6 ms·

I was wondering why they used EM instead of HF audio for positioning. Sub-nano must require expensive clocks and very tight tolerances. They need centimeter lev

by chime 7y ago

I was wondering why they used EM instead of HF audio for positioning. Sub-nano must require expensive clocks and very tight tolerances. They need centimeter level precision not sub-mm. Maybe the speed of sound varies over 100m ranges? Why not do embedded magnets or wires in the road? I don’t mean to judge their decision, just wondering how they settled on EM for positioning.

tlb 7y ago
Sound localization is directly affected by wind, because the propagation speed is relative to the moving air mass. A wind moving at 0.05 Mach (35 mph, not unlikely in an exposed port) will scale the distance measurements by 5 meters over 100 meters.
tcmb 7y ago
Could they do the positional shifting to prevent wear and tear of the asphalt surface with embedded magnets or wires?
- toss1 7y ago
  Seems like no problem, if they merely designed it so that instead of using the embedded positioning devices as cargo placement markers, they used them provide accurate carrier locations, then tell the carriers to put the cargo in different positions as needed.
toxik 7y ago
I’d say having landmarks (like literally spray marks on the land) and wheel encoders should be much more robust. Perhaps also with some ToF system as a secondary source of positioning. Come to think of it, could the ”we’re only semi automated” be a way around the unions?
- cr0sh 7y ago
  > I’d say having landmarks (like literally spray marks on the land) Such marks could wear away, or be obscured by spills, debris, or rain. Ideally, they should be included, along with other sensor systems for positioning, just to give another set of data points for the localization algorithm to work with. Practically, though, they probably aren't, because it raises costs both for development and maintenance of the systems.
  - toxik 7y ago
    Any system has failure modes. The advantage of a visual system is that it is also useful for human beings. Especially given how the original article talks about semi-automated settings, this type of collaborative approach could prove fruitful. It sounded like ToF did not work very well for them across the entire environment due to lots and lots of little steel cages (i.e. cargo crates) too.
lopmotr 7y ago
Phase information is already used by precise GPS receivers. The electronic components and software are probably much cheaper than wires in the ground everywhere. Also, the guy did say they have centimeter precision, not sub-mm. cm is the wavelength of microwaves. The nano referred to nanosecond timing, which is common in every computer these days. These kinds of suggestions of using a simple mechanical solution instead of a sophisticated one often come up when high tech machines are discussed. Driverless cars should use wires in the road, or communicate with each other using radio instead of vision, SpaceX booster landings should use towers and wires to guide it the final few meters, walking robots should use wheels, Boston dynamics' Handle robot should be a conventional 4-wheeled vehicle with a robot arm on it, aerodynamically unstable aircraft that depend on computer control should not be made, etc. I think people have a bias that says "Tasks I could imagine doing myself are cheap and tasks where I'd be out of my depth even knowing if they're possible are expensive.". But really, hardware is expensive and software and electronics are cheap, at least by unit costs.

by chime 7y ago

tlb 7y ago

Sound localization is directly affected by wind, because the propagation speed is relative to the moving air mass. A wind moving at 0.05 Mach (35 mph, not unlikely in an exposed port) will scale the distance measurements by 5 meters over 100 meters.

tcmb 7y ago

Could they do the positional shifting to prevent wear and tear of the asphalt surface with embedded magnets or wires?

toss1 7y ago
Seems like no problem, if they merely designed it so that instead of using the embedded positioning devices as cargo placement markers, they used them provide accurate carrier locations, then tell the carriers to put the cargo in different positions as needed.

toxik 7y ago

I’d say having landmarks (like literally spray marks on the land) and wheel encoders should be much more robust. Perhaps also with some ToF system as a secondary source of positioning. Come to think of it, could the ”we’re only semi automated” be a way around the unions?

cr0sh 7y ago
> I’d say having landmarks (like literally spray marks on the land) Such marks could wear away, or be obscured by spills, debris, or rain. Ideally, they should be included, along with other sensor systems for positioning, just to give another set of data points for the localization algorithm to work with. Practically, though, they probably aren't, because it raises costs both for development and maintenance of the systems.
- toxik 7y ago
  Any system has failure modes. The advantage of a visual system is that it is also useful for human beings. Especially given how the original article talks about semi-automated settings, this type of collaborative approach could prove fruitful. It sounded like ToF did not work very well for them across the entire environment due to lots and lots of little steel cages (i.e. cargo crates) too.

lopmotr 7y ago

Phase information is already used by precise GPS receivers. The electronic components and software are probably much cheaper than wires in the ground everywhere. Also, the guy did say they have centimeter precision, not sub-mm. cm is the wavelength of microwaves. The nano referred to nanosecond timing, which is common in every computer these days. These kinds of suggestions of using a simple mechanical solution instead of a sophisticated one often come up when high tech machines are discussed. Driverless cars should use wires in the road, or communicate with each other using radio instead of vision, SpaceX booster landings should use towers and wires to guide it the final few meters, walking robots should use wheels, Boston dynamics' Handle robot should be a conventional 4-wheeled vehicle with a robot arm on it, aerodynamically unstable aircraft that depend on computer control should not be made, etc. I think people have a bias that says "Tasks I could imagine doing myself are cheap and tasks where I'd be out of my depth even knowing if they're possible are expensive.". But really, hardware is expensive and software and electronics are cheap, at least by unit costs.