Propulsion - Thrusters

Each thruster is driven by a Hacker brushless motors running at ~28V. The thruster shaft mounts to a propeller designed specifically for use in water through a rotating shaft seal, allowing a watertight rotating connection. An aluminum shroud mounts to the thruster body to protect against accidental contact with the prop. Two threaded holes on the thruster wall allow for easy mounting with standard hardware. The rear of the unit mounts a single three-pin connector designed for submersible use, and a dual O-ring seal ensures that the connector end is watertight.

Since brushless motors are irreversible, relays are put inside the lower hull to provide this essential feature. The motors and the relays are then controlled by a single mini SSC motor controller – also inside the bottom hull. The SSC communicates to the on-board computer using a single serial line. This separation of control signal and high-power motor-drive electronics provide good electrical decoupling from the relatively noisy motors and drivers from the electronics inside the top
hull.

Software driver tabs to the SSC is designed to hide the physics of the thrusters – that they are reversible only through relay control – to provide a simple -100% to 100% thruster power control to higher level feedback and AI control.