Imagine a flying robot so small and lightweight that it can explore narrow spaces where conventional drones struggle to enter. Now imagine that it can fly without propellers, rotating motors, or flapping wings. Scientists are bringing this possibility closer to reality with a new ion-powered microrobot that combines an extremely lightweight structure with advanced electronic flight control.
Developed by Qiannan Tao and colleagues, the experimental flying robot weighs just 36.7 milligrams and uses electrically generated airflow to produce thrust. Despite its tiny size, it achieves a thrust-to-weight ratio of 5:1, allowing it to lift payloads several times heavier than itself. The researchers also demonstrated stable, controlled flight using an onboard inertial measurement unit (IMU).
The technology could eventually help develop tiny robotic systems for inspecting dangerous environments, exploring confined spaces, and assisting in disaster rescue operations.
How Does a Flying Robot Work Without Propellers?
Most flying robots depend on mechanical components to move through the air. Conventional drones use electric motors and spinning propellers, while some miniature robots rely on rapidly flapping wings.
Although these systems can provide effective flight, their mechanical components add weight and complexity. At very small scales, fitting motors, batteries, sensors, and control electronics into a lightweight body becomes particularly challenging.
The new microrobot takes a different approach by using ion wind propulsion, which generates thrust through electrically driven airflow rather than mechanical movement.
The process begins with a phenomenon called corona discharge. When a sufficiently strong electric field is applied to specially arranged electrodes, nearby gas molecules become electrically charged. These ions accelerate through the surrounding air and collide with neutral air molecules, transferring momentum to them.
This movement creates an airflow known as ion wind. By directing that airflow, the robot generates thrust that helps it lift and move.
Because the propulsion system does not require rotating propellers or flapping wings, it offers a potential way to simplify flying robots and reduce their mechanical weight.
However, generating enough thrust is only part of the challenge. A useful flying robot must also remain stable, respond to control commands, and carry the equipment needed to perform practical tasks.
A Robot Lighter Than a Grain of Rice
One of the most striking features of the new microrobot is its exceptionally low mass.
The device measures approximately 37.7 × 37.7 millimetres and weighs just 36.7 milligrams. Its lightweight structure is made using a thin, approximately 50-micrometre-thick tungsten-coated polymer film.
This material combines the electrical conductivity of metal with the flexibility and low weight of a polymer. It allows the researchers to construct the robot's structural framework and electrodes without relying on heavier conventional materials.
The design incorporates four ion-wind thrusters arranged in a cross-shaped configuration. By adjusting the electrical voltage applied to different thrusters, the researchers can change the generated thrust and influence the robot's orientation.
The robot achieves a thrust-to-weight ratio of 5:1, meaning its available thrust is approximately five times the force needed to support its own weight under the reported operating conditions.
More impressively, the researchers demonstrated flight while carrying a payload weighing 146.8 milligrams. This payload is approximately four times the robot's own mass.
The design also addresses the cost of manufacturing miniature flying machines. According to the researchers, the materials cost less than $0.10 per robot, and assembly takes under 30 minutes.
These features could make it easier to produce multiple microrobots for experiments and, eventually, coordinated missions.
The Biggest Breakthrough: Stable and Controlled Flight
Building a robot that can lift off the ground is one challenge. Making it fly in a controlled direction without constantly losing balance is another.
Tiny flying robots are especially sensitive to disturbances because their low mass and inertia allow relatively small changes in thrust to produce significant changes in orientation.
Ion propulsion adds another complication. The relationship between applied voltage and generated thrust is nonlinear, and environmental conditions such as temperature, humidity, and air pressure can affect performance.
To address these problems, the researchers equipped the microrobot with an inertial measurement unit, or IMU. This sensor measures changes in motion and orientation, helping the control system determine how the robot is tilting.
The researchers then implemented a closed-loop feedback control system.
In simple terms, the robot continuously measures its orientation, compares it with the desired orientation, and adjusts the voltage supplied to its ion thrusters. These adjustments change the generated thrust and help correct unwanted movements.
This is an important step beyond simply designing a robot that is naturally stable. Instead, the machine actively responds to changes in its flight.
During experiments, the microrobot successfully followed predefined rectangular and triangular flight paths. The researchers also reported substantial improvements in stability, with the root mean square errors in pitch and roll angles decreasing by 83.11% and 89.21%, respectively, under the reported comparison.
