Radio Control Joby Aircraft Uses Six Tiltrotors To Fly

January 29, 2022 by Lewin Day 3 Comments

eVTOL (Electric Vertical Take-off and Landing) craft are some of the more exciting air vehicles being developed lately. They aim to combine the maneuverability and landing benefits of helicopters with the environmental benefits of electric drive, and are often touted as the only way air taxis could ever be practical. The aircraft from Joby Aviation are some of the most advanced in this space, and [Peter Ryseck] set about building a radio-controlled model that flies in the same way.

The design is inspired by the Joby eVTOL test vehicle.

The result is mighty complex, with six tilt rotors controlled via servos for the utmost in maneuverability. These allow the vehicle to take off vertically, while allowing the rotors to tilt horizontally for better efficiency in forward flight, as seen on the Bell-Boeing V-22 Osprey.

The build uses a 3D-printed chassis which made implementing all the tilt rotor mounts and mechanisms as straightforward as possible. A Teensy flight controller is responsible for controlling the craft, running the dRehmFlight VTOL firmware. The assembled craft only weighs 320 grams including battery; an impressive achievement given the extra motors and servos used relative to a regular quadcopter build.

With some tuning, hovering flight proved relatively easy to achieve. The inner four motors are used like a traditional quadcopter in this mode, constantly varying RPM to keep the craft stable. The outer two motors are then pivoted as needed for additional control authority.

In forward flight, pitch is controlled by adjusting the angle of the central four motors. Roll is achieved by tilting the rotors on either side of the plane’s central axis, and yaw control is provided by differential thrust. In the transitional period between modes, simple interpolation is used between both modes until transition is complete.

Outdoor flight testing showed the vehicle is readily capable of graceful forward flight much like a conventional fixed wing plane. In the hover mode, it just looks like any other multirotor. Overall, it’s a great demonstration of what it takes to build a successful tilt rotor craft.

We’ve seen tilt rotor UAVs before, and they’re as cool as they are complicated to build. Video after the break.

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Underwater Drone Films, Is In Film

January 22, 2022 by Al Williams 3 Comments

Having a drone that can follow you running or biking with a camera isn’t big news these days. But French firm Notilo Plus has an underwater drone that can follow and video an underwater diver. The Seasam has been around since 2019, but recently made an appearance in a French film, The Deep House about a couple exploring an underwater haunted house, as reported by New Atlas. You can see a video about the drone — and a trailer for the movie — in the videos below.

To follow a diver, the robot uses an acoustic signal from the user’s control unit to find the approximate location of the user. This works even in dark conditions. Once close enough, computer vision zeros in on the diver while a sonar system allows safe navigation.

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Flying Sausage Rescues Pooch, Drone Pilots Save The Day

January 21, 2022 by Jenny List 8 Comments

When we write about drone stories from the United Kingdom, they often have a slightly depressing air to them as we relate tales of unverified air proximity reports closing airports or bungled official investigations that would make the Keystone Kops look like competent professionals.

But here’s a drone story from this rainswept isle sure to put a smile on the face of multirotor enthusiasts worldwide, as Denmead Drone Search And Rescue, an organisation who locate missing pets using drones, enticed lost dog Millie from a soon-to-be-engulfed tidal mudflat by the simple expedient of dangling a sausage from a drone for the mutt to follow (Facebook).

Lest you believe that Hackaday have lost their marbles and this isn’t worthy of our normal high standards, let us remind you that this is not our first flying sausage story. Behind the cute-puppy and flying meat product jokes though, there’s a serious side. Drones have received such a bad press over recent years that a good news story concerning them is rare indeed, and this one has garnered significant coverage in the general media. Maybe it’s too late to reverse some of the reputational damage from the Gatwick fiasco, but at this point any such coverage is good news.

For anyone wondering what lies behind this, let us take you back to Christmas 2018.

Indoor Blimp Sails Through The Air Using Ultrasonic Transducers

November 27, 2021 by Dave Rowntree 25 Comments

Quadcopter type drones can be flown indoors, but unless you have a lot of space, it usually just ends in a crash. The prospect of being hit in the face by the propellor blades, spinning at 10k RPM doesn’t bear thinking about, and then there’s the noise. So, as a solution for indoor photography, or operating in public spaces, they are not viable. Japanese mobile operator DOCOMO has a new take on an old idea; the blimp. But, surely even a helium filled vehicle needs blades to steer around the room, we hear you cry? Not so, if you use a pair of specialised ultrasonic transducer arrays to move the air instead! (Video, embedded below)

Three banks of thrusters provide a 180 degree steerable net force

Details are scarce, but DOCOMO have fitted a helium balloon with modules on either side that can produce a steerable thrust, allowing the vehicle to effect all the expected aerial manoeuvres with ease and grace. The module at the bottom contains the control electronics, an upwards facing RGB LED for some extra bling, and of course a video camera to capture those all-important video shots.

We’d love to find a source for those ultrasonic transducer devices, and can only guess at the physical arrangement that allows for air to pass in one direction only, to effect a net thrust. We can find a few research papers hinting at the ability to use ultrasound to propel through air, like this one (bah! IEEExplore Paywall!) but to our knowledge, this technology is not quite in the hands of hackers just yet.

