We saw some impressive research at ICRA this year showing that yaw control with two wings is possible, but four wings have additional advantages— namely, more wings means more power for lifting more stuff. And with more lifting power, it’s possible to have a fully self-contained robot insect, even if it’s slightly weird looking.

 

In Nature this week, researchers from Harvard’s Microrobotics Lab, led by Professor Robert J. Wood, are showing a four-winged version of their RoboBee platform. They are calling this version RoboBee X-Wing, and it's actually has the ability to do untethered flight thanks to solar cells and a light source that would put high noon(s) on Tatooine to shame.

 

We should mention that this is simply not the first light-powered self-contained winged robot insect that we've seen take flight. Last year at ICRA, a group from the University of Washington demonstrated a two-winged robot that could take off when a laser was directed at its solar cell. The Harvard researchers say that the flight of their robot is “sustained” rather than a “liftoff,” which is open to interpretation to some extent, but there is plenty of room for exciting innovation in this space, so being the “first” to do whatever is (in my opinion) less important than just making it work in the first place.

 

No matter what, RoboBee X-Wing is 5 centimeters long and weighs 259 milligrams. At the top are solar cells, and at the bottom are all of the drive electronics you need to boost the trickle of voltage coming out of the solar panels up to the 200 volts that are required to drive the actuators that cause the wings to flap at 200 Hz. The reason the robot’s bits and pieces are arranged the way that they are is to help keep the solar panels out of the airflow of the wings, while instantly keeping the overall center of mass of the robot where the wings are. The robot does not have any autonomous control, but it is steady enough for very short open loop flights lasting less than a second.

 

The reason for the solar cells is that the robot can't really lift the kind of battery that it would need to power its wings, so off-board power is important. And if you do not want a tether (and seriously, who wants a tether!) this means some kind of wireless power. UW used a laser, but X-Wing makes due with the sun. Sort of. Three suns, actually, since one isn’t enough, and the researchers emulate that with some powerful lamps. This means that X-Wing isn’t yet handy for outdoor operation, although they say that a 25 percent larger version (that they are really working on next) should eliminate the number of suns required to just 1.5, which means that maybe it would work on, like, Venus, or something.

 

In its latest version, RoboBee X-Wing does have some mass budget left over for things like sensors, but it sounds like the researchers are primarily focalized on getting that power requirement down to one sun or below. It's going to take some design optimization and extra integration work before RoboBee X-Wing gets to the point where it’s flying completely autonomously, but what we have seen here is a substantial amount of progress towards that goal. 

 

Source: Tronserve