Nanoengineering Marvels: Miniaturized Robot Fabrication in 3D

During that time, the concept of reducing robotic mechanisms to incredibly small sizes intrigued researchers due to the potential for achieving outstanding performance metrics like speed and precision. The smaller size and mass of these robots promised enhanced capabilities, but the challenge lay in overcoming limitations in microscale 3D manufacturing processes.

Fast forward nearly five decades, Ph.D. students Steven Man and Sukjun Kim, under the guidance of Mechanical Engineering Professor Sarah Bergbreiter, have devised a groundbreaking 3D printing technique for constructing miniature Delta robots known as microDeltas. Unlike their larger counterparts used for industrial tasks, these microDeltas, measuring 1.4 mm and 0.7 mm in height, offer potential applications in micromanipulation, micro assembly, minimally invasive surgeries, and wearable haptic devices.

Their pioneering work has been published in the prestigious journal Science Robotics.

Traditionally, creating robotic mechanisms at such minute scales necessitated manual assembly and intricate folding of microfabricated components.

Bergbreiter’s team introduced a novel 3D printing process for microrobotics utilizing two-photon polymerization, an advanced nanofabrication method where a precise laser solidifies photosensitive material with unparalleled accuracy. Subsequently, a thin metal layer is added to enable electrical functionality for the intricate 3D structures and actuators, eliminating the need for manual assembly or folding.

The microDelta robots, setting records as the smallest and fastest Delta robots ever demonstrated, stand as a testament to the researchers’ achievements. By scaling down the robots, they were able to validate predictions made half a century ago, showcasing improved precision to less than a micrometer, enhanced speed operating at frequencies exceeding 1 kHz, and ample power to propel a grain of salt—a projectile nearly 7.4% of the robot’s total mass.

Impressed by Man’s swift progress, Bergbreiter commended the team’s ability to iterate through eight design versions of the microDelta robots expeditiously. This rapid turnaround, facilitated by the 3D design and printing process, contrasts with traditional methods that could take weeks or months for design and fabrication.

“I am amazed by the speed at which Steven and Sukjun iterated through these designs. Moving forward, students can build upon this work more efficiently, leading to further advancements,” Bergbreiter remarked.

With the model established in this study, students can refine key metrics like bandwidth, accuracy, and workspace by adjusting the robot’s design parameters, creating extensive arrays of microDeltas, or incorporating enhancements such as sensing for closed-loop operation.

Researchers Zeynep Temel and Oliver Kroemer from the Robotic Institute are already leveraging arrays of larger Delta robots for intricate manipulation tasks. The miniature scale of microDelta robots opens up possibilities for densely packed arrays, enabling novel capabilities in small-scale robotics for immersive haptic feedback or previously unattainable micromanipulation tasks.

“The elimination of manual assembly offers significant advantages in terms of rapid fabrication and design iteration,” Bergbreiter explained. “At larger scales, researchers can assemble robots using off-the-shelf motors and mechanisms. However, at these tiny scales, both manufacturing and connecting minuscule pieces pose challenges. This new fabrication technique proves invaluable in overcoming these obstacles.”