A robot that grows like a fish, not like a machine
NYU Tandon School of Engineering's Nana Obayashi develops a length-scalable robotic fish that can be adapted for studying shallow creeks to open water
NYU Tandon School of Engineering
Propeller-powered underwater vehicles have long helped scientists explore and monitor aquatic environments. But they're limited by their own mechanics: spinning blades can snag on vegetation, stir up sediment, and startle the wildlife they're often sent to study, making them poorly suited to shallow creeks, dense weeds, or close encounters with fish.
That's one reason roboticists have spent years building machines that swim like fish instead, bending their bodies rather than spinning a propeller. The catch is that most fish-inspired robots are built for one size and one job, so scaling them up or down usually means starting from scratch.
A team of engineers says it's found a way to solve that problem. They've unveiled ScaFi, a robot modeled on fish like cod and mackerel. These fish swim by concentrating most of their body bending toward the tail end, a style that, in nature, spans an unusually wide range of body sizes.
"Right now, if you want to monitor a creek and then monitor a lake, you basically need two different robots, built and tested from the ground up," said NYU Tandon’s Nana Obayashi, currently an assistant professor of mechanical and aerospace engineering and a faculty member of the NYU Center for Robotics and Embodied Intelligence, who led the project while a doctoral researcher at EPFL. "The environments we care about don't come in one size, so we don't think the tools should either."
As described in a paper in npj Robotics, ScaFi has a rigid front section and a flexible tail made of fiberglass rods. A single motor pulls two tendons that cross near the tail's end, producing the "S"-shaped bend required for fish-like swimming motion.
The diameter of the rods forming the tail are the only part that must change with the size of the robot. They grow proportionally thicker as the robot scales up, to preserve similar tail-bending behavior. The underlying motor mechanism and crossed-tendon system stay the same.
That matters because it could cut the engineering effort needed to build fish-like robots for different environments. It also gives researchers a platform for studying how swimming performance changes with scale, a question that's hard to study systematically in animals or custom-made robots alike.
The team built three robots — roughly 0.6, 1.1, and 2.9 meters long — and tested how well each swam. The smallest produced swirling water patterns similar to those left by real fish, and across all three sizes, swimming motion lined up closely once adjusted for body size, evidence the authors say that their scaling approach preserved the fish-like gait even as the robots grew nearly fivefold in length.
They also deployed the robots in the field: the medium-sized one in a Swiss stream, the largest on Lake Geneva, the smallest in creeks only 15–30 centimeters deep. During the stream test, the robot kept swimming even after a GPS dropout.
Energy efficiency proved harder to scale. The two smaller robots performed similarly, but the largest was consistently less efficient and needed a different, more powerful motor. The authors suggest drag and inertia may be to blame, though the exact cause is unresolved, meaning the team scaled the swimming motion itself more cleanly than the energy it takes to produce it.
A similar tradeoff showed up in disturbance tests. The smallest robot was most agile but recovered slowest after being knocked off course, while the larger robots were less nimble but more stable.
The researchers suggest the same approach — scaling around one key structural parameter — could apply to other compliant robots, including ones outside water. Whether energetic performance can be scaled as successfully as the swimming motion remains an open question.
The study adds to broader aquatic robotics efforts at NYU Tandon. Industry Professor Christopher Clark's research includes autonomous underwater robotic systems for exploration and environmental monitoring, while Institute Professor Maurizio Porfiri has pioneered the use of biomimetic robotic fish to study and influence animal behavior.
The co-authors on Obayashi's paper are Josie Hughes, Alexandros Anastasiadis, Karen Mulleners, Kai Junge, and Kyle L. Walker of EPFL, and Jessica Gumowski of Queensland University of Technology. The research was partially funded by the European Union's Horizon 2020 programme under Marie Skłodowska-Curie grant agreement No. 945363.
