3-DOF Robot Arm Wrist Without The Motor Weight

A major challenge of robotic arms is the weight of the actuators, especially closer to the end of the arm. The long lever arm means more torque is required from the other actuators, and everything flexes a bit more. To get around this, [RoTechnic] moved the wrist stepper motors off the arms entirely.

He built a push-pull mechanism that uses braided fishing line to transfer motion to the robot arm’s wrist using Bowden tubes. The motors are mounted on the arm’s base, with a drum and two lengths of fishing line on the shafts. The lines pass through an adjustable tensioner before entering the Bowden tubes. This drum mechanism is also present on each of the three rotating axes of the wrist.

[RoTechnic] used an Arduino-powered RAMPS board as a controller, which is programmed to accept over the serial interface. He created a simple GUI and scripting interface in Jupyter Labs to generate and send command, which seems like an excellent solution for testing.

We can see this mechanism being a useful for a variety of motion applications, and definitely something to add to the idea toolbox. It is somewhat similar to some other cable-operated joints we’ve seen in humanoid robots and other 3D printed arms.

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Mini Mars Rover Runs On Pi Pico W

NASA’s Mars Rovers are robots that have inspired many budding engineers around the world. [Nikodem Bartnik] had a particular fondness for them himself, and set out to build a miniature version of his very own.

The Raspberry Pi Pico W is the brains of the operation, serving as both microcontroller and remote wireless link for control. The robot uses four mecanum wheels for locomotion, with each getting its own motor. This allows the robot to move in all directions simply by rotating the wheels in different configurations. On top, the rover sports a articulated robot arm controlled by servos, which allows it to pick things up and put them down. Plus, there’s an FPV camera on top that delivers a video feed so the robot can be driven remotely. This is achieved over WiFi, thanks to a bit of custom control code written in Python.

It’s a surprisingly capable bot on smooth surfaces, as the mecanum wheels allow strafing and other movements that regular wheels simply can’t do. It’s also fun having a bot that can interact with its environment, thanks to its motorized appendages.

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Robots Are Folding Laundry, But They Suck At It

Robots are used in all sorts of industries on a wide variety of tasks. Typically, it’s because they’re far faster, more accurate, and more capable than we are. Expert humans could not compete with the consistent, speedy output of a robotic welder on an automotive production line, nor could they as delicately coat the chocolate on the back of a KitKat.

However, there are some tasks in which humans still have the edge. Those include driving, witty repartee, and yes, folding laundry. That’s not to say the robots aren’t trying, though, so let’s take a look at the state of the art.

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Retrofitting Robots

Al Williams wrote up a neat thought piece on why we are so fascinated with robots that come in the shape of people, rather than robots that come in the shape of whatever it is that they’re supposed to be doing. Al is partly convinced that sci-fi is partly responsible, and that it shapes people’s expectations of what robots look like.

What sparked the whole thought train was the ROAR (robot-on-a-rail) style robot arms that have been popping up, at least in the press, as robot fry cooks. As the name suggests, it’s a robot arm on a rail that moves back and forth across a frying surface and uses CV algorithms to sense and flip burgers. Yes, a burger-flipping robot arm. Al asks why they didn’t just design the flipper into the stovetop, like you would expect with any other assembly line.

In this particular case, I think it’s a matter of economics. The burger chains already have an environment that’s designed around human operators flipping the burgers. A robot arm on a rail is simply the cheapest way of automating the task that fits in with the current ergonomics. The robot arm works like a human arm because it has to work in an environment designed for the human arm.

Could you redesign a new automatic burger-flipping system to be more space efficient or more reliable? Probably. If you did, would you end up with a humanoid arm? Not necessarily. But this is about patching robotics into a non-robotic flow, and that means they’re going to have to play by our rules. I’m not going to deny the cool factor of having a robot arm flip burgers, but my guess is that it’s actually the path of least resistance.

It feels kind of strange to think of a sci-fi timeline where the human-looking robots come first, and eventually get replaced by purpose-built intelligent machines that look nothing like us as the environments get entire overhauls, but that may be the way it’s going to play out. Life doesn’t always imitate art.

Trying To Build The World’s Fastest Roomba

A lot of people complain that Roombas are unreliable, poor at their job, or just plain annoying. Few people complain they’re not fast enough in a straight line. Regardless, [electrosync] set about building the world’s fastest Roomba for his own personal satisfaction.

For this challenge, [electrosync] set his own rules. The build must look like a Roomba, use two drive wheels, and one motor per wheel. It also has to maintain its vacuum functionality. After stripping down a used Roomba, he set about carving out space in the chassis for upgraded hardware. Brushed DC 775 motors were selected for the drivetrain, and these run through a 3:1 planetary reduction gearbox. 3D-printed mounts were then used to install the new motors in the existing chassis. New 3D-printed wheels completed the drivetrain. The original Ni-MH cells were replaced with a pair of 3-cell lithium polymer batteries for more power.

Measured with a Bluetooth GPS device, the upgraded Roomba achieved an impressive 36 km/h (22 MPH). With new wheel designs clad in urethane rubber and an improved anti-wheelie device, it hit a mighty 49 km/h (30 MPH). Adding 4-cell batteries pushed things further to 57 km/h (35 MPH), but the Roomba became difficult to control.

The gauntlet has been thrown down. Do you think you can build a faster Roomba? Time to get hacking! Video after the break.

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A picture of the JagerMachine consisting of rectangular, desktop sized drink serving machine with a wooden varnish, a 3.5 inch touchscreen on the front face on top and a cavity with a shot glass in it, lit up by blue leds, with liquid pouring into it.

Shoot An Email To Get A Shot

[_Pegor] wanted to create a shot pouring machine for their friends birthday. Unfortunately, the build wasn’t done in time, but at least the JagerMachine is finished now so that others can use it.

The JagerMachine has a peristaltic pump that moves liquid from a reservoir hidden in the back of the machine to the glass in front. The machine has a 3.5 inch DSI touch screen display for user input and a WS2812B LED ring for creating a small light show when the drinks are served. A 3.3 V to 5 V level shifter is used to power the LED ring and a motor driver module is used to drive the peristaltic pump motor. It looks like there’s a “shot glass detection” feature that uses a 3D printed mini platform with a notch for a magnet so that when a glass is placed on top of it, the hall sensor can detect the presence of the nearby magnet.

Part of the charm of this project is the software stack on the Raspberry Pi that allows for novel interaction, including being able to serve drinks from the receipt of emails. Using the Raspberry Pi as the controlling device allows for this rich set of interfacing options, including easily allowing the ability to drive the LEDs, detect the presence of the shot glass, along with establishing network connectivity. The setup procedures are all documented in the repository for anyone wanting to see how this type of functionality might transfer to their own project.

Drink mixing robots are, of course, a thing. ranging from small and cute to full shelf.

In Our Own Image: Do We Need Humanoid Robots?

Science fiction is full of things you don’t want to think too hard about. Why do starships with transporters have brigs with forcefields? Why not just beam a prisoner into an enclosed space?  Why do Cylons fly ships with human controls? Why not have a plug in their… well, you get the idea. For that matter, why do Cylons (and Kaylons, and Gort) even look human at all? Why aren’t some Cylons just ships?

Of course, the real reason is so we can identify with them and actors can play them with some cosplay gear and makeup. But real-life robots that are practical rarely look like humans at all.

No one is going to confuse a robot factory arm or a Roomba with a person, yet they are perfectly suited for their purpose. Yet we are fascinated with human-looking robots and continue to build them, like Nadia from IHMC Robotics in the video below. Continue reading “In Our Own Image: Do We Need Humanoid Robots?”