inr2action stores robot episodes as fixed-size weight deltas for recall and action
A preprint on arXiv proposes keeping long robot episodes as a single set of neural weight changes of fixed size. According to the paper, a language model can answer questions about past episodes and a decoder can predict commands, without searching stored video frames when a query arrives.
How the memory is built
The method fits a neural implicit representation to the video of an episode, starting from a shared initialization obtained through meta-learning. The difference between the fitted weights and that starting point, the weight delta, is what the authors treat as the memory.
According to the abstract, the size of this delta does not change with episode length. An episode of a hundred frames and one of a hundred thousand frames yield deltas of identical size, which the authors present as memory tied to essential information rather than to execution time.
Language and action outputs
A learned projector converts the weight delta into token embeddings, the numerical inputs a language model reads. These embeddings condition two components: a language model that answers questions and a decoder that regresses commands jointly. Neither component retrieves frames when a query comes in.
On the RoboMME benchmark, the language model is reported to exceed chance on every question type, and the decoder reaches a mean R² of 0.51.
Control runs point to the initialization
The authors describe two control experiments. Replacing the delta with matched noise lowers performance by 11.4 points. Weights that start from a random origin instead of the meta-learned initialization cannot be decoded, which the paper cites as evidence that the shared starting point is essential for encoding episode content.
The preprint is marked as a new submission and has so far been reported by one outlet, arXiv Robotics (cs.RO), which is the only source for these findings.
Open questions
- How well does the approach perform on robotic tasks beyond the RoboMME benchmark?
- How is the shared meta-learned initialization obtained, and how much does it depend on the training data?