Testing: Cycloidal vs Harmonic Drive 3D Printed Reducers

12 Apr 2021
160 960 Aufrufe

Over the last few weeks I've built two versions of Cycloidal Drive Reducers, and one Harmonic Drive / Strain Wave Reducer. This video is about testing both using an ODrive and an encoder on the motor so we can energise the motor coils correctly and apply motor holding power. I also want to make sure that the Cycloidal Reducer is tough so that is subject to some extra resilience testing. My Cycloidal Reducer will get developed further, probably removing the bearings, so we can use it in the next version of openDog.
You can support me on Patreon or buy my Merchandise:
Patreon: www.patreon.com/xrobots
Merchandise: teespring.com/stores/james-bruton
Affiliate links - I will get some money of you use them to sign up or buy something:
Matterhackers 3D printing supplies: www.matterhackers.com?aff=7500
Music for your DEhave videos: share.epidemicsound.com/xrobots
Other socials:
Instagram: instagram.com/xrobotsuk
Facebook: facebook.com/xrobotsuk/
Twitter: twitter.com/xrobotsuk
CAD and Code for my projects: github.com/XRobots
Huge thanks to my Patrons, without whom my standard of living would drastically decline. Like, inside out-Farm Foods bag decline. Plus a very special shoutout to Lulzbot, Inc who keep me in LulzBot 3D printers and support me via Patreon.
Below you can also find a lot of the typical tools, equipment and supplies used in my projects:
Filament from: www.3dfuel.com/
Lulzbot 3D Printers: bit.ly/2Sj6nil
Lincoln Electric Welder: bit.ly/2Rqhqos
CNC Router: bit.ly/2QdsNjt
Ryobi Tools: bit.ly/2RhArcD
Axminster Micro Lathe: bit.ly/2Sj6eeN
3D Printer Filament: bit.ly/2PdcdUu
Soldering Iron: bit.ly/2DrNWDR
Vectric CNC Software: bit.ly/2zxpZqv
Why not join my community, who are mostly made up of actual geniuses. There’s a Facebook group and everything: facebook.com/groups/287089964833488/
Former toy designer, current DEhave maker and general robotics, electrical and mechanical engineer, I’m a fan of doing it yourself and innovation by trial and error. My channel is where I share some of my useful and not-so-useful inventions, designs and maker advice. Iron Man is my go-to cosplay, and 3D printing can solve most issues - broken bolts, missing parts, world hunger, you name it.
XRobots is the community around my content where you can get in touch, share tips and advice, and more build FAQs, schematics and designs are also available.

  • Next week is a totally different robotics project - Patrons and DEhave Channel Members have it already!

    James BrutonJames BrutonVor Monat
    • James have you tried a planetary gearbox for arms yet? They would back drive fine, would be loud though with straight gears, if using helical gears maybe thrust could be an issue ?

      j5jdnj5jdnVor 19 Tage
    • @Max Civiletto I would agree; Using the formula; planetary gear ratio = 2x(1+(RP/RS)) if you used a planetary gear with radius RP = 4 x radius of the sun RS, you would get the x 10 that you are looking for. Note will be back drivable too.

      Caitlin MilneCaitlin MilneVor Monat
    • Does it involve prosthetics?

      boostinjdmboostinjdmVor Monat
    • Hey James, why wouldn’t you use a planetary gear box in this case.... just curious? Thx!

      Max CivilettoMax CivilettoVor Monat
    • Reduce the size of the drive itself, more dense packing. And it will move some weight.

      Max NMax NVor Monat
  • dehave.info/down/ZI5zXpGkb6OxuaQ/video Inversed timing belt transmission. Make this. Fully back-driveable

    Christopher NavoniChristopher NavoniVor 2 Stunden
  • Its a big safety issue to keep trying to stop the thing with your fingers/hand. Please don't.

    Alexis RiveraAlexis RiveraVor 5 Tage
  • Reminds me of one of the small Vietnam fishing boats when you were on the skateboard

    Randy HavardRandy HavardVor 6 Tage
  • Nice design and well put together video James. I'm glad you're going to try bushings - it was what I thought when you produced the first variant. Not that it would save on cost, but there are also needle roller bearings available (I am sure you are aware of these, of course) which could work in reducing weight and allow the cycloidal gear to have fewer and smaller holes cut into them as well as perhaps reducing the overall size of the entire gearbox. But then bushings would probably also be perfectly fine considering the RPM you are asking of them. Perhaps not quite as smooth but much easier to work with. If you dont have a lathe or access to one and need some made up, let me know and I'd be happy to make them for you.

