วีดีโอ

You can buy them for the XRP robot at Sparkfun www.sparkfun.com/caster-2-pack.html The ones in the video are 3d printed and for that reason not perfectly round.

@@wildwillyrobots Thanks. I am printing right now main body (one with just two motors, without gears). Once printed, I can then measure hole and print small plastic balls. So far, made RC trike... which can be also used for making robot. Just need to figure out what task it should to do. For now, it is just a toy for my cats to play. :)

Yes, a combination of the output from the 2 stationary motors makes the wheel rotate and spin. Look at this video, where you can see how the gears operate: th-cam.com/video/TP8wQRZUuk4/w-d-xo.html

And by placing a set of cogs in between the two planatery wheel housing you could power both wheels whilst keeping them in alignment. One motor many directions (haha all in one direction at a time though). 😂

Yes, two stationary motors working together to make two independent movements are like core xy.

The design was for the Printables contest, so I just thought it was a neat design feature, that you could change the mode of operation just by replacing one gear. But obviously you will never use both methods on the same robot.

No need for a belt - just move the driving cogs from the edges to the center, so each of them engages one ring on both wheels. Only two motors needed. Assuming you never want to control the two wheels separately, of course.

@AttilaAsztalos that's a good point, but wouldn't you actually want to drop a gear between them so they turn the same direction? Also yes, I very much meant 3 motors specifically so you can 360 in place if needed. With only 2 motors in that config, I think you can't turn, and are stuck 'straffing' in directions.

@@Roobotics I meant dropping the gear on the axis of the motor between them, not the two large ones directly contacting each other. Also, even with just two motors and both wheels doing the same thing the robot would still move like a car, with those other two roller balls as its "back wheels". No, it would no longer do 360s - but if you want two independent wheels, the design in the video is what you want.

@@AttilaAsztalos I think you are partially right, so long as the rollerballs impart enough friction it can likely pivot around on them, but if they are too frictionless it might try to skate sideways as a result. Probably some mixture of the two in application.

I don't have much experience with the coaxial. But one thing you can do with it, that you can't with the differential, is to have different motors for the rotation and spin. I.e. a slower but stronger motor for the rotation and a faster motor for the spin. I plan to make videos of the software to control both of them, but it will take some time.

one benefit I hear about for differential swerve is pushing power. If you're not steering, then you can have two motors driving the robot forward. I think the con for differential is the complexity added to the controls to coordinate the driving speed of swerve modules since steering reduces the max speed of a given module.

Fascinating design, subscribed. Can’t wait to see it with the motors and control software working…

I didn't buy the motors yet, as the contest was only about the design. But next step is to bring it alive.

As shown in the video, I didn't have the motors, when I did the design. Maybe a little adjustment to the bracket is required, to make it fit the actual motor. If you print it, and it doesn't fit, then leave a comment on the Printables model. Then I will change the bracket as required.

​​@@wildwillyrobotsI have old left over N20 motors but I burned a good number of them so I thought of ordering a slightly larger one (24.8x 47.4 mm without the shaft). Any suggestions for motor? I do not expect the motor to fit in the case you made but I will check all dimensions on the files on printables and will try to design something. I look forward to it. Obviously, i appreciate your help. Thank you. :)

I burned a lot of N20 too. For this robot th-cam.com/video/4N6FfiLL41w/w-d-xo.html I used CHP-20GP-180 motors. I had no problems with those, but they are obviously much bigger. I will most likely try to mount them on this model to make a video about how to control the swerves.

Both motors have encoders, and from them you can calculate changes in both the vertical and horizontal angle. In addition a magnet triggers the hall sensor mounted at th-cam.com/video/cgbXGslB3Ac/w-d-xo.html This is used for getting the initial angle of the wheel, as this can change when the robot is not powered. If you look at the wheels here th-cam.com/video/3W0p16vsgqA/w-d-xo.html, you can see that the wheels rotate to find the zero-position for the angle.

Yes probably, but they are quite expensive, and also I'm not sure how well they work for transferring encoder signals from the motors without adding noise to the signals.

It can climb obstacles of up to 100-150mm depending on how god grip the wheels have with the surface. It was made for a robot competition, where the steps are 120mm th-cam.com/video/9Od0E53R8PE/w-d-xo.html

If you look at the description at the model page at Printables, it will tell you which parts also needs to be printed mirrored.

@@wildwillyrobots ok very thanks

It's depending on what you want to learn. I don't have any formal education in 3d design. I just started watching some videos on the topic, and then decided to do a larger project (the rover) to learn how to use the design software. For electronics and software I have a masters degree, but again you can learn a lot from watching TH-cam tutorials.

