Tag Archives: new
#438553 New Drone Software Handles Motor ...
Good as some drones are becoming at obstacle avoidance, accidents do still happen. And as far as robots go, drones are very much on the fragile side of things. Any sort of significant contact between a drone and almost anything else usually results in a catastrophic, out-of-control spin followed by a death plunge to the ground. Bad times. Bad, expensive times.
A few years ago, we saw some interesting research into software that can keep the most common drone form factor, the quadrotor, aloft and controllable even after the failure of one motor. The big caveat to that software was that it relied on GPS for state estimation, meaning that without a GPS signal, the drone is unable to get the information it needs to keep itself under control. In a paper recently accepted to RA-L, researchers at the University of Zurich report that they have developed a vision-based system that brings state estimation completely on-board. The upshot: potentially any drone with some software and a camera can keep itself safe even under the most challenging conditions.
A few years ago, we wrote about first author Sihao Sun’s work on high speed controlled flight of a quadrotor with a non-functional motor. But that innovation relied on an external motion capture system. Since then, Sun has moved from Tu Delft to Davide Scaramuzza’s lab at UZH, and it looks like he’s been able to combine his work on controlled spinning flight with the Robotics and Perception Group’s expertise in vision. Now, a downward-facing camera is all it takes for a spinning drone to remain stable and controllable:
Remember, this software isn’t just about guarding against motor failure. Drone motors themselves don’t just up and fail all that often, either with respect to their software or hardware. But they do represent the most likely point of failure for any drone, usually because when you run into something, what ultimately causes your drone to crash is damage to a motor or a propeller that causes loss of control.
The reason that earlier solutions relied on GPS was because the spinning drone needs a method of state estimation—that is, in order to be closed-loop controllable, the drone needs to have a reasonable understanding of what its position is and how that position is changing over time. GPS is an easy way to take care of this, but GPS is also an external system that doesn’t work everywhere. Having a state estimation system that’s completely internal to the drone itself is much more fail safe, and Sun got his onboard system to work through visual feature tracking with a downward-facing camera, even as the drone is spinning at over 20 rad/s.
While the system works well enough with a regular downward-facing camera—something that many consumer drones are equipped with for stabilization purposes—replacing it with an event camera (you remember event cameras, right?) makes the performance even better, especially in low light.
For more details on this, including what you’re supposed to do with a rapidly spinning partially disabled quadrotor (as well as what it’ll take to make this a standard feature on consumer hardware), we spoke with Sihao Sun via email.
IEEE Spectrum: what usually happens when a drone spinning this fast lands? Is there any way to do it safely?
Sihao Sun: Our experience shows that we can safely land the drone while it is spinning. When the range sensor measurements are lower than a threshold (around 10 cm, indicating that the drone is close to the ground), we switch off the rotors. During the landing procedure, despite the fast spinning motion, the thrust direction oscillates around the gravity vector, thus the drone touches the ground with its legs without damaging other components.
Can your system handle more than one motor failure?
Yes, the system can also handle the failure of two opposing rotors. However, if two adjacent rotors or more than two rotors fail, our method cannot save the quadrotor. Some research has shown that it is possible to control a quadrotor with only one remaining rotor. But the drone requires a very special inertial property, which is hard to satisfy in real applications.
How different is your system's performance from a similar system that relies on GPS, in a favorable environment?
In a favorable environment, our system outperforms those relying on GPS signals because it obtains better position estimates. Since a damaged quadrotor spins fast, the accelerometer readings are largely affected by centrifugal forces. When the GPS signal is lost or degraded, a drone relying on GPS needs to integrate these biased accelerometer measurements for position estimation, leading to large position estimation errors. Feeding these erroneous estimates to the flight controller can easily crash the drone.
When you say that your solution requires “only onboard sensors and computation,” are those requirements specialized, or would they be generally compatible with the current generation of recreational and commercial quadrotors?
We use an NVIDIA Jetson TX2 to run our solution, which includes two parts: the control algorithm and the vision-based state estimation algorithm. The control algorithm is lightweight; thus, we believe that it is compatible with the current generation of quadrotors. On the other hand, the vision-based state estimation requires relatively more computational resources, which may not be affordable for cheap recreational platforms. But this is not an issue for commercial quadrotors because many of them have more powerful processors than a TX2.
What else can event cameras be used for, in recreational or commercial applications?
Many drone applications can benefit from event cameras, especially those in high-speed or low-light conditions, such as autonomous drone racing, cave exploration, drone delivery during night time, etc. Event cameras also consume very little power, which is a significant advantage for energy-critical missions, such as planetary aerial vehicles for Mars explorations. Regarding space applications, we are currently collaborating with JPL to explore the use of event cameras to address the key limitations of standard cameras for the next Mars helicopter.
