4 ms·

(Oops saw other comment linked, but I’ll leave this comment in case summary is helpful) Check out the SO100 arm, being supported by Huggingface and others. Onl

(Oops saw other comment linked, but I’ll leave this comment in case summary is helpful) Check out the SO100 arm, being supported by Huggingface and others. Only 4 axis, but cheap AF (<$250/arm) and using ML to make it more capable than 4 axis would seem. Also using identical arms for mirror teleportation/training. https://github.com/TheRobotStudio/SO-ARM100 https://github.com/TheRobotStudio/SO-ARM100

nullc 2y ago
4 is still though fundamentally limited: you need a minimum six DOF to position all three translational and rotational freedoms. The human arm has 7, and I think a case can be made the smart software would reduce the problems from having only exactly as many as required. ... but not eliminate: the extra degree of freedom lets you "get out of your own way" when moving objects that are not zero size trough multiple positions :) Perhaps 4 is enough for any specific application, but then again perhaps 3 is or 2. :P I've never programmed a robot arm, but I've spent a fair amount of time using a seven axis faro arm (a coordinate measuring device, sort of the opposite of a robot arm) and it certainly takes some practice to avoid "cant move there from here without reorienting everything", it's easy to take for granted what our brains do automatically for us. :)
- IanCal 2y ago
  Humans have 7 dof but we can't get into all positions, as I've found clearly today trying to reach things for my kids in the back seat of the car.
  - IshKebab 2y ago
    That's because of joint range of motion limitations. It's different to DoF limitations which is what was being discussed.
    - IanCal 2y ago
      The point is that you can achieve a lot without being able to access every position and the human arm having a lot of degrees of freedom doesn't necessarily mean it's more capable than a different arm with fewer.
      - nullc 2y ago
        Sure but why not, say, an XYZ or XYZT gantry instead? There are a lot of downsides in 'arms' -- stacking all the axis hurts their speed, stiffnes, accuracy, increase complexity (e.g. in pathing, limiting speed, restricting to safe areas), limited reach. I've always thought of them primarily as beneficial for flexibility at considerable cost, but if it's not 6dof then the flexibility isn't so great, then why not some other geometry?
- numpad0 2y ago
  in simpler term: an object has position and rotation, and we're in 3D, so we need minimum 6 linearly independent parameters to be able to both point at a direction and be at a location at the same time. Drone and helicopters has 4, and they are able to control max 4 of 6 parameters. Usually 3 positional + 1 rotational, and the rotatinal axis go first.
maujim 2y ago
its actually 250 for both, 130 for just the leader
numba888 2y ago
It uses cheap hobby servos which is, to put it mildly, not the same as steppers. You will never get 0.2mm precision with them. They will were out quickly and even quicker under load. BTW, looks like it doesn't have closed loop control. "0.2mm repetability" (should be repeAtability) is only 'under certain conditions', no load.
- easygenes 2y ago
  You'd be surprised what you can do with servos modified with encoders, setup with an industrial grade cascading control loop. First demo video below demonstrates threading a mechanical pencil lead in and out through the writing tip. Second video demonstrates a 187gram weight at the end of a 470mm long rod. Third video shows that the modification is now a quick fitting of some 3D printed parts to the servo motor axle and servo housing. https://www.youtube.com/watch?v=ECLrLupFW10 https://www.youtube.com/watch?v=_4mrb2T706s https://www.youtube.com/watch?v=Ctb4s6fqnqo https://github.com/adamb314/ServoProject
  - numpad0 2y ago
    Servos by definition has encoders...
    - easygenes 2y ago
      Yes, but this employs additional encoders to implement a more sophisticated cascading control loop: https://github.com/adamb314/ServoProject/blob/main/Doc/Theory.md https://github.com/adamb314/ServoProject/blob/main/Doc/Theor...
      - deleted 2y ago
        [deleted]
  - amelius 2y ago
    I hope Shenzhen is watching ...
- 2y ago
thoweirjwoj234 2y ago
(AliExpress sells 6/7-dof arms made with hobby-servos & metal construction, shipped for $50).
brcmthrowaway 2y ago
Can this actually do programmed movements ? It seems it learns through a camera only.

