A robot can predict failure and still be unable to prevent it. By the time a safety mechanism reacts, the nominal plan may already have spent the control authority that recovery requires, and fixed task priorities may block whatever response remains. Our key insight is that both aspects are decided inside the controller. Recoverability must inform actions while they are chosen rather than veto them afterward, and task objectives must be adapted as recoverability shrinks. Building on this, we present RAYA, a hybrid learned-analytic framework that places a learned finite-horizon recoverability margin inside an optimal controller with hard constraints and pairs it with a bounded learned scheduler that shifts task weights to facilitate recovery. Across 7,200 simulation episodes per controller spanning quadrotor and autonomous-vehicle benchmarks, RAYA not only improves survival rates, but also transfers the learned components zero-shot to unseen trajectories, disturbances, plant shifts, and friction layouts. We developed an embedded realization of RAYA and deployed it on-board a 35g Crazyflie quadrotor. Across 40 combined hardware flights under wind with either aerodynamic mismatch or an unmodeled 40% motor-command loss, each of three baselines fails in all trials, while RAYA completes 10/10 six-cycle missions. Project Website: https://raya-control.github.io/.
Figures & tables
Fig. 1: RAYA learns when recoverability is deteriorating and how the task should respond. Closed-loop rollouts train a finite-horizon recoverability predictor and a bounded reallocation scheduler. At deployment, their outputs jointly modify a predictive control problem where the recoverability margin shapes the constraints, while the scheduler reweights selected tracking objectives before the control action is optimized.
Fig. 2: Quadrotor disturbance robustness and zero-shot transfer. (A) Figure-8 survival across the wind sweep for nine controllers using 100 shared seeds per method–wind condition. Controller separation is largest between the benign and near-infeasible regimes. (B) Survival gain over nominal MPC for controllers that improve on unseen trajectories, turbulent wind, and mass/drag shift. Whiskers show 95% whole-seed clustered bootstrap intervals.
Fig. 3: F1TENTH recoverable operating envelope under latent friction loss. Left. Survival on periodic strips and unseen random multi-patch and single-patch layouts. Whiskers show 95% placement-clustered bootstrap intervals. Right. Survival over the periodic-strip friction-loss–exposure grid using 100 shared placements per condition. White curves mark the 50%-survival boundary, and yellow boxes mark scenarios included during training.
Platform
Configuration
Survival (95% CI)
Mean Reallocation
Quadrotor
Margin, K=1
37.48 [33.36,41.67]
0.000
Quadrotor
Margin, K=3
36.33 [32.29,40.57]
0.000
Quadrotor
RAYA , K=1
40.83 [36.55,45.24]
0.698
Quadrotor
RAYA , K=3
39.98 [35.74,44.36]
0.702
AV
RAYA , K=1
48.73 [46.93,50.53]
0.271
AV
RAYA , K=5
48.70 [46.90,50.50]
0.271
TABLE I: Recoverability-constraint depth ablation. Only K varies; learned components are fixed.
Quadrotor scheduler
Survival
XY error (m)
Mean Reallocation
No reallocation ( wˉ=0 )
37.48
0.295
0.000
Handcrafted ramp
40.31
0.321
0.467
Validated static ( wˉ=0.75 )
40.14
0.446
0.750
RAYA
40.83
0.390
0.698
Always-on ( wˉ=1 )
40.88
0.537
1.000
AV Scheduler
Survival
Track error (m)
Mean Reallocation
TABLE II: Reallocation-scheduling ablation. Only the reallocation schedule varies; the learned margin and reweighting rule are fixed. Static reallocation is selected on validation rollouts; lower mean reallocation indicates less reweighting.
Fig. 4: Six-cycle onboard recovery testbed. Both conditions use the same Figure-8 mission under two-fan airflow. The aerodynamic-mismatch condition adds a 3 g attachment, while the motor-loss condition applies an unmodeled 40% reduction to the front-left motor command.
