Autonomous Sentry Gun Packs A Punch And A Ton Of Build Tips

June 10, 2020 by Dan Maloney 17 Comments

What has dual compressed-air cannons, 500 roll-on deodorant balls, and a machine-learning brain with a bad attitude? We didn’t know either, until [Leo Fernekes] dropped this video on his autonomous robot sentry gun and saw it in action for ourselves.

Now, we’ve seen tons of sentry guns on these pages before, shooting everything from water to various forms of Nerf. And plenty of those builds have used some form of machine vision to aim the gun onto the target. So while it might appear that [Leo]’s plowing old ground here, this build is chock full of interesting tips and tricks.

It started when [Leo] saw a video on TensorFlow basics from our friend [Edje Electronics], which gave him the boost needed to jump into an AI project. The controller he ended up with looks for humans in the scene and slews the turret onto target, where the air cannons can do their thing. The hefty ammo is propelled by compressed air, which is dumped into the chamber using a solenoid valve with an interesting driver that maximizes the speed at which it opens. Style points go to the bacteriophage T4-inspired design, and to the sequence starting at 1:34 which reminded us of the factory scene from RoboCop.

[Leo] really put a ton of work into this project, and the results show. He is hoping to get an art gallery or museum to show it as an interactive piece to comment on one possible robot-human future, presumably after getting guests to sign a release. Whatever happens to it, the robot looks great and [Leo] learned a lot from it, as did we.

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Dropping A Glider From 18,000 Feet

April 17, 2020 by Richard Baguley 37 Comments

[Tarik and Kemal] have an objective in mind: to drop a home-made autonomous glider from a high-altitude balloon and safely return it to home. To motivate them, [Tarik] has decided not to cut his hair until they reach 18,000 feet. Given the ambition of their project, it isn’t surprising that his hair is getting rather long now.

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Drones Can Undertake Excavations Without Human Intervention

March 16, 2020 by Sharon Lin 4 Comments

Researchers from Denmark’s Aarhus University have developed a method for autonomous drone scanning and measurement of terrains, allowing drones to independently navigate themselves over excavation grounds. The only human input is a starting location and the desired cliff face for scanning.

For researchers studying quarries, capturing data about gravel, walls, and other natural and man-made formations is important for understanding the properties of the terrain. Controlling the drones can be expensive though, since there’s considerable skill involved in manually flying the drone and keeping its camera steady and perpendicular to the wall it is capturing.

The process designed is a Gaussian model that predicts the wind encountered near the wall, estimating the strength based on the inputs it receives as it moves. It uses both nonlinear model predictive control (NMPC) and a PID controller in its feedback control system, which calculate the values to send to the drone’s motor controller. A long short-term memory (LSTM) model is used for calculating the predictions. It’s been successfully tested in a chalk quarry in Denmark and will continue to be tested as its algorithms are improved.

Getting a drone to hover and move between GPS waypoints is easy enough, but once they need to maneuver around obstacles it starts getting tricky. Research like this will be invaluable for developing systems that help drones navigate in areas where their human operators can’t reach.

[Thanks to Qes for the tip!]

Ask Hackaday: What Good Is A Robot Dog?

September 25, 2019 by Dan Maloney 63 Comments

It is said that Benjamin Franklin, while watching the first manned flight of a hot air balloon by the Montgolfier brothers in Paris in 1783, responded when questioned as to the practical value of such a thing, “Of what practical use is a new-born baby?” Dr. Franklin certainly had a knack for getting to the heart of an issue.

Much the same can be said for Spot, the extremely videogenic dog-like robot that Boston Dynamics has been teasing for years. It appears that the wait for a production version of the robot is at least partially over, and that Spot (once known as Spot Mini) will soon be available for purchase by “select partners” who “have a compelling use case or a development team that [Boston Dynamics] believe can do something really interesting with the robot,” according to VP of business development Michael Perry.

The qualification of potential purchasers will certainly limit the pool of early adopters, as will the price tag, which is said to be as much as a new car – and a nice one. So it’s not likely that one will show up in a YouTube teardown video soon, so until the day that Dave Jones manages to find one in his magic Australian dumpster, we’ll have to entertain ourselves by trying to answer a simple question: Of what practical use is a robotic dog?

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Skid Steer Mows Airport Grass Autonomously

August 28, 2019 by Bryan Cockfield 32 Comments

Sure, mowing the lawn is a hassle. No one really wants to spend their time and money growing a crop that doesn’t produce food, but we do it anyway. If you’re taking care of a quarter acre in the suburbs it’s not that much of a time sink, but if you’re taking care of as much grass as [Roby], you’d probably build something similar to his autonomous skid-steer mower, too.

This thing isn’t a normal push mower outfitted with some random electronics, either. This is a serious mower that is essentially a tractor with blades attached to it. Since it’s a skid steer, it turns by means of two handles that control the speed of the left or right drive wheels. Fabricating up some servo linkages to attach them to specialized servos takes care of the steering portion, and the brain is ArduPilot hooked up to a host of radios, GPS, and a compass to allow it to drive all around the runways at the airport without interfering with any aircraft.

This is a serious build and goes into a lot of detail about how servos and linkages should behave, how all the software works, and the issues of actually mounting everything to the mower. The entire project is open source too, so even if you don’t have a whole airport runway to mow you might be able to find something in there to help with your little patch of grass.

Thanks to [Vincent] for the tip!

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ArduRover Boat Uses Tub To Float

August 18, 2019 by Ben James 16 Comments

There’s nothing quite like the sight of a plastic box merrily sailing its way around a lake to symbolise how easy it is to get started in autonomous robotics. This isn’t a project we’re writing about because of technical excellence, but purely because watching an autonomous plastic box navigate a lake by itself is surprisingly compelling viewing. The reason that [rctestflight] built the vessel was to test out the capabilities of ArduRover. ArduRover is, of course, a flavour of the extremely popular open source ArduPilot, and in this case is running on a Pixhawk.

The hardware itself is deliberately as simple as possible: two small motors with RC car ESCs, a GPS, some power management and a telemetry module are all it takes. The telemetry module allows the course/mission to be updated on the fly, as well as sending diagnostic data back home. Initially, this setup performed poorly; low GPS accuracy combined with a high frequency control loop piloting a device with little inertia lead to a very erratic path. But after applying some filtering to the GPS this improved significantly.

Despite the simplicity of the setup, it wasn’t immune to flaws. Seaweed in the prop was a cause of some stressful viewing, not to mention the lack of power required to sail against the wind. After these problems caused the boat to drift off course past a nearby pontoon, public sightings ranged from an illegal police drone to a dog with lights on its head.

If you want to use your autonomous boat for other purposes than scaring the public, we’ve written about vessels that have been used to map the depth of the sea bed, track aircraft, and even cross the Atlantic.

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Automate The Freight: Platooning

August 13, 2019 by Dan Maloney 34 Comments

On yet another one of those long, pointless road trips that seemed to punctuate my life starting when I got my license, I was plying the roads somewhere in eastern Pennsylvania with a friend. He told me that on long trips he’d often relieve the boredom by finding another car from the same state as his destination, and then just follow it. I wasn’t sure then how staring at the same car, hour after hour, mile after mile, would do anything but increase the boredom while making you look sort of creepy, but it seemed to work for him.

What works for college kids in cars also works for long-haul truckers, and the concept of a convoy has long been a fact of life on the road and a part of popular culture. Hardly a trip on the US Interstate goes by without seeing a least two truckers traveling in close formation, partly for companionship and mutual support but also for economic reasons. And now technology is poised to take convoying to the next level, as platooning becomes yet another way to automate the freight.

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