Picotaur, a 15.4 mg and 7.9 mm long hexapod robot, is capable of walking forward and backward, turning, climbing microscale stairs, and even delivering loads! This remarkable functionality was achieved by 3D-printing two degrees of freedom (2 DoF) leg mechanisms directly onto the flexible printed circuit board robot body. The integration of fast electrostatic actuation with the 2 DoF legs enabled Picotaur to achieve various gait patterns, resulting in versatile locomotion.

Flexible printed circuit boards (FPCBs) have significnat potential for microrobotic applications due to their advantages of being lightweight, flexible, and easily integrated with electronic components. In this study, we directly fabricated 3D electrostatic actuators on top of FPCBs and demonstrated two microrobotic applications. Our 4mg crawling robot (shown on the left) is one of the lightest legged microrobots that does not require external fields such as magnetic fields for actuation. We also created a micromirror array (shown on the right) that integrates microcontrollers and MOSFETs, enabling individual control of 3D printed mirrors on a flexible substrate.

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Effectively utilizing thin-film NiTi shape memory alloy at the microscale presents a significant challenge due to the difficulty in applying a large strain on the thin films. In this work, we addressed this by integrating thin-film NiTi with magnetic springs, which allowed us to apply a large strain on NiTi. 3D printing with TPP enabled manufacturing of complex 3D structure for magnetic springs. By leveraging large force and high speed actuation, our actuator successfully demonstrated the ability to launch a grain of salt using an integrated microscale linkage mechanism.

Thin-film NiTi shape memory alloy actuators are capable of generating a large force at a relatively low voltage (~2 V). In this work, we have designed a flexure-based 4 bar linkage mechanism for an adaptive microgripper and actuated it with thin-film NiTi actuators. This allows each finger of the gripper to adapt to the shape of the objects it picks up, enabling it to grasp objects of various shapes.

We developed a novel manufacturing process to create 3D microactuators. We leveraged 3D printing at the microscale with two-photon polymerization followed by physical vapor deposition of metal (e.g, Al, Au, and NiTi) to demonstrate microscale actuators with complex 3D geometries which are extremely difficult to achieve with traditional microfabrication processes. 

A long and lightweight robotic arm is useful for unmanned aerial vehicles (UAVs) as it allows UAVs to perform tasks in the spaces where the body of the UAVs cannot access. We developed a foldable module with embeded locking mechanism. The locking mechanism takes advantage of the principle of perpendicular folding. The locker can be easily installed and removed by permanent magnets and a novel tendon-driven actuation method. A 700 mm long foldable robotic arm was demonstrated by connecting a series of modules. The arm can be folded flat with a single DC motor.