Good question. If you look at 11:05 you will see 2 small gears fixed to the arms, and one larger gear being installed between the two smaller ones. When all wheels are touching the surface, the arms will not move, so the two small gears does not move. That in turn means that the larger gear cannot move. The larger gear is fixed to the frame of the body, and therefore the body cannot rotate around the main axle of the two arms. The purpose of this "differential" gear is to make sure all wheels are touching the surface. It can be seen at 11:28, that if the arm on one side goes up, the arm on the other side will go down. This makes the force on the wheels the same on both sides when driving in rough terrain.

@@wildwillyrobots Nice. So when a wheel goes up the body tilts and goes up half the distance ? Very clever stabilisation

@@yannmassard3970 Yes, the body will tilt with half the angle. Nasa uses the design on their Mars robots, but implemented slightly differently. If you look at this picture en.wikipedia.org/wiki/Rocker-bogie#/media/File:Mars_Science_Laboratory_wheels.jpg you can see a black bar on the top of the rover. It is connected to the main arms, and serves the same purpose as the internal gear in my design.

I assume you are talking about the part at 6:40? It is included with the servos, but I have cut the ends of it slightly to make it fit in the gear.

Typically the wire and connectors are included with the motor, like in this listing: www.aliexpress.com/i/32932735768.html I soldered longer wires to the end to extend them to be long enough to run through the arms.

@@wildwillyrobots Hello, are these motors able to be purchased on another platform such as Amazon? Or are these exact ones only available on Aliexpress? Thank you!

​@@wildwillyrobots i and my team loved this project and is planning to build this.. but i am finding some difficulties.. is the .stl of the part used inside the "gear_servo.stl" available? i didnt find it.. also i am finding it hard to get the alternative of tyres as its not available here. Is there any .stl of the tires available..i am planning to print it using TPU

@@thebeanieboochannel6483 It is a 25mm gear DC motor. I think it is commonly called JGA25-370 or 25GA370. The one I used is 6V 130RPM. I use one with encoder, because my primary use is autonomous driving, where I need to know the position of the motor precisely. If you just want to remote control it, you probably don't need the encoder version.

@@bhagya.s1584 Are you talking about the white servo horn? I don't have a drawing of this. It is just what was included with the servos. If you look at www.printables.com/model/194299-stair-climbing-rover/remixes someone created a TPU tire. I'm havent tried this myself.

Actually not that many. Started by designing one wheel assembly, and build on top of that. Some parts took a few tries to get the tolerances correct.

@@wildwillyrobots Those look like pretty high-torque final drive gear motors - are they 6V or 12V? Also, luv the steering setup.

@@PeterOhlmus I think I used 6V in the video. They are cheap 25 mm gear motors. Torque is not super important, as it almost always have 6 wheels touching the ground, so the motors share the load.

​@@wildwillyrobots Just checked out the links - cool! So, are you running multiple Arduinos to handle steering and RC inputs?

@@PeterOhlmus The 6+6 motors are controlled by a custom made driver board based on a Raspberry Pico. I have mainly used it for autonomous driving, i.e. not remote controlled. For that use I have used a Raspberry Pi with a camera. I know a few others have used Arduino's and separate drivers for the motors for remote control.

Look at the comments at Printables:. www.printables.com/model/194299-stair-climbing-rover/comments There are mentions of different ones, that should fit, but no one has confirmed that they work, so I didn't add them to the parts list.

I don't remember exactly. But most of the design has features that are 2-3mm thick, meaning that most of it will consist of walls and little infill. So, you don't need high volume infill.

Yes, the wires are soldered to the three pins of the sensor (A3144). The connector is a 3 pin dupont style, because I use 2.54mm headers on my driver board. Be aware that the polarity of the magnet matters. Before glueing it in, you should check that it activates the sensor. If not, it should be turned 180 deg.

@@wildwillyrobots Thank you much for clueing me in on both. Soon I will have to figure out how to make the driver board and then the programming for the rasp and pico.

When you finish the mechanical build, I would love to see images at www.printables.com/model/599137-swerve-drive-robot/comments

Corbyn Kites - Staycation th-cam.com/video/mJy2lq7fBzQ/w-d-xo.html

I updated the link to one with same tire but a different looking hub. The size is 75x28 mm.

@@wildwillyrobots YOU ARE AWESOME. Thank you so much. I have everything printed so now when tires get here I can start putting together and then work on software. Thanks again.

