The Minion Research Platform
The Minion ASV achieves propulsion with Copenhagen Subsea VM RDP (rim-driven propellers). These are a special type of marine electric motor in which a brushless motor is built around the propeller. This increases efficiency and minimizes the risk of snagging or interfering with wildlife. The RDPs can be azimuthed +/- 85 degrees using Volz DA30 servos, greatly improving the ASV’s agility. The RDPs can also be automatically retracted from the water with Linak LA36 linear actuators, reducing the human intervention required when launching, retrieving, and beaching the ASV. This propulsion system is packaged in custom aluminum motor pods, filled with closed cell expanding foam for buoyancy.
Minion ASV’s payload tray has been upgraded to realize the goal of a more useable autonomous research platform. To do this a modular rail system has been installed around its perimeter. This rail uses the ubiquitous picatinny mounting system to ensure easy installation and secure attachment, allowing for the tool-less installation of hardware with no modification to Minion.
Minion has a hydrophone array to detect acoustic underwater pingers. The hydrophone array consists of a diamond shaped, planar array of four Teledyne Reson hydrophones. Signals are amplified and sampled before being processed in software. To deploy the array, a linear actuator is used to rotate the array and pole mount 90 degrees downward into the water. The mounting pole serves to lower the array deep enough to limit the impact of surface reflections.
The MAST (Minion Autonomous Systems Tray) furthers the concept of a modular and upgradable Minion ASV. This system consists of support and mounting for Minions batteries, ESC’s, control board, expansion bay, and computer hardware. These systems are readily accessible, upgradable, and removable using only a single tool. MAST lowers Minions overall CG, while allowing ample storage for equipment atop the deck. Equipment can be mounted to the deck using the pre-drilled, threaded bolt pattern.
The hardware of the Minion perception suite is responsible for detecting and characterizing waterborne objects. Primary sensing is provided by four Lidar sensors providing up to 1.6 million data points per second. The location and orientation of these sensors optimizes return density on objects to the port, starboard and bow of Minion. Lidar data is fused with imagery from two 100-degree field-of-view, 5MP cameras for improved object detection and characterization.
“Anchor” AUV and Deployment
The Minion ASV can deploy a small ROV, Anchor. Anchor is a Blue Robotics BlueROV 2, which is run autonomously through a tethered link to Minion. A custom winch system can quickly raise and lower Anchor. The deployment system mounts on the MAST and uses a deployment arm to raise and lower Anchor from the centerline of the platform. This minimizes the risk of Anchor hitting Minion’s pontoons during retrieval, but returns it to an elevated and balanced position after retrieval.
The 2018 Minion ASV Racquetball Turret builds upon the lessons learned from developing a turret in 2016, creating a more robust and logisticially simple system that is easier to manufacture, operate, and maintain. The turret features self-contained power and control systems, giving it the ability to be a drop-in addition to the deck of the WAM-V when the competition demands it.