Are Ball Shaped Wheels Practical?

back in 2016 goodyear published some information about their concept future tire design which is a ball apparently it would use magnetic levitation to attach it to the car although it's hard to say how well this would work and how well things like braking would work ball wheels would have several advantages such as allowing the car to move in any direction to make maneuverability easier and allowing the tyres to be reoriented to spread the wear evenly over the surface but how practical would it be to have wheels that are actually balls there are various ways to put ball wheels on a vehicle or robot the most practical is to use omni wheels to drive the ball like i did with my ball balancing robot and there are various other examples of this on youtube the omni wheels are a wheel with smaller wheels all around the outside so they can slide sideways you could of course just put omni wheels or mechanism wheels on the vehicle though and there are also many examples of this if things get sketchy when driving i think i'd rather have my car wheels properly attached to the car so i did some more research and found a video about a ball wheel concept from osaka university this research group has developed a ball wheel attached to an axle and also used it to drive treads to make an omni tank style robot the design looks like it's just two hemispheres which can both rotate freely and independently attached to an axle which will be driven by a motor so i put together my own version which is two 3d printed hemispheres on a 3d printed axle and it's just got a bolt going through the middle so that they rotate i'm going to put some marks on each side so we can see that they rotate independently so we can see that rotates in that orientation and the axle can drive it in the other orientation so that should make an omni wheel that should work pretty well but what happens if we try and drive in this orientation and rotate the wheel well it actually keeps driving surprisingly well as we get to a smaller and smaller circumference on the hemisphere until we get to the point where the axis is completely vertical and then of course the balls won't run at all now i do have a hole in each hemisphere on the end of the axis which is where my bolt head is but even if it were a complete sphere it still wouldn't run well with the axis in that orientation obviously it works well in the other orientation but this is a bit of a problem if we're going to make an omni wheel so let's check back on that video yep we've definitely got our hemispheres which rotate independently and they're fixed to the axle in the same way but what's that on the end of the axis yep it's a wheel so let's imagine i've got a wheel attached to each hemisphere and i've just put a bit of blue tape on now to show the orientation of the wheel so obviously that wheel is going to have to be oriented with the axle so that actually runs in the right direction because as those hemispheres rotate the wheel would get misoriented and then it wouldn't run in the right direction anymore so we have to basically make sure that the wheel is attached to the axle and the hemisphere rotates around it but before we look at that it's time for a quick ad from the video's sponsor which is pcbway pcby provide both pcb manufacture and pcb assembly under the same roof so you can get them to solder the components onto your pcb as well as make the board and they'll do surface mount and through-hole assembly pcbway have also launched new cnc services including online cnc machining sheet metal fabrication 3d printing and injection molding pcbway cnc machining services include a wide range of materials including aluminium stainless steel and various plastics if you don't see the material you like you can also choose from custom materials check out the pcb way website to browse through a variety of finishes and get a quote pcb way manufacture all sorts of boards including standard fiberglass pcbs but also aluminium pcbs flexible pcbs and rigid flex pcbs which are part rigid and part flexible prices start at five dollars for ten standard pcbs and thirty dollars for ten pcbs with assembly but new customers can get five dollars credit so you can get ten pcbs for free the first time you order find out more now at pcbway.com and i'll put that link in the description to this video so here's my new design i've got two hemispheres which are again attached to an axle and i've got that wheel which is attached to the axis they rotate on and those wheels are attached to the axle so they always stay oriented and run in that direction with the hemispheres rotating around them [Music] [Music] thanks to 3d fuel for the filament for this project and lots of other projects so check out my channel for more 3d printed projects and check out 3dfuel.com the key part of this is what i'm now calling the perpendicular axle which has that wheel on which is made of tpu and of course that will be oriented with the main axle so that wheel always drives in one direction my two hemispheres have bearings inserted in them a pair of bearings these aren't the most slimline bearings i could have bought but they were the cheapest which is why they're quite chunky and those just push fit into the back and front a bit like a skateboard wheel that of course slots over the perpendicular axle and there'll be a pair of these to make up the whole ball wheel and as you can see that leaves the little wheel oriented in the same orientation no matter what happens to