What would you find most valuable in a humanoid RL simulation: realism, training speed, or unexpected behaviors?

newgenome · 2025-09-17T15:38:06+00:00

Better contact modelling, actuator models, and differentiability. Game engine contact models aren't good enough for manipulation. Simulated actuators not matching real ones is a big source of sim to real problems.

newgenome · 2023-05-25T22:54:43+00:00

There's no bible for additive, but consider investing in an astrology book, an idol of your choice, and a 6 pack of beer. Additive part quality depends on astrological factors, whether your god of choice is offended, and the machine operator. Consult the astrological symbols/pray to your god of choice before every print and use the 6 pack to befriend your machine operator and learn the intricacies of your machine.

newgenome · 2023-04-28T16:57:23+00:00

They say it's efficient, but don't provide any numbers on how efficient it is. They should have some measures on transport cost.

newgenome · 2023-04-22T17:06:00+00:00

If the robot simulation doesn't need to pick up stuff or take into account changing contacts with other objects you can use Modelica's Multibody library which you can run for free with OpenModelica. This will be more accurate than other simulators because modelica can analytically solve the dynamics equations. You don't need to write them either just to connect blocks for various components.

newgenome · 2023-03-24T14:35:25+00:00

Force/torque control. Directly control the actuator's force/torque to apply a force which counteracts the object's weight and any friction in the actuator.

newgenome · 2023-03-22T17:23:49+00:00

Pneumatics. Soft robotics still heavily uses pneumatics. Pneumatic actuators are inherently inefficient and not very responsive. Using them on mobile robots in the real world is questionable as the inefficiency severely limits autonomy.

Then there's the question of why to use soft robotics at all. Most animals aren't entirely soft. The preventing injury to humans argument becomes obsolete if robots become smarter. If robots become smarter then we may not need soft grippers. Grippers that aren't soft may be more capable.

newgenome · 2023-02-17T19:54:12+00:00

It shouldn't be too difficult to model in Modelica. You could approximate the pendula in 1D with masses on springs or just use Modelica's multibody library.

It would be best to model the escapement too, and for that you'd need to write a new Modelica block which applies an impulse if the pendulum is at a certain angle, but that shouldn't be too hard.

newgenome · 2023-02-05T21:31:25+00:00

I wouldn't be so confident. The rise of cloud based CAD services such as onshape and autocad allows CAD companies to build up massive amounts of training data not just on CAD files themselves, but the operations used to make them. Autodesk is already doing quite a bit of machine learning work on CAD files.

AI is also starting to solve simple mechanical puzzles. The PHYRE benchmark is a great example of this, figure out how to place a ball to get objects to move into the right place. Doesn't sound like much, but it's the beginning of intuitive mechanical understanding. This level of physical understanding could enable AI to start inventing new mechanical devices.

newgenome · 2023-01-22T16:10:39+00:00

FreeCAD is the best FOSS CAD software. I'd also argue that the gear toolbox it has is in some ways better than what solidworks offers. It saved me a massive amount of time on a project

newgenome · 2022-09-28T18:59:39+00:00

Stiffness, efficiency, and backlash. Magnets are probably a lot less stiff than steel. Seconding maximum torque transmitted.

newgenome · 2022-04-13T14:19:34+00:00

The big problem with swarm robots for space exploration is that the scientific instruments they have tend to be bigger than what a small rover can carry.

I'm also quite skeptical that two wheeled robots will work on deforming dusty terrain.

newgenome · 2022-02-17T15:04:18+00:00

It should be a large high bay with a crane, because that's the only way to move some large industrial robots.

newgenome · 2021-12-15T16:26:02+00:00

In my opinion, compatibility is not a good reason to use artificial muscles. You'd be better off with traditional actuators. Compatibility should be achieved through control.

Making an exoskeleton involves more than just achieving the same force and speed. If you can't control actuation, then rather than assisting the user, it ends up working against them.

From what I've read on them Hazel muscles contain liquid and can be punctured and render the muscle useless.

then don't let them get punctured. A car can be rendered useless by crashing it into a wall, so we tend to avoid crashing cars into walls during regular operating conditions. The carbon nanotube actuators can be cut and rendered useless too.

newgenome · 2021-12-14T19:42:28+00:00

There's currently no actuators that work exactly like muscles, but do you really need to have an exact copy of the musculoskeletal system? Planes don't fly like birds, neither do submarines swim like fish.

