Progress Reward Modeling for Robotic Learning: A Comprehensive Survey
Summary
This survey unifies the fragmented field of progress reward modeling for robotic learning, addressing the challenge of sparse terminal success signals in complex, dynamic environments. Traditional robotic learning struggles to provide intermediate feedback, hindering credit assignment and failure detection. Progress rewards offer dense, continuous feedback during task execution. The survey organizes existing literature into three interconnected perspectives: first, the model's interface, defining its inputs (task state representation, goal specification) and outputs (scalar scores, progress deltas, rankings, programmatic rewards); second, the construction methods, including frozen foundation model scoring, learning from temporal/relative supervision, instruction-tuned prediction, and programmatic reward generation; and third, the data and benchmarks, detailing supervision sources (human-driven, human-in-the-loop, automated) and evaluation protocols (fidelity, robustness, utility). It also outlines current limitations and future research.
Key takeaway
For Robotic Learning Engineers designing reward functions for complex, long-horizon tasks, relying solely on terminal success signals is insufficient. You should integrate progress reward modeling to provide dense, intermediate feedback, improving credit assignment and enabling robust policy learning. Carefully evaluate progress model interfaces, construction methods, and data sources, considering trade-offs like temporal context versus online usability. Be mindful of current limitations such as coarse-grained sensitivity and inference latency for real-time deployment.
Key insights
Progress rewards are crucial for robotic learning, offering dense, intermediate feedback to overcome limitations of terminal success signals in complex tasks.
Principles
- Progress estimation is latent and history-dependent, harder than binary success detection.
- Longer temporal context improves progress inference but reduces online usability.
- Human supervision provides semantic grounding; automation offers scalability.
Method
Analyze progress reward models by their interface (input/output), construction methods (signal source and conversion), and data/benchmarking (supervision and evaluation protocols).
In practice
- Specify goals with language for simple tasks, or vision for physical details.
- Employ programmatic rewards for tasks with explicit subgoals or API access.
- Augment successful trajectories with failures to reduce success-only bias.
Topics
- Robotic Learning
- Progress Reward Modeling
- Reinforcement Learning
- Vision-Language Models
- Task Planning
- Reward Function Design
- Benchmarking
Code references
Best for: Research Scientist, AI Scientist, Robotics Engineer, Machine Learning Engineer
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Editorial summary, takeaway, and curation by AIssential. Original article published by cs.CL updates on arXiv.org.