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The WAM-V

(Unmanned Surface Vehicle)

Team AMORE has received a 16 foot Wave Adaptive Modular Vessel (WAM-V) unmanned surface vehicle (USV) in September 2021. The vehicle has since been fitted with propulsion, safety, and guidance, navigation, and control (GNC) systems.

USV Platform

Team AMORE received the WAM-V from Robonation. For more information about the WAM-V please visit Marine Advanced Robotics

Major Dimensions for the WAM-V

Beam: 96 inches (244 cm) [outside to outside]
Overall Hull Length: 154 inches (391 cm)
Ski Length: 112 inches (284 cm)
Hull Diameter: 16.75 inches (42.6 cm)
Payload: 300 lbs. (136 kg) maximum
Full Load Displacement: 560 lbs. (255 kg) estimated
Draft: 6.5 inches (16.5 cm) estimated

The information found on this page was sourced from "Owner's Operation and Service Manual Maritime RobotX Challenge WAM-V USVx" https://robonation.org/app/uploads/sites/2/2019/09/WAM-V-USVx-for-RobotX-Service-and-Operation-Manual-rev_1.pdf

Propulsion System

Components:

12V MinnKota PowerDrive V2 Trolling motors (Bow Thrusters)
36V Newport NT300 Electric Outboard motors (Stern Thrusters)
Teensy 4.1 microcontroller integrated with a printed circuit board
12 V AGM batteries
36 V Lithium (LiFePO4) Newport Battery

Overview:

The WAM-V's propulsion system, developed as part of a senior project in 2023/24, sought to increase the speed of the WAM-V and allow it to function in larger waves than the previous limited thrusters by integrating new stern thrusters. The previous thrusters were moved forward and integrated as bow thrusters to make the WAM-V fully-actuated while station-keeping, providing more accurate positioning for accurate data collection, and for more reliability for completing RobotX tasks such as task 6. There are two separate Proportional Integral Derivative (PID) controllers which carry this out. During waypoint navigation a Heading and Speed controller uses only the stern thrusters, Newport trolling motors capable of 490 N each, providing sufficient speed and maneuverability via differential thrust. This conserves power in the smaller bow thruster batteries. For Stationkeeping, the bow thrusters, Minnkota motors producing 245 N, are activated to allow fully-actuated movement, with the stern thrusters' thrust output saturated at 245N to match the bow thrusters’.

Sensors

Pixhawk 6C Flight Controller (IMU, GPS, Compass)
Pozyx GPS on Landing Platform for Drone Recovery
Velodyne VLP-16 (Donated by Robonation)
ZED 2i
Hydrophones (Coming soon)

Guidance, Navigation, and Control System

Components:

Jetson TX2
Ubiquiti Rocket M5 (Not pictured)
R12DS RC Receiver
Teensy 4.1 Microcontroller integrated in PCB
Newport LCD Screens
Pixhawk 6C Flight Controller

Overview:

The GNC box is located aboard the payload tray and is responsible for all communication aboard the USV. The GNC box houses the Jetson TX2 computer, a Teensy 4.1 microcontroller integrated with a printed circuit board, and the integrated safety system. The main function of the GNC box is to act as a management device for all sensors and components aboard the WAM-V. This is achieved using Robotic Operating System (ROS) as middleware to communicate between various sensors and components in software. Using ROS, the low-level controllers aboard the WAM-V have access to vital peripheral data, such as the current GPS location, that can be used to dynamically adjust the propulsion system’s output to reach a desired state and respond to changing environmental conditions. This setup allows the WAM-V to achieve accurate and reliable movement, essential for tasks such as navigating complex waterways, performing scientific data collection, and conducting autonomous operations.

Heading and Speed Controller

Overview:

The Heading and Speed controller is a PID controller that utilizes the stern thrusters with differential thrust to navigate over long distances. The bow thrusters are not utilized by this controller, so the vehicle uses differential thrust with the stern thrusters. The parameters governed by the Heading and Speed controller are velocity and heading Given a desired point, the WAM-V will hold its heading to face the point as it navigates. As the WAM-V approaches the point, its velocity decreases to allow for a smooth transition between the Heading and Speed controller and the Station Keeping controller. The maximum velocity allowed for the WAM-V during the use of the Heading and Speed controller is directly proportional to the distance to the point. For both controllers, the output is desired forces Tx, Ty and moment Mz on the vehicle. Since the Heading and Speed controller only uses the stern thrusters, the output of the controller is transformed into thrust for the port and starboard stern thrusters FxSP, FxSS. The free-body diagram of the forces from the thrusters during the use of the Heading and Speed controller is shown in the following figure.

Stationkeeping Controller

Overview:

The Station Keeping controller is a PID controller that utilizes all four thrusters simultaneously to hold the WAM-V at a desired point. Since the USV utilizes all four thrusters using this controller, the USV is considered over- actuated, which generates the thrusters’ output FxSP, FxSS, FyBP, FyBS. The motions governed by the Station Keeping controller are position and heading . The free-body diagram of the forces from the thrusters during the use of the Station Keeping controller is shown in the left figure. An autonomous water quality testing mission using both the Heading and Speed controller and the Stationkeeping controller is shown below.

Updates in Progress

Acoustic System

Hydrophones: Aquarian Audio H2D or the Aquarian AS1
Data Acquisition Device: Keyence NRX. Used to convert real-world physical phenomena into digital signals.
Will be developed by end of Spring 2025 by senior project team
Will be used in RobotX 2026