Journal
npj Robotics
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
ScaFi: length-scalable, compliant, parametric robotic fish design for operation in multiple environmental niches
Article Publication Date
24-Aug-2026
Paramedic cockroaches: Cyborg care when rescuers can’t reach
image:
Biorobotics researchers from UQ have transformed North Queensland giant burrowing cockroaches (Macropanesthia rhinoceros) into minature cyborg paramedics.
view moreCredit: The University of Queensland
‘Swarms’ of cyborg cockroaches with cameras and miniature medical injectors could deliver supervised emergency care to people trapped in collapsed buildings, caves or other places too dangerous for rescuers to reach.
The ‘Paraborgs’ developed by University of Queensland biorobotics researchers, working with biomedical engineers at the University of New South Wales (UNSW), move cyborg insects of the future beyond searching for survivors to actively assisting them.
UQ biorobotics engineer Dr Thang Vo-Doan said their research transforms the cyborg insect from a mobile sensor into a tiny rescue platform, while critical medical decisions remain under human control.
“Cyborg insects have been designed for ‘search and explore’ missions for the past couple of decades,” Dr Vo-Doan said.
“We wanted to take the next step. Once they find someone, can they actually help?”
The researchers equipped North Queensland giant burrowing cockroaches (Macropanesthia rhinoceros) with lightweight electronics and either cameras for visual feedback or remotely activated auto-injection systems custom-made for the species.
“Augmenting their natural biomechanics could allow these cyborg insects to deliver timely emergency assistance when direct access to people trapped in narrow, debris-filled spaces isn’t possible,” Dr Vo-Doan said.
In proof-of-concept testing at UQ’s School of Mechanical and Mining Engineering, the paraborgs achieved 95 per cent success with close-range injection – positioned within 15 centimetres of the target.
The complete navigation-and-injection task succeeded in 72 per cent of trials.
PhD candidate Hai Nhan Le said accurate positioning of the paraborgs was one of the key engineering challenges.
“The cyborg insect has to navigate to the target, position itself accurately and remain stable enough to perform the injection,” Mr Le said.
“A lot of people might not like the sight of a giant cockroach scurrying towards them, but if you’re trapped in rubble or stuck in a cave and need help, it could make a real difference between life and death.”
Unlocking new tools with insect biomechanics
Director of the UNSW Medical Robotics Lab Associate Professor Thanh Nho Do said the paraborg technology could extend the reach of emergency medicine.
“From a biomedical perspective, the opportunity is to bring treatment to a patient when the patient cannot yet be brought to treatment,” Associate Professor Do said.
“The long-term goal is targeted, human-supervised intervention in places conventional medical technologies cannot access.”
Dr Vo-Doan said the research demonstrates the UQ Biorobotics Lab’s ability to adapt cyborg technology across different insect platforms.
The team has previously demonstrated cyborg beetles capable of controlled climbing, while the larger cockroaches provide greater capacity to carry specialised rescue and medical equipment.
“Rather than building one robot to do everything, we can harness the natural strengths of different insects and equip them for different missions,” Dr Vo-Doan said.
The cockroaches, like the team’s previous cyborg insect models, are anaesthetised during electrode and microchip fitting and live for as long as other cockroaches once the harnesses are removed.
Superintendent Tim Hassiotis, Manager Natural Disaster and Humanitarian at Fire and Rescue NSW, said the technology could extend the reach of rescue teams.
“If cyborg insects can safely enter spaces we can’t, locate casualties and ultimately help deliver emergency care, they could become another valuable tool in the future of urban search and rescue,” Superintendent Hassiotis said.
A swarm with specialised roles
Dr Vo-Doan said the longer-term vision was to deploy swarms of specialised cyborg insects, with individuals performing complementary roles.
“Some could carry cameras and environmental sensors, while others could carry specialised emergency or medical equipment,” he said.
“The vision is not to replace first responders, but to give them another way to see, reach and potentially help people when direct access is impossible.
“Hopefully, within the next 5 to 10 years, we could see cyborg insect rescue teams deployed to help people in real emergencies, provided we have the resources to accelerate the research and field testing.”
Read the research published in Advanced Science.
Journal
Advanced Science
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Paraborg: Paramedic Cyborg Insects for In Situ Emergency Drug-Delivery
Article Publication Date
25-Aug-2026