Projection-Based Constrained Policy Optimization
Not on the map. Why?
Abstract (arXiv)
We consider the problem of learning control policies that optimize a reward function while satisfying constraints due to considerations of safety, fairness, or other costs. We propose a new algorithm, Projection-Based Constrained Policy Optimization (PCPO). This is an iterative method for optimizing policies in a two-step process: the first step performs a local reward improvement update, while the second step reconciles any constraint violation by projecting the policy back onto the constraint set. We theoretically analyze PCPO and provide a lower bound on reward improvement, and an upper bound on constraint violation, for each policy update. We further characterize the convergence of PCPO based on two different metrics: normltwo norm and Kullback-Leibler divergence. Our empirical results over several control tasks demonstrate that PCPO achieves superior performance, averaging more than 3.5 times less constraint violation and around 15% higher reward compared to state-of-the-art methods.
Key facts. Cited by 195 papers in the map (data through 7 Oct 2026). First posted on arXiv 7 Oct 2020.
Builds on
No reference list yet.
Built on by
Citing papers per year: 2021: 25; 2022: 30; 2023: 45; 2024: 40; 2025: 29; 2026: 26.
195 papers.
Sort:
By area:
- 2022A Review of Safe Reinforcement Learning: Methods, Theory and Applicationscited by 169
- 2023Safety-Gymnasium: A Unified Safe Reinforcement Learning Benchmarkcited by 135
- 2021Learning Policies with Zero or Bounded Constraint Violation for Constrained MDPscited by 78
- 2023OmniSafe: An Infrastructure for Accelerating Safe Reinforcement Learning Researchcited by 76
- 2022Constrained Variational Policy Optimization for Safe Reinforcement Learningcited by 69
- 2023Constrained Decision Transformer for Offline Safe Reinforcement Learningcited by 65
- 2022Saute RL: Almost Surely Safe Reinforcement Learning Using State Augmentationcited by 63
- 2024Safe Offline Reinforcement Learning with Feasibility-Guided Diffusion Modelcited by 62
- 2022Penalized Proximal Policy Optimization for Safe Reinforcement Learningcited by 60
- 2021Exploration in Deep Reinforcement Learning: From Single-Agent to Multiagent Domaincited by 57
- 2022Constrained Update Projection Approach to Safe Policy Optimizationcited by 55
- 2022Reachability Constrained Reinforcement Learningcited by 52
38 more
- 2023SafeDreamer: Safe Reinforcement Learning with World Modelscited by 50
- 2024Enhancing LLM Safety via Constrained Direct Preference Optimizationcited by 47
- 2024A Survey of Constraint Formulations in Safe Reinforcement Learningcited by 42
- 2022On the Robustness of Safe Reinforcement Learning under Observational Perturbationscited by 38
- 2021DOPE: Doubly Optimistic and Pessimistic Exploration for Safe Reinforcement Learningcited by 34
- 2021Context-Aware Safe Reinforcement Learning for Non-Stationary Environmentscited by 33
- 2021Safe Reinforcement Learning with Linear Function Approximationcited by 33
- 2023Not Only Rewards But Also Constraints: Applications on Legged Robot Locomotioncited by 33
- 2023Iterative Reachability Estimation for Safe Reinforcement Learningcited by 33
- 2022Trustworthy Reinforcement Learning Against Intrinsic Vulnerabilities: Robustness, Safety, and Generalizabilitycited by 32
- 2021Enforcing Policy Feasibility Constraints through Differentiable Projection for Energy Optimizationcited by 31
- 2022Provably Safe Reinforcement Learning: Conceptual Analysis, Survey, and Benchmarkingcited by 31
- 2021Feasible Actor-Critic: Constrained Reinforcement Learning for Ensuring Statewise Safetycited by 30
