Modular Robotics Made Easier With ROS

A robot is made up of many hardware components each of which requires its own software. Even a small robot arm with a handful of servo motors uses a servo motor library.

Add that arm to a wheeled vehicle and you have more motors. Then attach some ultrasonic sensors for collision avoidance or a camera for vision. By that point, you’ve probably split the software into multiple processes: one for the arm, another for the mobility, one for vision, and one to act as the brains interfacing somehow with all the rest. The vision may be doing object recognition, something which is computationally demanding and so you now have multiple computers.

Break all this complexity into modules and you have a use case for ROS, the Robot Operating System. As this article shows, ROS can help with designing, building, managing, and even evolving your robot.

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DIY Submersible Aims For Low Cost, Ease Of Operation

If you’re like us, a body of water is a source of wonder and awe. The wonder comes from imagining what lies hidden below the surface, and the awe is from the fear of trying to find out and becoming one of those submerged objects on a permanent basis. So if you want to explore the depths in relative comfort and safety, a DIY remotely operated underwater vehicle might be the thing you need to build.

Most ROV builds these days seem to follow more or less similar designs, which is probably because they all share project goals similar to those of [dcolemans]: build something to take a look around under the water, make it easy to operate, and don’t spend a ton of money. To achieve that, he used 1/2″ PVC pipe and fittings to build the frame and painted it yellow for visibility. A dry tube for the electronics was fashioned from 4″ ABS pipe. The positive buoyancy provided by the dry tube is almost canceled out by the water flooding the frame through weep holes and the lead shot ballast stored in the landing skids. Propulsion is provided by bilge pump cartridges with 3D-printed ducted propellers. A nice touch is a separate topside control box with a screen for the ROV’s camera that talks to a regular RC controller, along with simplified controls and automatic station keeping. Check out the recent swimming pool test in the video below.

There’s a lot going on under the sea, and plenty of ways to explore it. You could deploy sensors shaped like clams, zap underwater lice with lasers, or even glide your way to a Hackaday Prize.

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Smiling Robot Moves Without Wires

What could be cuter than a little robot that scuttles around its playpen and smiles all day? For the 2018 Hackaday prize [bobricius] is sharing his 2D Actuator for Micro Magnetic Robot. The name is not so cute, but it boasts a bill of materials under ten USD, so it should be perfect for educational use, which is why it is being created.

The double-layer circuit board hides six poles. Three poles run vertically, and three of them run horizontally. Each pole is analogous to a winding in a stepper motor. As the poles turn on, the magnetic shuttle moves to the nearest active pole. When the perpendicular windings activate, it becomes possible to lock that shuttle in place. As the windings activate in sequence, it becomes possible to move left/right and forward/back. The second video demonstrates this perfectly.

[bobricius] found inspiration from a scarier source, but wants us to know this is his creation, not a patent infringement. We are not lawyers.

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RoMeLa's ALPHRED - quadruped robot

RoMeLa’s Sideways Walking Robot Has Evolved More Limbs

Despite the success shown in prototypes from groups like Boston Dynamics, bipedal walking is still really hard to implement. When the robot lifts one leg, it has to shift its center of gravity over the other leg to avoid falling sideways.

The Autonomous Legged Personal Helper Robot with Enhanced Dynamics (ALPHRED) is getting around this problem by coming at it from a different angle. ALPHRED walks sideways and throws away the distinction between arms and legs.

The bot is RoMeLa at UCLA’s latest evolution in their approach to traditional bipedal roadblocks. Sideways walking is something we covered when we talked about their previous version, NABi, which had only two legs. ALPHRED expands that to four limbs. As the video below shows, all four limbs can be used for walking using either a wide, stable sprawl or the limbs can reorient to a narrower dog or horse-like stance for faster running.

Beyond walking, one or two of the limbs can be put to use as hands to open a door or hand over a package, which is why they refer to them as limbs instead of legs or hands. Only an animation is shown of that configuration but RoMeLa is a robotics lab which we keep an eye on so we’ll let you know if they demonstrate it.

The video goes on to show a neat actuator with active compliance which they call BEAR, Back-drivable Electromagnetic Actuator for Robots. A search turned up no further details but let us know in the comments if you have any. We also liked seeing how they use a speaker to give a rough idea of the amount of current being drawn. While it’s both practical and a hack, it also adds a nice sci-fi touch.

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Gentle Electric Eel

It’s no shock that electric eels get a bad rap for being scary creatures. They are slithery fleshy water snakes who can call down lightning. Biologists and engineers at the University of California had something else in mind when they designed their electric eel. Instead of hunting fish, this one swims harmlessly alongside them.

Traditional remotely operated vehicles have relied on hard shells and spinning propellers. To marine life, this is noisy and unnatural. A silent swimmer doesn’t raise any eyebrows, not that fish have eyebrows. The most innovative feature is the artificial muscles, and although the details are scarce, they seem to use a medium on the inside to conduct a charge, and on the outside, the saltwater environment conducts an opposite charge which causes a contraction in the membrane between to the inside and outside. Some swimming action can be seen below the break, and maybe one of our astute readers can shed some light on this underwater adventurer’s bill of materials.

One of our favorite submarines is the 2017 Hackaday Prize winner, The Open Source Underwater Glider. For a more artistic twist on submersibles, the Curv II is one of the most elegant we have seen.

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Modular Robotics: When You Want More Robots In Your Robot

While robots have been making our lives easier and our assembly lines more efficient for over half a century now, we haven’t quite cracked a Jetsons-like general purpose robot yet. Sure, Boston Dynamics and MIT have some humanoid robots that are fun to kick and knock over, but they’re far from building a world-ending Terminator automaton.

But not every robot needs to be human-shaped in order to be general purpose. Some of the more interesting designs being researched are modular robots. It’s an approach to robotics which uses smaller units that can combine into assemblies that accomplish a given task.

We’ve been immersing ourselves in topics like this one because right now the Robotics Module Challenge is the current focus of the Hackaday Prize. We’re looking for any modular designs that make it easier to build robots — motor drivers, sensor arrays, limb designs — your imagination is the limit. But self contained robot modules that themselves make up larger robots is a fascinating field that definitely fits in with this challenge. Join me for a look at where modular robots are now, and where we’d like to see them going.

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Mike's robot dog

Mike’s Robot Dog Is A First Step In The Right Direction

Humans can traverse pretty much any terrain thanks to their legs and fast-acting balancing system. So if you want a robot which should have equal flexibility, legs are a good way to go, this confirmed by all the achievements of Boston Dynamics’ robots. It was therefore natural for [Mike Rigsby] to model his robot dog after Boston Dynamics’ dog-like robot, SpotMini.

The build log on his Hackaday.io page makes for interesting reading. For example, he started out with the legs oriented like SpotMini but found that when trying to stand, the front legs worked fine but the rear ones slid or the dog shifted rearward or both happened. His solution was to take a cue from his 1990s Sony robot dog, Aibo, by reversing the orientation of the rear legs. He then upgraded his servo motors to ones with double the torque and increased the strength of the legs’ structure. In the first video below, you can see that his dog now lifts itself up to a standing position perfectly.

So far, to give it more of a dog-like personality he’s mounted Google’s AIY Vision Kit which changes a light’s color based on the degree to which a person is smiling, though we think a wagging tail would work well too. The possibilities are endless but one step at a time. See the second video below for a demonstration of the use of the Vision Kit.

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