Most of the legged robots we see here are of the hexapod variety, and with good reason. Hexapods are very stable and can easily move even if one or more of the legs has been disabled. [Radomir] has taken this a step farther and has become somewhat of an expert on the more technically difficult quadruped robot, building smaller and smaller ones each time. He has been hard at work on his latest four-legged creation called the Pico-Kubik, and this one will fit in the palm of your hand.
The Pico-Kubik runs Micropython on a VoCore board, which allows for it to have a small software footprint to complement its small hardware footprint. It accomplishes the latter primarily through the use of HK-282A Ultra-Micro Servos, an Arduino Pro Mini, and a tiny lithium ion battery. It’s still a work in progress, but the robot can already crawl across the tabletop.
This isn’t [Radomir]’s first time at the tiny quadruped rodeo, either. He has already built the Nano-Kubik and the µKubik, all of which followed the first (aptly-named) Kubik quadruped. Based on the use of SI prefixes, we can only assume the next one will be the hella-Kubik!
We’ve all seen videos of those crazy Boston Dynamics running quadruped robots that can reach up to 28 mph. Those things are amazing and it’s almost impossible to imagine how to even start building one. [Max] loves his robots and wanted to build a quadruped but, being a robot hobbyist, didn’t have the serious cash needed to make an extravagant robot like those of Boston Dynamics. Instead he started bridging the gap by designing a quadruped robot that is a little bit slower and tons cheaper.
[Max] designed all of the mechanical parts himself. After weighing the advantages and disadvantages of different materials, he decided that the frame would be made from 5mm acrylic sheet. The main body of the robot has acrylic ribs that are spaced apart by threaded rods. Twelve RC servos make up all of the joints, 3 in each leg. Notice in this photo how there is one servo that immediately rotates another servo. To support the other side of the rotating servo, [Max] epoxied on a T-nut, stuck in a short length of threaded rod which is then supported in the frame by a ball bearing. Simple and effective! The upper portions of the legs are also made from acrylic sheet and the lower legs are from a cheap camera tripod. Rubber feet ensure a slip resistant stance.
All of the servos are controlled by an Arduino Mega. [Max] is currently writing a sketch that will perform the complex math and determine coordinated servo motions for movements us humans take for granted, like ‘walk forward’. As you can see in the videos, [Max’s] robot won’t be catching the Boston Dynamics’ Cheetah any time soon but he is off to a great start.
Future plans for this project include bluetooth control and integrating the ultrasonic sensor proactively installed in the ‘head’ of the robot. Check out the videos after the break. [Max] is looking for some feedback on his project. We here at HaD think this needs a great name. Let’s hear some suggestions in the comments…
Continue reading “Baby Quadruped Robot, Learning To Walk”
Back at New York MakerFaire 2012, we noticed an amazing little steampunk quadruped robot walking around in the crowd outdoors. The robot was amazingly well executed, and had a unique ability to draw children over with it’s puppy like animations. It turns out this is [Drew’s] Little Walking Robot (AKA Puppy Bot).
Puppy Bot has actually been around for quite a while. He was born from the spare parts [Drew] had left over after competing in Robot Wars and Battlebots. The robots in these competitions were often controlled by Radio Control plane or car transmitters. Most of these systems are sold as packs for an RC car or plane. In addition to the transmitter and receiver, the pack usually included a battery and 3 or 4 servos. Standard RC servos were much too weak for use in battle robots, so they remained in his parts box.
On what [Drew] calls a slow weekend, he started putting the servos together, and ended up with a basic robot that could crawl around the room. After that the robot took on a life of its own. [Drew] improved the battery system, and added a microcontroller to automate the various gaits and animations. He brought the robot along with him to one of his battlebot competitions, and it took home the “Coolest Robot” award – even though it wasn’t actually competing!
Continue reading “Quadruped Robot Thinks it’s a Puppy”
This robot doesn’t know if it’s a walker or a tank. It’s the brain-child of [Marc Hamende] who works as a mechanical engineer by day and mad roboticist at night. The best place to find full details is by digging into the long thread he’s been posting to for about six weeks. It will give you a pretty good snapshot of his approach, starting with SolidWorks renderings of the project, and adding in assembled components as he brings the project together.
The mechanism for each foot is fascinating. He milled the white pieces which stack together to encapsulate the motor that runs the treads. These assemblies pivot to bring the metal rod serving as a walking foot in contact with the ground. But they also make it possible to adjust the treads to deal with rough terrain. A Propeller chip drives the device, with an Xbee module to communicate with the controller.
Don’t miss the video after the break. You’ll hear some skidding as it makes turns, but [Marc] plans to add code to adjust motor speed in order to compensate for the inside/outside differential issues. He’s also posted an image album over at Flickr.
Continue reading “Quadruped walks of four legs, rolls on four treads”
Sure, we see hexapods all the time at [HAD], but moving around with four legs can be more tricky kinematics-wise. This Instructable shows you how to make one out of balsa wood.
Although one might not think of balsa to make their robot out of [vexedpheonix] explains that this was chosen because it’s extremely light and easy to work with. Since he was trying to keep costs down, the cheapest servos available were used. These weren’t all that powerful, so the lighter the body the better! According to the included bill of materials, he was able to keep the entire robot build under $100.
According to the article, the hardest part was making four copies of the same leg. We might suggest using a CNC router, but building one would obviously add a huge layer of complication to the project!
Thanks for the tip on this one [SteveT]! Be sure to check out the video of this little robot waving one of it’s legs or trying to walk after the break! Continue reading “An Arduino Based Quadruped Robot”
A lot of 3D printing and a many servo motors went into this snake-like robot, and it’s only about half of what [Toby Baumgartner] plans to accomplish. In this orientation the snake is rolled into a circle, and apparently some special movements in the segments allow it to roll around like this. He compares it to a tank tread without the tank attached to it. Notice that each link is rounded on the outside. When the snake opens itself up, the toothed inside of the links contacts the ground for added traction.
It looks like eventually the larger link at the bottom will be about three times as wide. This will make room for him to mount a second ring of links. The idea is that the larger link will act as the body and this can unfold itself into a quaruped. Motors that allow the segments to pivot side to side would make it something like a four-legged spider bot.
Those following the evolution of quadrupedal assist robots will recognize the specimen seen above as a relative of BigDog. This is AlphaDog, one of the latest prototypes in Boston Dynamics’ Legged Squadron Support Systems program. It’s designed to carry 400 pounds of payload, which explains the disc weights seen on either side of the torso. Like its diminutive sibling, LittleDog, it’s able to take on all kinds of terrain. Here it’s being tested with boxes full of rocks.
The robot is capable of picking itself up and getting under way again without intervention. The first video after the break shows test footage where the robot starts nearly upside-down and has no trouble righting itself again. When we looked in on a biped version back in 2009 we also linked to the BigDog prototype which showed developers trying to tip it over mid stride. This version has the same balance resiliency.
Also embedded after the break is a video showing the evolution of the design over about seven years of development.
Continue reading “New BigDog video doesn’t fail to impress”