This Force Controlled Robot Gripper Is Less Likely To Break Stuff

March 25, 2019 by Lewin Day No comments

While robotic arms can handle a wide variety of tasks, the specific job at hand will have a major influence on the type of end effector used. For sorting ferromagnetic parts an electromagnet might be enough, while for more accurate location a mechanical gripper could be employed. If you’re working with particularly delicate objects or in concert with human beings, it may be desired to have a force controlled gripper to avoid damage. [James Bruton] has been whipping up a design of his own for just this purpose.

The basic gripper is 3D printed, with 3 fingers consisting of two joints each. Retraction of each finger is courtesy of bungee cord, while extension is via a servo attached to the finger through a spring. The position of each finger is measured with a resistive flex sensor. An Arduino Uno is employed to run the servos and read the attached sensors.

As force is applied by the servo, the spring begins to stretch. This leads to a greater difference between the servo position and the finger position as the applied force increases. By calculating this difference, it’s possible to determine the force applied by the fingers. This can then be used to limit the applied force of the gripper, to avoid breaking delicate objects or crushing soft, fleshy humans.

[James] notes that there are some drawbacks to the current design. The force required to move the fingers is inconsistent along their travel, and this interferes somewhat with accurate measurement. Overall though it’s a solid proof of concept and a good base for further revisions. Files are on Github for those who wish to tinker at home.

Being aware of the forces applied in mechanical settings can be key to getting good results. We’ve even seen arbor presses modified for just such a purpose. Video after the break.

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Kid Rover Is Six Wheels Of Awesome

March 22, 2019 by Lewin Day 15 Comments

There are plenty of ways to go about learning to TIG weld. Most involve a series of practice parts making butt joints and welding together various sections of pipe. [Kris Temmerman] decided to go a little bit farther, however. The result is a kid rover that’s sure to be the envy of every neighbourhood child for a few zipcodes around.

The chassis is an all-aluminium affair, making TIG welding the perfect choice for the job. Of course, [Kris] wasn’t content to simply build a basic go-kart or buggy. This sweet ride is inspired by the rocker-bogie designs of NASA’s Mars rovers, giving it the ride height and flexibility to roam over serious obstacles. Naturally, there’s six-wheel drive and four-wheel steering to complete the dynamic package. It should also be noted that yellow wheels are a stunning design choice that we just don’t see enough of.

It’s a beautifully crafted vehicle, and a testament to [Kris]’s machining and design skills. We can’t wait to see it given a shakedown run on the muddy fields of Belgium. If you’re eager to start your own rocker-bogie build, NASA’s got the open source designs to get you started. Video after the break.

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Origami Gripper Is Great For Soft And Heavy Objects

March 18, 2019 by Lewin Day 5 Comments

Robotic arms are fascinating devices, capable of immense speed and precision when carrying out their tasks. They’re also capable of carrying great loads, and a full-sized industrial robot in operation at maximum pace is a sight to behold. However, while it’s simple to design grippers to move strong metal objects, picking up delicate or soft objects can be much harder. A team at MIT CSAIL have been working on a solution to this problem, which they call the Origami gripper.

The gripper is highly capable at lifting objects with complex shapes.

The gripper consists of a flexible, folding skeleton surrounded by an airtight skin. When vacuum is applied, the skeleton contracts around the object to be picked up. The gripper is capable of grasping objects sized up to 70% of its diameter, and over 100 times its weight.

Fabrication of the device involved the creation of 3D printed molds to produce the silicone rubber skeleton. Combined with precise lasercutting and advanced layering techniques, this created a part that can self-fold itself into shape under the right conditions. The structure was inspired by a “magic ball” origami design. The outer skin is remarkably simple in comparison – consisting of a regular latex balloon.

The team show off the gripper performing some impressive feats, with the robot able to pick up objects of all shapes, sizes, and weights without damage. The paper is available to read for the full story on the device. The use of vacuum for delicate gripping tasks is something we’ve seen before, too.

Tweetbot Expresses Twitter Emotions

March 16, 2019 by Lewin Day 3 Comments

When reading textual communications, it can be difficult to accurately acertain emotional intent. Individual humans can be better or worse at this, with sometimes hilarious results when it goes wrong. Regardless, there’s nothing a human can do that a machine won’t eventually do better. For just this purpose, Tweetbot is here to emotionally react to Twitter so you don’t have to.