- 2021Direct Behavior Specification via Constrained Reinforcement Learningcited by 30
- 2021On-Policy Deep Reinforcement Learning for the Average-Reward Criterioncited by 29
- 2022Safe Reinforcement Learning for Legged Locomotioncited by 29
- 2025Think Smarter not Harder: Adaptive Reasoning with Inference Aware Optimizationcited by 29
- 2022Towards Safe Reinforcement Learning with a Safety Editor Policycited by 28
- 2023Last-Iterate Convergent Policy Gradient Primal-Dual Methods for Constrained MDPscited by 27
- 2022Convergence and sample complexity of natural policy gradient primal-dual methods for constrained MDPscited by 26
- 2021Safe Pontryagin Differentiable Programmingcited by 25
- 2021Density Constrained Reinforcement Learningcited by 25
- 2021Differentiable Trust Region Layers for Deep Reinforcement Learningcited by 24
- 2022Provably Safe Reinforcement Learning via Action Projection using Reachability Analysis and Polynomial Zonotopescited by 23
- 2021Policy Optimization for Constrained MDPs with Provable Fast Global Convergencecited by 22
- 2025Trust Region Constrained Measure Transport in Path Space for Stochastic Optimal Control and Inferencecited by 22
- 2024Balance Reward and Safety Optimization for Safe Reinforcement Learning: A Perspective of Gradient Manipulationcited by 21
- 2023Trust Region-Based Safe Distributional Reinforcement Learning for Multiple Constraintscited by 20
- 2021Escaping from Zero Gradient: Revisiting Action-Constrained Reinforcement Learning via Frank-Wolfe Policy Optimizationcited by 18
- 2021Faster Algorithm and Sharper Analysis for Constrained Markov Decision Processcited by 18
- 2022Benchmarking Constraint Inference in Inverse Reinforcement Learningcited by 18
- 2022Evaluating Model-free Reinforcement Learning toward Safety-critical Taskscited by 18
- 2021Safe Continuous Control with Constrained Model-Based Policy Optimizationcited by 17
- 2022SABLAS: Learning Safe Control for Black-box Dynamical Systemscited by 17
- 2023Constraint-Conditioned Policy Optimization for Versatile Safe Reinforcement Learningcited by 17
- 2022CUP: A Conservative Update Policy Algorithm for Safe Reinforcement Learningcited by 16
- 2022Safe Model-Based Reinforcement Learning with an Uncertainty-Aware Reachability Certificatecited by 16
- 2023SaFormer: A Conditional Sequence Modeling Approach to Offline Safe Reinforcement Learningcited by 16
50 most cited of 195 All 195 (JSON)
- 2026Vision--Language Signals in Constrained RL: Safety Gains Without Anticipation28 Sep 2026
- 2026Beyond Average Safety: Chance-Constrained LLM Fine-tuning24 Sep 2026
- 2026BCPPO: Bachelier-Inspired Constrained Proximal Policy Optimization for Tail-Risk-Aware Safe Reinforcement Learning31 Aug 2026
- 2026Boundary-Seeking Policy Gradient for Safe Reinforcement Learning10 Aug 2026
- 2026Navigating the Proximity-Safety Balance: Constraint Decomposition for Human Following in Pedestrian Crowds10 Aug 2026
- 2026SteinGate: Tail-Sensitive Safe Reinforcement Learning via Stein Discrepancy14 Jul 2026
- 2026Towards Value-Constrained Credit Assignment in Fully Delegated AI Cooperatives26 Jun 2026
- 2026CSPO: Constraint-Sensitive Policy Optimization for Safe Reinforcement Learning12 Jun 2026
- 2026Utility-Constrained Policy Optimization12 Jun 2026
- 2026Seeing Before Colliding: Anticipatory Safe RL with Frozen Vision-Language Models9 Jun 2026
- 2026Interaction-Limited Safe Continuous-Time RL for Dynamical Medical Treatment31 May 2026
- 2026Latent Q-Barrier Shielding for Safe In-Context Reinforcement Learning24 May 2026
38 more
- 2026Action-Conditioned Risk Gating for Safety-Critical Control under Partial Observability14 May 2026
