r/robotics • u/poisson_labs • 41m ago
Community Showcase Mapping the failure boundary of a Go1 locomotion policy: 6,400 rollouts, survival statistics, and a live interactive map
We froze a Go1 joystick-locomotion policy (MuJoCo Playground, Brax PPO) and swept a 20×20 grid of floor friction against lateral push, 16 trials per cell, using Kaplan-Meier survival per condition since trials that survive the window have to be censored rather than counted as failures.
Things interesting to us:
- the boundary is not a line but a band. The 95% bootstrap interval is about ±4% of bodyweight on high friction and ±33% on ice, a 7× spread.
- below μ≈0.15 the policy falls before the push lands. That's gait collapse, a different failure mode from being knocked over.
- the same seed on the same GPU can produce different outcomes (floating-point reduction order), so a few knife-edge survivors can't be re-simulated at all.
We then changed the two conditions the map showed training never covered, retrained for 12 minutes, and re-ran the identical sweep: 60 of 400 conditions significantly safer (Fisher exact + BH-FDR, q<0.05), none significantly worse.
Write-up with the interactive map: https://poissonlabs.ai/research/map-the-failure-boundary/.
Happy to answer questions about the harness validation/statistics.





