How do you enable a robotic bird to fly? You launch it off the back of a fast little roach.
That's just what the folks at Berkeley have been working on. Their original VelociRoach, created within the Biomimetrics Millisystems Lab, was one of several versatile robots inspired by nature. The critter was fitted with rolling, C-shaped legs instead of the straight legs found on real roaches, and the X2 version of VelociRoach went on to break the robot speed record in its size group, scurrying along at a brisk 4.9 meters per second.
So they decided to harness that speed to improve the takeoff capabilities of another nature-inspired robot: the H2Bird ornithopter.
The 13.2-gram H2Bird, known to those in the biz as a MAV (micro air vehicle), was affixed to the 32-gram roachbot by a small latticework of supports. Using its ingenious undulating legs, the new hybrid could reach speeds of 2.7 meters per second, which should be just enough to get the little bird off the ground. But it still needed a few adjustments.
Although the H2Bird can flap its wings, it can't produce enough thrust to enable the MAV to take off from a stationary point. So its creators, which included graduate researchers Cameron Rose, Ron Feering, and grad student Pars Mahmoudieh, worked inside a wind tunnel, collecting data that enabled them to adjust the rig in order to elevate the nose of the H2Bird. After determining the minimum required launch speed, the VelociRoach, scuttling at around 1.2 meters per second, can now successfully launch H2Bird into the air.
Although the added weight of the MAV consumes battery power about 25% faster than the unencumbered VelociRoach, the upgraded roachbot has added stability, thanks to the MAV. And with the MAV in its cradle, they've reduced the bird's pitch and roll velocity by about 90% and increased its overall velocity by around 12%.
All that's left is to determine the perfect launch conditions. The team will present their findings this week at the IEEE Robotics & Automation Society meeting in Seattle, Washington.