- 2026Stochastic Minimum-Cost Reach-Avoid Reinforcement Learning12 May 2026
- 2026Shaping Zero-Shot Coordination via State Blocking12 May 2026
- 2026Beyond ESG Scores: Learning Dynamic Constraints for Sequential Portfolio Optimization10 May 2026
- 2026Global Optimality for Constrained Exploration via Penalty Regularization30 Apr 2026
- 2026CAPSULE: Control-Theoretic Action Perturbations for Safe Uncertainty-Aware Reinforcement Learning26 Apr 2026
- 2026Safe Reinforcement Learning with Preference-based Constraint Inference24 Mar 2026
- 2026HALO: Learning Human-Robot Collaboration via Heterogeneous-Agent Lyapunov Policy Optimization4 Mar 2026
- 2026Reinforcing Real-world Service Agents: Balancing Utility and Cost in Task-oriented Dialogue26 Feb 2026
- 2026Solving Parameter-Robust Avoid Problems with Unknown Feasibility using Reinforcement Learning17 Feb 2026
- 2026Safe Langevin Soft Actor Critic31 Jan 2026
- 2026Safety Generalization Under Distribution Shift in Safe Reinforcement Learning: A Diabetes Testbed28 Jan 2026
- 2026Enhance the Safety in Reinforcement Learning by ADRC Lagrangian Methods26 Jan 2026
- 2026Controlling Underestimation Bias in Constrained Reinforcement Learning for Safe Exploration17 Jan 2026
- 2025SB-TRPO: Towards Safe Reinforcement Learning with Hard Constraints29 Dec 2025
- 2025Mitigating the Safety Alignment Tax with Null-Space Constrained Policy Optimization12 Dec 2025
- 2025LPPG-RL: Lexicographically Projected Policy Gradient Reinforcement Learning with Subproblem Exploration11 Nov 2025
- 2025Provably Efficient Sample Complexity for Robust CMDP10 Nov 2025
- 2025Primal-Only Actor Critic Algorithm for Robust Constrained Average Cost MDPs7 Nov 2025
- 2025Exchange Policy Optimization Algorithm for Semi-Infinite Safe Reinforcement Learning6 Nov 2025
- 2025Curriculum Design for Trajectory-Constrained Agent: Compressing Chain-of-Thought Tokens in LLMs4 Nov 2025
- 2025KFCPO: Kronecker-Factored Approximated Constrained Policy Optimization2 Nov 2025
- 2025Learning Boltzmann Generators via Constrained Mass Transport21 Oct 2025
- 2025SPiDR: A Simple Approach for Zero-Shot Safety in Sim-to-Real Transfer23 Sep 2025
- 2025Incentivizing Safer Actions in Policy Optimization for Constrained Reinforcement Learning11 Sep 2025
- 2025Multi-Agent Reinforcement Learning for Task Offloading in Wireless Edge Networks1 Sep 2025
- 2025HAEPO: History-Aggregated Exploratory Policy Optimization26 Aug 2025
- 2025Rectified Robust Policy Optimization for Model-Uncertain Constrained Reinforcement Learning without Strong Duality24 Aug 2025
- 2025Trust Region Constrained Measure Transport in Path Space for Stochastic Optimal Control and Inference17 Aug 2025
- 2025Proactive Constrained Policy Optimization with Preemptive Penalty3 Aug 2025
- 2025One Subgoal at a Time: Zero-Shot Generalization to Arbitrary Linear Temporal Logic Requirements in Multi-Task Reinforcement Learning3 Aug 2025
- 2025Temporally smoothed incremental model-based heuristic dynamic programming for command-filtered cascaded online learning flight control6 Jul 2025
- 2025PNAct: Crafting Backdoor Attacks in Safe Reinforcement Learning1 Jul 2025
- 2025Dual-Objective Reinforcement Learning with Novel Hamilton-Jacobi-Bellman Formulations19 Jun 2025
- 2025Situational-Constrained Sequential Resources Allocation via Reinforcement Learning17 Jun 2025
- 2025Efficient Policy Optimization in Robust Constrained MDPs with Iteration Complexity Guarantees25 May 2025
- 2025A Survey of Safe Reinforcement Learning and Constrained MDPs: A Technical Survey on Single-Agent and Multi-Agent Safety22 May 2025