Blimps are by no means scarce on these fine pages, here is a Blimpduino, an Arduino controlled 3D printed blimp, an illuminated blimp art installation by Japanese artist [Kensho Miyoshi] and if using helium is just too darn safe for you (or if you want to help prevent this allegedly precious resource from being lost into space) you could just build a remote controlled blimp using hydrogen instead. Just don’t light a match.

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Inverted Pendulum Balanced On A Drone

November 25, 2021 by Dave Rowntree 9 Comments

[Nicholas Rehm] works during the day at the Applied Physics Laboratory at Johns Hopkins, Maryland, so has considerable experience with a variety of UAV applications. The question arose about how the perseverance mars rover landing worked, which prompted [Nicholas] to hang a rock under his drone, attached via a winch. This proved to be interesting. But what is more interesting for us, is what happens when you try to attach an inverted pendulum to the top of a drone in flight? (video embedded, below)

This is a classic control theory problem, where you need to measure the angle of the pendulum with respect to the base, and close the loop by calculating the necessary acceleration from the pendulum angle. Typically this is demonstrated in one dimension only, but it is only a little more complicated to balance a pendulum with two degrees of freedom.

[Nicholas] first tried to derive the pendulum angle by simply removing the centering springs from an analog joystick, and using it to attach the pendulum rod to the drone body. As is quite obvious, this has a big drawback. The pendulum angle from vertical is now the sum of the joystick angle and the drone angle, which with the associated measurement errors, proved to be an unusable setup. Not to be discouraged, [Nicholas] simply added another IMU board to the bottom of the pendulum, and kept the joystick mechanism as a pivot only. And, as you can see from the video after the break, this indeed worked.

The flight controller is [Nicholas’] own project, dRehmFlight (GitHub), which is an Arduino library intended for the Teensy 4.0, using the ubiquitous MPU6050 6-DOF IMU. [Nicholas] also made an intro video for the controller, which may prove instructive for those wishing to go down this road to build their own VTOL aircraft. The code for pendulum experiment is not available at the time of writing, perhaps it will hit the GitHub in the future?

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Omnirotor flies over obstacles with its gimballed, caged, coaxial rotors.

Gimballed Omnirotor Goes Over Great Obstacles

November 13, 2021 by Ryan Flowers 6 Comments

What can drive on the ground, hop in the air, and continuously move its coaxial rotor assembly without ever having to reset its position? The answer is [New Dexterity]’s Omnirotor All-Terrain Platform.

Although still very much a prototype, the video below the break shows that the dexterity claimed by Omnirotor isn’t just a lot of hype. Weaving through, around, and over obstacles is accomplished with relative ease by way of a coaxial rotor configuration that’s sure to turn some heads.

While not novel in every aspect, the Omnirotor’s strength comes from a combination of features that are fairly unique. The coaxial rotors are fully gimballed, and as such can be moved to and from any direction from any other direction. In other words, it can rotate in any axis infinitely without needing to return to a home position. Part of this magic comes from a very clever use of resources: The battery, speed controllers, and motors are all gimballed as one. This clever hack avoids the need for large, heavy slip rings that would otherwise be needed to transmit power.

Adding to the Omnirotor’s agility is a set of wheels that allow the craft to push itself along a surface, presumably to decrease power consumption. What if an obstacle is too difficult to drive around or past? The Omnirotor takes to the air and flies over it. The coaxial rotors are caged, protecting them from the typical rotor-snagging dangers you’d expect in close quarters.

[New Dexterity] has Open Sourced the entire project, with the Omirotor design, Firmware, and even the benchmarking platform available on Github so that others can share in the fun and iterate the design forward even further.

You might also enjoy this tetrahedron based omnirotor, or another omnirotor that knows how to play fetch. Really.

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[Nick Rehm] explains the workings of a gps-less self guided drone

Autonomous Drone Dodges Obstacles Without GPS

November 3, 2021 by Ryan Flowers 5 Comments

If you’re [Nick Rehm], you want a drone that can plan its own routes even at low altitudes with unplanned obstacles blocking its way. (Video, embedded below.) And or course, you build it from scratch.

Why? Getting a drone that can fly a path and even return home when the battery is low, signal is lost, or on command, is simple enough. Just go to your favorite retailer, search “gps drone” and you can get away for a shockingly low dollar amount. This is possible because GPS receivers have become cheap, small, light, and power efficient. While all of these inexpensive drones can fly a predetermined path, they usually do so by flying over any obstacles rather than around.

[Nick Rehm] has envisioned a quadcopter that can do all of the things a GPS-enabled drone can do, without the use of a GPS receiver. [Nick] makes this possible by using algorithms similar to those used by Google Maps, with data coming from a typical IMU, a camera for Computer Vision, LIDAR for altitude, and an Intel RealSense camera for detection of position and movement. A Raspberry Pi 4 running Robot Operating System runs the autonomous show, and a Teensy takes care of flight control duties.

What we really enjoy about [Nick]’s video is his clear presentation of complex technologies, and a great sense of humor about a project that has consumed untold amounts of time, patience, and duct tape.

We can’t help but wonder if DARPA will allow [Nick] to fly his drone in the Subterranean Challenge such as the one hosted in an unfinished nuclear power plant in 2020.

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