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Low Cost Robot Arm
- jerzmacow 3y agoWow, I was building a Thor 3D printed arm, and this project looks way better! I think I'm going to Pivot. Side bar: these servos are a game changer.
- brcmthrowaway 3y agoAre the servos better than SG90?
- regularfry 3y agoDramatically. They cost (give or take) ten times more and weigh twice as much, for which you get (give or take) four times the stall torque, serial positional control, and a 360 degree range of motion. Still got plastic gears though.
- michaelt 3y agoThey're "smart" which means you can form a serial bus of them, query individual motors' encoder positions and motor temperatures and whatnot, adjust the PID parameters yourself, and so on. You can also daisy-chain them together, which might reduce your cable routing problems. Downside is when they break, you're out $50 or more - and you're going to break at least one. And the manufacturer wants you to operate them at 11.1v which isn't very convenient. And when it comes down to it, it's still got plastic gears, a plastic case, and enough backlash to be noticeable.
- brcmthrowaway 3y agoWish there was something inbetween that and SG90!
- potatoman22 3y agoI printed a robotic arm for school. Unfortunately, we weren't using a high quality enough printer, so the tolerances were off and things didn't slot together well. I'd recommend people to know the precision of their printer before setting off to build this.
- dailykoder 3y agoLearning this is part of the journey imho. You don't even have to know that you have to pay attention to tolerances beforehand. You'll inevitably learn about it when building such thing. Just always be aware that these things will never be perfect and don't get anxious because there are so many perfect looking projects on the internet. They most likely went through the same mistakes and might even have more people in the background. Just enjoy the journey
- throwup238 3y agoAlternatively, make everything just a tad out of tolerance and drill/sand/machine it to a more precise size.
- steve_adams_86 3y agoI tend to do this. I know I could get better at printing (though my printer is pretty old), but sand paper and a rotary tool are really fast and can be pretty precise and accurate too.
- deleted 3y ago[deleted]
- moffkalast 3y agoIt's not so much the printer's fault as the slicer's. Calibration is key.
- numpad0 3y agoI'd PSA recommend anyone just add 0.25mm fit clearance to every single mating surfaces within their designs. It's not ISO or anything compliant - somewhere between Atrocious and Enormous range and perhaps an mechanical equivalent of Python code with no __main__, but just works for me, and it should for lots of purposes.
- easygenes 3y agoAnyone know how the accuracy of this compares to the similar-cost adamb314/ServoProject arm? [1] It utilizes a servo mod adding dual encoders to compensate for backlash and achieves accuracy of +/- 0.05mm (enough to thread a mechanical pencil lead in and out of the tip of a pencil). [2] He's been working on the project for 5 years, with significant improvements still in the last year. [3][4] [1]: https://github.com/adamb314/ServoProject [2]: https://www.youtube.com/watch?v=SioCwvR_PYY [3]: https://www.youtube.com/watch?v=_4mrb2T706s [4]: https://www.youtube.com/watch?v=Ctb4s6fqnqo
- serf 3y agoit should be similar given similar construction; one of the reasons dynamixels tend to be pricey is the dual inboard encoder setup. if price is a factor then a servo+encoders setup will always be cheaper; there are some dirt cheap encoders out there for the creative hacker. dynamixels offer a crappy value compared to DIY solutions, they're just easy to use off-the-shelf and have nice features that aid construction.. but hardly anything game changing.
- throwup238 3y ago> but hardly anything game changing. Speak for yourself! When I worked on liquid handlers a decade ago the fully integrated servos were at least ten times as expensive as they are now. Every time I step away for a few years and jump back in, there seems to be at least a half dozen game changing pieces of hardware on the market.
- deleted 3y ago[deleted]
- hyperswine 3y agowow, thats really amazing. Are you a hardware engineer?
- NalNezumi 3y agoI've built my own GELLO setup (the setup the author based it's arm on) and it's quite neat, but as I only use it for teleoperation of an real arm, I wonder how useful this low cost arm really is? Considering limited range, probably backlash, and the limited torque Also it doesn't seems to use springs like GELLO which was a nice add, although the 3D printed parts where the spring was mounted broke quickly.
- monkeydust 3y agoCool, how are you controlling it, VR (Quest) type setup or something else?
- alex_suzuki 3y agoAnyone who finds this interesting might also like this one, it‘s not DIY – comes fully assembled: https://www.waveshare.com/roarm-m2-s.htm https://www.waveshare.com/roarm-m2-s.htm I have one and the build quality is really impressive for the price point.