- 2025Adaptive Shielding for Safe Reinforcement Learning under Hidden-Parameter Dynamics Shifts20 May 2025
50 newest of 195 All 195 (JSON)
- 2023Constrained Decision Transformer for Offline Safe Reinforcement Learningcited by 65
- 2024Safe Offline Reinforcement Learning with Feasibility-Guided Diffusion Modelcited by 62
- 2023SaFormer: A Conditional Sequence Modeling Approach to Offline Safe Reinforcement Learningcited by 16
- 2024Latent Safety-Constrained Policy Approach for Safe Offline Reinforcement Learningcited by 7
- 2022Regularized Soft Actor-Critic for Behavior Transfer Learningcited by 1
- 2025Don't Trade Off Safety: Diffusion Regularization for Constrained Offline RLcited by 0
- 2025Don't Trade Off Safety: Diffusion Regularization for Constrained Offline RL18 Feb 2025
- 2024Latent Safety-Constrained Policy Approach for Safe Offline Reinforcement Learning11 Dec 2024
- 2024Safe Offline Reinforcement Learning with Feasibility-Guided Diffusion Model19 Jan 2024
- 2023Constrained Decision Transformer for Offline Safe Reinforcement Learning14 Feb 2023
- 2023SaFormer: A Conditional Sequence Modeling Approach to Offline Safe Reinforcement Learning28 Jan 2023
- 2022Regularized Soft Actor-Critic for Behavior Transfer Learning27 Sep 2022
- 2023SafeDreamer: Safe Reinforcement Learning with World Modelscited by 50
- 2023SafeDreamer: Safe Reinforcement Learning with World Models14 Jul 2023
- 2022A Review of Safe Reinforcement Learning: Methods, Theory and Applicationscited by 169
- 2023Safety-Gymnasium: A Unified Safe Reinforcement Learning Benchmarkcited by 135
- 2021Learning Policies with Zero or Bounded Constraint Violation for Constrained MDPscited by 78
- 2023OmniSafe: An Infrastructure for Accelerating Safe Reinforcement Learning Researchcited by 76
- 2022Constrained Variational Policy Optimization for Safe Reinforcement Learningcited by 69
- 2022Saute RL: Almost Surely Safe Reinforcement Learning Using State Augmentationcited by 63
- 2022Penalized Proximal Policy Optimization for Safe Reinforcement Learningcited by 60
- 2021Exploration in Deep Reinforcement Learning: From Single-Agent to Multiagent Domaincited by 57
- 2022Constrained Update Projection Approach to Safe Policy Optimizationcited by 55
- 2022Reachability Constrained Reinforcement Learningcited by 52
- 2024A Survey of Constraint Formulations in Safe Reinforcement Learningcited by 42
- 2022On the Robustness of Safe Reinforcement Learning under Observational Perturbationscited by 38
12 most cited of 180 All 180 (JSON)
- 2026Vision--Language Signals in Constrained RL: Safety Gains Without Anticipation28 Sep 2026
- 2026Beyond Average Safety: Chance-Constrained LLM Fine-tuning24 Sep 2026
- 2026BCPPO: Bachelier-Inspired Constrained Proximal Policy Optimization for Tail-Risk-Aware Safe Reinforcement Learning31 Aug 2026
- 2026Boundary-Seeking Policy Gradient for Safe Reinforcement Learning10 Aug 2026
- 2026Navigating the Proximity-Safety Balance: Constraint Decomposition for Human Following in Pedestrian Crowds10 Aug 2026
- 2026SteinGate: Tail-Sensitive Safe Reinforcement Learning via Stein Discrepancy14 Jul 2026
- 2026Towards Value-Constrained Credit Assignment in Fully Delegated AI Cooperatives26 Jun 2026
- 2026CSPO: Constraint-Sensitive Policy Optimization for Safe Reinforcement Learning12 Jun 2026
- 2026Utility-Constrained Policy Optimization12 Jun 2026
- 2026Interaction-Limited Safe Continuous-Time RL for Dynamical Medical Treatment31 May 2026
- 2026Latent Q-Barrier Shielding for Safe In-Context Reinforcement Learning24 May 2026
- 2026Action-Conditioned Risk Gating for Safety-Critical Control under Partial Observability14 May 2026
12 newest of 180 All 180 (JSON)