Landbeest, A Single Servo Walking Robot

Walking robots have a rich history both on and off the storied pages of Hackaday, but if you will pardon the expression, theirs is not a field that’s standing still. It’s always pleasing to see new approaches to old problems, and the Landbeest built by [Dejan Ristic] is a great example.

It’s a four-legged walker with a gait dictated by a cam-and-follower mechanism that allows it to perform the full range of leg movement with only one motor. Each cam can control more than one leg in synchronisation, and in his most recent prototype, there are two such mechanisms that work on opposite corners of a four-legged machine. The legs are arranged in such a way that the two corner-to-corner pairs pivot at their centres in a similar manner to a pair of scissors; allowing a servo to steer the robot as it walks.

The result certainly isn’t as graceful as [Theo Janssen]’s Strandbeest, from which it evidently takes inspiration for its name, but it’s no less capable for it. After the break you can see a video he’s posted which clearly illustrates its operation and demonstrates its ability to traverse obstacles.

The only thing that’s missing are the files and software should you wish to create your own. He’s unapologetic about this, pointing out that he’d prefer to wait until he is satisfied with it before letting it go. Since he’s put a lot of work in so far and shows no sign of stopping, we’re sure he’ll reach that point soon enough.

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Little Flash Charges In 40 Seconds Thanks To Super Capacitors

We’ve all committed the sin of making a little arduino robot and running it off AA batteries. Little Flash is better than that and runs off three 350 F capacitors.

In fact, that’s the entire mission of the robot. [Mike Rigsby] wants people to know there’s a better way. What’s really cool is that 10 A for 40 seconds lets the robot run for over 25 minutes!

The robot itself is really simple. The case is 3D printed with an eye towards simplicity. The brains are an Arduino nano and the primary input is a bump sensor. The robot runs around randomly, but avoids getting stuck with the classic reverse-and-turn on collision.

It’s cool to see how far these capacitors have come. We remember people wondering about these high priced specialty parts when they first dropped on the hobby scene, but they’re becoming more and more prevalent compared to other solutions such as coin-cells and solder tab lithium batteries for PCB power solutions.

Sensing, Connected, Utility Transport Taxi For Level Environments

If that sounds like a mouthful, just call it SCUTTLE – the open-source mobile robot designed at Texas A&M University. SCUTTLE is a low cost (under $350) robot designed for teaching Aggies at the Multidisciplinary Engineering Technology (MXET) program, where it is used for in-lab lessons and semester projects for the MXET 300 – Mobile Robotics undergraduate course. Since it is designed for academic purposes, the robot is very well documented, making it easy to replicate when you follow the instructions. In fact, the team is looking for others to build SCUTTLE’s and give them feedback in order to improve its design.

Available on the SCUTTLE website are a large collection of videos to walk you through fabrication, electronics setup, robot assembly, programming, and robot operation. They are designed to help students build and operate the mobile robot within one semester. Most of the mechanical and electronics parts needed for the robot are off-the-shelf and easy to procure and the rest of the custom parts can be easily 3D printed. Its modular design allows you the freedom to try different options, features and upgrades. SCUTTLE is powerful enough to carry a payload up to 9 kg (20 pounds) allowing additional hardware to be added. To keep cost low and construction easy, the robot uses a simple, two wheel drive system, using a pair of geared motors. This forces the robot to literally scuttle in a “non-holonomic” fashion to move from origin to destination in a sequence of left / right turns and forward moves, so motion planning is interestingly tricky.

The SCUTTLE robot is programmed using Python3 running under Linux and has been tested working on either a BeagleBone Blue or a Raspberry Pi. The SCUTTLE software guide is a good place to get acquainted with the system architecture.

The standard configuration uses ultrasonic sensors for collision avoidance, a standard USB camera for vision, and encoders coupled to the wheel drive pulleys for determining position with respect to the starting origin. An optional USB LiDAR can be added for area mapping. The additional payload capability allows adding on extra sensors, actuators or battery packs.

To complement information on the website, additional resources are posted on GitHub, GrabCAD and YouTube. Building a SCUTTLE robot ought to be a great group project at maker spaces wanting to get hackers started with Robotics. We have covered many Educational Robot projects in the past, but the SCUTTLE really shines with its ability to carry a pretty decent payload at a low cost.

