We end up covering a lot of space topics here on Hackaday, not because we’re huge space nerds — spoiler alert: we are — but because when you’ve got an effectively unlimited budget and a remit to make something that cannot fail, awe-inspiring engineering is often the result. The mirror actuators on the James Webb Space Telescope are a perfect example of this extreme engineering, and to understand how they work a little better, [Zachary Tong] built a working model of these amazing machines.
The main mirror of the JWST is made of 18 separate hexagonal sections, the position of each which must be finely tuned to make a perfect reflector. Each mirror has seven actuators that move it through seven degrees of freedom — the usual six that a Stewart platform mechanism provides, plus the ability to deform the mirror’s curvature slightly. [Zach]’s model actuator is reverse-engineered from public information (PDF) made available by the mirror contractor, Ball Aerospace. While the OEM part is made from the usual space-rated alloys and materials, the model is 3D printed and powered by a cheap stepper motor.
That simplicity belies the ingenious mechanism revealed by the model. The actuators allow for both coarse and fine adjustments over a wide range of travel. A clever tumbler mechanism means that only one motor is needed for both fine and coarse adjustments, and a flexure mechanism is used to make the fine adjustments even finer — a step size of only 8 nanometers!
Hats off to [Zach] for digging into this for us, and for making all his files available in case you want to print your own. You may not be building a space observatory anytime soon, but there’s plenty about these mechanisms that can inform your designs.
Continue reading “Working Model Reveals Amazing Engineering Of Webb’s Mirror Actuators”
Thanks to 3D printing and cheap hobby servos, building you’re own small walking robot is not particularly difficult, but getting them to walk smoothly can be an entirely different story. Knowing this from experience, [Max.K] tackled the software side first by creating a virtual simulation of his ZeroBug hexapod, before building it.
Learning from his previous experience building a quadruped, ZeroBug started life in Processing as a simple stick figure, which gradually increased in complexity as [Max.K] figured out how to make it walk properly. He first developed the required movement sequence for the tip of each leg, and then added joints and calculated the actuator movements using reverse kinematics. Using the results of the simulations, he designed the mechanics and pulled it back into the simulation for final validation.
Each leg uses three micro servos which are controlled by an STM32F103 on a custom PCB, which handles all the motion calculations. It receives commands over UART from a python script running on a Raspberry Pi Zero. This allows for user control over a web interface using WiFi, or from a gamepad using a Bluetooth connection. [Max.K] also added a pincer to the front to allow it to interact with its environment. Video after the break.
The final product moves a lot smoother than most other servo-driven hexapods we’ve seen, and the entire project is well documented. The electronics and software are available on GitHub and the mechanics on Thingiverse.
Continue reading “ZeroBug: From Simulation To Smooth Walking”
For some, the idea of several hours of painting and designing intricate models with minute details and features sounds like a delightful afternoon spent. Some of us would much rather just have it come already painted with motors so that it can move. [Cory Collins] sought to combine these two hobbies by building a highly detailed motorized tank dubbed Tankbot 2.3. (Video, embedded below.)
It’s based on a simple hexapod kit ordered online that includes a built-in Arduino compatible board (it’s based on the Arduino 2560 Mega). The legs were redesigned to match the aesthetic that [Cory] was going for. The redesign allows for an extra pivot in the leg mechanism. The turret section was designed and built on top of the base with support for a servo to turn it (though the firmware isn’t quite there yet). After all the parts were 3d printed, the laborious process of painting began. With some delicate airbrushing and some quick stencils cut for the decals, it was complete.
We are amazed by the types of kits and parts that you can find online and the fact that they’re usually inexpensive to boot. We’ve come a long way since 2013 when we covered a much simpler Arduino based tank.
Continue reading “Building A Half Toy Half Model Tank Robot”
In the time since the Hackaday Prize was first run it has nurtured an astonishing array of projects from around the world, and brought to the fore some truly exceptional winners that have demonstrated world-changing possibilities. This year it has been extended to a new frontier with the launch of the Hackaday Prize China (Chinese language, here’s a Google Translate link), allowing engineers, makers, and inventors from that country to join the fun. We’re pleased to announce the finalists, from which a winner will be announced in Shenzhen, China on November 23rd. If you’re in Shenzen area, you’re invited to attend the award ceremony!
All six of these final project entries have been translated into English to help share information about projects across the language barrier. On the left sidebar of each project page you can find a link back to the original Chinese language project entry. Each presents a fascinating look into what people in our global community can produce when they live at the source of the component supply chain. Among them are a healthy cross-section of projects which we’ll visit in no particular order. Let’s dig in and see what these are all about!