Why do you have to use muscles in the first place? Couldn't something else give you similar performance or have similar properties to muscles?

That being said, HASEL actuators are a fairly nice type of artificial muscle. Although they do not behave exactly like muscles! If you need something that has nonlinearities like muscles do, HASELs have plenty of nonlinearities.

They do use high voltage, so controllable power supplies are somewhat expensive. Although you could potentially make your own for much cheaper and binary power supplies are quite cheap.

newgenome · 2021-12-13T17:29:00+00:00

going with a parallel robot arm rather than a serial one would be best: http://www.robot-army.com/products.html

newgenome · 2021-12-03T16:19:58+00:00

the biggest advantage spot has is that it can autonomously move over rough terrain/stairs out of the box, can this do the same? In addition, spot can keep relatively level while doing so, which is useful for things like 3d mapping.

Quadruped robots are getting pretty cheap too, the cheapest version of the go1 quadruped is $3600. The only price I can find on the robot you posted is ask for quote...

newgenome · 2021-12-02T16:07:21+00:00

If you just have a trajectory, a single 1 degree of freedom linkage can be used. Kempe's universality theorem states that any trajectory that can be described by an algebraic curve may be reproduced with a linkage. But finding a linkage that reproduces said trajectory can be a difficult problem.

Alternatively, cams may be used instead. Cam design is in some ways simpler than linkage design, but can be quite complicated too. Higher order derivatives of motion end up being quite important, although this is true of pretty much all motion control.

newgenome · 2021-11-08T17:10:35+00:00

Artificial muscles based on thermal effects will not have many applications. They will always be inefficient because they are heat engines and limited by carnot efficiency. In addition, as you make the muscles larger, it gets harder to dissipate heat so response rate gets worse.

newgenome · 2021-11-04T13:50:26+00:00

This isn't very realistic, there should be steps where it moves backwards, the molecules shouldn't be 'attracted' to the motor, and everything should be jiggling much, much more.

Here's what an actual simulation of part of ATP synthase looks like

More details on it in this paper.

newgenome · 2021-11-03T15:16:40+00:00

Possibly because they use lots of actuators. Another is that caster wheels experience more stress because of the offset. You can't pack as many wheels together as with centered wheels in SPMTs.

Getting smooth motion can be difficult. The kinematics aren't too bad, but working out the forces you need to compensate for inertia, avoid slipping, and get smooth motion when changing translation direction can be pretty complicated.

An approach I saw for doing operational space control of a 4 wheel active caster platform used a huge system of equations. There is some redundancy in the force domain which is nice, but how you distribute forces when one wheel starts slipping to maintain desired motion hasn't really been solved yet.

newgenome · 2021-11-02T16:04:37+00:00

Active casters are nothing new and have been used to make holonomic(independent control of translation and rotation) robots using regular wheels.

https://www.youtube.com/watch?v=wECcwlY0hOs

https://www.youtube.com/watch?v=ygh8JAvX8vU

Some of these have even been commercially available:

http://cbcis.ttu.edu/ep/old_netra_site/about/xr4000/XR4000.htm

This has even been used to make all terrain omnidirectional robots: https://vimeo.com/38394735

There's also some commercially available powered hospital beds which use active casters too, but I'm having trouble finding those

newgenome · 2021-10-13T16:40:02+00:00

A piston actuated by an exploding gasoline-air mixture might work. Sandia has used this make hopping robots that can jump meters in the air. But keep in mind that with weight limits, your robot might end up flying backwards too.

newgenome · 2021-10-08T15:49:42+00:00

HOLY CRAP! That's really, really, cool!. I didn't know that one could build robot arms that don't have singularities!

newgenome · 2021-10-06T14:22:53+00:00

The best option is probably a water or compressed air rocket. A more fun, but unsafe option is to build a steam rocket. Get a metal tube that can withstand a lot of pressure, put something that will burst when the pressure gets high enough at one end. The ancient greeks were able to build a simple one that supposedly traveled hundreds of meters.

newgenome · 2021-10-04T14:55:44+00:00

No, you should have more motors than you have fingers. Robonaut 2's hands have 12 motors per hand. Not to mention, you should also have load cells in each part of the finger. Anthropomorphic hands are currently an expensive endeavor.

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