Transforming Drone Can Be A Square Or A Dragon

January 1, 2021 by Danie Conradie 8 Comments

When flying drones in and around structures, the size of the drone is generally limited by the openings you want to fit through. Researchers at the University of Tokyo got around this problem by using an articulating structure for the drone frame, allowing the drone to transform from a large square to a narrow, elongated form to fit through smaller gaps.

The drone is called DRAGON, which is somehow an acronym for the tongue twisting description “Dual-Rotor Embedded Multilink Robot with the Ability of Multi-Degree-of-Freedom Aerial Transformation“. The drone consists of four segments, with a 2-DOF actuated joint between each segment. A pair of ducted fan motors are attached to the middle of each segment with a 2-DOF gimbal that allows it to direct thrust in any direction relative to the segment. For normal flight the segments would be arranged in the square shape, with minimal movement between the segments. When a small gap is encountered, as demonstrated in the video after the break, the segments rearrange into a dragon-like shape, that can pass through a gap in any plane.

Each segment has its own power source and controller, and the control software required to make everything work together is rather complex. The full research paper is unfortunately behind a paywall. The small diameter of the propellers, and all the added components would be a severe limiting factor in terms of lifting capacity and flight time, but the concept is to definitely interesting.

The idea of shape shifting robots has been around for a while, and can become even more interesting when the different segment can detach and reattach themselves to become modular robots. The 2016 Hackaday Grand Prize winner DTTO is a perfect example of this, although it did lack the ability to fly. Continue reading “Transforming Drone Can Be A Square Or A Dragon” →

Federal Aviation Administration Announces Major Drone Rule Changes

December 29, 2020 by Dan Maloney 61 Comments

If new rules from the FAA regarding unmanned aircraft operations in the US are any indication, drones are becoming less of a niche hobby and more integrated into everyday life. Of course, the devil is in the details, and what the Federal Aviation Administration appears to give with one hand, it takes away with the other.

The rule changes, announced on December 28, are billed as “advanc[ing] safety and innovation” of the drone industry in the United States. The exciting part, and the aspect that garnered the most attention with headline writers, is the relaxation of rules against night operation and operating above people and moving vehicles. Since 2016, it has been against FAA regulations to operate drones less than 55 pounds (25 kg) at night or over people without a waiver. This rule can be seen as stifling innovations in drone delivery, since any useful delivery service will likely need to overfly populated areas and roadways and probably do so at night. The new rules allow these operations without a waiver for four categories of drones, classified by how much damage they would do if they were to lose control and hit someone. The rules also define the inspection and certification regimes for both aircraft and pilot, as well as stipulating that operators have to have their certificate and ID on their person while flying.

While this seems like great news, the flip side of the coin is perhaps less shiny. The rule changes also impose the requirement for “Remote ID” (PDF link), which is said to be “a major step toward full integration of drones into the national airspace system.” Certain drones will be required to carry a system that transmits identification messages directly from the aircraft, including such data as serial number, location and speed of the drone, as well as the location of the operator. The rules speculate that this would likely be done over WiFi or Bluetooth, and would need to be receivable with personal wireless devices. The exact technical implementation of these rules is left as an exercise to manufacturers, who have 30 months from the time the rules go into effect in January to design systems, submit them for certification, and get them built into their aircraft. Drone operators have an additional year to actually start using the Remote ID drones.

For the drone community, these rule changes seem like a mixed bag. To be fair, it’s not exactly unexpected that drones would be radio tagged like this, and the lead time allowed by the FAA for compliance on Remote ID seems generous. The ability to operate in riskier environments will no doubt be welcomed by commercial drone operators. So who knows — maybe the rules will do what they say they will, and this will stimulate a little innovation in the industry. If so, it could make this whole thing a net positive.

Custom Powerbank In Compact Form Factor

December 27, 2020 by Danie Conradie 28 Comments

The wide availability and power density of 18650 lithium-ion cells have made them a good option for everything from electric cars to flashlights. [Theo] needed a new power source for his FPV drone goggles, so he designed his own power bank with a very compact charge controller.

