Straight from the Aerospace Controls Laboratory comes a variable-pitch quadrocopter designed by [Mark Cutler] and [Jonathan P. Howe]. While real, full-sized helicopters always have variable pitch rotors, changing the pitch of the blades on remote control aircraft is a fairly uncommon modification. When it’s done right, though, being able to easily change the thrust direction of a propeller leads to very cool flights, like having an airplane hover nose down.
[Mark] and [Jonathan] identified two interesting techniques that a variable pitch quadrotor can bring to the table. The first is trajectory generation – because of the added maneuverability, their quadrotor can perform more aggressive banking turns when following a preprogrammed path. The second benefit to their design is quick deceleration. In the first video after the break, you can compare the deceleration rates of a variable pitch and fixed pitch quadrocopter. While the fixed pitch quad continues climbing after being commanded to stop, the quadrocopter outfitted with variable pitch rotors can stop on a dime.
We’re still waiting for the equivalent of the Red Bull Air Races for quadrocopter builds, but when it comes we know what would win the slalom event.
Continue reading “Variable Pitch Quadrocopter Flies Upside Down”
[DJ Sures] has been pulling all-nighters lately to get his AR Drone Parrot build off the ground. Now that it’s up and flying around, he managed to get it to follow objects around the room using on board cameras.
For the build, [DJ Sures] used the AR Drone ‘flying video game’ quadrocopter. This toy has two on board cameras that can viewed over wifi. All that’s needed is some interesting software to make things fun. The camera tracking of EZ-Builder software was brought into the mix so the AR Drone can be controlled via object or speech recognition, wiimotes, tablets, or terminals.
[DJ Sures] has come up with some
slightly terrifying awesome builds like a Bluetooth Teddy Ruxpin, realistic Wall-E, and an awesome Omnibot 2000 refurb. This is his first flying hack, and the first to fully exploit the camera tracking of the EZ-Builder software. Check out [Sures]’ copter following him around a room after the break.
Continue reading “Easy Camera Tracking With A Quadrocopter”
Quadrocopters are all the rage lately, and while we have seen our fair share of large devices, [Arnaud Taffanel, Tobias Antonsson, and Marcus Eliasson] have been dutifully working to buck that trend. Their CrazyFlie is a miniature quadrocopter that uses its PCB as the main structure of the device.
Since the goal was to use a PCB as its frame, the copter’s footprint from the edge of one motor to the other is a modest 8cm, and it weighs in at a measly 20 grams! The entire platform runs on a Cortex-M3 CPU that takes input from an accelerometer and pair of gyroscopes to help keep its balance. Wireless communications are handled via a 2.4Ghz radio transmitter, and the quadrocopter’s power is supplied by a tiny 110 mAh LIPO battery pack scavenged from an R/C plane.
All of the control and telemetry is handled by a PC, which relays control messages it receives from the pilot’s game pad to the CrazyFlie. We’d love to see if they could retain this small footprint if everything was handled by the quadrocopter itself. Either way, this thing rocks – we most definitely want one!
Stick around to see a quick video of their mini quadrocopter in action, and be sure to check out our coverage of U. Penn’s quadrocopter creations if you are interested in seeing more.
Continue reading “Mini Quadrocopter Is Crazy Awesome”
When it comes to robotic navigation, the usual approach is to go as technically advanced and “smart” as possible. Yet the most successful lifeforms that we know of follow a completely different approach. With limited senses and cognitive abilities, the success of invertebrates like ants and honeybees lie in cooperation in large numbers. A joint team of researchers from TU Delft, University of Liverpool and Radboud University of Nijmegen, decided to try this approach and experimented with a simple navigation technique to allow a swarm of tiny flying robots to explore an unknown environment.
The drones used were of-the-shelf Crazyflie 2.0 micro quadcopters with add-on boards. Sensors consisted of it’s onboard IMU, simple range finding sensors on a Multi-ranger deck for obstacle detection, and a down pointing optical flow sensor, on a Flow deck, to keep track of the distance travelled. To navigate, the drones used a “swarm gradient bug algorithm” (SGBA). Each drone in has different preferred direction of travel from takeoff. When an obstacle encountered, it follows the contour of the obstacle, and then continues in the preferred direction once the path is clear. When the battery drops to 60%, it returns to a wireless homing beacon. While this technique might not be the most efficient, it has the major advantage of being “lightweight” enough to implement on a cheap microcontroller, an STM32F4 in this case. The full research article is available for free, and is a treasure trove of information.
