Overview

A project of BORO, the robotics community I led, to build an underwater vehicle for the Singapore AUV Challenge (SAUVC) 2025. The 12-member team covered mechanical, electrical, and software work.

Problem

A competition-ready underwater vehicle needs reliable propulsion, and SAUVC requires a hardware-level safety mechanism that works even if the software fails. A team without a working kill switch cannot pass qualification.

Approach

• Propulsion: four BLDC thrusters, two vertical and two horizontal, driven by bidirectional ESCs so that thrust can be applied in both directions.
• Control: a Pixhawk running ArduSub (ArduPilot) takes signals from a remote control and drives the thrusters.
• Gripper: the competition task is to grasp objects and move them, so the design includes a gripper. It is still a rough design.
• Kill switch: a hardware fail-safe that opens the power circuit through a solid state relay, independent of the software, so the vehicle can always be disabled safely.

My Contribution

• Propulsion system: set up the BLDC thrusters, bidirectional ESCs, and the Pixhawk/ArduSub configuration.
• Kill switch: designed the solid-state-relay kill switch, a mandatory requirement for SAUVC qualification.
• Team leadership: as head of the BORO community, led the 12-member team through design, build, and testing.

Result

The team passed the SAUVC 2025 video qualification. It did not travel to the competition because of limited funding.

Limitations and Lessons

• Waterproofing: waterproofing is still an open problem.
• Not autonomous yet: the vehicle is currently driven by remote control. Autonomous behavior has not been implemented.
• Gripper: still a rough design, so the vehicle cannot yet grasp and move objects.
• Thruster count: the vehicle has four thrusters for now.