Are these Walking Wheels Practical?

i recently experimented with various alternative types of wheels and tracks both on the directional ball shaped wheels rotoped tracks and various balancing robots including one that balances on one wheel i've been looking for a solution for climbing stairs though and i previously built a robot which has legs and wheels to help lift itself over objects i recently came across a concept called a ped rail wheel this has what looks like a lot of feet all around its circumference which follow a guide in the center the guide seems to have some spring suspension in it and it can rotate which helps point all of the feet up slopes or steps as the wheel rotates i can't find any video or examples of this in use at all though so i thought i'd have a go at building one to see how well it could work [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 printing projects and check out 3dfuel.com each of the feet on my ped rail wheel slide in and out in a channel that's printed into the base and then i've got these little yellow caps that screw on all the way around to stop them falling out the insides of the little legs have to run on the guide so i've got a skate bearing with an eight millimeter internal diameter fitted to each one and these also provide some mass so they flop in and out really well this seems to run pretty well and you can see there's multiple feet touching the ground on the bottom at a time and all of those comply with the ground and they run on the flat piece of the guide at the bottom the guide needs to move around though so i've made a special base with two pegs that are going to constrain it and that's screwed into the middle of the wheel the guide itself has two slots which will allow it to move but not swivel all the way around so it can comply with any slopes so that fits in the middle and it only moves in each direction about 20 degrees as i mentioned it's flat at the bottom and that means all of the legs at the bottom will align with it and they'll align with the ground so that they can get traction in one straight line it can also tilt so that it can drive up hills and drive all those feet in a straight line up hills or steps in either direction however there's one major oversight with the design which is as the wheel rotates round and round the guide rotates round and round as well and we can't keep the flat piece at the bottom and that's because we've got one main hub with that base with the two pegs attached so we need a different design that allows that guide to stay stationary in the middle and allows all of the little feet to move around it that means the flat will always stay at the bottom and allow the feet to align with the ground or the guide to move slightly left and right to go up and down hills here's my version 2 wheel and you'll notice it's very similar apart from having a huge hole in the middle and that's where i can put the hub which will stay stationary in order to do that we've got this backing which is basically a cup with a bearing in each side and also an extension on which will allow a belt drive that screws onto the back of the wheel and allows the whole assembly to run on those two bearings an axle fits in the middle which has the hub on where we're going to install the guide we'll need to mount the axle onto a chassis so i've built this part which fixes onto that axle and it's got just the right spacing to keep the bearing nice and tight on the back there's a cap which screws onto the axle and onto the mount so now the whole thing can run on that and you'll have noticed i left some screw holes in there to attach to 2020 extrusion that will come onto shortly the guide base with the pegs and the guide now mount onto the central hub and that of course stays stationary while all of the little feet and everything else rotate around it that seems to run pretty well and you should be able to see the little guide in the middle rotating so that the little feet can comply with whatever object it drives over i've made actual feet which have little ankles which rotate and attach to each of the little legs that i've installed so far in the main wheel the ankle joints are pretty loose and that means the feet just fall down with gravity and that means the flat of the foot is always facing the ground or whichever object it tries to climb over and that seems to work pretty reliably and yes i've been making two of them so we can put them on a test vehicle but before we see how well that works it's time for a quick act from the video sponsor which is free trade free trade is a commission free investing app you pay no commissions when buying stocks or exchange traded funds some other brokers charge up to 12 pounds for every trade but free trade doesn't charge any commission fees so you can keep or reinvest more of your profits the free trade app has a really simple design which makes it easy to use for any 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well it really works each of my ped rail wheel assemblies is attached to a piece of 2020 extrusion and there's some plastic parts in the middle that hold the lock together and give me a platform to attach electronics i've made a caster wheel out of an inline skate wheel and that always drags i'm using two 24 volt worm gear driven gearboxes and motors each one has a belt drive onto each of the wheels i'm using two bts 7960 motor drivers to drive those with a 24 volt lipo strapped to the bottom the main electronics is an arduino uno with an nrf24l01 chip for the radio and as usual i'm using my opendog 2 remote that i use for most robots now it does go pretty slow but then it's supposed to be something for climbing over stairs and things like that so it's not a racing car but it's pretty maneuverable and those legs have traction even though the feet are just smooth on the bottom and i haven't bothered putting any rubber shoes or anything like that on them so i'm pretty happy with the way it runs it seems to reliably put the flats of its feet on the ground and it seems to comply with the ground at least on a flat surface which seems like it's working pretty well so far but of course we need to test a variety of objects to see how practical it is actually climbing over things so i'm using some discarded 3d prints from various projects and it looks like it actually works pretty well obviously there are a few issues with the flat feet slipping sometimes but it's a pretty good test to see if the mechanism works i put a stripe of blue tape on the bottom of the guide so you should be to see that leaning backwards and forwards and complying with the object as it runs up and down steps so it looks like it works here but let's try some steeper steps so here we can see that stripe goes all the way up and all the way down on the other side again so that seems to be working pretty well let's have a look at that again in slow motion [Applause] [Applause] as i mentioned i haven't put rubber feet on this and i didn't think that would be a fair test because pretty much any spoke shape like that with rubber grippy feet would probably climb over any object and i really wanted to see if the concept of the ped rail having feet that change length and comply with the objects and actually step up on the objects would actually work however it does still drive okay on a smooth surface there's a little bit of slip but it seems to work on the hole okay so far the environment's been pretty controlled so let's try some crazy objects like a hose pipe and some pieces of wood and of course it becomes apparent fairly quickly why we don't have practical vehicles with ped rail wheels on now this is on a slope so the camera is straight but the ground slopes down at the left and that seems to cause a real issue for the ped rail here at least for objects that are loose but yes once again it's got all caught up in the hose pipe and there's absolutely no way to get it out i think maybe rubber grips on the feet might be helpful but it really struggles going uphill with loose objects let's try that the other way and that's much less of a problem the caster wheel is not very helpful ideally i could have done with four wheel drive but i think you get the idea i thought i should try those tests again on level grounds and that seems a little bit better let's just go back the other way and drive over again still struggling there with the loose wood and of course the caster gets caught so it'd be much better with four wheels so it seems to work okay if it can get a foot flat directly on top of the object but if it's not perfectly on there then it just slips and pushes everything out of the way so pretty much completely impractical i think it probably would climb up steps okay as long as the steps perfectly aligned with the flats of the feet as they came round and it wasn't half on a step because then it would slip off and the next one would slip off and it would never climb up so i think the test i did at the start with the 3d prints stacked up perfectly to match the feet work really well but basically everything else is a complete nightmare also a massive catching safety hazard for people's arms and legs and cables and hoses and anything else which is probably why we don't find tractors with these on and i can't find any footage of a practical vehicle that's got wheels like this so i am going to publish all the canon code as usual that you can find on github and the links in the description to this video so if you'd like to support me through patreon or youtube channel membership those links are in the description below as well and youtube channel members and patrons can get access to all the videos up to a week early and also access to sneak peeks and pictures of what's coming up to be part of all that discussion all right that's all for now [Music] [Applause] [Music] you

Channel: James Bruton

Views: 234,154

Keywords: predrail wheel, weird wheels, ball shaped wheels, rotaped tracks, walking wheel, building a walking wheel, building a pedrail wheel, 3d printed mechanism, innovative wheel design, how to make a 3D printed robot, robot that can climb steps, stair climbing robot concept, innovative robot concept, how to build a robot

Id: Ei68T6tE8SM

Length: 13min 21sec (801 seconds)

Published: Tue Sep 14 2021