the hemisphere i'm just using m8 studding as the main axle and i've done two pairs of hex nuts up against each other and that means they won't slip and i can use those as a keyway and those fit neatly into the perpendicular axle a pair of those perpendicular axles get screwed together and that means that shaft is nicely fixed provided the hex nuts don't come undone which i shouldn't because i did them up really tight that'll allow us to drive the axle in the future i used contact adhesive to glue the tpu treads into the two hemispheres i did allow screw holes but for now i'm going to rely on the glue and hopefully that should hold it but we can always come back and put a lot of screws in if they get detached in use and those hemispheres fit on either side of my perpendicular axle allowing the main axle to stay oriented with the little wheels two retainer clips hold the hemispheres on and this really could have been designed so that they clipped into a recess unfortunately i didn't design it like that and as well as printing two of them i've actually printed six as you'll see later in the video so for now they just clip on on the build lines and then unfortunately we have to glue them on with super glue this is one design change to actually have them removable since their ring that would be quite springy anyway if they clipped into a recess that would allow disassembly at a later date on top of that is another tpu piece which is attached to the hemispheres that of course rotate around those retainer clips and around the little wheel and these make up the contour of the ball with those raised treads so that we can transition smoothly to running on the little wheel rather than on the edge of the hemisphere there is one disadvantage which is that those are quite flexible so i might reprint them in something more rigid so they don't bind on that retainer but we'll see how it goes for now so let's see how well it runs i need to hold the axle perfectly parallel with the table most of the time it would run anyway apart from when we run on that little wheel of course there isn't much clearance around the other tpu piece where the wheel sticks out and if i don't hold the axle perfectly parallel then the tpu ring binds on the table so that's one disadvantage of this design i guess it's not much worse than anomaly wheel with lots of small wheels around the outside and the probability of actually driving on that little wheel is much less than with an omni wheel weather everywhere but that seems to run okay in all directions and you can see those hemispheres spinning right up to the point until i tip it onto the wheel and then the wheel runs and the hemisphere stops spinning but that seems to move pretty freely but what about if it was a robot or a vehicle with more than one and as i mentioned earlier in the video i've actually printed everything three times or six times depending on how you look at it and i've attached them to this frame with skate bearings so they rotate really freely on their axles so that seems to move incredibly freely i'm really happy with the way this has actually turned out obviously there's some lumps and bumps between the gaps between the two hemispheres and the gaps between the treads but it seems to run okay so let's try and force it to run on that wheel and see how it goes and that seems to run okay you can see the transition between the hemisphere and the little wheel on the end but overall that feels incredibly smooth it does feel like sometimes that tpu ring around the wheel is actually compressing and binding on that retaining clip so we probably need to print that in something more rigid but the probability of actually hitting it's pretty low when you drive with an omni robot so that's one improvement to make but overall it just seems to glide around and works really smoothly so i'm pretty happy with the results i'm pretty surprised has turned out so well and it just seems to glide really smoothly that i'm really happy with thanks to osaka university of course for the design concept i'm not sure if i want to drive a car with wheels like this but it's pretty good for an omni road but i really like the way it looks as well with those balls for wheels so next time i'm going to try and put motors on and try and drive it around and maybe turn it into a robot that can navigate and map its environment autonomously we'll see how that goes so don't forget to like the video if you liked it and subscribe for more on this project and lots of other projects i'm going to publish the cad for this as well if you want to have a go at building one or building something similar and most of the stuff i do is open source so if you'd like to support me through patreon or youtube channel membership those links are in the description to this video as well and patrons and youtube channel members can get access to all the videos up to a week early and sneak peace of pictures of what's coming up so you can be involved in all of that discussion all right that's all for now [Music] foreign you

Channel: James Bruton

Views: 467,337

Rating: 4.9504371 out of 5

Keywords: omni wheel, goodyear ball shaped tyre, making omni wheels, ball shaped wheel, 3d printing robot wheels, omni robot wheels, making your own omni wheels, omnidirectional wheels, innovative robot, futuristic robot locomotion, alternative wheel design, TPU robot wheels 3d printing, 3d printing tpu, how to make an omni vehicle

Id: rHDCIng0Wak

Length: 11min 20sec (680 seconds)

Published: Mon May 17 2021