- ipsum2 3y agoHow is the software support?
- alex_suzuki 3y agoI‘ve only just started using it via the web UI, no idea.
- dr_kiszonka 3y agoNice. What do you use it for?
- alex_suzuki 3y agoReproducible test scenarios for barcode scanning with a smartphone.
- dr_kiszonka 3y agoVery clever. This use case would never cross my mind.
- devsda 3y agoUnless it has to do something with the print quality itself, can't this be achieved using a stationary phone with its camera towards a monitor displaying 3D transformed barcode images ?
- alex_suzuki 3y agoYes, possibly. But reading from the screen is quite different from reading actual barcode prints, for instance you have to deal with Moirè patterns and such. And frankly it was just a good excuse to buy an arm. Sue me! ;-)
- fragmede 3y agoHow's the software side of this? How is the Dynamixel SDK to use?
- isquaredr 3y agoThe geek in me is drooling, but are there any practical home uses others have found for robotic arms? Hacking is always more fun with a good project
- dr_kiszonka 3y agoAn impractical use would be to have a few of them replace monitor arms in a multi monitor setup. You could then rapidly switch between a few configurations. Also, have one to stir pasta in the kitchen.
- Havoc 3y agoI doubt this is strong enough to carry a screen
- etrautmann 3y agoPasta is one of the few things you’re not supposed to stir while cooking?
- dr_kiszonka 3y agoI think you should stir it occasionally. It might depend on the pasta, though. https://www.thekitchn.com/kitchen-mysteries-why-stir-pas-112147 https://www.thekitchn.com/kitchen-mysteries-why-stir-pas-112...
- vasco 3y agoMulti monitor robot arm stands would do some cool things. An automated rotating sequence when you boot up would feel like a scifi movie.
- throwaway38375 3y agoOn the topic of automatically stirring pasta, I saw this the other day! https://www.amazon.com/StirMATE-Automatic-Variable-Self-Adjusting-Powerful/dp/B076HH4WZM/ https://www.amazon.com/StirMATE-Automatic-Variable-Self-Adju...
- MaxikCZ 3y agoI want the arm to wander around my house, pick up articles of loose clothing and put them into washing machine. Then pull them out and spread them on a drying hanger. How far away from that are we?
- pulse7 3y agoIt has been here for several millennia... it even has two legs to walk around and two rotating cameras connected to a very powerful LLM...
- yjftsjthsd-h 3y agoNah, that model is expensive and buggy, not to mention closed source.
- melagonster 3y agobut it work. I can't believe that we choose from different robots.
- Ekaros 3y agoDepends where you live... In some places those models are entirely affordable. But likely will also there get less and less affordable.
- seniorivn 3y agomost of those are trained on a very flawed data, so in order to use it for anything non trivial, you will have to invest a lot in fine-tuning, maybe even to an extent to call it training
- imtringued 3y agohttps://youtube.com/watch?v=HaaZ8ss-HP4 https://youtube.com/watch?v=HaaZ8ss-HP4 A decade at most?
- cocoflunchy 3y ago
- ipsum2 3y agoDoes anyone have any suggestions on something that's a little higher quality, i.e. more torque and larger, like the size of a UR5 but cheaper than $30k? There's always seems to be a gap between "robot arm with dynamixels/off the shelf servos" and "research-grade arms".
- antoniuschan99 3y agoI have a dobot mg400 but there are quite a few others: uFactory, elephant robotics, annin, dorna, epson (vt6L and their scaras), and lynxmotion is releasing their ses-v2.
- ipsum2 3y agoWow, thanks for the list of resources. My problem with most robot arms are either they have small payloads, accuracy isn't very high, are too slow, or software support is terrible. Do you have any specific suggestions for 6DoF? The MG400 looks to have 4.
- antoniuschan99 3y agoMg400 is great for the price no issues. Very smooth! Check out this review video: https://youtu.be/6nGexb_i0aM?si=IP0E76MCGxrTrQEH https://youtu.be/6nGexb_i0aM?si=IP0E76MCGxrTrQEH What payload are you looking for? Cartesian Gantry’s are your next bet if you want to handle higher loads. Eg. Epson vt6l is ~14k but I’m sure you can build a gantry system to handle higher loads for a bit less! Dobot software sucks though, I ended up programming it in python. It’s definitely not on the same level as say a Kuka or Yaskawa. Epson seems like the best value out of all the higher end arms. Software looks good, the arms are built well, has a long history in industry, and price is decent
- numpad0 3y agoYou don't want a cheap && powerful && fast robot in your home! Let alone sell a bunch of.