Method
Mission complete
Mean cycles completed
Mean time to failure (s)
3 g attachment + wind
Nominal MPC
✗ 0/5
0.615/6
2.44
In-solver CBF
✗ 0/5
1.188/6
4.74
Post hoc Learned Margin
✗ 0/5
2.135/6
8.55
RAYA
✓ 5/5
6.000/6
–
40% M1 loss + wind
TABLE III: Real-world performance over five flights per condition. Both conditions use the same six-cycle Figure-8 mission under two-fan airflow. Reported cycle counts and failure times are averaged over five flights.
Robot policies inevitably encounter failures when deployed in real environments. Naive retries often repeat the same mistakes, while many existing recovery methods rely on human intervention. In this paper, we propose Failure-Aware Retry (FAR), a framework that enables robots to learn from previous failures at test time, adapt their behavior accordingly, and eventually complete the task autonomously. FAR combines Failure-Contrastive Preference Adaptation, which constructs preference learning data from failures to steer the policy away from previously unsuccessful behaviors, with lightweight action perturbations during retries to encourage local exploration. We further incorporate successful recovery trajectories into a training loop for continual policy improvement. Experiments in both simulation and real-world manipulation tasks show that FAR substantially improves success rates and robustness, with average gains of 17.6% over the standard diffusion policy in simulation and 11.7% in the real world. In addition, FAR improves data efficiency under both reset and timestep budgets during continual policy improvement by exploiting informative failure cases. Videos and code are available at https://hoar012.github.io/FAR-Project.
Intelligent robots should not only recover from failures, but also acquire the abstract knowledge needed to avoid them in the future. While reinforcement learning (RL) can learn reactive recovery behaviors, training a separate policy for every distinct failure mode is highly inefficient. We introduce Recovery-Driven Synthesis of Relational Concepts (ReSYNC), the first approach that progressively discovers and refines state abstractions (relational predicates) from failure-recovery experience to support abstract planning. Unlike purely reactive methods, ReSYNC jointly learns skills and concepts through an incremental dual-learning process. In the skill-learning phase, the robot uses RL to learn to recover from failures seen in training tasks. In the concept-learning phase, the robot discovers new relational predicates and refines its abstract planning model to explain and generalize the learned recovery behaviors. This interaction enables ReSYNC to convert local recoveries seen during training into global failure avoidance at test time. Across four simulated domains, we show that ReSYNC's ability to continually expand and refine its abstraction library allows it to solve long-horizon, previously unseen problems, outperforming strong baselines by over 50%. Additionally, we demonstrate sim-to-real transfer of ReSYNC, where it performs real-world non-prehensile manipulation skills and generalizes to unseen scenarios through abstract planning. Overall, ReSYNC represents a significant step toward robots that autonomously acquire abstractions for scalable, failure-aware planning in the physical world.
Manipulation failures can leave scenes in states from which a task policy cannot recover. Learning corrective behaviors requires scalable failure exploration and physical grounding. We present Recova, an agent-guided framework that jointly develops task execution and recovery in a reconstructed digital twin, then verifies and refines both through real-world experience. In the twin, the agent diagnoses failures, tests corrective programs, and collects successful task and recovery rollouts for separate policies. During deployment, it monitors progress, invokes a learned or programmatic recovery, verifies scene restoration, and resumes execution. When no suitable recovery is available, a human demonstration resolves the failure and enters the learning loop, allowing the system to expand its recovery capabilities. Physical rollouts and human demonstrations are routed to the corresponding policy for DAgger training. Across six LIBERO-Pro settings and four MolmoSpaces categories, Recova achieves 78.8% and 64.9% mean success, compared with 71.7% and 38.0% for the strongest baselines. With parallel collection across four real-robot workstations, DAgger fine-tuning raises mean success from 23.8% to 77.5%, and recovery skills further raise it to 87.5%. Over four collection rounds on one task, observed human intervention falls from 87.5% to 0%. Together, these results show how agent-guided recovery turns failures into reusable capabilities, improving robustness while progressively reducing human intervention. Project page: https://www.liuisabella.com/Recova
Isabella Liu, An-Chieh Cheng, Johan Bjorck +6
University of California, San Diego · NVIDIA · University of Texas at Austin