nullc 2y ago

4 is still though fundamentally limited: you need a minimum six DOF to position all three translational and rotational freedoms. The human arm has 7, and I think a case can be made the smart software would reduce the problems from having only exactly as many as required. ... but not eliminate: the extra degree of freedom lets you "get out of your own way" when moving objects that are not zero size trough multiple positions :) Perhaps 4 is enough for any specific application, but then again perhaps 3 is or 2. :P I've never programmed a robot arm, but I've spent a fair amount of time using a seven axis faro arm (a coordinate measuring device, sort of the opposite of a robot arm) and it certainly takes some practice to avoid "cant move there from here without reorienting everything", it's easy to take for granted what our brains do automatically for us. :)

IanCal 2y ago
Humans have 7 dof but we can't get into all positions, as I've found clearly today trying to reach things for my kids in the back seat of the car.
- IshKebab 2y ago
  That's because of joint range of motion limitations. It's different to DoF limitations which is what was being discussed.
  - IanCal 2y ago
    The point is that you can achieve a lot without being able to access every position and the human arm having a lot of degrees of freedom doesn't necessarily mean it's more capable than a different arm with fewer.
    - nullc 2y ago
      Sure but why not, say, an XYZ or XYZT gantry instead? There are a lot of downsides in 'arms' -- stacking all the axis hurts their speed, stiffnes, accuracy, increase complexity (e.g. in pathing, limiting speed, restricting to safe areas), limited reach. I've always thought of them primarily as beneficial for flexibility at considerable cost, but if it's not 6dof then the flexibility isn't so great, then why not some other geometry?
numpad0 2y ago
in simpler term: an object has position and rotation, and we're in 3D, so we need minimum 6 linearly independent parameters to be able to both point at a direction and be at a location at the same time. Drone and helicopters has 4, and they are able to control max 4 of 6 parameters. Usually 3 positional + 1 rotational, and the rotatinal axis go first.

maujim 2y ago

its actually 250 for both, 130 for just the leader

numba888 2y ago

It uses cheap hobby servos which is, to put it mildly, not the same as steppers. You will never get 0.2mm precision with them. They will were out quickly and even quicker under load. BTW, looks like it doesn't have closed loop control. "0.2mm repetability" (should be repeAtability) is only 'under certain conditions', no load.

easygenes 2y ago
You'd be surprised what you can do with servos modified with encoders, setup with an industrial grade cascading control loop. First demo video below demonstrates threading a mechanical pencil lead in and out through the writing tip. Second video demonstrates a 187gram weight at the end of a 470mm long rod. Third video shows that the modification is now a quick fitting of some 3D printed parts to the servo motor axle and servo housing. https://www.youtube.com/watch?v=ECLrLupFW10 https://www.youtube.com/watch?v=_4mrb2T706s https://www.youtube.com/watch?v=Ctb4s6fqnqo https://github.com/adamb314/ServoProject
- numpad0 2y ago
  Servos by definition has encoders...
  - easygenes 2y ago
    Yes, but this employs additional encoders to implement a more sophisticated cascading control loop: https://github.com/adamb314/ServoProject/blob/main/Doc/Theory.md https://github.com/adamb314/ServoProject/blob/main/Doc/Theor...
    - deleted 2y ago
      [deleted]
- amelius 2y ago
  I hope Shenzhen is watching ...
2y ago

thoweirjwoj234 2y ago

(AliExpress sells 6/7-dof arms made with hobby-servos & metal construction, shipped for $50).

brcmthrowaway 2y ago

Can this actually do programmed movements ? It seems it learns through a camera only.