A Handy Way To Cheaply Print A Robotic Arm

August 29, 2019 by 5 Comments

There’s something fascinating about humanoid robotic hands, if only because of how they are such close approximations of our own hands. One could almost picture them with tendons and skin covering them. Sadly, making your own is quite prohibitive because in addition to being complex bits of machinery, making one of these marvels of engineering is usually rather expensive.

[Gray Eldritch]’s Humanoid Robot Arm project seeks to fix both points, by providing a ready to print project. All it takes is about a kilogram of PLA filament, some TPU filament, five MG996r servos (or equivalent), an SG90 servo or similar, an Arduino Uno board and a few other bits and pieces. This should result in a robotic arm with hand as covered in the video of the Mark 3 version that is embedded after the break.

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Self-aware Robotic Arm

April 24, 2019 by 16 Comments

If you ever tried to program a robotic arm or almost any robotic mechanism that has more than 3 degrees of freedom, you know that a big part of the programming goes to the programming of the movements themselves. What if you built a robot, regardless of how you connect the motors and joints and, with no knowledge of itself, the robot becomes aware of the way it is physically built?

That is what Columbia Engineering researchers have made by creating a robot arm that learns how it is connected, with zero prior knowledge of physics, geometry, or motor dynamics. At first, the robot has no idea what its shape is, how its motors work and how they affect its movement. After one day of trying out its own outputs in a pretty much random fashion and getting feedback of its actions, the robot creates an accurate internal self-simulation of itself using deep-learning techniques.

The robotic arm used in this study by Lipson and his PhD student Robert Kwiatkowski is a four-degree-of-freedom articulated robotic arm. The first self-models were inaccurate as the robot did not know how its joints were connected. After about 35 hours of training, the self-model became consistent with the physical robot to within four centimeters. The self-model then performed a pick-and-place task that enabled the robot to recalibrate its original position between each step along the trajectory based entirely on the internal self-model.

To test whether the self-model could detect damage to itself, the researchers 3D-printed a deformed part to simulate damage and the robot was able to detect the change and re-train its self-model. The new self-model enabled the robot to resume its pick-and-place tasks with little loss of performance.

Since the internal representation is not static, not only this helps the robot to improve its performance over time but also allows it to adapt to damage and changes in its own structure. This could help robots to continue to function more reliably when there its part start to wear off or, for example, when replacement parts are not exactly the same format or shape.

Of course, it will be long before this arm can get a precision anywhere near Dexter, the 2018 Hackaday Prize winner, but it is still pretty cool to see the video of this research:

An In-Depth Look At Dexter, The Robotic Arm

November 15, 2018 by 25 Comments

Dexter, a really great robot arm project, just won top honors in the 2018 Hackaday Prize, and walked away with $50,000 toward continuing their project. As a hat tip to Hackaday and the community, Haddington Dynamics, the company behind Dexter, agreed to open-source their newest version of Dexter as well. As James Newton said when accepting the trophy during the award ceremony, “because of your faith in us, because of this award, we have been moved to open-source the next generation of Dexter.” Some very clever work went into producing Dexter, and we can’t wait to see what further refinements have been made!

Dexter isn’t the only robotic arm in town, by any means. But in terms of hobbyist-level robotics, it’s by far the most complete robot arm that we’ve seen, and it includes a couple of design features that make both its positional accuracy and overall usability stand out above the rest. This is a robot arm with many of the bells and whistles of a hundred-thousand dollar robot, but on a couple-thousand dollar budget. Continue reading “An In-Depth Look At Dexter, The Robotic Arm” →

Dexter Robotic Arm Wins The 2018 Hackaday Prize

November 3, 2018 by 19 Comments

Dexter, an open-source, high-precision, trainable robotic arm has just been named the Grand Prize winner of the 2018 Hackaday Prize. The award for claiming the top place in this nine-month global engineering initiative is $50,000. Four other top winners were also named during this evening’s Hackaday Prize Ceremony, held during the Hackaday Superconference in Pasadena, California.

This year’s Hackaday Prize featured challenges with five different themes. Entrants were asked to show their greatest Open Hardware Design, to build a Robotics Module, to design a Power Harvesting Module, to envision a Human Computer Interface, or to invent a new Musical Instrument. Out of 100 finalists, the top five are covered below. Over $200,000 in cash prizes have been distributed as part of this year’s initiative where thousands of hardware hackers, makers and artists compete to build a better future.

Dexter: High Precision Robotic Arm

Dexter is the Grand Prize winner of the 2018 Hackaday Prize. This remarkable robotic arm design brings many aspects of high-end automation to an open source design which you can utilize and adapt for your own needs. In addition to impressive precision, the design is trainable — you can move the joints of the arm and record the motion for playback.

The image here shows position data from one arm being moved by a human, controlling another arm in real time. Each joint utilizes a clever encoder design made up of a wheel with openings for UV sensors. Sensing is more than merely “on/off”. It tracks the change in light intensity through each opening for even greater granularity. The parallel nature of an FPGA is used to process this positioning data in real time.

Hack a $35 Wearable to Build Mental Health Devices

Manufacturing custom electronics is a tricky, costly, and time-consuming process. What if you could sidestep most of that by starting with a powerful, proven consumer good that is modified to your specifications? This project takes existing fitness trackers and customizes the hardware and software to become sensor suites for mental health research. Dig into this one and see how they can help patients become aware of unconscious behaviors (like trichotillomania which is compulsive hair pulling) and change them over time.