[ UZH RPG ] Continue reading
#438294 Video Friday: New Entertainment Robot ...
Video Friday is your weekly selection of awesome robotics videos, collected by your Automaton bloggers. We’ll also be posting a weekly calendar of upcoming robotics events for the next few months; here's what we have so far (send us your events!):
HRI 2021 – March 8-11, 2021 – [Online Conference]
RoboSoft 2021 – April 12-16, 2021 – [Online Conference]
ICRA 2021 – May 30-5, 2021 – Xi'an, China
Let us know if you have suggestions for next week, and enjoy today's videos.
Engineered Arts' latest Mesmer entertainment robot is Cleo. It sings, gesticulates, and even does impressions.
[ Engineered Arts ]
I do not know what this thing is or what it's saying but Panasonic is going to be selling them and I will pay WHATEVER. IT. COSTS.
Slightly worrisome is that Google Translate persistently thinks that part of the description involves “sleeping and flatulence.”
[ Panasonic ] via [ RobotStart ]
Spot Enterprise is here to help you safely ignore every alarm that goes off at work while you're snug at home in your jammies drinking cocoa.
That Spot needs a bath.
If you missed the launch event (with more on the arm), check it out here:
[ Boston Dynamics ]
PHASA-35, a 35m wingspan solar-electric aircraft successfully completed its maiden flight in Australia, February 2020. Designed to operate unmanned in the stratosphere, above the weather and conventional air traffic, PHASA-35 offers a persistent and affordable alternative to satellites combined with the flexibility of an aircraft, which could be used for a range of valuable applications including forest fire detection and maritime surveillance.
[ BAE Systems ]
As part of the Army Research Lab’s (ARL) Robotics Collaborative Technology Alliance (RCTA), we are developing new planning and control algorithms for quadrupedal robots. The goal of our project is to equip the robot LLAMA, developed by NASA JPL, with the skills it needs to move at operational tempo over difficult terrain to keep up with a human squad. This requires innovative perception, planning, and control techniques to make the robot both precise in execution for navigating technical obstacles and robust enough to reject disturbances and recover from unknown errors.
[ IHMC ]
Watch what happens to this drone when it tries to install a bird diverter on a high voltage power line:
[ GRVC ]
Soldiers navigate a wide variety of terrains to successfully complete their missions. As human/agent teaming and artificial intelligence advance, the same flexibility will be required of robots to maneuver across diverse terrain and become effective combat teammates.
[ Army ]
The goal of the GRIFFIN project is to create something similar to sort of robotic bird, which almost certainly won't look like this concept rendering.
While I think this research is great, at what point is it in fact easier to just, you know, train an actual bird?
[ GRIFFIN ]
Paul Newman narrates this video from two decades ago, which is a pretty neat trick.
[ Oxford Robotics Institute ]
The first step towards a LEGO-based robotic McMuffin creator is cracking and separating eggs.
[ Astonishing Studios ] via [ BB ]
Some interesting soft robotics projects at the University of Southern Denmark.
[ SDU ]
Chong Liu introduces Creature_02, his final presentation for Hod Lipson's Robotics Studio course at Columbia.
[ Chong Liu ]
The world needs more robot blimps.
[ Lab INIT Robots ]
Finishing its duty early, the KR CYBERTECH nano uses this time to play basketball.
[ Kuka ]
senseFly has a new aerial surveying drone that they call “affordable,” although they don't say what the price is.
[ senseFly ]
In summer 2020 participated several science teams of the ETH Zurich at the “Art Safiental” in the mountains of Graubunden. After the scientists packed their hiking gear and their robots, their only mission was “over hill and dale to the summit”. How difficult will it be to reach the summit with a legged robot and an exosceletton? What's the relation of synesthetic dance and robotic? How will the hikers react to these projects?
[ Rienerschnitzel Films ]
Thanks Robert!
Karen Liu: How robots perceive the physical world. A specialist in computer animation expounds upon her rapidly evolving specialty, known as physics-based simulation, and how it is helping robots become more physically aware of the world around them.
[ Stanford ]
This week's UPenn GRASP On Robotics seminar is by Maria Chiara Carrozza from Scuola Superiore Sant’Anna, on “Biorobotics for Personal Assistance – Translational Research and Opportunities for Human-Centered Developments.”
The seminar will focus on the opportunities and challenges offered by the digital transformation of healthcare which was accelerated in the COVID-19 Pandemia. In this framework rehabilitation and social robotics can play a fundamental role as enabling technologies for providing innovative therapies and services to patients even at home or in remote environments.
[ UPenn ] Continue reading