First controlled flight of an insect-sized robot

Researchers from the Wyss Institute and the School of Engineering and Applied Sciences at Harvard have developed a millimeter-scaled insect robot that can autonomously control its flight. Their findings were published in the prestigious journal Science. The amazing high-speed video below shows the robot taking off, hovering in place and steering left and right on demand. Controlling such small flyers has been impossible so far because of challenges in fabricating tiny actuated systems, and the chaotic movement of small flapping-wing robots. You’ve seen a fly move around your living room, doesn’t seem easy to control right?

Fabrication
Rob Wood’s Microrobotics Laboratory at Harvard has a long history of developing small flying robots using a clever fabrication technique intended for easy and cheap mass-production. The method described in the video below is inspired from pop-up books that you can cut and fold to make articulated three-dimensional structures. By sandwiching flexible materials between laser-cut carbon fiber layers, they are able to rapidly fabricate robot skeletons that can be folded and locked into shape by soldering dedicated attachment points. The skeleton of the controllable robot is augmented with two piezoelectric muscles to differentially drive the wings. These muscles are made of special materials that contract and expand when electricity is applied to them. Power is provided by an external cable.

Control
To control its position, the robot needs to change how it beats its wings. Beating the left wing harder than the right wing will produce a torque on the robot’s body. The robot is inherently unstable and a very fast and precise control is needed to keep it aloft. It would be nearly impossible for a human to manually control the wing motions or preset them based on flight dynamics. Instead, the robot continuously compares its actual position to its intended position and corrects the wing motions accordingly (closed-loop control). The position of the robot is provided by an external camera system which tracks markers on the body of the robot. Using this technique the robot is able to stay in place, and move to a designated location. This is a remarkable feat for such a small and highly dynamic flyer. Previous version of the robot had been seen taking off and controlling altitude:

Applications
This work is part of the Robobees project which brings together 10 laboratories to fabricate, control and power bio-inspired roboinsects that can function in swarms. Applications, although still a long way in the future, include autonomously pollinating a field of crops, search and rescue, hazardous environment exploration, military surveillance, high resolution weather and climate mapping and traffic monitoring.

Listen to our podcast interviews with the authors of the paper including Kevin Ma, Pakpong Chirarattananon and Sawyer Fuller.

Links:

• Official Press Release
• Controlled Flight of a Biologically Inspired, Insect-Scale Robot, Kevin Y. Ma, Pakpong Chirarattananon, Sawyer B. Fuller, Robert J. Wood, SCIENCE 2013

Photo Credits: Kevin Ma and Pakpong Chirarattananon, Harvard University.

Sabine Hauert is President of Robohub and Associate Professor at the Bristol Robotics Laboratory

Sabine Hauert is President of Robohub and Associate Professor at the Bristol Robotics Laboratory