Scaling robot learning to long-horizon tasks remains a formidable challenge. While end-to-end policies often lack the structural priors needed for effective long-term reasoning, traditional neuro-symbolic methods rely heavily on hand-crafted symbolic priors. To address the issue, we introduce ENAP (Emergent Neural Automaton Policy), a framework that allows a bi-level neuro-symbolic policy to adaptively emerge from demonstrations. Specifically, we first employ adaptive clustering and an extension of the \(L^*\) algorithm to infer a Mealy state machine from visuomotor data, which serves as an interpretable high-level planner capturing latent task modes. Then, this discrete structure guides a low-level reactive residual network to learn precise continuous control via behavior cloning. By explicitly modeling the task policy with discrete transitions and continuous residuals, ENAP achieves high sample efficiency and interpretability without requiring task-specific labels. Extensive experiments on complex manipulation and long-horizon tasks demonstrate that ENAP outperforms state-of-the-art end-to-end VLA policies by up to 27% in low-data regimes, while offering a structured representation of robotic intent.
ENAP follows a three-stage pipeline—(i) symbol abstraction, (ii) structure extraction via an extended \(L^*\), and (iii) bi-level control—to learn structured policies from demonstrations.
ENAP resolves multi-modal decisions by leveraging a learned state machine and observation-conditioned residual control to guide transitions into the correct logical branch.
| Method | Param (M) | DualStack | Peg |
|---|---|---|---|
| Cube (%) | Insert (%) | ||
| Oracle | 2.98 | 98.3 ±0.4 | 86.7 ±0.8 |
| Transformer | 63.81 | 38.7 ±6.0 | 51.8 ±5.5 |
| GMM | 46.11 | 73.6 ±2.3 | 53.1 ±2.6 |
| Diffusion Policy | 114.39 | 41.2 ±7.2 | 31.1 ±6.8 |
| OpenVLA | 7652.10 | 69.8 ±2.0 | 42.3 ±2.8 |
| \(\pi_0\) | 3288.52 | 73.4 ±1.2 | 51.6 ±1.4 |
| ENAP (Oracle) | 2.66 | 98.8 ±0.3 | 85.6 ±0.6 |
| ENAP* (DINO) | 22.94 | 76.0 ±2.0 | 63.2 ±2.4 |
| Method | Seq. (%) | Hier. (%) | ||
|---|---|---|---|---|
| 3/5 | 5/5 | 3/5 | 5/5 | |
| FLOWER | 91.0 ±0.6 | 90.6 ±0.5 | 90.8 ±0.7 | 15.9 ±0.4 |
| ENAP (FLOWER) | 97.0 ±0.4 | 96.8 ±0.3 | 95.5 ±0.5 | 28.2 ±0.6 |
| Method | Param (M) | Speed (ms) | Stack | Pick | Hanger |
|---|---|---|---|---|---|
| Lego | Place | Task | |||
| \(\pi_{0.5}\) | 3403 | 6841 | 58.82 | 76.47 | 64.71 |
| ENAP* (DINO) | 23 | 281 | 88.24 | 94.12 | 94.12 |







StackLego is a high-precision assembly task where a blue brick must be placed onto a fixed red brick without force feedback, evaluated by graded stacking success.





Hanger is a manipulation task requiring the agent to unhook a hanger and transfer it across an obstacle to the opposite side of a rack.









MultiGoalPickPlace is a sorting task where the agent must match and place multiple colored cans into their corresponding bowls from randomized initial positions.