Extreme sensitivity to weak wrists on G1

[carlosdp]

Hey! So we figured out the issue with our G1s.

One of them had a busted waist_pitch joint, and FALCON freaks out because it seems the waist is very important to it's balancing (dec_loco worked OK on this robot, because it doesn't control waist).

The other had wrists that were weakened/defective, and this results in FALCON freaking out too. I wanted to note this as we've observed the issue with wrists is common in some batches of G1s, so others might run into the same issue and be confused. This is something that should be addressable in training, because the Unitree base policies worked fine on that robot, for what it's worth.

Replacing the wrists on robot 2 completely fixed it and FALCON works great zero shot!

[hang0610]

Thanks for the heads up! Will update a better training setting soon.

[shijiancode]

Hey! So we figured out the issue with our G1s.

One of them had a busted waist_pitch joint, and FALCON freaks out because it seems the waist is very important to it's balancing (dec_loco worked OK on this robot, because it doesn't control waist).

The other had wrists that were weakened/defective, and this results in FALCON freaking out too. I wanted to note this as we've observed the issue with wrists is common in some batches of G1s, so others might run into the same issue and be confused. This is something that should be addressable in training, because the Unitree base policies worked fine on that robot, for what it's worth.

Replacing the wrists on robot 2 completely fixed it and FALCON works great zero shot!

Will a problem with the wrist joint of a robot cause it to lose control during deployment? It seems that when I deployed it, I lost control because my wrist joint was broken

[carlosdp]

@shijiancode yes, for this kind of whole body policy, it's pretty typical in my experience for a broken wrist joint to cause the policy to freak out. For some, it's because it's an out of distribution observation. For FALCON, I suspect it's because it interprets the wrist falling as weight (like a box) being added to the forearm, compensates (but overdoes it because there isn't actually force being applied), oscillates and then enters a bad state and freaks out.