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>> Having more zeros does not equal to being more "precise" Isn't having more decimal places the exact definition of precision (vs accuracy)?
The point is that those decimal places don't have to be zeros. 7.893 is just as precise as 8.001.
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I don't think it is fair to downvote this comment. It is a genuine concern and should be addressed. Amusingly, given that the thought has entered mass consciousness by means of question on 'whether all this is a simulation', matrix ( the animated series ) explored this question a little and it is interesting in how the timeline aligns with what the movie presented.
Earlier quoted context omitted.
I think it's about kinematics, the more precise your gears the better the model fits the real world. That's why pro crews don't use gears and ropes. At high impulses deformations and elasticity throw the kinematics off what's actually happening. Modeling the deformations and the elasticity is a computational no no. Instead what you see is the motors right on the joints. At least that was the case last time I had a lo…
> That's why pro crews don't use gears and ropes. [...] Instead what you see is the motors right on the joints. The answer here, as with so many things in robotics, is: It Depends. UR10e robot arm that can lift a 4kg object with a reach of 1m and has sub-1mm repeatability? Strain wave gears in the base and shoulder joints, 100:1 ratio. MIT Mini Cheetah robot dog that can do backflips? 6:1 planetary gearbox. Shadow Ha…
>Mid-price CNC milling machine
A ball-screw is mostly decorative on small machines... =3
Earlier quoted context omitted.
> That's why pro crews don't use gears and ropes. [...] Instead what you see is the motors right on the joints. The answer here, as with so many things in robotics, is: It Depends. UR10e robot arm that can lift a 4kg object with a reach of 1m and has sub-1mm repeatability? Strain wave gears in the base and shoulder joints, 100:1 ratio. MIT Mini Cheetah robot dog that can do backflips? 6:1 planetary gearbox. Shadow Ha…
In general, for some platforms each gear mechanism adds backlash precision loss, lower energy efficiency, and might not be back driven. >Mid-price CNC milling machine A ball-screw is mostly decorative on small machines... =3
Back-drivability is the enemy of precision, so many robotic applications can do without it.
Earlier quoted context omitted.
I think it's about kinematics, the more precise your gears the better the model fits the real world. That's why pro crews don't use gears and ropes. At high impulses deformations and elasticity throw the kinematics off what's actually happening. Modeling the deformations and the elasticity is a computational no no. Instead what you see is the motors right on the joints. At least that was the case last time I had a lo…
> That's why pro crews don't use gears and ropes. [...] Instead what you see is the motors right on the joints. The answer here, as with so many things in robotics, is: It Depends. UR10e robot arm that can lift a 4kg object with a reach of 1m and has sub-1mm repeatability? Strain wave gears in the base and shoulder joints, 100:1 ratio. MIT Mini Cheetah robot dog that can do backflips? 6:1 planetary gearbox. Shadow Ha…
Cara is the Irish word for 'friend'. Not sure if thats what was intended or is just a coincidence.
There is a weird mixture of hope and dread in me as I watch this. I am ridiculously excited over a person like me being able to mess around with something that, until recently, was gated behind, well, a lot of hard problems to overcome ( I am only now slowly getting through old Peter Scott's robotics to get some perspective ). By comparison, it should be so much easier to explore aspects of robotics that may go beyon…
Why dread?
CARA is a super cool project which is never going to kill anybody, but it's another piece of evidence that the cost of the technology for such weapons has decreased enormously.
That said, talking about the dread is going to get boring fast, because nearly every story on the HN front page is catapulting us toward that future.
Earlier quoted context omitted.
In general, for some platforms each gear mechanism adds backlash precision loss, lower energy efficiency, and might not be back driven. >Mid-price CNC milling machine A ball-screw is mostly decorative on small machines... =3
On the other hand, a 100:1 gearbox gives you much-needed torque if you're lifting a load at the end of a long arm, it makes your encoder 100x more precise (in terms of repeatability) and it makes your motor brake 100x stronger. Back-drivability is the enemy of precision, so many robotic applications can do without it.
The old "fast, cheap, or good... choose any two joke is mostly still true. =3