Introduction

The Otter ASV is a 2 meters long catamaran propelled by two electrical fixed thrusters. This means that steering has to be done through differential thrust by the controller.

The controller box is based on a Raspberry Pi 4 with 4GB of RAM. Connected through it's GPIO pins is a Strato Pi CAN board that provides a robust power supply in addition to multiple communications interfaces and an independent hardware watchdog. A CAN network connects the Raspberry Pi to the Torqeedo Interface card. Thus it has access to both power channel and motor control. There is a passive PoE injector providing power for the external BulletAC IP67. It also contains s SLIM interface board that synchronizes and reads the RS-485 serial communication from the TBR-700 -/RT hydrophone.

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The batteries are of the shelf Torqeedo batteries developed for use with their electrical outboard motors. The Otter can carry four of these batteries, for a total capacity of 3660Wh, or 124Ah. This provides the Otter with up to 20 hours of battery powered operation, depending on speed and payload(according to Maritime Robotics).