    M KaseM KaseVor 7 Tage
  • awsome Men!! greating from Ensenada Mexico.

    juan carlos narvaezjuan carlos narvaezVor 11 Tage
  • I understood about 2 words in 3. Are English translations available ?

    Martin MoyesMartin MoyesVor 12 Tage
  • Don't cut your fingers off mate

    dielaughing73dielaughing73Vor 12 Tage
  • What's the power consumption of those motors? Could you have it pull along a trailer with a power source?

    CreeperOnYourHouseCreeperOnYourHouseVor 14 Tage
  • What about this dehave.info/down/d4N9i9Sxrne2x3Y/video

    vbart1776vbart1776Vor 17 Tage
  • 3:17 dude, you are not using your head in this video, I respect that you want to present this to the camera and us. But please find a better way. I'll bet since you can't stop it with your hand that if your fingers managed to get pinched in close to the motor it'd do awful things. Even robots like Spot have warnings that their backdrivable motors might pinch your fingers off if you get careless. backdrivable does not mean they are still compliantly stoppable when you put a torque motor on the other end.

    RooboticsRooboticsVor 18 Tage
  • How come it is better to have backdrive vs not having backdrive. I always thought u didn't want backdrive

    Kaulin HallKaulin HallVor 19 Tage
  • What if you combined this gearbox with a 1:1 or 2:1 belt drive to get a bit of extra spring, and the additional durability from the belts?

    Wolven EdgeWolven EdgeVor 20 Tage
  • My anxiety when you try to stall the motors 📈📈📈📈📈

    Antonio AguilarAntonio AguilarVor 21 Tag
  • I am glad I'm not the only one with the wobbly wheel problem. I bought some wheels that were not seated properly when they were manufactured and i experienced the wobly with 4 wheels. LOL Thanks for sharing!

    Bent SprocketBent SprocketVor 21 Tag
  • dehave.info/down/lJyBddaSoYfWyqA/video how about something like this?

    szaszafajaszaszafajaVor 26 Tage
  • I allways wonder how many job offers he gets or would get

    Crack-Up BoomCrack-Up BoomVor 27 Tage
  • Why do you think it is important that the legs need to be springy and the dog bounces? I would think that the smoother the operation the better.

    Roy OettingRoy OettingVor 27 Tage
  • This seriously makes me think about putting some cycloidal gears into practice. Very inspiring.

    EnnarEnnarVor 27 Tage
  • That's getting strong, you should scale up a bit and make a steampunk horse and ride into town on it!

    jsnthurst1jsnthurst1Vor 28 Tage
  • @James Bruton ....build a BB-8...infused with a raspberry pi 4b...plus an alexa...that responds to you(the owner)...

    Martin NdiranguMartin NdiranguVor 28 Tage
  • Imagine one day all of the DEhave engineers come together....not for money...but to get the human race to a better place in the Cosmos...we would overcome anything in onur path...including the impossible...nice project James Burton...All love support from Africa...🔥🔥🔥🌊💯

    Martin NdiranguMartin NdiranguVor 28 Tage
  • Great Video as usual, can you make a comparison between the cycloidal and the Compound Planetary Gearbox? Skyentific addressed the Compound Planetry Gearbox in this video dehave.info/down/ZJl3kKeaqYaOzoI/video&ab_channel=Skyentific

    Mohamed elsheraiyMohamed elsheraiyVor 29 Tage
  • James - if you want to cheat slightly on the Cycloidal profile, Camnetix Gear-Trans software has a Cycloidal option. The software itself is fairly expensive - but there's a fully functional trial. I've found the results are very good.

    Simon RaffertySimon RaffertyVor 29 Tage
  • 4:16 in the last video a grey mass + a black mass was 12kg now its 16kg :D

    HisfantorHisfantorVor 29 Tage
  • Hi James great projects could you do pi pico and would the pi pico work instead of an arduino with window wiper motor pwm and motor driver ?

