Design and fabrication of payload computer module for the Clearpath Robotics Kingfisher M200

Abstract

The Clearpath Robotics Kingfisher M200 robot is an unmanned water surface vehicle with payload autonomy capability. This allows users to develop autonomy control on an offboard computer until it is ready for use on the autonomous vehicle. The Massachusetts Institute of Technology's Battelle Autonomy Laboratory plans to utilize this feature in both teaching and research applications so that users can develop autonomous missions on off-board single-board computers and then easily integrate their missions with the vehicles when ready. Although the M200's payload bay includes a waterproof data connection port, there is no provided environmental protection for the payload computer itself. This paper documents the design and production of a waterproof payload computer module that allows for the operation of the single-board computer, data interface with the M200's on-board computer and for the attachment of additional USB components. The Raspberry Pi was selected as the most appropriate single-board computer and the Otterbox Drybox 3000 was selected as the most appropriate enclosure. Electrical circuitry was designed to allow for power to the computer, data communication with the M200 and USB connections for additional components, and combination of cable glands and panel-mounted connectors were used to allow these connections to be accessible from the outside of the enclosure while retaining a NEMA 4 waterproof enclosure rating. In order to create a robust and user-friendly module, a system of strain relief and component orientation was designed. Continuous testing and adapting of prototypes resulted in a compact, operational payload module that can easily be interfaced with the Kingfisher M200 to provide payload autonomy as well as offer two additional USB ports for the connection of additional components. This design aims to be easily reproducible by other Kingfisher M200 users, as well as adaptable to other payload autonomy applications.