Test-time action-chunk selection for frozen VLA policies
Robot teams using chunked VLA policies can add an execution-time selector for tasks where small errors ruin the rollout, such as insertion, stacking, and drawer handling. DREAM-Chunk gives a concrete pattern: sample several action chunks from the frozen policy, use a small latent world model to predict each chunk’s future state, then execute the action from the chunk whose predicted state matches the observed rollout. The reported hardware result is large enough to justify a lab check: on a precise insertion task under external perturbation, π0.5 success rose from 10% open-loop to 65% with DREAM-Chunk. A related residual-RL result points to another low-latency correction path: a 2-layer pose-based residual policy trained in simulation raised real FR3 success across five tabletop tasks from 42% to 76%, while adding about 0.06 ms per GPU forward pass next to a roughly 140 ms VLA call. A practical first test is to run the selector or residual only on a few failure-prone tasks and compare recovery after injected pose shifts, object nudges, and gripper occlusion.