The main application researchers have in mind is for search and rescue. A swarm of drones can explore an unstable or dangerous area, and identify key areas to focus rescue efforts on. This can drastically reduce wasted time and risk to rescue workers. It is always cool to see complex problems being solved with simple solution, and we are keen to see where things go. Check out the video after the break. Continue reading “Tiny Drones Navigate Like Real Bugs”
We spend a lot of time here at Hackaday talking about drone incidents and today we’re looking into the hazard of operating in areas where people are present. Accidents happen, and a whether it’s a catastrophic failure or just a dead battery pack, the chance of a multi-rotor aircraft crashing down onto people below is a real and persistent hazard. For amateur fliers, operating over crowds of people is simply banned, but there are cases where professionally-piloted dones are flying near crowds of people and other safety measures need to be considered.
We saw a skier narrowly missed by a falling camera drone in 2015, and a couple weeks back there was news of a postal drone trial in Switzerland being halted after a parachute system failed. When a multirotor somehow fails while in flight it represents a multi-kilogram
flying weapon widow-maker equipped with spinning blades, how does it make it to the ground in as safe a manner as possible? Does it fall in uncontrolled flight, or does it activate a failsafe technology and retain some form of control as it descends?
Continue reading “Safety Systems For Stopping An Uncontrolled Drone Crash”
Inverted Quadcopter? That generally means a crash is soon to follow. Not so for a new crop of quadcopter fliers. These new quadcopters are capable of sustained inverted flight. We’ve seen inverted quadcopters before here on hackaday. However, previous inverted quadcopters always used collective pitch to control the thrust produced by the blades. Collective pitch on a quadcopter is much simpler than it is on the main rotor of a traditional helicopter. R/C and full-scale helicopters mix collective and cyclic pitch to articulate the main rotor blades. A quadcopter only needs the collective portion, which is similar to a traditional helicopters tail rotor mechanism, or a variable pitch prop on an airplane.
These new quadcopters are using a much simpler method of flying inverted: Spin the motors backwards. Quadcopters control their flight by quickly varying the speed of rotation of each motor. Why not completely reverse the motor then? Today’s brushless outrunner motors have more than enough power to quickly reverse direction. The problem becomes one of propellers. Standard propellers are designed to create thrust in one direction only. Every quadcopter uses two clockwise rotation and two counterclockwise rotation propellers. Propellers will generate reverse thrust if they are spun backwards, however they will not be as efficient as they would when spinning the direction they were designed for. The quad fliers have found a partial solution to this problem: Remove the curve from the blade. R/C propeller blades are sold by diameter and blade pitch. The pitch is a measure of the angle of attack of the blades. R/C blades also have an airfoil style curve molded into them. Removing this curve (but not changing the pitch) has helped the problem.
This final problem is control systems. Since quadcopters already are relying on computer control for basic flight, it’s simply a matter of loading custom firmware onto your flight board to support motor rotation reversal. Speed controls also have to be capable of reverse rotation, which means new firmware as well. We’re curious to see how the quadcopter community settles on the control systems for inverted flight. The R/C helicopter community went through several iterations of control systems over the years. At one point they were using “Invert switches” which reversed controls as well as handled the collective pitch changes. As time went on, these switches fell out of favor and are now known as “Crash switches” due to the result of accidentally hitting one while flying, or before engine start.
Continue reading “Quadcopters Go Inverted By Reversing Their Motors”
The Fourth of July is fast approaching, and what better way to celebrate the independence of your country than by blowing up a small piece of it? [Anzel360] decided to take that line of thought to a whole new level by adding a bomb bay to his quadrocopter.
[Anzel360] recently upgraded his transmitter to a Spektrum DX8, giving him two extra channels on his four-channel quadrotor. After adding a small servo to the quad, it was a simple matter of taping a box to the undercarriage and filling it full of fireworks.
The ammo [Anzel] is using is just a handful of Snappin’ Pops – otherwise known as the lamest firework ever created. We won’t hold that against him, though; a remote ignition system for a few Black Cats mounted on a fancy quadrocopter is just asking for trouble. We do recall a throwable cap gun bomb from our youth, though, that would allow for year-round ammo replenishment…