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Bobble-Bot Teaches Modern Real-Time Robot Control

Bobble-Bot uses the standard inverted pendulum problem to teach modern robotic control using a Raspberry Pi, RT-Linux, and ROS.

We’re really impressed by the polish and design effort put into this project, and it’s no surprise that it’s a finalist in the 2019 Hackaday Prize. Bobble-Bot is a top heavy bot sitting on two BLDC motors. The brains of the operation is a Raspberry Pi running real-time Linux and ROS. This allows the robot to respond in a predictable manner to its inputs, and also allows for more control over thread priority than a regular kernel. In the past we’ve seen these inverted pendulum bots mostly being run on micro-controllers for just this reason, so it’s cool to see it make the jump to Linux.

Mechanically the bot can be printed on any consumer grade printer and assembled. We really appreciate the small details like making sure one screw size could be used to assemble the entire bot, eliminating the need for multiple tools.

They also have a simulator, and the bot’s software was built inside of that. It was a big moment when the real-world behavior finally matched the simulated performance. In fact, if you’re interested in the Bobble-Bot, you can try it out in simulation before committing to building the whole thing.

This project seems like a fun build for any hacker. We would have loved to have a project as polished and up-to-date as this one when we were learning controls in university. Video introducing it after the break.


SmallKat: An Adorable And Dynamic Robot

SmallKat is a cute little robot with a lot of capability designed around teaching and experimenting with dynamic robot control. It’s a shame we haven’t covered SmallKat yet, as it’s both a finalist in the 2019 Hackaday Prize and was one of the Bootstrap Winners this year.

Many hobby robots move by repeating a pre-programmed sequence of movements. Most hexapods for example follow this line of thought. However, robots like Spot and the MiniCheetah show a different world where robots determine the locations of their limbs by their current state, the measured state of their environment, and some imagined future. These robots are capable of so much more than their predecessors.

However, even a cost-effective version of these robots climb into the tens of thousands of dollars at a steep curve. SmallKat will help there: based around hobby servos and an ESP32 the hardware stays affordable. Data can be streamed to a much larger computer for experimentation which saves on some of the weight that supporting a larger device like a Pi would add.

This device will let students experiment with all kinds of dynamic models and even machine learning-based movements without breaking the bank. There’s even a nice software studio for experimentation to aid in the learning process.  Video of it shuffling around after the break.

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These Maple Pod Inspired Drones Silently Carry Payloads

Researchers from the Singapore University of Technology and Design (SUTD) recently released a video showing their nature-inspired drone that is capable of breaking out into five separate smaller drones. The drones each have auto-rotating wings that slow their rate of descent, similar to seed pods from a maple tree. Due to their design, the drones are only made to be used for a one-way trip, with the five components each carrying a separate payload. The drones are designed to detach within a specified distance from their destination, allow the collective body to safely spiral downwards towards land.

In their paper published on the same subject, the researchers discuss how they optimized the balsa wood wings with servos, a LiPo battery, and a receiver attached to a 3D-printed body. Four are equipped with just these components, while the fifth also holds a 3-axis magnetometer, a Teensy 3.5 board, a GPS module, and a Pixracer controller.

They experimented with several motion capture setups and free-flight drop tests to verify their simulations on the models for the drones. Apart from simply detaching, they are also designed to cater to different mission profiles based on the environment they are dropped in.

We’ll admit that the implementation and design of the drones does seem fairly dystopian, especially when you wonder what could possibly be the payloads these drones are designed to carry. But in terms of nature-inspired robotics, the maple seed pod idea is pretty interesting.

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BEAM Dragonfly Causes A Flap

Normal people throw away stuff when it breaks. But not people like us. Or, apparently, [NanoRobotGeek]. A cheap robotic dragonfly died, and he cannibalized it for robot parts. But he kept the gearbox hoping to build a new dragonfly and, using some brass rod, he did just that.

The dragonfly’s circuitry uses a solar panel for power and a couple of flashing LEDs. This is a BEAM robot, so not a microcontroller in sight. You can see a brief video of how the dragonfly moves.

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