Be aware that the N20 motors easily heat up and stop working. I would suggest, that you modify the covers that fixes the motors, and add holes in them, so that the motors are not fully enclosed and can get rid of some of the heat. I the v2 of this robot, I used different motors, because I burned a lot of the N20's

It is the Raspberry Pi High Quality Camera

I design in Onshape. It has a FeatureScript, that does the design for you. You just put in the number of teeth for both gears, and it will generate a gear set automatically. It is called "Bevel Gear Pair" and is here cad.onshape.com/documents/83c8fc667f6bea1744752759/w/d4dd842d4f160c0640d45404/e/cae5f7edb8683ff8f41c5bf3

I design in Onshape. It has a FeatureScript, that does the design for you. You just put in the number of teeth for both gears, and it will generate a gear set automatically. It is called "Bevel Gear Pair" and is here cad.onshape.com/documents/83c8fc667f6bea1744752759/w/d4dd842d4f160c0640d45404/e/cae5f7edb8683ff8f41c5bf3

@@wildwillyrobots thank you for the quick reply:). Yeah, i found it before and already started to make a swerve drive.. If you got any tips i would be very gratefull to hear them. Thx again!

@@danmax3418 I would recommend a closed design, so you don't get dirt in the gears. Maybe this design I did, can be used as inspiration: www.printables.com/model/951372-omnidirectional-xrp-robot

I'm not sure. The N20 motors I used in this demo is not strong enough for heavier load. In this three wheeled design th-cam.com/video/4N6FfiLL41w/w-d-xo.html I used stronger motors. I think it can handle several kgs before the load on the plastic parts is too much.

They are U624ZZ. You can find a part list here www.printables.com/model/300105-differential-swerve-drive

The encoders of the motors are used to calculate the angle of the drive wheel and the direction of the module. Because the direction of the module is random, when I power up the robot, I turn the direction until the hall sensor is trigged by the magnet. So the hall sensor is only used for zeroing the direction. After this only the encoders of the motors are used. Maybe I should create a video explaining this in detail.

If you look very closely at the wheel when I start the robot in this video, th-cam.com/video/3W0p16vsgqA/w-d-xo.html , you can see all the wheels changing direction, when they search for the zero position.

It is the Wowstick 1F

End of video should link to demonstrations. If not, then here are a video driving autonomously th-cam.com/video/9Od0E53R8PE/w-d-xo.html, and another driving remote controlled th-cam.com/video/90HxqwZaWRA/w-d-xo.html

It didn't go exactly as planned in the competition, because I made a stupid mistake in the programming. But I did get to use the arm of the robot for solving obstacle with the qr code boxes. It can see it in action here: th-cam.com/video/Al4ebXraGM8/w-d-xo.html

Yes, all the plastic parts are 3d-printet. There is a link to the design files in the description.

Thank you. I'm quite happy of the design myself, and the newest iteration with bigger motors works great.

Nice to meet you there. I hope we will see more teams from Odense next year.

My electronics setup is a bit complicated, because I use it for autonomous driving. If you just want to remote control it, it can be done much simpler, but I don't have much experience with that. I would suggest, that you try to contact others, that have built it. Look at the comments section at Printables here: www.printables.com/model/194299-stair-climbing-rover/comments There is also a link to my custom PCB for the electronics, but again, that is most likely overkill for remote control.

I forgot to mention that I also love your implementation of the magnets for the covers. You rock!

Yeah, the magnets are quite nice. I will share the complete design at some point, but I need to clean it up a bit first.

I'm not fully satisfied with the colors, but had a bunch of the green filament, so ended up using that😀. Still a lot of work to make it actually run.

Have you tried ros2 on your robots?

No, it is just running my own software. I have looked at bit at ros, but it takes some time to understand how it works, and I'm not sure I have the time to invest in that.

Don't get your hopes too high. Currently I'm struggling just getting the cameras to work reliably.

I hope you will get it sorted out! On your old robot the camera seemed to work as intended, but maybe it only had the rgb camera?

Problem was a bad connection in the cable on the RGB camera. I fixed it by soldering the usb cable directly to the camera board. I had the TOF sensor on the blue robot, but never used it because of a driver issue. The sensor was quite new at that time. This year I got the sensor working on a Pi4, but in the end decided to use Pi5 on the robot. And then I had the same problem with missing driver support for Pi5. Arducam released support for Pi5 a few days go, but I didn't have the time to implement it.

Great news! Did you manage to get a run in too? I only do dumb industrial robots which just performs the same actions over and over. At some point I would like to add some kind of vision to them too, but so far I haven't found anything (at a not too crazy price) which can handle what I need.

Yeah, I did run today in the competition, but the result was not great. I made stupid mistake of merging to programs for different parts of the track into one, but never actually tested that it was working. But I did solve the qr code box challenge, so the gripper in the video worked decently. I work with industrial robots and vision in my day time job, so I know that part very well😀

Thank you. It is mostly an evolution of the hardware, but so far it has not run that much, so I'm not sure it is better.

Yeah, it has been a long time since we have seen anyone do a Crazy Ivan

@@wildwillyrobots Maybe next year!

We definitely need someone who can write decent software in the competition😀