- dosssman 3y ago
- gnarlouse 3y agoThis is fantastic! Thank you so much
- cs2818 3y agoAs a longtime Dynamixel user I agree the U2D2 adapter is pricey in comparison to other options, but I would like some quantification of the “latency is very high” claim. I have always found it to be a sure bet for low latency (~1ms) across a wide variety of platforms.
- deleted 3y ago[deleted]
- alexanderkoch 3y agoIt works fine with Linux. The latency issues only exists with macos. https://forum.robotis.com/t/u2d2-high-latency/5319 https://forum.robotis.com/t/u2d2-high-latency/5319
- omeze 3y agoIm currently waiting on the motors for this, but my bambu p1s printed out the parts with minimal stringing in like 90 mins. Really to try it out for cooking experiments
- jack_riminton 3y agoIs there a video of it working anywhere?
- alexanderkoch 3y agoI've published quite a few videos on Twitter: https://twitter.com/alexkoch_ai https://twitter.com/alexkoch_ai
- NeilSmith2048 3y agoits really cool!
- 7373737373 3y agoI'm surprised (or perhaps very unaware) that there doesn't seem to exist a company yet that mass produces cheap, high quality, reasonably standardized robot arms. So many things like 3D printers or CNC machines have entered the consumer/amateur level price realm, but this seems to be something still largely unexplored. Seems to have Arduino/Raspberry Pi scale potential, but I haven't heard of a name/ecosystem that popular yet
- regularfry 3y agoThere have been a few around, but the limiting factor (as you can see from the BOM in the link) is the cost of the actuators. They get expensive fast.
- hackable_sand 3y agoI was looking at electroactive polymers (EAPs) and I could not find a single company with consumer pricing... I wish there was more visibility here without requiring a PhD.
- FeepingCreature 3y agoIf they don't have to move fast, could you DIY an actuator with a stepper and a threaded shaft? Steppers are pretty cheap thanks to 3D printers.
- RobotToaster 3y agoThere are arms using steppers and 3d printed epicyclic or cycloidal drives.
- FrojoS 3y agoFor a useful robot arm, you need high forces/torques. Usually, this is achieved by high ratio [1] gearboxes between the motor and the joint. Those are expensive, and inefficient and make estimating the output force via the motor current almost impossible. [1] In the order of 1:100, see e.g. https://www.harmonicdrive.net/ https://www.harmonicdrive.net/
- SSNLF 3y agoIt's cool but just reminds me of the robotic manipulation episode of big bang theory.
- rini17 3y agoWhy not start with something less ambitious, like low cost robot platform able to follow people and carry stuff around and avoid obstacles. No arms, I am okay using mine to put stuff on and off it. When I had leg injury and used crutches, carrying stuff around suddenly became a problem. There are many people with impaired movement. And even without that, I often misplace things and it could help there. There are plenty of toy robot undercarriages on aliexpress but too small (under 20cm largest dimnsion) to be practical.
- MattHeard 3y agoi was going to ask if turtlebot was too small for you, but thought i should check the price first so uh, yeah, i'm guessing you're thinking the 250 price point instead of the turtlebot's 1000+
- deelly 3y ago> low cost robot platform able to follow people and carry stuff around and avoid obstacles. So, basically autonomous self-driving mini vehicle. Сompanies spend billions on self-driving cars with quite limited luck.
- penjelly 3y agothat is because they run in a very different environment than an RC-size car in your living room would
- RobotToaster 3y ago> Сompanies spend billions on self-driving cars with quite limited luck. That's in part because it needs to be very reliable to not kill people. If the worst that can happen is killing a garden gnome or running over someone's toes you can tolerate more error.
- eichin 3y agoYeah, a "small enough to kick out of your way" autonomous driving project is a one or two semester student project (if you're starting from nothing, Sebastian Thrun's old Udacity course was a good way to bootstrap through the algorithmic parts, then maybe watch James Bruton for "everything you could possibly imagine doing with wheels, motors, and an infinite supply of 3d printer filament")
- xchip 3y agoPlease stop gluing 3 servos together and claiming you built a robot :D (servos motion is quite jerky, that is why they don't have a video showing off this "robot" operating)
- alexanderkoch 3y agoHere are some videos of the robot moving: https://twitter.com/alexkoch_ai https://twitter.com/alexkoch_ai. The advantage of this robot arm design is that it's very lightweight. The XL330 motors are just 18g each. This makes it very suitable for teleoperation and robot learning.
