A Mechanical Edge-Avoiding Robot

December 27, 2020 by Danie Conradie 19 Comments

In the age of cheap sensors and microcontrollers, it’s easy to forget that there might be very simple mechanical solutions to a problem. [gzumwalt]’s 3D printed mechanical edge avoiding robot is a beautifully elegant example of this.

The only electric components on this robot is a small geared DC motor and a LiPo battery. The motor drives a shaft fixed to a wheel on one side, while the opposite wheel is free-spinning. A third wheel is mounted perpendicular to the other two in the center of the robot, and is driven from the shaft by a bevel gear. The third wheel is lifted off the surface by a pair of conical wheels on a pivoting axle. When one of these conical wheels go over the edge of whatever surface it’s driving on, it lowers front and brings the third wheel into contact with the surface, spinning the robot around until both front wheels are back on the surface.

Mechanical alternatives for electronic systems are easily overlooked, but are often more reliable and rugged in hostile environments. NASA is looking at sending a rover to Venus, but with surface temperatures in excess of 450 °C and atmospheric pressure 92 times that of Earth, conventional electronics won’t survive. Earlier in the year NASA ran a design competition for a completely mechanical obstacle detection system for use on Venus.

[gzumwalt] is a very prolific designer on ingenious 3D printed mechanical devices. This mechanism could also be integrated in his walking fridge rover to explore the front of your fridge without falling off. Continue reading “A Mechanical Edge-Avoiding Robot” →

Legged Robots Put On Wheels And Skate Away

December 26, 2020 by Roger Cheng 6 Comments

We don’t know how much time passed between the invention of the wheel and someone putting wheels on their feet, but we expect that was a great moment of discovery: combining the ability to roll off at speed and our leg’s ability to quickly adapt to changing terrain. Now that we have a wide assortment of recreational wheeled footwear, what’s next? How about teaching robots to skate, too? An IEEE Spectrum interview with [Marko Bjelonic] of ETH Zürich describes progress by one of many research teams working on the problem.

For many of us, the first robot we saw rolling on powered wheels at the end of actively articulated legs was when footage of the Boston Dynamics ‘Handle’ project surfaced a few years ago. Rolling up and down a wide variety of terrain and performing an occasional jump, its athleticism caused quite a stir in robotics circles. But when Handle was introduced as a commercial product, its job was… stacking boxes in a warehouse? That was disappointing. Warehouse floors are quite flat, leaving Handle’s agility under-utilized.

Boston Dynamic has typically been pretty tight-lipped on details of their robotics development, so we may never know the full story behind Handle. But what they have definitely accomplished is getting a lot more people thinking about the control problems involved. Even for humans, we face a nontrivial learning curve paved with bruised and occasionally broken body parts, and that’s even before we start applying power to the wheels. So there are plenty of problems to solve, generating a steady stream of research papers describing how robots might master this mode of locomotion.

Adding to the excitement is the fact this is becoming an area where reality is catching up to fiction, as wheeled-legged robots have been imagined in forms like Tachikoma of Ghost in the Shell. While those fictional robots have inspired projects ranging from LEGO creations to 28-servo beasts, their wheel and leg motions have not been autonomously coordinated as they are in this generation of research robots.

As control algorithms mature in robot research labs around the world, we’re confident we’ll see wheeled-legged robots finding applications in other fields. This concept is far too cool to be left stacking boxes in a warehouse.

Continue reading “Legged Robots Put On Wheels And Skate Away” →

Ten Robot Mechanisms For Your Design Toolbox

December 25, 2020 by Danie Conradie 10 Comments

The convergence of mechanics and electronics in robotics brings with it a lot of challenges. Thanks to 3D printing and low cost components, it’s possible to quickly and easily experiment with a variety of robotics mechanism for various use cases. [Paul Gould] has been doing exactly this, and is giving us a taste of ten designs he will be open sourcing in the near future. Video after the break.

Three of the designs are capstan mechanisms, with different motors and layouts, tested for [Paul]’s latest quadruped robot. Capstan mechanisms are a few centuries old, and were originally used on sailing ships to give the required mechanical advantage to tension large sails and hoist cargo.

Two of the mechanisms employ GUS Simpson Drives, which use a combination of belts and a rolling joint. These were inspired by the LIMS2-AMBIDEX developed at the University of Korea. The ever-popular cycloidal gearbox also makes and appearance in the form of a high torque dual disk linked, two stage, NEMA17 driven gearbox.

[Paul] also built a room sized skycam-like claw robot for his daughter, suspended by four ball chain strings reeled in by four brushless motors with ESP32 powered motor controllers. We are looking forward to having a close look at these designs when [Paul] releases them, and to see how his quadruped robot will turn out.

[Thanks TTN for the tip!]

Hyundai Mini 45 EV Is A Small Car With Grand Ambitions

December 23, 2020 by Roger Cheng 20 Comments

One of Hyundai’s recent concept cars was an electric vehicle named “45” in honor of its inspiration, another concept car from 45 years ago. When footage of a child-sized “Mini 45” surfaced, it was easy to conclude the car was a motorized toy for children. But Jalopnik got more information from Hyundai about this project, where we learned that was not nearly the whole picture.

