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"Heliogen uses computer vision software, automatic edge detection and other sophisticated technology to train a field of mirrors to reflect solar beams to one s
by splittingTimes 7y ago
"Heliogen uses computer vision software, automatic edge detection and other sophisticated technology to train a field of mirrors to reflect solar beams to one single spot."
In principle I think you are right, but that would mean for each plant you build you need the exact position of each mirror, the oven chamber and the motion of the sun through the day and year. I think the "AI" approach scales better, as it is rather simple "AI" application.
- gonzo41 7y agowouldn't just giving all of the mirrors survey quality GPS do the same. you'd be able to then just have them work out the angles as it relates to them and the target. It doesn't really seems like and AI problem.
- stinky613 7y agoI think that would depend on how precisely they need to be calibrated, right? IIRC even military GPS is still only accurate to within a few feet.
- gonzo41 7y agoSurvey quality GPS is able to have centimeter accuracy. https://en.wikipedia.org/wiki/Real-time_kinematic https://en.wikipedia.org/wiki/Real-time_kinematic
- mlyle 7y agoBut centimeter accuracy is of limited value. It doesn't tell you how the mirror base inclination has changed due to subsidence and thermal effects. If every mirror has drifted a small angle, and you're trying to point them all at a very small target-- it's hard.
- Waterluvian 7y agoRTK GPS is 1cm RMS. And I still can't get over how awesome it is. It's magic.
- abakker 7y agoIt’s 1cm in altitude! In lat long, it can be better. It really is awesome.
- localhost 7y agoI had no idea what RTK was before your comment. Thanks! Here's a link[1] for others who might be curious. Looks like the key is being within ~6mi of a RTCM (Radio Technical Commission for Maritime) station that transmits GPS correction data. If not, the cool thing is that you can create your own station as well by daisy-chaining off of an existing station that's within 6mi. [1] https://learn.sparkfun.com/tutorials/what-is-gps-rtk/all https://learn.sparkfun.com/tutorials/what-is-gps-rtk/all
- mlyle 7y agoFor these purposes, you could just have a single reference receiver at the site. That is, with two GPSes, you can measure their vector distance very precisely by correlating their measurements. But it doesn't help you precisely measure angles, which is a big part of this problem.
- amelius 7y agoCan't you then solve this by having a bunch of photodiodes under the edge of each panel, indicating if the panel is placed correctly?
- sansnomme 7y agoSsh, hacker news hates simple solutions like fiducial markers. I wonder if HN would dare to ride a spaceship that uses neural network to perform docking alignment.
- kjeetgill 7y agoAre you saying Heliogen took a harder approach to impress HN? Or maybe that your offhand dismissal is the most "HN" thing here?
- kjeetgill 7y agoFrom my reading of the article, one of the big issues to overcome was cost of CSP vs Photo Voltaic . They're even using smaller flat mirrors that are less sophisticated since per panel costs add up fast. One of the advantages is that this takes 4 cameras across the full plant, not a per panel cost. That's just my reading of it, not asserting anything myself.
- trickstra 7y agoHow many photodiodes it takes before you reach the cost of 4 cameras?
- JshWright 7y ago>or each plant you build you need the exact position of each mirror, the oven chamber and the motion of the sun through the day and year Yeah, depending on the level of precision required, there are _tons_ of variables that could have an impact here. Year to year the angle of the sun changes slightly on any given solar date, as various components of the Earth's orbit "wobble" (axial tilt, eccentricity, precession, etc). Even on an hour by hour basis, thermal expansion could have a significant impact. Any significant structure is going to settle to some extent over time, etc...
- SiempreViernes 7y agoThe motion of the Earth in space is very well determined and studied; the thermal expansion and deformation of the structure is most likely the dominant source of uncertainty for the pointing.
- splittingTimes 7y agoI am wondering if these effects are really important and warrant the use of "AI". If so, then what is the size of the target? If it is only some cm^2, then they still have a long way to go till it can handle industrial sized problems. Once you are at industrial scale, do you still need that kind of accuracy??
- pbhjpbhj 7y agoI don't think it's about warranting "complex AI" it's that this solution plays out as easier to apply in practice. I think it's a scale issue, each mirror needs the same apparatus and AI, but doing it traditionally with reactive optics would need a multitude of different pieces?
- sanxiyn 7y agoThese effects are really important. That's why previous attempts failed.
- mlyle 7y agoGround subsidence and related structural effects on the mirrors and mirror field are the main issue. But also the position of the sun in the sky is not predictable enough to do this completely open loop because of variances in atmospheric refraction... but it's pretty easily measured at the site.