Portal Point Generator

This project focuses on an alternative power source for times when traditional infrastructure is not functioning or simply not available. You may be familiar with generators made using DC motors. The Portal Point Generator replicates that simplicity, but goes beyond with instructions for building the generator itself for far greater efficiency. A winding jig is used to make the coils which are placed inside of the 3D printed generator parts along with permanent magnets to complete the build. Here you can see it in testing as a wind generator in Antarctica, but it is easily adapted to other applications like using water wheels.

EmotiGlass

There is a body of research that suggest a link between cardiac cycle and anxiety-producing visuals; you may have a different emotional reaction to the things you see based on what part of a heartbeat is occurring when your brain process information from your eyes. This could have profound implications in areas like PTSD research. EmotiGlass uses LCD screens to selectively block the wearer’s vision. This can be synchronized with heat beat, avoiding the instant where a negative emotional response is most likely. Think of them as 3D shutter glasses for mental health research.

PR-Holonet: Disaster Area Emergency Comms

Recovering from natural disasters is an enormous challenge. The infrastructure that supports the community is no longer in place and traditional communications simply cease to exist. PR-Holonet was inspired by the recovery process after hurricanes in Puerto Rico. It leverages the availability of commercial electronics, solar power sources, and enclosures to build a communications system that can be deployed and operated without the need for specialized training. Once in place, local devices using WiFi can utilize text-based communications transferred via satellite.

Congratulations to all who entered the 2018 Hackaday Prize. Taking time to apply your skill and experience to making the world better is a noble pursuit. It doesn’t end with the awarding of a prize. We have the ability to change lives by supporting one another, improving on great ideas, and sharing the calling to Build Something that Matters.

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A Robotic Arm For Those Who Like Their Kinematics Both Ways

October 19, 2018 by 1 Comment

A robotic arm is an excellent idea if you’re looking to get started with electromechanical projects. There’s linkages to design, and motors to drive, but there’s also the matter of control. This is referred to as “kinematics”, and can be considered in both the forward and inverse sense. [aerdronix] built a robotic arm build that works in both ways.

The brains of the build is an Arduino Yun, which receives commands over the USB interface. Control is realised through the Blynk app, which allows IoT projects to easily build apps for smartphones that can be published to the usual platforms.

The arm’s position is controlled in two fashions. When configured to use inverse kinematics, the user commands an end effector position, and the arm figures out the necessary position of the linkages to make it happen. However, the arm can also be used in a forward kinematics mode, where the individual joint positions are commanded, which then determine the end effector’s final position.

Overall, it’s a well-documented build that lays out everything from the basic mechanical design to the software and source code required to control the system. It’s an excellent learning resource for the newcomer, and such an arm could readily be used in more complex projects.

We see plenty of robotic arms around these parts, like this fantastic build based on an IKEA lamp. If you’ve got one, be sure to hit up the tip line. Video after the break.

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Wood Shines In This SCARA Robotic Arm Project

September 13, 2018 by 9 Comments

[igarrido] has shared a project that’s been in the works for a long time now; a wooden desktop robotic arm, named Virk I. The wood is Australian Blackwood and looks gorgeous. [igarrido] is clear that it is a side project, but has decided to try producing a small run of eight units to try to gauge interest in the design. He has been busy cutting the parts and assembling in his spare time.

Besides the beautifully finished wood, some of the interesting elements include hollow rotary joints, which mean less cable clutter and a much tidier assembly. 3D printer drivers are a common go-to for CNC designs, and the Virk I is no different. The prototype is driven by a RAMPS 1.4 board, but [igarrido] explains that while this does the job for moving the joints, it’s not ideal. To be truly useful, a driver would need to have SCARA kinematic support, which he says that to his knowledge is something no open source 3D printer driver offers. Without such a driver, the software has no concept of how the joints physically relate to one another, which is needed to make unified and coherent movements. As a result, users must control motors and joints individually, instead of being able to direct the arm as a whole to move to specific coordinates. Still, Virk I might be what’s needed to get that development going. A video of some test movements is embedded below, showing how everything works so far.

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A Servo Powered Robotic Arm, But Like You’ve Never Seen Before

September 4, 2018 by 26 Comments

We’ve written about a lot of DIY robotic arms. Some of them are high-performance, some are inexpensive, and some are just uniquely fun. This one certainly falls into the last category; whilst watching an episode of Black Mirror, [Gear Down For What] was struck by inspiration for a thin robotic limb. After some iterations he has a final prototype, and it’s quite something to see in action.

To make a robotic arm as slender as possible, the actuators can’t be mounted on the arm itself but must instead drive the arm remotely. There are a number of ways of doing this, and though [Gear Down For What] considered using pneumatics or hydraulics, he opted to keep it simple with RC servos which produced a nifty solution that we really like.

The arm is made out of a series of 3D printed ball joints, allowing rotation in any direction. The tricky bit is transferring the force from the servos to each joint. Initially bare fishing line was considered, but this made the remote joints difficult to control when lower joints were moving. The solution was to use the fishing line inside of tubing, similar to the way that bike brakes operate. This allows the force to be carried to the appropriate joint regardless of lower movement. Each joint needs an x and y tension to allow it to rotate in any direction, which means an army of sixteen servos is needed to operate the eight segment arm.

Robotic arms are always fun to build and we’ve seen some pretty neat uses for them, such as mapping magnetic fields in 3D, or teaching sign language.

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