KFCPO: Kronecker-Factored Approximated Constrained Policy Optimization

• URL: http://arxiv.org/abs/2511.00880v1
• Date: Sun, 02 Nov 2025 10:33:57 GMT
• Title: KFCPO: Kronecker-Factored Approximated Constrained Policy Optimization
• Abstract summary: KFCPO is a Safe Reinforcement Learning (Safe RL) algorithm based on second-order policy optimization with safety-aware gradient manipulation.<n>Experiments on Safety Gymnasium using OmniSafe show that KFCPO achieves 10.3% to 50.2% higher average return across environments.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We propose KFCPO, a novel Safe Reinforcement Learning (Safe RL) algorithm that combines scalable Kronecker-Factored Approximate Curvature (K-FAC) based second-order policy optimization with safety-aware gradient manipulation. KFCPO leverages K-FAC to perform efficient and stable natural gradient updates by approximating the Fisher Information Matrix (FIM) in a layerwise, closed form manner, avoiding iterative approximation overheads. To address the tradeoff between reward maximization and constraint satisfaction, we introduce a margin aware gradient manipulation mechanism that adaptively adjusts the influence of reward and cost gradients based on the agent's proximity to safety boundaries. This method blends gradients using a direction sensitive projection, eliminating harmful interference and avoiding abrupt changes caused by fixed hard thresholds. Additionally, a minibatch level KL rollback strategy is adopted to ensure trust region compliance and to prevent destabilizing policy shifts. Experiments on Safety Gymnasium using OmniSafe show that KFCPO achieves 10.3% to 50.2% higher average return across environments compared to the best baseline that respected the safety constraint, demonstrating superior balance of safety and performance.

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