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RAMU

Risk-Averse Model Uncertainty

OnlineRobust safeBase · PPOClaims · dynamic shift

A risk measure over sampled next-state perturbations, applied to reward and cost targets.

Features

Feature Value
Group Robust Safe Algorithms
Setting Online, with a cost constraint
Family Robust safe
Base algorithm PPO
Claimed robustness Dynamic shift
Shifted-env rollout No
Adversarial network No
Learned model No
Training budget Isaac Lab recipe
Original paper Queeney and Benosman Risk-Averse Model Uncertainty for Distributionally Robust Safe Reinforcement Learning. NeurIPS, 2023.

Mechanism

RAMU applies a risk measure over sampled next-state perturbations to both the reward and the cost targets. The original method is defined for TD learners; the library's row is a PPO adaptation that applies the same transform to PPO's value targets.

Run the method

./isaaclab.sh -p isaac/train.py --task g1 --method ramu --seed 0 --headless
./isaaclab.sh \
    -p isaac/evaluate.py --task g1 --checkpoint runs/isaac/g1_ramu/seed0/model_1499.pt --condition all --headless
File Path
Implementation isaac/methods/ramu.py

Training is on the nominal task. The configuration files are explained in Train an algorithm, and the evaluation of the frozen checkpoint in Evaluation Protocol.

References

  • Queeney and Benosman Risk-Averse Model Uncertainty for Distributionally Robust Safe Reinforcement Learning. NeurIPS, 2023.