The ‘bot receives tweets over a bluetooth link, handled by a PIC32, which also displays them on a small TFT screen. The PIC then analyses the tweet for emotional content before sending the result to a second PIC32, which displays emotes on a second TFT screen, creating the robot’s face. Varying LEDs are also flashed depending on the emotion detected – green for positive emotions, yellow for sadness, and red for anger.

The final bot is capable of demonstrating 8 unique emotional states, far exceeding the typical Facebook commenter who can only express unbridled outrage. With the ‘bot packing displays, multiple microcontrollers, and even motor drives, we imagine the team learned a great deal in the development of the project.

The project was the product of [Bruce Land]’s ECE 4760 course, which has shown us plenty of great hacks in the past – Bike Sonar being one of our favorites. Video after the break.

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Wood SCARA Arm Gets A Grip

March 14, 2019 by Donald Papp 4 Comments

[Ignacio]’s VIRK I is a robot arm of SCARA design with a very memorable wooden body, and its new gripper allows it to do a simple pick and place demo. Designing a robot arm is a daunting task, and the fundamental mechanical design is only part of the whole. Even if the basic framework for a SCARA arm is a solved problem, the challenge of building it and the never-ending implementation details make it a long-term project.

When we first saw VIRK I in all its shining, Australian Blackwood glory, it lacked any end effector and [Ignacio] wasn’t sure of the best way to control it. Since then, [Ignacio] has experimented with Marlin and Wangsamas support for SCARA arms, and designed a gripper based around a hobby servo. It’s as beautiful to see this project moving forward as it is to see the arm moving ~~ping-pong~~ balls around, embedded below.

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Uncertain Future Of Orphaned Jibo Robots Presents Opportunities

March 8, 2019 by Roger Cheng 17 Comments

In our modern connected age, our devices have become far more powerful and useful when they could draw upon resources of a global data network. The downside of a cloud-connected device is the risk of being over-reliant on computers outside of our own control. The people who brought a Jibo into their home got a stark reminder of this fact when some (but not all) Jibo robots gave their owners a farewell message as their servers are shut down, leaving behind little more than a piece of desktop sculpture.

Jibo launched their Indiegogo crowdfunding campaign with the tagline “The World’s First Social Robot For The Home.” Full of promises of how Jibo will be an intelligent addition to a high tech household, it has always struggled to justify its price tag. It cost as much as a high end robot vacuum, but without the house cleaning utility. Many demonstrations of a Jibo’s capabilities centered around its voice control, which an Amazon Echo or Google Home could match at a fraction of the price.

By the end of 2018, all assets and intellectual property have been sold to SQN Venture Partners. They have said little about what they planned to do with their acquisition. Some Jibo owner still hold hope that there’s still a bright future ahead. Both on the official forums (for however long that will stay running) and on unofficial channels like Reddit. Other owners have given up and unplugged their participation in this social home robotics experiment.

If you see one of these orphans in your local thrift store for a few bucks, consider adopting it. You could join the group hoping for something interesting down the line, but you’re probably more interested in its hacking potential: there is a Nvidia Jetson inside good for running neural networks. Probably a Tegra K1 variant, because Jibo used the Jetson TK1 to develop the robot before launch. Jibo has always promised a developer SDK for the rest of us to extend Jibo’s capabilities, but it never really materialized. The inactive Github repo mainly consists of code talking to servers that are now offline, not much dealing directly with the hardware.

Jibo claimed thousands were sold and, if they start becoming widely available inexpensively, we look forward to a community working to give new purpose to these poor abandoned robots. If you know of anyone who has done a teardown to see exactly what’s inside, or if someone has examined upgrade files to create custom Jibo firmware, feel free to put a link in the comments and help keep these robots out of e-waste.

If you want to experiment with power efficient neural network accelerators but rather work with an officially supported development platform, we’ve looked at the Jetson TK1 successors TX1 and TX2. And more recently, Google has launched one of their own, as has our friends at Beaglebone.