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Autonomous excavator constructs a six-metre-high dry-stone wall

ethz.ch

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Re: Autonomous excavator constructs a six-metre-high dry-stone wall

#111

Post by nabla9 »

schiffern wrote: post #87
samtho wrote: post #86

Earlier quoted context omitted.

The problem with dry stone construction is that you cannot determine the performance characteristics required for, say, a building foundation. Not all boulders are created equal, but a professional concrete pour, mixed and installed to the manufacturer’s specification is going to have a guaranteed maximum strength- something random boulders will not have. What we can do is create our own concrete mix using Portland c…

So the question becomes, how do existing concrete manufacturers determine whether locally sourced materials ("random rocks") are suitable? In traditional dry stone construction, strength of each rock is determined by sound and by sight. It seems crazy, but nowadays this should be feasible with a neural net. If you want to get fancy (or achieve high reliability) add ultrasound in the grippers or other sensor modalitie…

A Deep Learning Based Method for the Non-Destructive Measuring of Rock Strength through Hammering Sound Appl. Sci. 2019, 9(17), 3484; https://doi.org/10.3390/app9173484

Acoustic inverse problems are solved routinely in seismology and exploration geophysics. Seeing trough a rock the cracks and internal structure using acoustics seems solvable.

Re: Autonomous excavator constructs a six-metre-high dry-stone wall

#113

Post by dryrocks »

evilaubergine wrote: post #104
rkangel wrote: post #98

Earlier quoted context omitted.

It absolutely matches the reflection in the water - you can see the hard hat of the person and the colour transition. The change in colour will be the result of a change in source of boulder. The whole point is that they are "recycling".

where were the wireframe mesh rocks sourced from?

The excavator creates a mesh of each stone by scanning it "in hand", and updates the settled positions of them as it builds. The left side of the image is the 3D digital twin model that is maintained by the system, captured from the same perspective to show how it matches the real wall.

Re: Autonomous excavator constructs a six-metre-high dry-stone wall

#114

Post by buro9 »

This is incredible because the vast majority of what it takes to build roads, rail tracks, docks, and such infrastructure is all in the clearing and relandscaping of land. It doesn't have to be perfect in terms of aesthetics or seals, but it has to be very stable and able to take the thin layer of road surface, rails, concrete on top and the weight that they'd carry.

To be able to automate the landscaping is to massively reduce the cost of infrastructure projects in terms of labour and materials, but also likely the time to deliver them too.

Re: Autonomous excavator constructs a six-metre-high dry-stone wall

#115

Post by sschueller »

lnsru wrote: post #91
1-6 wrote: post #88

I wish there were more companies in the US that can look at problem and solve it to a great deal of technical complexity. It seems like we’re too focused on large and shiny objects.

Robotics is expensive. One needs a team of software developer, electronics engineer and mechanical engineer to develop something. 3 people over 3 years with expensive hardware and couple millions $ for MVP needed. How many google ads for an app could one buy for this sum?

That is what public funded universities and research is for. Many claim projects like CERN is a waste of money but this is where many new ideas and tech comes from as a side effect of trying to solve problems that arise while trying to build a bigger and more powerful accelerator.

Re: Autonomous excavator constructs a six-metre-high dry-stone wall

#116

Post by crotchfire »

diroussel wrote: post #103
beambot wrote: post #99

Earlier quoted context omitted.

> how do existing concrete manufacturers determine whether locally sourced materials ("random rocks") are suitable? They test individual samples from each pour on a calibrated press. For large buildings and critical pours, they'll keep & test multiple samples that undergo accelerated aging to make sure they're up to spec for the anticipated lifetime of the building (or until the concrete fully stabilizes over a few m…

So could catagorization of local stone based on acoustic and visual indicators, combined with random sampling and strength testing provide the assurance needed that a wall will have the required structural properties?

The point is that the concrete manufacturers pulverize and homogenize the aggregate. This makes random sampling acceptable.

If you haven't pulverized and mixed the inputs, a random sample is merely a random sample. It isn't meaningful unless it comes from a high-entropy source.

Re: Autonomous excavator constructs a six-metre-high dry-stone wall

#119

Post by Obscurity4340 »

Daub wrote: post #55

Having made a few dry stone walls I can attest to the merit of this achievement. Judging where rocks are to be placed, and in what orientation is a zen art. Anecdotally... I once tried to get wild flowers to grow on a stone wall. Every year we would seed the wall, only for the seeds to fall out or be eaten by birds. On inspiration, my boss filled a few shotgun cartridges up with seeds and fired them at the wall. Perf…

Didn't they do that in The Grinch?

Re: Autonomous excavator constructs a six-metre-high dry-stone wall

#120

Post by 123pie123 »

chaboud wrote: post #83
kbenson wrote: post #60

Earlier quoted context omitted.

I really enjoyed that show, but I have no confidence that production assistants weren't gallavanting about at night acting as gremlins. Clarkson is first and foremost an entertainer, and I'm sure he'd agree with that assessment.

Clarkson is the sort of guy who would have both friend and foe knocking over his walls just to mess with him. Nonetheless, sheep farming can be incredibly difficult, and sheep love to assert just enough independence to be annoying.

the adjoining farm next to our backgarden had sheep that was obsessed with getting into my backgarden - no idea why. they would jump over the 5ft wall with barb on the top.

When we complained he move the sheep to another field, they escaped that field and entered our back garden through a totaly different way - through our front garden. eating loads of our plants - I can understand the pain Clarkson went through (made up or not)

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