    James HarrisJames HarrisVor Monat
  • I feel as though you could make a planetary gear set much lighter weight as it wouldn't require upwards of 40 bearings and 16 steel shafts!

    SaberShipSaberShipVor Monat
  • You should send the designs to rctestflight and tell him to try those on his solar automated rc car. He can post update videos to test resiliency. The car has a waypoint path that runs and stops when out of charge the. Startups up again doing a figure eight. He runs that nonstop for months. Chews through his pla cycloidal drives. But he is not using the bearings you are.

    egondroegondroVor Monat
  • dehave.info/down/mHx5XpXFf43bnYo/video

    WoodWorks500WoodWorks500Vor Monat
  • Reduce the reduction to half, thus dubble the speed, perhaps add one set of legs?

    A_SA_SVor Monat
    • @James Bruton but if you add one set of legs, then you can take more load and take damages.

      A_SA_SVor Monat
    • My existing openDog V2 is already 5:1 reduction, but I need more torque, which is why I developed this

      James BrutonJames BrutonVor Monat
  • Heii James - Thank you very much for this really nice videos!! What do you think is the achievable with your drive? Looking for a drive for mounting a telescope a bit more compact✌🏻

    L SL SVor Monat
  • This implementation of harmonic drive is so bad doesn't that it doesn't really deserve the name.

    asdfasdfVor Monat
  • James, maybe you know this already but onshape has an Cycloidal gear generator, this makes experimenting with ratio's a lot easier Search for: onshape Cycloidal gear generator

    Martijn ElsermanMartijn ElsermanVor Monat
  • what is the overall BOM cost on opendog v2? I would like to make it

    ThatBulgarianThatBulgarianVor Monat
  • "We can upgrade to petg ,3D printed nylon or laser cut..... something"

    I don'tI don'tVor Monat
  • So you've made a Wankel engine looking thing (13B?)

    PotatoPotatoVor Monat
  • Anxiety peaked as I expected him to scissor his fingers during torque testing

    mozkito lifemozkito lifeVor Monat
  • Wow.

    Kester GascoyneKester GascoyneVor Monat
  • STOP with the moving your hand between the downward moment and table goodness man if your going to do in with you hand regardless of us in the comment atleast test from the opposite side with down ward pressure ... it would even fix the issue with the table but seriously you have kids watching

  • hum ??? 45 degrees???? was that not 90 ? XD

    Vincent AulenVincent AulenVor Monat
  • Make Wheatley!!??? Plz :(

    Malachi CarrilloMalachi CarrilloVor Monat
  • 10:43 "lazy cunt"

    Servail CatseyeServail CatseyeVor Monat
  • has a new sport been invented? pole boarding anyone?

    HdresdendocHdresdendocVor Monat
  • I can see someone making an anime about the power stick skating that involves fighting with them as well.

    WistrelChiantiWistrelChiantiVor Monat
  • Hey James, take a look at the skyentific channel where he makes a lighter, still backdrivable, low backlash, durable and completely 3d-printed (no bearings) robot actuator pancake gearbox, probably worth a look!

    Raphaël CasimirRaphaël CasimirVor Monat
  • That is a lot of bearing. Seems expensive to build.

    Johg RangerJohg RangerVor Monat
  • And here I was, waiting for sheared fingers...

    countZ74countZ74Vor Monat
  • For a second I thought the thumbnail was about comparing funky new-generation pokemon that I hadn't heard about yet

    JamesJamesVor Monat
  • I would consider using UHMW instead of nylon for the bushings, if you can get it at a good cost. It is the typical bushing material used in power tools and is far cheaper than Delrin.

    KnightsWithoutATableKnightsWithoutATableVor Monat
  • ah yes the skateboard outboard motor longevity test, a tried and true classic

    daktahdaktahVor Monat
  • at 3:20 and here, we see the invention of the scissors, a stationary blade and a moving blade, doesnt matter that they arent sharp i love your videos, but i think losing your fingers might slow you down, you dont want that.

    Rob KRob KVor Monat
  • Have you measured for backlash yet on your drive? Curious to know what it is. Great job btw!