The robot also demonstrated one hour of stable tethered hovering.
This result shows that ion-wind propulsion can be combined with sensor-based feedback to achieve controlled flight at the microrobot scale.
Carrying Sensors to See and Understand Its Surroundings
A flying robot becomes far more useful when it can collect information about its environment.
The researchers demonstrated that their microrobot could carry an image sensor and a fibre Bragg grating (FBG) sensor while retaining sufficient manoeuvrability for experimental tasks.
The image sensor allows the robot to record visual information during flight. In principle, such a capability could help inspect narrow passages, small machinery components, or areas that are difficult for larger robotic systems to reach.
The FBG sensor provides a different kind of information. Fibre Bragg grating sensors detect changes in reflected light associated with variations in the fibre's physical conditions. Depending on the sensor design and calibration, these changes can be used to measure properties such as strain or temperature.
The experiments demonstrate the potential for miniature ion-powered robots to carry specialised sensing equipment instead of serving only as basic flying platforms.
In the future, similar systems could help inspect industrial equipment, investigate confined spaces, or collect information from locations that are unsafe for humans to enter. Its lightweight design could also inspire future miniature robots for inspecting spacecraft interiors, exploring confined areas of space stations, or investigating difficult-to-access locations during planetary missions.
Could Swarms of Tiny Flying Robots Transform Rescue Operations?
The low manufacturing cost and compact design suggest another possibility: deploying multiple microrobots instead of relying on a single machine.
Imagine a damaged building following an earthquake. Small robots could potentially enter narrow gaps, inspect hidden spaces, and gather visual information about the surrounding structure. Similar systems might eventually assist with inspections inside industrial facilities or other hazardous environments.
A group of inexpensive robots could also cover several locations simultaneously, provided that suitable coordination, communication, and control systems are developed.
The researchers' origami-inspired manufacturing approach supports this longer-term vision. The thin polymer film can be fabricated and assembled into a three-dimensional structure, reducing the need for expensive microfabrication equipment and complicated manual construction.
Nevertheless, coordinated autonomous swarms remain a future development goal rather than an established real-world capability of this prototype.
Important Challenges Still Remain
Despite its promising performance, the microrobot is not yet a fully independent alternative to conventional drones.
One major limitation is its power supply. The robot consumes approximately 0.45 watts under the reported operating conditions, but its tiny size makes it difficult to carry a battery and the necessary high-voltage electronics without significantly increasing its mass.
The researchers therefore propose a carrier-deployed approach in which a larger aircraft supplies electrical power and houses heavier control electronics while deploying the smaller robots through tethers.
This arrangement could be useful for certain inspections, but it limits how freely the microrobot can operate.
The propulsion system also uses voltages in the kilovolt range, requiring careful electrical insulation, engineering safeguards, and reliable operation. Low current does not automatically eliminate every electrical hazard.
Additional work is needed to miniaturise the control electronics, improve power autonomy, and demonstrate reliable performance under changing environmental conditions. Practical applications would also require testing flight duration, durability, communication, and obstacle avoidance.
A New Direction for the Future of Flying Robots
The development of this 36.7-milligram ion-powered microrobot demonstrates how electrical propulsion and feedback control can be combined in an extremely lightweight flying machine.
Its ability to carry a payload around four times its own mass, follow predefined flight paths, and maintain tethered hovering for an hour represents progress toward more capable microrobots.
The most important achievement is not simply that the robot flies without propellers. It is that the researchers have demonstrated a way to control its orientation and movement using onboard sensing and electrical thrust regulation.
Although battery-powered autonomous flight and practical swarm deployment remain significant challenges, this approach could help engineers develop smaller, simpler, and less expensive flying machines.
In the future, robots of this kind might help inspect places that larger drones cannot reach, collect information in dangerous environments, and support rescue teams after disasters.
The bigger question is whether engineers can eventually make these tiny machines completely untethered, independently powered, and capable of working together as a coordinated swarm.
Reference: Tao, Q., Gu, Y., Wang, X. et al. Controlled flight of high-thrust ultralight ion-propelled microrobot with integrated sensing. Nat Commun 17, 9530 (2026). https://doi.org/10.1038/s41467-026-76462-y
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