UAV Coaxial Copter Uses Unique Drive Mechanism

Personal UAV’s are becoming ubiquitous these days, but there is still much room for improvement. Researchers at [Modlab] understand this, and they’ve come up with a very unique method of controlling pitch, yaw, and roll for a coaxial ‘copter using only the two drive motors.

In order to control all of these variables with only two motors, you generally need a mechanism that adjusts the pitch of the propeller blades. Usually this is done by mounting a couple of tiny servos to the ‘copter. The servos are hooked up to the propellers with mechanical linkages so the pitch of the propellers can be adjusted on the fly. This works fine but it’s costly, complicated, and adds weight to the vehicle.

[Modlab’s] system does away with the linkages and extra servos. They are able to control the pitch of their propellers using just the two drive motors. The propellers are connected to the motors using a custom 3D printed rotor hub. This hub is specifically designed to couple blade lead-and-lag oscillations to a change in blade pitch. Rather than drive the motors with a constant amount of torque, [Modlab] adds a sinusoidal component in phase with the current speed of the motor. This allows the system to adjust the pitch of the blades multiple times per rotation, even at these high speeds.

Be sure to watch the demonstration video below. Continue reading “UAV Coaxial Copter Uses Unique Drive Mechanism”

Quadcopter pair plays table tennis without the table

This pair of quad-rotor helicopters does a better job of keeping a ping-pong ball in the air than we could. The two flying drones are performing inside of the flying machine arena, a 1000 cubic meter indoor space surrounded by nets with a foam-padded floor. This makes for a prototype-friendly space, protecting the copters from hard landings and the experimenters from the maiming that might accompany a runaway robot.

This project is headed by researcher [Raffaello D’Andrea]. Previously, we’ve seen his work on a distributed flight array. This time around he’s not working with configurable modules, but completely separate units. Don’t miss the video after the break to see several iterations used to keep a ball in the air. Each bot has the head of a tennis racket mounted at its center. Throw a ball at them and they’ll to what they can to prevent it touching the ground.

While we’re on the topic, we caught a story on NPR about hobby drones. Sounds like their growing popularity has caught the attention of the non-hacker community and restrictions might be on the way. So what are you waiting for? Get out there and make your own flyer while it’s still the wild-west of personal drones.

Continue reading “Quadcopter pair plays table tennis without the table”

Distributed Flight Array

Though it is in the beginning stages of development, the Distributed Flight Array is already looking very interesting. Each unit can scuttle across the ground using the down force from its prop, but when 4 or more join forces, they can take off and fly. The documentation shows that they should be smart enough to fly in random configurations, though in the video we only see the standard 4 prop layout. This is being worked on by the same people who produced the balancing cube.

[via BoingBoing]


Quad copters have been pretty popular for the last few years, but this one is new to us. Take the same basic layout, but bump it to 6 rotors. Then you’ll have the hexacopter (google translated). With 6 rotors, built in GPS and stabilization and a camera mounted on the bottom, this thing is pretty well equipped. You can see how agile and stable it is in the video above. We know it isn’t necessarily new, but it is new to us. Of course, you don’t have to stop at 6 rotors. You could always just continue on to 8.

Autonomous hovering drones invade Germany

We welcome the swarm of autonomous hovering robot overlords being made by students at Humboldt University. The goal of this project is to build an autonomous hovering platform that is controlled via adapted insect behavior. Navigation comes from monitoring real time inputs, such as air pressure and optical sensors, not by predefined paths and GPS coordinates.  Some examples of this adapted behavior are: navigation via polarized sun light like African ants, and optical flow similar to bees.

You can see the platforms in action on Spiegel Online, but unless you understand German, you won’t get much else out of it.

If any of this seems familiar, it’s because we covered CCCamp 2007, which was near Berlin and had some very similar quadcopters. While the large quadcopter platforms have been around for a while and are steadily coming down in price, there are some new alternatives out there that are quite tempting.  Anyone want to build some autonomy into this little baby?

[thanks fh]