This looks like a nice, approachable robotic model of a human hand that can be printed and experimented with.
But... is a human hand the best design for a robot to grip things with? Or could we surmise that the human hand evolved as a pretty good hand given the materials and senses that were available to evolve humans from, while in theory a totally different design might be optimal for gripping when constructed from metal, plastic, motors, etc.?
A human hand is probably the most appropriate design for a robot to grip a variety of things that were designed to be gripped by human hands.
For any one specific thing, be it a doorknob, a rope, a sheet of paper or fabric, or a pair of scissors, there's probably a different design that's several orders of magnitude simpler and cheaper, and also much stronger and more reliable. Single-axis parallel grippers, circumferential chucks, vacuum cups/vacuum pads, electromagnets, cam lock and release mechanisms, and so on are common in industrial robotics.
Assume your robot's only task is to grab a spool with a 35 +/-0.5 mm ID core from from an infeed rack and place it on a spindle, you're not going to try to build a five-finger human sized servo-operated hand and tuck two of those fingers away to awkwardly pinch outwards from the inside, you're going to grab a Schunk JGZ concentric gripper off the shelf and plumb a pair of air lines to it. If it also needs to grab a tab from some tape on the spool and pull it into the machine, you're just going to add an asymmetric pincer like an angular tumor on two of the jaws - or graft on an entire separate parallel gripper like some polydactyl appendage, or tool-change, amputating and reattaching hands at will.
I have also observed that humans are quite good at anthropomorphizing robot arms: a small, well-tuned motion can be universally recognized as a nod of agreement, shrug of confusion, wave of acknowledgement, or sigh of disappointment, even if the equipment is a bright yellow 6-axis piece of cast iron with menacing claws where the hand (or face? they're often the same) should be. Googley eyes and a "Hi my name is" sticker make this even more convincing.
But if you need a single tool to grip a doorknob, a rope, a sheet of paper, a pair of scissors, AND an unknown variety of other arbitrary household objects... it's probably best to start with an approximation of the human hand. Also, while claws may be appropriate for a work environment with the robot inside a fence, in collaborative situations hands are just less intimidating.
> For any one specific thing, be it a doorknob, a rope, a sheet of paper or fabric, or a pair of scissors, there's probably a different design that's several orders of magnitude simpler and cheaper, and also much stronger and more reliable.
Also, if you’re designing a robot gripper for any one specific thing, it’s quite possible that you can tweak the design of that specific thing to make the task easier. As an extreme example, screws and screw drivers evolve in parallel.
As an aside, this "robot tentacle" paper was referenced in a recent HN story: "SpiRobs: Logarithmic Spiral-shaped Robots for Versatile Grasping Across Scales"[1]
Seems like a pretty high bang-for-the-buck for versatility and capability with only a few cables controlling it.
The question you are asking opens up a whole other field of questions. The amount of AI and robotics "in the field" is only going to increase. As that increase comes do we want to continue to build for a human capabilities and limitations, or do we want to build for machine capabilities and limitations.
I think the ethical approach is to build for human capabilities and limitations. We have already seen what happens when we allow business to optimize for the lowest common denominator, and that is why we have regulations that emphasize accessibility. If we allow or encourage businesses to build robots that lack human capabilities and limitations that operate in the real world alongside humans, then even if those robots are assistive in nature (either a prosthetic robot hand, or a full blown humanoid robotic assistant), we will displace or redefine what humans are capable of, and diminish the role of and respect for human beings in our society.
If anything, the human world is built for humans, so a lot of existing things are naturally compatible with human hands. Also, take into account flexibility. It might not be the best for one job, but it's really okay at a lot of jobs.
Is there a better design? I ask this genuinely, I really don't know but I suspect that the human hand is versatile enough to allow it to be programmable for a variety of tasks.
The human hand is arguably the best general purpose gripper of human-scale objects. Only took evolution a couple of hundred million years to figure it out.
If you can limit the scope of things to be gripped, e.g. a sheet of paper, a baby chicken or a 100x100mm square steel girder then no doubt there is a better design out there.
Not exactly. The human hand is really advanced within the constraint of "you can't just arbitrarily replace damaged parts". If you can swap in replacement fingers, 3 of them is fine (and much easier to model and perform grasping calculations.)
Our modern world was built for hand-havers, so we build hand-havers for general interaction with the modern world. This vicious cycle will end, but a certain amount of inertial clunkiness is inevitable in nascent technological disruptions. Especially in moments as grand as the second industrial revolution.
Feet are used for roughly the same reason a human-like hand is preferable - human-designed spaces tend to not be perfectly compatible with wheeled locomotion.
The ability to negotiate stairs is table stakes for a household robot. It's already a pain when one's Roomba-like is defeated by a small ledge...
But... is a human hand the best design for a robot to grip things with? Or could we surmise that the human hand evolved as a pretty good hand given the materials and senses that were available to evolve humans from, while in theory a totally different design might be optimal for gripping when constructed from metal, plastic, motors, etc.?