Instant Policy
How it works
1) Graph representation: from segmented point-cloud observations a heterogeneous graph is built that jointly expresses the context (demonstrations), the current observation and future actions, introducing suitable inductive biases and enabling structured reasoning over robot–environment relationships. 2) ICIL as graph generation via diffusion: a distribution over graphs is learned with a diffusion process using forward/backward Markov chains — during training noise is added to the representation and the model learns to remove it. 3) Inference: starting from actions sampled from a normal distribution, the model iteratively updates (denoises) only the parts of the graph that represent robot actions, implicitly modelling the conditional action distribution (e.g. 8 future actions). 4) Data: trained on pseudo-demonstrations — arbitrary trajectories generated in simulation — as a virtually infinite data pool.
Problem solved
Classic imitation learning / behavioural cloning encodes each task into network weights and needs many demonstrations plus costly per-task training. Instant Policy removes per-task retraining: new skills are acquired instantly from 1–2 demonstrations supplied as context, drastically cutting the time to deploy a new robot behaviour.
Components
A graph built from segmented point-cloud observations that jointly represents the context (demonstrations), the current observation and future actions, introducing inductive biases for structured reasoning.
A diffusion model learning a distribution over graphs (forward/backward Markov chain). At inference it iteratively denoises only the action nodes, implicitly modelling the conditional distribution of robot actions.
Arbitrary trajectories generated in simulation, used as a virtually infinite pool of training data instead of hand-collected per-task demonstrations.
Implementation
Evolution
First version of "Instant Policy: In-Context Imitation Learning via Graph Diffusion" (2024-11-19).
Accepted to ICLR 2025 as an Oral; won the Best Paper Award at the Robot Learning Workshop (WRL@ICLR 2025).
Hyperparameters (configurable axes)
Number of demonstrations supplied as in-context examples. The paper reports 1–2 are sufficient.
Number of future actions predicted in a single graph-generation step.
Number of denoising iterations in the diffusion process when generating actions.