Btw, today i have replaced box feet with compounds of spheres.
I expected this to give more robust contacts, but the win on accuracy is much bigger than thought
that's quite correct. Using three spheres makes so that the contacts are consistent.
I am however still going to use a box, for simplicity. My new objective is not to use the contacts as support point, but instead use the heel ankle point.
That is why I made the swivel/position effector joint.
I now finished the file format phase, and I am ready to resume the work on self-balancing.
As I stated before, I will start far more humbled with unit cycle.
unitcycles has been around for centuries, here is a better picture than the funny one I posted before.
- Untitled1.png (97.7 KiB) Viewed 14588 times
basically, is a heavy body balanced on a rolling wheel.
I set up the environment already when running, it passes the first two test.
1- Conservation of momentum. this is if you put the model on the free space, no gravity.
if the model move any limb, the resulting motion should not add any global rotation or translation to the body. when I run the test, I was expectation that over time the error will crip in and the model will gain some rotation, but to my surprised it run stable for a very long time.
I was very pleased with the first result.
2-secund est, when the h model is resting in equilibrium on the ground, the next force and Torque should be zero.
The engine IK solver actually failed the test.
It took me some time to figure out why.
what I got was a net force of about two newton down, so the model should sinc into the floor,
but it did not, so, it look like there was some bug on the iksolver.
then after some debugging I realized that the IK solver set the contact the same way it's set for the general solver, but the general solver works in contact penetration, that is compensated penetration error with a penalty proportional to the penetration. so essentially the contacts act as a very strong spring.
the IK solver cannot work that way, because if it uses that force which is not part of equilibrium state, I will try to make false corrections on the model actuators.
after making the fix, now everything works as I expect so far.
in the next day or two, I will work on making that model to keep its balance under some small perturbation.
I have seeing many videos where people from Deep Mind use these Reinforcement learning AI algorithm to control humanoid models, and it is quite appalling how these people take their target audience for fools.
here is one
https://www.youtube.com/watch?v=SsJ_Aus ... tg&index=2you can see how the physics is just terrible, I have a trained Eye to see that those models are not conserving momentum, in fact there shouldn't even be standing up for a frame or two. it is obvious there are God forces that keeps the body up. Yet they say that it is the same as this.
https://www.youtube.com/watch?v=RbyQcCT6890n the secund model, you can see that the robot has very big feet, therefore the model already has a large defined support polygon, and the model moves already statically stable. Where the simulation only moves the actuators keeping the com inside the polygon defined by the large foot plan.
The AI maybe be good, but the physics is quite terrible.
That's is also my goal, but I do not plan on cheating,