. Many popular commercial drones use Cube modules in their own designs as well.

In-House Designed Carrier Board:

The cube autopilot module sits on an in-house designed carrier board built to integrate many of the electronics systems on the drone. This saves weight, complexity of wiring, and allows for functionality not available in off the shelf solutions.

GPS Unit:

The standard LAM6 configuration uses dual Here3 GPS units which can provide enhanced accuracy and redundancy. The Here3 uses the u-blox M8P high precision GNSS module with integrated support for RTK precision navigation.

Telemetry and Manual RC:

The LAM6 includes support for dual independent mavlink telemetry and “manual RC” control systems. The RFD900x module operates in the 900MHz ISM band and provides up to a 40 Km range with a transparent UART port from the flight controller to a Ground Control Station (GCS). It can also be configured to manually control the LAM6 with a compatible RC controller.

The Herelink system provides an integrated solution for control, telemetry, and video / data transmission. The herelink system uses a controller with a built in android tablet that can run Qgroundcontrol or Solex GCS apps. It can also display a real time video feed from the vehicle. It can connect to a wifi network or create a local hotspot allowing sharing of telemetry and video with nearby computers.
In the LAM6 standard configuration the herelink system is the primary control and telemetry device and the RFD900x serves only as a backup.

Payload Integration

The LAM6 is uses a standardized payload mounting system that allows large and heavy payloads to be quickly added and removed from the drone. This system is much more secure and easy to use than the more common rail system found on some other drones. The payload can interface with the flight controller through a standard USB com port interface (micro USB), and draw power from the LAM6 through an XT30 connector located on the underside of the drone.

MAVLink is a messaging protocol for communicating with drones and is supported by Arducopter and most ground control stations.

Dronekit is a python API that allows easy generation of MAVLink messages to monitor and control nearly every aspect of a drone. (Typically from a companion computer in the payload)

Payloads that fit in a 200 x 200 x 300 mm area adjacent to the mounting plate will not interfere with the legs and folding mechanism. Larger payloads are definitely possible but could interfere and may need to be removed for transport.
We use the common payload mounting plate to either directly build the payload on or to make an adaptor to an existing payload. The 4 spring loaded pins locate into locking holes in the plate while the slot constructed from carbon fiber plate supports the payload vertically. As long as at least one pin is engaged, the plate cannot slide out.

Payload Mounting Slots

Tabs in Locked Position

Payload Example

Propulsion

Motors ESC & Propellers

The LAM6 standard configuration uses the HobbyWing XRotor Pro X6 integrated propulsion system. This is a Motor, ESC (Electronic Speed Controller), and propeller that have been designed to work together as one complete unit. This provides a much higher level of performance, optimization, and integration than is usually possible when building with discrete components. These are very cost effective and easy to get in North America.
The LAM6 uses six of the X6 variety which includes a 23” propeller and each provides up to 11.9 Kg of thrust.

If even more payload is needed and you are able to fly beyond the 55 lb (25 Kg) FAA sUAS limit, the LAM6-H is a configuration that replaces the HobbyWing X6 system with their XRotor Pro X8, these provide up to 15.3 Kg of thrust per motor, and supports an AUW of 42 Kg.
This configuration uses 30” propellers so the motor arms need to be extended as well to provide clearance. Eventually detailed plans for that will be provided along with the standard configuration.

Battery System

The Current Standard LAM6 configuration uses two 25Ah 6S LiHV batteries in series, this has been tested to provide 47 minutes of hover time in relatively windy conditions. In the future we plan to provide a graph of flight time vs. payload with various battery configurations when we have enough flight data to provide accurate results.
Using the same mechanism as the payload mount, the battery trays can be quickly swapped out in the field. The current design uses velcro straps to mount the batteries but a design with the battery more directly integrated into the mounting tray is in progress. This integrated battery will include smart functions such as built in balancing, current, temperature, capacity, and voltage measurement.
The LAM6 uses standard commercially available batteries, and can work with a variety besides what is mentioned here.

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