Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Low Cost Robot Arm

github.com

Post reply on HN
Print view View original

211–220 of 258 posts

Re: Low Cost Robot Arm

#211

Post by ska »

7373737373 wrote: post #69

I'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 po…

> at there doesn't seem to exist a company yet that mass produces cheap, high quality, reasonably standardized robot arms.

These do exist, it's just that "reasonably cheap" is typically low - mid 5 figures for any sort of reach an payload.

Re: Low Cost Robot Arm

#212

Post by ska »

TomK32 wrote: post #82
Ekaros wrote: post #77

Earlier quoted context omitted.

Also I have understood that robot arms are in real life rather complicated to program to operate correctly. So any process would take substantial effort. Magnitude harder than controlling some relays or reading some sensor data.

Wouldn't be the easiest way to program a robot to "show" it its task by simply moving the arm a few times in the paths it has to replicate afterwards?

Yes, they have systems to learn this way, but it assumes the environment is controlled (always) and the task identical (always).

Lots of automation works this way, but it actually limits the applications quite a bit.

A robot that can safely work along side people (i.e., a "cobot") and adjust to environment changes and changing work patterns is a whole different beast.

Re: Low Cost Robot Arm

#213

Post by ska »

ectopasm83 wrote: post #145
jfoutz wrote: post #85

Earlier quoted context omitted.

I don't know, but I think the big real industrial kind can really really hurt or kill people. I think the limiter on smaller arms is quality servos with real location encoders - this one costs a couple hundred bucks for motors. Not claiming the software is easy! But I think sourcing parts is (or has been) really hard.

I've explored the idea of using super cheap servos to build a robot arm/tentacle to pick cherry-tomatoes and it seems the only reason you'd want to use location encoders is in tasks that require high precision in an open-loop system (the robot is blind to its environment but has info about his own body). To me it seems you can get rid of this requirement if you allow the robot to sense its environment using cheap, 80…

> cheap, 800x600 cameras with depth estimation ML algos

This typically won't be accurate enough for closed loop kinematics, especially at any sort of speed.

Re: Low Cost Robot Arm

#214

Post by [deleted] »

RobotToaster wrote: post #139
Ekaros wrote: post #77

Earlier quoted context omitted.

Also I have understood that robot arms are in real life rather complicated to program to operate correctly. So any process would take substantial effort. Magnitude harder than controlling some relays or reading some sensor data.

I think the main issue is inverse kinematics and path planning. Which is partly why SCARA is popular with amateur robot arms, the maths is simpler.

[deleted]

Re: Low Cost Robot Arm

#216

Post by ska »

mtreis86 wrote: post #134

I 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…

How many degrees of freedom do you actually need, and what reach? Those parameters (plus speed) drive a lot of choices.

1-2k build cost is tiny in this space. I've paid that in individual motors (specialized ones, to be fair).

Re: Low Cost Robot Arm

#217

Post by spxneo »

MaxikCZ wrote: post #17

I 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?

You have to tradeoff between privacy, automation and cost.

The scenario you described is tough to solve because of edge cases sort of like FSD.

If you want that work done then its cheaper to hire a maid. It would be nice to have complete privacy and have a robot perform all those tasks flawlessly but the price point would make it economical to get a human to do it.

Perhaps you can get someone to drive the robot but that puts privacy at risk.

Same thing with sex robots it is cheaper to hire a sex worker so until something that can get us past the uncanny valley I don't think we will see a robot revolution quite yet. The hardware alone is prohibitively expensive and there is not enough people tinkering at the problem (because to hire humans is always safer and easier and cheaper).

Re: Low Cost Robot Arm

#218

Post by ska »

boesboes wrote: post #163
mtreis86 wrote: post #134

I 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…

Have you considered using belts and sprockets? They seem effective in 3d printers and pretty cheap

There are lots of belt driven industrial robots. They have a different set of trade-offs and challenges.

Re: Low Cost Robot Arm

#219

Post by ska »

jfoutz wrote: post #85
Ekaros wrote: post #77

Earlier quoted context omitted.

Also I have understood that robot arms are in real life rather complicated to program to operate correctly. So any process would take substantial effort. Magnitude harder than controlling some relays or reading some sensor data.

I don't know, but I think the big real industrial kind can really really hurt or kill people. I think the limiter on smaller arms is quality servos with real location encoders - this one costs a couple hundred bucks for motors. Not claiming the software is easy! But I think sourcing parts is (or has been) really hard.

> I don't know, but I think the big real industrial kind can really really hurt or kill people.

Many medium sized arms are quite capable of generating forces that can kill a person.

Re: Low Cost Robot Arm

#220

Post by [deleted] »

iiJDSii wrote: post #186
xchip wrote: post #112

Please 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)

As 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.

[deleted]
Post reply on HN