MACO – Introduction
The autonomous underwater vehicle (AUV) MACO was developed at the University of Victoria, in partnership with FlexMet Technologies Inc. The vehicle was tested in collaboration with Defence Research and Development Canada (DRDC) to investigate the use of an AUV to support rapid deployment of acoustic element arrays. The requirements on the AUV to stop and hover, while triggering a low frequency sound source, lead to the multiple thruster, hybrid design of MACO.
A hover capable AUV combines design attributes from the hydrodynamic AUV and the more maneuverable ROV. Research centres from around the world have been working with Unmanned Underwater Vehicles(UUVs) to develop research platforms that can be used to nurture new technologies in the field of autonomous control and provide a better platform for collecting scientific data. These platforms exhibit varying levels of autonomy and many have variable-configuration capabilities which allow them to be used for a myriad of scientific missions.
MACO is a hybrid vehicle design that borrows attributes from both the traditional ROV and the AUV to meet its functional requirements. MACO uses two vertical thrusters used to control the pitch and depth of the AUV and two horizontal thrusters to provide forward propulsion and the necessary torque for turning. To minimize drag, MACO has a long slender hydrodynamic body with a 9:1 length-to-width ratio. Furthermore, the vertical thrusters are contained completely within the hull profile and the horizontal thrusters are located adjacent to the hull to minimize parasitic drag while still providing MACO with adequate turning capability. MACO is 1.52m long, 0.17m wide, 0.44m high (excluding tower, thrusters and external instrumentation), and the tower is 0.29m high and the horizontal thrusters bring the total body width up to 0.41m. It weighs 70kg dry and -0.25kg wet (excluding payload).
The body is constructed from PVC throughout with the exception of anodized aluminium pressure case end caps and thruster brackets. The instrument housing provides a one atmosphere environment for computer equipment, electronics, batteries, speed controllers, etc. The wet hull has removable side panels which improve the hydrodynamics while providing access to flotation and payload bays. The bulkheads structurally connect the pressure casings and provide mounting for the thrusters and other peripheral devices. The thrusters are contained in an aluminium housing and can provide between 22N and 35N of thrust depending on direction.