The video (embedded below) explained this little vehicle is a concept car in its own right, and most of the video is a scripted performance illustrating their concept: using technology to help calm young patients in a hospital, reducing their anxiety as they faced treatment procedures. Mini 45 packs a lot more equipment than the toy cars available at our local store. The little driver’s heartbeat and breathing rate are monitored, and a camera analyzes facial expressions to gauge emotional stress. The onboard computer has an animated avatar who will try to connect with the patient, armed with tools like colorful animations, happy music, candy scent dispenser, and a bubble-blowing machine.

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These Micro Mice Have Macro Control

December 6, 2020 by Kerry Scharfglass 7 Comments

Few things fascinate a simple Hackaday writer as much as a tiny robot. We’ve been watching [Keri]’s utterly beguiling micromouse builds for a while now, but the fifth version of the KERISE series (machine translation) of ‘bots takes the design to new heights.

A family of mice v1 (largest) to v5 (smallest)

For context, micromouse is a competition where robots complete to solve mazes of varying pattern but standardized size by driving through them with no guidance or compute offboard of the robot itself. Historically the mazes were 3 meter squares composed of a 16 x 16 grid of cells, each 180mm on a side and 50mm tall, which puts bounds on the size of the robots involved.

What are the hallmarks of a [Keri] micromouse design? Well this is micromouse, so everything is pretty small. But [Keri]’s attention to detail in forming miniaturized mechanisms and 3D structures out of PCBs really stands out. They’ve been building micromouse robots since 2016, testing new design features with each iteration. Versions three and four had a wild suction fan to improve traction for faster maneuvering, but the KERISE v5 removes this to emphasize light weight and small size. The resulting vehicle is a shocking 30mm x 32mm! We’re following along through a translation to English, but we gather that [Keri] feels that there is still plenty of space on the main PCBA now that the fan is gone.

The processor is a now familiar ESP32-PICO-D4, though the wireless radios are unused so far. As far as environmental sensing is concerned the v5 has an impressive compliment given its micro size. For position sensing there are custom magnetic encoders and a 3 DOF IMU. And for sensing the maze there are four side-looking IR emitter/receiver pairs and one forward-looking VL6180X laser rangefinder for measurements out to 100 or 150mm. Most of these sensors are mounted on little PCB ‘blades’ which are double sided (check out how the PCB shields the IR emitter from it’s receiver!) and soldered into slots perpendicular to the PCBA that makes up the main chassis. It goes without saying that the rest of the frame is built up of custom 3D printed parts and gearboxes.

If you’d like to build a KERISE yourself, [Keri] has what looks to be complete mechanical, electrical, and firmware sources for v1, v2, and v3 on their Github. To see the KERISE v5 dance on a spinning sheet of paper, check out the video after the break. You don’t want to miss it!

Continue reading “These Micro Mice Have Macro Control” →

Parkinson’s Spoon Uses Control Theory For Good

December 6, 2020 by Al Williams 18 Comments

When we first saw [Barqunics’] design for a self-stabilizing spoon for people suffering from Parkinson’s disease, we wondered how well something like that could work. But take a look at the video below and you’ll see this does a fine job of responding to the user’s hand movements and keeping the spoon perfectly level through a wide range of motion.

There’s at least one commercial product that attempts to stabilize a spoon in the same way so that people suffering from that affliction can retain a measure of independence. This shows that you don’t need injection molding and factory made boards to prove the concept. An MPU6050 provides sensor information and two servo motors control the spoon using PID control.

PID — short for proportional, integral, derivative — is a way to adjust something to a desired point. For example, consider trying to heat a cup of water to 95 °C. If you simply turn the heater on full blast until you get to 95 °C, the water will actually get hotter because you’ll overshoot. Using PID, the amount of heating provided will depend on how far off you are now (proportional), how far off you’ve been over the long term (integral), and how much change you’ve effected recently (derivative). The same algorithm works for spoon-balancing and many other types of controls.

This isn’t the first bootstrapped assistive spoon project we’ve seen. We even looked at the commercial version, awhile back.

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Incredible Discrete MOSFET Rover Has Maximum Blink

December 4, 2020 by Maya Posch 12 Comments

What do you get when you stick 1738 MOSFETs together? If your answer was a ‘4-bit CPU’, you would be totally correct. Available as a product over at Marutsu as the ‘CPU1738’, it seems to target beginners to computer theory, with build instructions that explain how the CPU is built up from individual MOSFETs that are combined into logic gates.

While decidedly more compact in its SMD format than it would have been with pure through-hole parts, the use of countless small PCBs on top of the larger PCBs make for a pretty hefty package. Board after board build up the CPU, and the assembly continues with the addition of sensors, motors, and wheels. In the end, a robot emerges, albeit a somewhat wobbly-looking one.

Check out the video linked after the break, though before starting one up, note the 50,000 Yen (approximately $500) price tag for the CPU block alone. On the other hand, in addition to the 1738 MOSFETs, there are also 1070 LEDs, so you get what you pay for in blinkies.

Continue reading “Incredible Discrete MOSFET Rover Has Maximum Blink” →