    BillBillVor Monat
  • Cyclo are not usually back drivable? i know i cant on my factor built one anyways. Mybe its just the way it was built.

    joe hackenburgjoe hackenburgVor Monat
  • You are great!

    inoidinoidVor Monat
  • I've been working on some cycloidal gear drives as well! Your video definitely gave me some insight for durability & lash back. Happy building!

    FlynntasticFlynntasticVor Monat
  • It seems like belts are just great, and your only issue is getting 10:1 without a huge diameter. Have you investigated more novel designs that are essentially belt drives?

    John DługoszJohn DługoszVor Monat
  • James: tries to stop the second drive Drive: am I a joke to you *moves table instead*

    Sir Lord of DerpSir Lord of DerpVor Monat
  • Hey James, might it be a good idea to integrate a temperature sensor in those drives to monitor the internal temperature? Then you can prevent it from overheating and melting the PLA.

    misterthekaithemanmisterthekaithemanVor Monat
  • I think the downfall of the harmonic drive was simply due to the flexible material of the core deforming at the tooth level to allow the gears to slip. Commercial versions use clever metal rings that flex at the ring level but are almost completely inflexible at the tooth level.

    Lucien86Lucien86Vor Monat
  • Where did you get the wheel? Good video!

    qorjeqorjeVor Monat
  • 8:08 can someone make a thug life meme out of this?

    David SchweighoferDavid SchweighoferVor Monat
  • Your skateboard is technically illegal. Motor driven, no pedals. May I suggest taping a set of pedals to each "experiment" so it matches UK law. Me bitter over the stupid law not being consistent? No... never. /s

    TechyBenTechyBenVor Monat
  • Love the durability testing😂 really taking the prototype for a spin

    Tomás Navedo BarriosTomás Navedo BarriosVor Monat
  • Hey James, I mean you chop off your fingers if you want but I'd have a hard time still calling you an engineer. Your actions seem scary to me. Be safe.

    Basil DaoustBasil DaoustVor Monat
  • You've decided to negate your durability test, and do the exact thing you didn't want to do, which is print out 12 of them before you know what effect the wear will have. You said it yourself 10:12 The BEARINGS are why it may have suffered no wear.

    odinataodinataVor Monat
  • Awesome, I got to try building this for my snowboard.

    Scifi WorkshopScifi WorkshopVor Monat
  • 5:25 "So we now need to do some comparisons with an actual dog leg" I'm calling the SPCA

    gracefoolgracefoolVor Monat
  • I love this, gives me ideas to modify my wheelchair to make my own power drive. Just wish I had a 3D printer and/or someone to help me

    Dr RenardDr RenardVor Monat
  • Very nice work! Don't you think that going to bushings instead of bearings will increase friction, resulting in less output torque? It would be interesting to see you do a side by side of the two. I suspect the bushing drive will have about 50-70% of the output torque of the bearing version.

    Raymond GageRaymond GageVor Monat
  • Have anything against a good old planetary gear set?

    SaberShipSaberShipVor Monat
  • That looks like it would be great as the internals of an one-wheel type skateboard.

    EuanEuanVor Monat
  • I think that its really cool of you to post all of your cad files online for free

    Trade of all JacksTrade of all JacksVor Monat
  • You could 3d print bearings and still have the weight and cost reductions with still pretty good bearing performance but it does still add a point of failure.

    Oliver DowningOliver DowningVor Monat
  • Is that the skateboard equivalent of a long tail boat?

    ElliotElliotVor Monat
  • I'm afraid to ask how much the cost of bearings are for one drive. Particularly the thin-section large ID ones.

    peepzorzpeepzorzVor Monat
  • so replacing the bearings with large bolts reduces the weight? LOL

    davidvdbergendavidvdbergenVor Monat
  • I love your projects - big inspiration.

    Onofe EromoseleOnofe EromoseleVor Monat
  • #LandKayak James invents new sport

    Brandon YoungBrandon YoungVor Monat
  • Why are you debating between a terrible design and an even worst one?

    Chuck DaltonChuck DaltonVor Monat
  • This really has me hopeful for my dream project. The hope is to make a "mech" that "eats" recyclables and churns out stuff made from the plastic or metal picked up. Mostly focusing on the out product being parts for our "guerilla solarpunk" art projects. So like ride this thing around, feed it litter/stuff from bins, it pops out parts for like a plastic bench with artwork embedded in the design so you could use a paper/pencil to it.

