One of the most compelling uses of robots involves deploying them in environments that are too hazardous or confined for humans to safely access. Robots such as these can inspect infrastructure, search for victims of natural disasters, or even explore distant planets — all without putting any humans in harm’s way. By leveraging robotic systems, we can significantly reduce the risk of injury or loss of life, while also gaining valuable insights and data from previously inaccessible or unexplored environments.
But before these benefits can be fully realized, technological advancements are needed. Many components of robots have received some significant upgrades in recent years, from sensors to processing units and batteries. But when the robots arrive at their destination, they often need to interact with the world in some very precise ways, and this is where modern technologies fall flat — especially when the scale of the robot is very small. Tiny actuators, in particular, are just not up to the task when something as precise as cell manipulation or chip component assembly is involved.
An overview of the robot’s design (📷: R. Kinoshita et al.)
Researchers have recently proposed a promising solution to these challenges — the Holonomic Beetle 3 (HB-3). This tiny, untethered, and autonomous robot sports a micromanipulator that is designed to perform highly precise tasks in confined environments where traditional robotic systems fail. Developed by engineers at Yokohama National University, HB-3 is equipped with novel piezoelectric actuators, a compact power system, and an onboard computing platform that enables it to function independently in extreme conditions.
Unlike conventional actuators that rely on bulky motors or pneumatics, piezoelectric actuators generate motion by expanding or contracting in response to electrical signals. This allows for movements at the nanometer scale, making them ideal for delicate tasks like assembling semiconductor chips, handling biological samples, or manipulating nanomaterials.
The piezoelectric materials used in HB-3 include lead zirconate titanate, a ceramic material that is highly responsive to electrical input. By integrating these materials into the actuator design, HB-3 can achieve positioning accuracy as fine as 0.08 mm along the x-axis and 0.16 mm along the y-axis, ensuring excellent precision in its tasks.
In one experiment, the robot mounted chips on a PCB (📷: R. Kinoshita et al.)
HB-3 is entirely self-contained. Its autonomy is enabled by the combination of a Raspberry Pi 4 B single-board computer and an Arduino Nano Every microcontroller. The Raspberry Pi serves as the central processing unit, handling image recognition, machine learning algorithms, and overall decision-making for the robot’s tasks. Meanwhile, the Arduino is responsible for real-time control of the piezoelectric actuators and motors. The two devices communicate via serial connections, ensuring smooth and coordinated operation.
The robot also features an integrated camera that provides real-time visual feedback, allowing it to detect objects, measure distances, and adjust its movements accordingly. Using OpenCV-based image processing techniques, HB-3 can determine the position and orientation of objects with high accuracy, making it capable of executing complex pick-and-place operations autonomously.
As technology continues to evolve, innovations like HB-3 demonstrate the increasing accessibility of autonomous, ultra-precise robotic systems. By combining advanced piezoelectric actuation, embedded computing, and machine learning, this tiny yet powerful robot is pushing the boundaries of what is possible in confined and extreme environments — bringing us one step closer to a future where robots handle tasks that once seemed impossible.
