Experiential Robotics Challenge

My entry to the Experiential Robotics Challenge at Printables.com. The design won the main prize.
The design adds swerve drive modules to the XRP robot platform.
You can find the model here: www.printables...
Like my design? Support by buying me a coffee: buymeacoffee.c...

[@aL3891_]

awesome design, would love to have seen it driving around though :)

[@wildwillyrobots]

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

[@Synthminator]

Very clever design, congrats!

[@mike_at]

great design 👍

[@mandrakejake]

Neat design. Kinda reminds me of a core xy, and a differential. I like it's simplicity

[@wildwillyrobots]

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

[@Gasykala]

Congrats!!! It looks great, really. I will try to print this coming week.

[@wildwillyrobots]

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.

[@Gasykala]

​​@@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. :)

[@wildwillyrobots]

I burned a lot of N20 too. For this robot kzbin.info/www/bejne/an-Zd5mfgbFnZ9k 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.

[@rklauco]

Nice work. Idea - make the mechanism in a way that rotating the motor to one side rotates the wheel and changing the motor direction actually spins it - by this you can achieve driving to any direction my single motor :)

[@BenjaminWard-ov8wh]

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). 😂

[@Roobotics]

I was trying to wrap my head around why you would want two different drive systems on a single bot, and what the kinematics would be to keep them synced, then realized I was overthinking it and you are just demoing both. If you want another possible option, instead of 4 motors, maybe you can add cutouts for a TPU belt option to sneak in there to grab a gear from each wheel. Then you could use it as a common pivot driver, and the other two could remain independent. You could probably think of it as kinematics with the training wheels on, but it also needs one less motor assembly to function, can still 360 spin and drive sideways, etc.

[@wildwillyrobots]

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.

[@AttilaAsztalos]

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.

[@Roobotics]

@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.

[@AttilaAsztalos]

@@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.

[@Roobotics]

@@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.

[@Pokornz]

I would love to hear the pros and cons of the coaxial and differential approach!

[@wildwillyrobots]

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.

[@charetjc]

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.

[@simontillson482]

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

[@milankarakas3005]

Where to find that two balls? And is that just ping-pong balls or something else?

[@wildwillyrobots]

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.

[@milankarakas3005]

@@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. :)

[@milankarakas3005]

@ Okay, I found the diameter of the ball - it is 25.4 mm. Sometimes it is difficult to measure and tell others. :(

[@kunalshah7539]

ohh i had a working version of this i never made a decent yt video of this tho 😢