    Wes LambWes LambVor Monat
  • igus bushings ?

    zeuss194zeuss194Vor Monat
  • What about using two stage cycloidal reducer to reduce the number of bearings?

    Тимофей ДовгальТимофей ДовгальVor Monat
  • in order to reduce weight and cost you need to test designs without bearing. Have you thought about 3dprinted discs with a brass bush insert???

    Out of the BOTSOut of the BOTSVor Monat
  • Priceless James! I've just started looking at drive types as I decide the style of robotic arm to print. I'd ideally like to get maximum leverage and torque of course. Even more so as I'm wanting to design interchangeable tool heads for the arm to use it to drill, mill, cut, etc... I'd like to make it strong enough to work with wood, metal, plastic. The cycloidal drive looks at first glance to be more than capable of handling that! You're the bomb Bruton, THE BOMB!

    Jack WilliamsJack WilliamsVor Monat
  • I've got big respect of what you are doing there! And I was wondering what the Cycloidal drive would cost to build right now. Do you know that? I recently could have used a high tourge increase the for a College project but was too lazy to make some 3d printed gears worke for me with such a high reduction. If this Cycloidal drive is cheap (conserning everything needed) I might really get one myself. And also my biggest respect for that robot. I guess as an Mechatronich student that will be my goal within the future to build such amazing thingies😀

    Brombeer KralleBrombeer KralleVor Monat
  • Just want to say: Thank you for sharing all your work. I would like to build the dog, I need a 3D-printer first :)

    Catalin AlbCatalin AlbVor Monat
  • Someone knows some forums for 3d printing?

  • I really appreciate the amount of r&d he puts into all of his robots

    mastercat2012mastercat2012Vor Monat
  • Hybrid single stage planetary gearset and belt drive - this is the way.

    HzMeisterHzMeisterVor Monat
  • The harmonic drive stalls out earlier because the strain wave gear can't mesh with the other gear under load. Oiling the strain gear should improve that. TPU is just too sticky.

    Dirk HerrendoerferDirk HerrendoerferVor Monat
  • You said you tried to lift 16 kg of kettle bells, but I think it was really 12 kg.

    Liam BohlLiam BohlVor Monat
  • Congratulations, this seems like a breakthrough. Bushings save weight and costs. Perhaps you could consider the filament from "igus" specially developed for slide bearings? The rotors completely could be made from "igus"-filament with integrated bushings. dehave.info/down/fqR8XrXNeoyyrJw/video

    Falk GerbigFalk GerbigVor Monat
  • one thing i never understood about Boston dynamics Spot, and open dog, is why not use wheels on the tip of the legs instead of it just acting as a leg? would this not drastically increase its speed as well as its ability to maneuver? sure it might not always walk like a dog, but it would have the ability to. best of both worlds if you ask me. though i do not know about how this would affect the legs weight. might be the reason why not but if it somehow works, i would love to see the result.

    Nao KimajiNao KimajiVor Monat
  • You know that that you have the same way of speaking as Murray Walker (of Formula One fame), who emphasises odd syllables in the middle of sentences. It was wearing to listen in him, and so it is with you. Do you converse with other people using this odd cadence? Perhaps you could become easier to listen to, by imagining that you're speaking to a person next to you, rather than trying to address ten thousand from a stage.

    Nicole KNicole KVor Monat
  • There was a youtube video of something called an abacus drive. Maybe that's different?

    orazorazVor Monat
  • Hi James just be careful you don't get caught riding your illegal electric skateboard! (stupid British law says electric skateboards are not allowed)

    JakeJakeVor Monat
  • This is exciting, well done James :)

    Tilen ModerTilen ModerVor Monat
  • un exoesqueleto con estos motores, tal vez ?

    honay nonayhonay nonayVor Monat
  • So trying to stop the lever with your hand between the table ffs, you're going to crush it!

    spiltmilkmaniacspiltmilkmaniacVor Monat
  • Why not using nylon bearings?

    David Torres OcañaDavid Torres OcañaVor Monat