Swim-and-Breach at Palm Scale: A Rudder-Steered Two-Propeller Underwater Robot Platform with Differential-Thrust Pitch Control
Abstract
We present a palm-scale (65 mm, 34 g) swim-and-breach robot platform. Two vertically stacked propellers provide both propulsion and differential-thrust pitch control under a proportional-integral-derivative (PID) loop, and a tail rudder adds yaw control. The hull, evaluated by flow simulation, reduces the drag five-fold relative to an equivalent cuboid, and the propellers are optimized using B-series modeling validated by dynamometer measurements. The current robot swims at 13.9 body lengths per second and turns at 209 deg per second, corresponding to the upper limits reported for underwater robots. In free swimming, the pitch loop turns the body to any commanded nose-up pitch angle, and, with the rudder stabilizing the exit, the current robot leaps 1.6 body lengths high and 3.7 long in a seamless cruise-leap-cruise sequence. The platform can be used to build small-scale robots that cross barriers and dry gaps between pools for inspection in streams, flooded structures, and industrial systems.
Related
- One pure steered state implies Einstein-Podolsky-Rosen steering for two-qubit entangled states
- Propeller-wing interactions of a lift + cruise eVTOL configuration during transition
- On the aerodynamics of an accelerating and decelerating propeller in hover at low Reynolds numbers
- Design, implementation and validation of a web-based dynamic simulation platform for pumped storage hydropower plant control systems
- Interscale energy transfer in a propeller-driven homogeneous and isotropic turbulence generation device
BibTeX
@misc{choi2026swimandbreach,
title = {{Swim-and-Breach at Palm Scale: A Rudder-Steered Two-Propeller Underwater Robot Platform with Differential-Thrust Pitch Control}},
author = {Daehyun Choi and Ian Bergerson and Hengjia Zhu and Tianjun Lan and Saad Bhamla},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.17240},
eprint = {2609.17240},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.17240},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Swim-and-Breach at Palm Scale: A Rudder-Steered Two-Propeller Underwater Robot Platform with Differential-Thrust Pitch Control
AU - Daehyun Choi
AU - Ian Bergerson
AU - Hengjia Zhu
AU - Tianjun Lan
AU - Saad Bhamla
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.17240
UR - https://arxiv.org/abs/2609.17240
AB - We present a palm-scale (65 mm, 34 g) swim-and-breach robot platform. Two vertically stacked propellers provide both propulsion and differential-thrust pitch control under a proportional-integral-derivative (PID) loop, and a tail rudder adds yaw control. The hull, evaluated by flow simulation, reduces the drag five-fold relative to an equivalent cuboid, and the propellers are optimized using B-series modeling validated by dynamometer measurements. The current robot swims at 13.9 body lengths per second and turns at 209 deg per second, corresponding to the upper limits reported for underwater robots. In free swimming, the pitch loop turns the body to any commanded nose-up pitch angle, and, with the rudder stabilizing the exit, the current robot leaps 1.6 body lengths high and 3.7 long in a seamless cruise-leap-cruise sequence. The platform can be used to build small-scale robots that cross barriers and dry gaps between pools for inspection in streams, flooded structures, and industrial systems.
ER -