Researchers at Tsinghua University and Beihang University have developed a new type of microrobot that can continuously transform into different shapes and safely lock into precise forms. This technology holds the potential to transform operations executed in intricate, dangerous, and cramped environments. The innovation is a big step for soft robotics, the field where multifunctionality and adaptability are primary challenges. Through the combination of advanced materials engineering and precision control, the researchers have unveiled new avenues for robotic applications.

The Heart of the Innovation: A Miniature Actuator

According to the study published in Nature Machine Intelligence, the key to this shape-shifting ability lies in a newly developed thin-film small-scale actuator. This actuator serves as the “heart” of the microrobot, allowing its flexible and dynamic movements. The process of fabrication is complex: it starts with the deposition of a silicone coating on a silicon wafer, followed by transfer-printing a polyimide film onto the substrate. A copper layer is deposited through electron beam evaporation for accurate thin-film deposition. Photolithography and wet-etching define the copper circuitry and structures, while laser cutting finalises the actuator’s shape and size.

Professor Zhang Yihui, who led the research at Tsinghua University’s School of Aerospace Engineering and the State Key Laboratory of Flexible Electronics Technology, emphasised that previous small-scale actuators (typically under five centimetres) struggled to achieve continuous transformation and stable locking. The new actuator fixes this by enabling highly accurate electric control over deformation, allowing the microrobot to shift into any desired shape and lock firmly into place. This breakthrough greatly expands the microrobot’s operational versatility, allowing it to easily walk, run, jump, fly, and climb.

Building the Microrobot: A Lego-Inspired Approach

The researchers used a “Lego-inspired” modular architecture to build the microrobot. By integrating the new actuators with other functional elements—such as rotors for flight, motors for ground locomotion, control modules, and a small lithium battery for wireless power—the researchers developed a microrobot only nine centimetres long and weighing 25 grams. It can move consecutively between ground and air travel, reaching ground speeds of up to 1.6 meters per second. The researchers say this is the lightest and smallest untethered robot that can move on both land and in the air.

Diverse Applications

This microrobot’s capability of morphing into rolling and flying shapes opens different applications. Its application in fault diagnosis and repair in narrow or hazardous environments, archaeological excavation, and search missions is proposed by Zhang. Its actuator technology also has great potential for applications in bioelectronic devices like shape-adaptive vascular stents and improved virtual and augmented reality haptic feedback systems. The innovations of the team provide new paths for next-generation mini-robots, combining strength, flexibility, and innovative design in a groundbreaking fashion.