3 ms·

it's disappointing to realize that we still haven't caught up to fundamental biological systems yet, even though the research is 2+ decades old. Given that we'

it's disappointing to realize that we still haven't caught up to fundamental biological systems yet, even though the research is 2+ decades old. Given that we're the result of billions of years of natural selection, shouldn't we expect that?

clairity 8y ago
in general, yes (natural selection is amazing), but the knowledge in this case has been readily available for literally decades but not applied appropriately. organisms have evolved over billions of years to take advantage of passive dynamics, which is basically the application of newtonian physics to what is mostly a mechanical design problem. we've known for a long time that passive dynamic elements are not only energetically more efficient, but also makes computations simpler. by contrast, active dynamic locomotion is akin to putting a joint between the front fork of a bike and the shaft, and installing a hand pump that you have to constantly actuate to keep the bike stable while you're riding it. you could do it, but it's not the best solution.
- stcredzero 8y ago
  The trick is in the application. Most of our "industrial lego" is for making mostly rigid things with some spinny parts and a few, mostly passive sproingy/squishy bits. However, we ourselves are mostly sproingy/squishy and a lot of that is dynamic. By the same token, most of the tooling and parts for building airplanes isn't all that useful for building orinthopters. So it's not just knowledge. It's knowledge expressed in the form of industrial infrastructure and products.
  - clairity 8y ago
    yes, legged robots at scale requires such industrial infrastructure, but at the current r&d stage, they can still apply these learnings.
- dbcurtis 8y ago
  > but the knowledge in this case has been readily available for literally decades but not applied appropriately. This isn’t a kinematics homework where you can draw the links and joints and get full marks. You have to actuate them. For a human gait, you need to generate the same torque, at the same velocities, and the mass of the actuator needs to distribute across the linkages in the same proportion. Guess what? Actuators like that are hard to find.
  - clairity 8y ago
    the proper kinematics makes both the mechanical design and the control systems simpler, including leeway in choosing the actuators. you’re right in that we don’t have muscle-like fast-acting axial actuators with pliable multi-insertion endpoints, but you don’t need to exactly mimic a human leg (which is effectively impossible right now) to apply these principles.
  - stcredzero 8y ago
    This isn’t a kinematics homework where you can draw the links and joints and get full marks. You have to actuate them. I should paraphrase that for interviews. "This isn't a CS homework where you can cite Big-O and get full marks. We have to be able to implement code that uses them." And by that, I don't mean that you have to write all of the actual code. But one needs to be able to specify it exactly so someone could implement it and know enough about that to tell someone of the pitfalls in the current problem context/framework.

clairity 8y ago

in general, yes (natural selection is amazing), but the knowledge in this case has been readily available for literally decades but not applied appropriately. organisms have evolved over billions of years to take advantage of passive dynamics, which is basically the application of newtonian physics to what is mostly a mechanical design problem. we've known for a long time that passive dynamic elements are not only energetically more efficient, but also makes computations simpler. by contrast, active dynamic locomotion is akin to putting a joint between the front fork of a bike and the shaft, and installing a hand pump that you have to constantly actuate to keep the bike stable while you're riding it. you could do it, but it's not the best solution.

stcredzero 8y ago
The trick is in the application. Most of our "industrial lego" is for making mostly rigid things with some spinny parts and a few, mostly passive sproingy/squishy bits. However, we ourselves are mostly sproingy/squishy and a lot of that is dynamic. By the same token, most of the tooling and parts for building airplanes isn't all that useful for building orinthopters. So it's not just knowledge. It's knowledge expressed in the form of industrial infrastructure and products.
- clairity 8y ago
  yes, legged robots at scale requires such industrial infrastructure, but at the current r&d stage, they can still apply these learnings.
dbcurtis 8y ago
> but the knowledge in this case has been readily available for literally decades but not applied appropriately. This isn’t a kinematics homework where you can draw the links and joints and get full marks. You have to actuate them. For a human gait, you need to generate the same torque, at the same velocities, and the mass of the actuator needs to distribute across the linkages in the same proportion. Guess what? Actuators like that are hard to find.
- clairity 8y ago
  the proper kinematics makes both the mechanical design and the control systems simpler, including leeway in choosing the actuators. you’re right in that we don’t have muscle-like fast-acting axial actuators with pliable multi-insertion endpoints, but you don’t need to exactly mimic a human leg (which is effectively impossible right now) to apply these principles.
- stcredzero 8y ago
  This isn’t a kinematics homework where you can draw the links and joints and get full marks. You have to actuate them. I should paraphrase that for interviews. "This isn't a CS homework where you can cite Big-O and get full marks. We have to be able to implement code that uses them." And by that, I don't mean that you have to write all of the actual code. But one needs to be able to specify it exactly so someone could implement it and know enough about that to tell someone of the pitfalls in the current problem context/framework.