Continue reading “Hackaday Prize China Finalists Announced”
What’s more awesome than a normal hexapod robot? What about a MEGA hexapod?
Max the Megapod, a six-legged 3D-printed walking robot, is an open source, Arduino-based, Bluetooth controlled, Scratch programmable creation made possible by [Steven Pendergrast]. The design for Max was based on a previous hexapod project, Vorpal the Hexapod, which has since been built at hundreds of schools worldwide.
Max clocks in at two feet in diameter, expanding to three when sprawled out on the ground. In addition, the hexapod is able to dance, walk, and run as fast as the smaller version, covering ground at twice the speed due to its size.
The scaling for the project – about 200% from the original hexapod – required some creativity, as the goal was for the components to be printed on a modest-sized printer with an 8 inch cube bed. In addition, since Max weighs 9 pounds on average, real bearings (608 Skate bearings) needed to be used for the servo mounts.
The electrical system had to be changed to account for the larger currents drawn by the larger servos (MG958s). and the power distribution harness needed to be redesigned. The current harness take about two hours to build for the larger hexapod, compared to 15 minutes for the original design.
The results are both hilarious and adorable, especially given the endless modifications made to give Max a unique flair. Perhaps a GIGApod could be coming up next?
Continue reading “What Better Than A Hexapod?”
Take a dozen or so fish hooks, progressively embed them in plastic with a 3D printer and attach them to the feet of your hexapod and you’ve got a giant cockroach!
A team of researchers at Carnagie Mellon University came up with this ingenious hack which can easily be copied by anybody with a hexpod and a 3D printer. Here you can see the hooks embedded into the ends of a leg. This ‘Microspine technology’ enables their T-RHex robot to climb up walls at a slightly under-whelming 55 degrees, but also grants the ability to cling on severe overhangs.
Our interpretation of these results is that the robot needs to release and place each foot in a much more controlled manner to stop it from falling backwards. But researchers do have plans to help improve on that behavior in the near future.
Sensing and Closed Loop Control: As of now, T-RHex moves with an entirely open-loop, scripted gait. We believe that performance can be improved by adding torque sensing to the leg and tail actuators, which would allow the robot to adapt to large-scale surface irregularities in the wall, detect leg slip before catastrophic detachment,and automatically use the tail to balance during wall climbs.This design path would require a platform overhaul, but offers a promising controls-based solution to the shortcomings of our gait design.
No doubt we will all now want to build cockroaches that will out perform the T-RHex. Embedding fish hooks into plastic is done one at a time. During fabrication, the printer is stopped and a hook is carefully laid down by human hand. The printer is turned on once again and another layer of plastic laid down to fully encapsulate the hook. Repeat again and again!
Your robot would need the aforementioned sensing and closed loop control and also the ‘normal’ array of sensors and cameras to enable autonomy with the ability to assess the terrain ahead. Good luck, and don’t forget to post about your projects (check out Hackaday.io if you need somewhere to do this) and tip us off about it! We’ve seen plenty of, sometimes terrifying, hexapod projects, but watch out that the project budget does not get totally out of control (more to be said about this in the future).
Continue reading “Fish Hooks Embedded In Robot Toes Make Them Climb Like Cockroaches”
Walking robots come in many forms, and each presents their own unique challenges. Bipedal style locomotion is considered particularly difficult to do well, however designs with more legs offer certain advantages. Hexapods offer the possibility of keeping several legs on the ground while others move, providing a useful degree of stability. [How To Mechatronics] developed this ant robot, which is an excellent example of the form.
The hexapod has as the name suggests, six legs, each of which consist of 3 joints. This necessitates 3 servos per leg, for 18 servos total just for locomotion. Further servos are then used to control the abdomen, head, and mandibles. This gives the robot strong ant credentials, above and beyond being simply a 3D printed lookalike.
Brains come courtesy of an Arduino Mega, chosen for its ability to control a large number of servos. A custom PCB is printed as a shield to ease the connection of all the necessary hardware. An HC-05 Bluetooth module is used for communication with an Android app, which controls the ant. The piece de resistance is the ultrasonic sensors in the head, which allow the ant to automatically defend itself against predators that get too close.
It’s an involved build, requiring plenty of 3D printing and over 200 fasteners. Fundamentally though, it’s a fully working and tested hexapod build with full plans available for download, ready to toil in your underground sugar caves.
If your hexapod tastes skew more anime than insectoid, check out this Ghost in the Shell build. Video after the break.
[Thanks to Baldpower for the tip!]
Continue reading “Welcome Our New Insect Overlords With Arduino-Powered Ant Bot”