While [Theo] could charge the batteries with an RC battery charger, he preferred the convenience of one with a standard 5V micro USB input, and wanted battery level indication to avoid having the FPV goggles die unexpectedly mid-flight. When four 18650 cells are held in a cube arrangement, a 8x8x65 mm gap is formed between the cells. In this space [Theo] was able to fit a custom PCB with a micro USB jack, 1.3 mm power jack, BQ25606 charge controller, TPS61085 boost converter, and ATtiny MCU with LED for battery level feedback. The charge controller also allows 5V devices to be charged via USB, while the boost converter outputs 9V via the 1.3mm jack for [Theo]’s FPV goggles. Everything fits inside a nice compact 3D printed enclosure.

The project was not without hiccups. After ordering and building the PCB he discovered some minor PCB layout mistakes, and realized the boost converted could only output 600mA at 9V, which was not enough for his more power-hungry googles. He plans to fix this in the next version.

We’ve seen custom power banks in quite a few shapes and sizes, including one that runs on power tool batteries (which probably also have 18650s inside) and one that has just about every output you could want, including AC and wireless QI charging.

The Gatwick Drone: Finally Someone Who Isn’t Us Asks Whether It Ever Really Existed

December 7, 2020 by Jenny List 70 Comments

It’s taken two years, but finally it’s happened. Finally a respected national mass-media outlet has asked the question Hackaday were posing shortly after the event: what evidence was there that a drone was actually present in restricted airspace?

The Guardian newspaper in the UK is the outlet looking into the mystery of the Gatwick drone. It was the worldwide story of the moment around this time back in 2018 when the London airport closed down for several days in response to a series of drone reports. The assumption being put forward was that bad actors in the drone community were to blame, but there was significant disquiet in those ranks as the police and media story simply lacked credibility to anyone with knowledge of drones. At no point could they point to evidence that held water, the couple they arrested turned out to be innocent, and eventually a police officer admitted that there might not have been a drone after all. The damage had by then been done, as Received Opinion had it that irresponsible drone enthusiasts had put lives in danger and caused huge economic damage by closing an airport for several days.

The Guardian piece paints a fascinating and detailed picture of the events surrounding the investigation, by bringing the investigative journalism resources of a national newspaper into tracing and interviewing people involved from all sides. They talk to former Gatwick employees, off-the-record police officers with knowledge of the case, a drone specialist journalist, and the drone community including some of its members with significant professional experience in the world of aviation. It talks about the slow drip-feed of freedom of information requests revealing the machinations behind the scenes and furthermore the continuing lack of tangible proof of a drone. It’s very much worth a read, and we hope it will prompt further investigation of the events without the focus being on a non-existent drone.

We’d like to invite you to read Hackaday’s coverage from a few days after the event, and for an overview of the subject including the later Heathrow event, watch the CCCamp talk I presented on the topic in 2019. Then as now, our wish is for competent police investigations, responsible media reporting of drone stories, and credible official investigations of air proximity reports surrounding drones.

Header: Lucy Ingham, CC BY-SA 4.0.

Tracking Drone Flight Path Via Video, Using Cameras We Can Get

November 13, 2020 by Roger Cheng 4 Comments

Calculating three-dimensional position from two-dimensional projections are literal textbook examples in geometry, but those examples are the “assume a spherical cow” type of simplifications. Applicable only in an ideal world where the projections are made with mathematically perfect cameras at precisely known locations with infinite resolution. Making things work in the real world is a lot harder. But not only have [Jingtong Li, Jesse Murray et al.] worked through the math of tracking a drone’s 3D flight from 2D video, they’ve released their MultiViewUnsynch software on GitHub so we can all play with it.

Instead of laboratory grade optical instruments, the cameras used in these experiments are available at our local consumer electronics store. A table in their paper Reconstruction of 3D Flight Trajectories from Ad-Hoc Camera Networks (arXiv:2003.04784) listed several Huawei cell phone cameras, a few Sony digital cameras, and a GoPro 3. Video cameras don’t need to be placed in any particular arrangement, because positions are calculated from their video footage. Correlating overlapping footage from dissimilar cameras is a challenge all in itself, since these cameras record at varying framerates ranging from 25 to 59.94 frames per second. Furthermore, these cameras all have rolling shutters, which adds an extra variable as scanlines in a frame are taken at slightly different times. This is not an easy problem.

There is a lot of interest in tracking drone flights, especially those flying where they are not welcome. And not everyone have the budget for high-end equipment or the permission to emit electromagnetic signals. MultiViewUnsynch is not quite there yet, as it tracks a single target and video files were processed afterwards. The eventual goal is to evolve this capability to track multiple targets on live video, and hopefully help reduce frustrating public embarrassments.

