I agree, Elizabeth. I'm glad you brought it up because the whole concept of what could work as a secondary, stronger connection method is an interesting design--and manufacturing--problem. Pinions might be too complex and expensive, and at much smaller dimensions probably wouldn't work at all.
Jim, after writing about sophisticated optimization software I saw demo'ed at the Altair conference, I'm even more acutely aware of how much the smallest changes can make in efficiency and manufacturability of a design, not to mention cost. So I'm not at all sure that adding extra volume to each cube that's only going to be used in only a few of them would be a good idea from a cost and price standpoint of manufacturing thousands or more. That's not done in any other high-volume product; I doubt it would be in robots. The economies of scale you seem to be thinking of are usually applicable to zillions of semiconductor chips or millions of very simple consumer products. Economies of scale don't work the same in different types of product designs.
OK, point taken. SO, thinking about it from a product design perspective you still benefit from economy of scale by designing the basic cube package with void space areas that can house the special features you mention on enhanced cubes. Like adding bells & whistles option to a car; the base model remains the same.
Jim, that identical-cube scenario is called a homogeneous architecture, which does have the advantage of interchangeable cubes that are easily replaced in a structure, as we discussed in this feature article on self-assembled devices:
But the researchers say that they do envision "special-purpose cubes, containing cameras, or lights, or battery packs, or other equipment, which the mobile cubes could transport." This is a heterogeneous architecture, which gives the structure, or robot, built with such modules much more potential functions and capabilities.
Rob, the researchers say in the press release that they hope to get the module size down a lot smaller, as is typical in modular robotics for self-assembly, as we discussed here: http://www.designnews.com/author.asp?section_id=1392&doc_id=261138
Ann, then it will certainly be interesting to see what the team comes up with next. While the cubes show a new take on movement and control, the next step may be a practical application. Perhaps integrated drive reassembly as a plant shifts from one product to the next.
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