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- iiJDSii 3y agoAs someone a lot deeper into robotics I totally get this sentiment... But I also think it's good to encourage people to share the basics, look how many newcomers in this thread find it interesting and may explore it further. I wonder how smooth one could make a cheap servo-based robot arm operate with decent control algorithms.
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- robmurrer 3y agoobligatory shout out to Annin Robotics AR4. Here is my build: https://commandpattern.org/2023/03/19/ar4-robotic-arm-build/ https://commandpattern.org/2023/03/19/ar4-robotic-arm-build/ $2K USD. 2kg payload. millimeter repeatability (if you build it well :)
- iiJDSii 3y agoNice build! I always wanted one of those AR robot arms but I'd rather buy it off-the-shelf than assemble from scratch. I don't think anyone sells them pre-built though. This type of 'high level hobbyist robotics' is in a bit of business dead-zone unfortunately, as it's some combination of too small a market and not enough use cases to justify having a company around. Or maybe there's potential there but no one's thought of it yet. Btw I bet your arm's movement smoothness can be improved with some different deceleration rates. It was really fun watching it sort those beans! My research goal with one of these 'good enough' 1mm repeatability robots would be vision-guided adaptive control to complete tasks after seeing examples of them done via human manual control. Would be a really interesting ML/AI problem. Just need a reasonable hardware platform to get started. Right now I'm leaning more towards simple/smaller servo motors like in the OP of this post (plus there's the cost/time trade-off).
- robmurrer 3y agothis is where my research is going. camera -> llm -> targets -> tasks -> ros2 arm :)
- mtreis86 3y agoI started working on a similarly sized arm. I've got a use-case, long time friends with a glass blower. I was thinking of using it to make faceted glass pendants. They've got a faceting machine but it is manually operated. The hard part is repeatability. You need tight tolerances and each joint in the arm adds inaccuracy the further you get from the base. If the base has 1mm of wiggle, the 20cm arm has 4mm wiggle at the end, and the arm beyond it has even more. You also, for faceting purposes, need much finer resolution than an ungeared servo will have. Gearing it is tricky because you want backlash to keep the join tight, but not so much that it has high friction when moving. You don't really want to use a worm gear because they're both slow and overly rigid. So a cycloidal gear is the best bet for the gears in the arm. You also need real servos with some amount of feedback because grabbing at glass is sketchy at best. I was estimating 1-2k build cost, bulk of that is in the gearboxes.
- eutectic 3y agoIs it not possible to compensate for inaccuracy, if you have a sufficiently precise measurement at the hand?
- flutas 3y agoUneducated in hardware, mostly a software guy for perspective, so I could be way off. Would using something like a stepper motor geared way down with a cycloidal gear box work for a situation like this? (in my mind) It would give you a very controllable and repeatable way to position, with the backlash handled by the gearbox mainly. Would love to know if I'm wrong though, like I said mostly a software guy trying to venture into hardware!
- mglz 3y agoServo + Cycloidal or Harmonic gears are usually the way to go, but to get them backlash-free is hard (or expensive, if you're buying). Once you got that down challenges include: * How rigid are the links between my joints? Plastic will wobble, metal is better * How heavy is my arm and how does that limit its movement? If you go for stiff metal castings, you add weight you need to move. The lever arm relative to the base can get really long * Motors are heavy! Ideally you can mount them towards the base, but then you need drive shafts or belts, which again add flex. (See KUKA arms which have motors 4, 5 and 6 on the elbow often) * How much payload do you need to move? 5kg is already challenging in ~1m arms and if you need to move it fast the problem gets even bigger. * Where do you run your cables? Internal is tricky to build, external can get you tangled. And so on. When approaching this you get a totally new appreciation for biological arms which arae insane in most aspects except for repeatability. And on the software side you can enjoy inverse kinematics :)
- Mbartu 3y agoA $250 robotic arm is really a price consumers can reach. How does it perform in practical scenarios in terms of durability and precision? Is it functional?
- schneems 3y agoAny idea how much weight this could hold? I’m wanting to manipulate a fan in my home gym with some eye tracking to get it to blow air on my face when I work out, but the fan is a few pounds. Alternatively: any hardware motor suggestions for such a project?
- leoedin 3y agoMost of these robots will use servo motors - that gives you dexterity but means that holding any position requires constant holding torque - which means limited payload and a lot of wasted power. For a heavy fan (don't forget the reaction force from moving air too), you'd be better off mounting it on a some sort of bearing and just using a motor to turn it. That way the motor isn't trying to fight gravity all the time. The robot arm linked here using Dynamixel servos - you could just use one of them to spin a fan on a lazy susan. Much cheaper and less complicated!
