According to a study published on January 26th, 2025, in the journal Advanced Intelligent Systems, engineers from Yokohama National University have created a tiny, lightweight, cordless robot capable of acting independently and with ultra-high precision in all directions under the most extreme conditions.
Palm-sized untethered autonomous holonomic precise robot for multi-purpose tasks in confined narrow space. Image Credit: YOKOHAMA National University
The robot, which the designers refer to as “Holonomic Beetle 3” (or HB-3) because it was inspired by the movements and anatomy of the rhinoceros beetle, combines piezoelectric actuators with autonomous technology to enable micro-scale manipulation tasks that were previously impossible for robots.
HB-3 addresses a rising requirement in various industries—including laboratory automation, medical treatments, and scientific research—for precise manipulation at numerous scales, from nanomaterial and cell manipulation to chip component assembly, where human intervention is limited or impossible. This is especially important in vacuum, clean, draft, and biohazard safety chambers.
In recent years, autonomous (cordless) robots have been used in various industries, disaster areas, medical fields, severe settings, or limited spaces where human access is impossible. Meanwhile, the shrinking of internal electrical components for all types of devices has advanced rapidly, including the invention of micro batteries and micro-supercapacitors that are only a few microns thick.
However, conventional positioning devices remained stubbornly big and heavy compared to those tiny elements, leaving plenty of possibility for improvement in energy and space economy. Even if the driving circuits and batteries have shrunk, their range and operating freedom remain severely limited.
To overcome these challenges, several precision actuators—essentially, a robot's “muscles " that transform energy (electrical, hydraulic, or pneumatic) into motion—have been created to improve these positioning devices. Piezoelectric actuators, in particular, have demonstrated considerable potential. Piezoelectric materials, such as quartz in quartz timepieces or synthetic ceramics like PZT (lead zirconate titanate), develop an electric charge when subjected to mechanical stress.
They also do the opposite: they deform when an electric field is introduced. This piezoelectric feature enables ultra-fine movements by expanding or contracting in response to highly precise electrical signals, sometimes at the nanometer scale.
While several miniature robots and grippers have been developed, no mobile micromanipulators have been developed that combine piezoelectric actuation technologies, are autonomous and untethered, and can be used in real-world applications.
The HB-3's small, lightweight structure—weighing only 515 grams and measuring barely 10 cubic cm—is key to its design. An integrated driving circuit based on a single-board computer resolves challenges posed by power supply cables in the team’s previous research. HB-3 also has an inside camera and uses machine learning algorithms to adapt its real-time movements, which was impossible with earlier micromanipulators.
With an average positioning accuracy of only 0.08 mm along the x-axis and 0.16 mm along the y-axis, the HB-3 showed remarkable performance in a wide range of tasks in small, isolated environments using various tools, such as precise tweezers for picking and placing a chip part or an injector for applying a tiny droplet.
Eighty-seven percent of tasks were considered successful. The tools can be dynamically transformed into measurement probes, soldering irons, screwdrivers, and other precision instruments at various scales, from the meter to the nanometer.
We’ve been able to push the boundaries of miniaturization to create a truly autonomous, untethered device that can operate in tight, hazardous spaces. The HB-3 can not only handle complex tasks but also do so with unmatched precision.
Ohmi Fuchiwaki, Associate Professor, Faculty of Engineering, Yokohama National University
The team is still working to improve their small beetle, though. They believe that by transferring object recognition to an external high-performance computer, HB-3's processing speed—which is dependent on a Raspberry Pi CPU—may be increased, and the robot’s object detection time could be shortened.
In the future, the researchers hope to increase its speed and accuracy and investigate integrating internal side-view and top-view cameras to increase the accuracy of z-axis positioning.
Journal Reference:
Kinoshita, R. et. al. (2025) Untethered Autonomous Holonomic Mobile Micromanipulator for Operations in Isolated Confined Spaces. Advanced Intelligent Systems. doi.org/10.1002/aisy.202400872