[IROS 2020 Presentation video (duration 14:45) requires free registration, available until at least Nov. 25th 2020.]

One Wheel Is All We Need To Roll Into Better Multirotor Efficiency

November 7, 2020 by Roger Cheng 18 Comments

Multirotor aircraft enjoy many intrinsic advantages, but as machines that fight gravity with brute force, energy efficiency is not considered among them. In the interest of stretching range, several air-ground hybrid designs have been explored. Flying cars, basically, to run on the ground when it isn’t strictly necessary to be airborne. But they all share the same challenge: components that make a car work well on the ground are range-sapping dead weight while in the air. [Youming Qin et al.] explored cutting that dead weight as much as possible and came up with Hybrid Aerial-Ground Locomotion with a Single Passive Wheel.

As the paper’s title made clear, they went full minimalist with this design. Gone are the driveshaft, brakes, steering, even other wheels. All that remained is a single unpowered wheel bolted to the bottom of their dual-rotor flying machine. Minimizing the impact on flight characteristics is great, but how would that work on the ground? As a tradeoff, these rotors have to keep spinning even while in “ground mode”. They are responsible for keeping the machine upright, and they also have to handle tasks like steering. These and other control algorithm problems had to be sorted out before evaluating whether such a compromised ground vehicle is worth the trouble.

Happily, the result is a resounding “yes”. Even though the rotors have to continue running to do different jobs while on the ground, that was still far less effort than hovering in the air. Power consumption measurements indicate savings of up to 77%, and there are a lot of potential venues for tuning still awaiting future exploration. Among them is to better understand interaction with ground effect, which is something we’ve seen enable novel designs. This isn’t exactly the flying car we were promised, but its development will still be interesting to watch among all the other neat ideas under development to keep multirotors in the air longer.

[IROS 2020 Presentation video (duration 10:49) requires no-cost registration, available until at least Nov. 25th 2020. Forty-two second summary embedded below]

Continue reading “One Wheel Is All We Need To Roll Into Better Multirotor Efficiency” →

How To Improve A Smart Motor? Make It Bigger!

November 7, 2020 by Donald Papp 25 Comments

Brushless motors can offer impressive torque-to-size ratios, and when combined with complex drive control and sensor feedback, exciting things become possible that expand the usual ideas of what motors can accomplish. For example, to use a DC motor in a robot leg, one might expect to need a gearbox, a motor driver, plus an encoder for position sensing. If smooth, organic motion is desired, some sort of compliant mechanical design would be involved as well. But motors like the IQ Vertiq 6806 offered by [IQ Motion Control] challenge those assumptions. By combining a high-torque brushless DC motor, advanced controller, and position sensing into an integrated device, things like improved drone performance and direct-drive robotic legs like those of the Mini Cheetah become possible.

IQ Vertiq 6806 brushless DC motor with integrated controller, driver, and position sensing.

First, the bad news: these are not cheap motors. The IQ Vertiq 6806 costs $399 USD each through the Crowd Supply pre-order ($1499 for four), but they aren’t overpriced for what they are. The cost compares favorably with other motors and controllers of the same class. A little further than halfway down the Crowd Supply page, [IQ Motion Control] makes a pretty good case for itself by comparing features with other solutions. Still, these are not likely to be anyone’s weekend impulse purchase.

So how do these smart motors work? They have two basic operating modes: Speed and Position, each of which requires different firmware, and which one to use depends on the intended application.

The “Speed” firmware is designed with driving propeller loads in mind, and works a lot like any other brushless DC motor with an ESC (electronic speed control) on something like a drone or other UAV. But while the unit can be given throttle or speed control signals like any other motor, it can also do things like accept commands in terms of thrust. In other words, an aircraft’s flight controller can communicate to motors directly in thrust units, instead of a speed control signal whose actual effect is subject to variances like motor voltage level.

The “Position” mode has the motor function like a servo with adjustable torque, which is perfect for direct drive applications like robotic legs. The position sensing also allows for a few neat tricks, like the ability to use the motors as inputs. Embedded below are two short videos showcasing both of these features, so check them out.

Continue reading “How To Improve A Smart Motor? Make It Bigger!” →