- dekhn 3y agoyes, a belt-driven lazy susan is the right answer here (for azimuth).
- mclightning 3y agothis is why servo-powered robotic arms are not interesting to me at all. I want one with brushless motors and harmonic or planetary drive gearbox. unfortunately you cant build those under $750 as far as I have seen so far. that's putting aside the added complexity. but I will definitely build one some day. there are quite few opensource projects with that setup. I believe it offers higher torque, better precision and ability to just stick to a position with relatively low/or no power due to gearing-side resistance.
- spspeaker 3y agoWhy not: keep most weight off the arm by using a fan/compressor installed in the base and routing a conduit to the arm? Then it will only have to move the conduit, not the heavy motor.
- nerdjon 3y agoI have zero idea what I am going to use this for, but the idea of having a robot arm has fascinated me since I was a kid and I am 100% going to start working on this this weekend. I think I could find some fun projects. I wonder if it could hold my microphone and it turn into an automatic microphone arm...
- ozten 3y agoImpractical, but here are my kitchen use-cases: - Hold a hot pan and drip bacon grease into a jar - Hold "almost empty" bottles like olive oil upside down to drain them - Making dishes that require constant stirring over a long period (tapioca, risotto, etc)
- gertlex 3y agoHah! Not actually a robot... but I half suspect I could convince the that wife a fold-out arm with a modest clamp (that could rotate a bit if needed) at the end would be worth mounting to a wall along the kitchen counters for holding/draining various containers like your first two use-cases.
- ozten 3y agoJulia Child's kitchen was famously functional with a peg board wall for quick access to hanging supplies. I could see her doing that!
- gertlex 3y agoNice idea for helping convince! I too am for the functional stuff; I use a tension rod (like used for shower curtains sometimes) between cupboards, over the kitchen sink to hang S hooks off, and let a significant number of pots and pans hang to dry after washing.
- wedesoft 3y agoBought a Sainsmart robot arm because it was cheap and has 6 degrees of freedom. I don't use it for anything serious though. It was just to practice some robotic programming. https://github.com/wedesoft/arduino-sainsmart https://github.com/wedesoft/arduino-sainsmart
- tsycho 3y agoHere's what I want to build: A rotatable, table-top round disc base, with a contraption to keep a mobile phone straight and stable. The stand itself will have 4 small unidirectional mics, to figure out which direction (after filtering for human frequencies, ideally) is the sound coming in. And based on that, it will rotate the phone to face that direction (continuosly). The use case is family video calls that I do frequently from my dining table (my whole family is sitting around the table, hence there is no one good spot to keep the phone). With this self-rotating stand, the phone will auto-rotate towards whoever is speaking. I can write audio-processing code, but I have no idea how to get started with the hardware. Feel free to steal my idea, but please share with me how you are building it. I just want this to exist, and I want to know how to build it for myself as a fun project.
- mbrameld 3y agoAn alternative would be a 360 camera and do the cropping in software. It has the advantage of being able to show multiple speakers at once.
- willy_k 3y agoIf you can write the code, it could be pretty straightforward. From a quick search, motorized turntables already exist, from $10-100, both with and without remotes. So you could either wire a controller into one, or reverse the remote’s signals. I also found this guide for a DIY one[0], if that’s your preferred route. [0] https://www.instructables.com/15-Motorized-Rotating-Display-Turntable/ https://www.instructables.com/15-Motorized-Rotating-Display-...
- spxneo 3y agoi just want a DIY robot arm (6DOF preferred) that can give me massages? is there a community around this?
- CTrabandt 3y agoDoes anyone have any suggestions on something that can be used to for threading a small needle with a very fine thread? Would need high accuracy and repeatability. Higher price would not be a problem.
- ben_utzer 2y agoI'm surprised that no one point to this : https://github.com/peng-zhihui/Dummy-Robot https://github.com/peng-zhihui/Dummy-Robot It's probably a bit hard to read though.
- fasa99 3y agoAs a level 12 necromancer, I myself am a fan of necrobiotics: https://onlinelibrary.wiley.com/doi/10.1002/advs.202201174 https://onlinelibrary.wiley.com/doi/10.1002/advs.202201174 Spiders move not through direct-muscle limb manipulation as we do, but something more akin to hydraulic pressure moving a joint. Thus they become self-building hydraulic soft actuators with a very simple i/o interface(psi in the necrospider)