SAIL: Faster-than-Demonstration Execution of Imitation Learning Policies

Offline Imitation Learning (IL) methods such as Behavior Cloning are effective at acquiring complex robotic manipulation skills. However, existing IL-trained policies are confined to executing the task at the same speed as shown in demonstration data. This limits the task throughput of a robotic system, a critical requirement for applications such as industrial automation. In this paper, we introduce and formalize the novel problem of enabling faster-than-demonstration execution of visuomotor policies and identify fundamental challenges in robot dynamics and state-action distribution shifts. We instantiate the key insights as SAIL (Speed Adaptation for Imitation Learning), a full-stack system integrating four tightly-connected components: (1) a consistency-preserving action inference algorithm for smooth motion at high speed, (2) high-fidelity tracking of controller-invariant motion targets, (3) adaptive speed modulation that dynamically adjusts execution speed based on motion complexity, and (4) action scheduling to handle real-world system latencies. Experiments on 12 tasks across simulation and two real, distinct robot platforms show that SAIL achieves up to a 4x speedup over demonstration speed in simulation and up to 3.2x speedup in the real world. Additional detail is available at https://nadunranawaka1.github.io/sail-policy

Adapt3R: Adaptive 3D Scene Representation for Domain Transfer in Imitation Learning

Imitation Learning (IL) has been very effective in training robots to perform complex and diverse manipulation tasks. However, its performance declines precipitously when the observations are out of the training distribution. 3D scene representations that incorporate observations from calibrated RGBD cameras have been proposed as a way to improve generalizability of IL policies, but our evaluations in cross-embodiment and novel camera pose settings found that they show only modest improvement. To address those challenges, we propose Adaptive 3D Scene Representation (Adapt3R), a general-purpose 3D observation encoder which uses a novel architecture to synthesize data from one or more RGBD cameras into a single vector that can then be used as conditioning for arbitrary IL algorithms. The key idea is to use a pretrained 2D backbone to extract semantic information about the scene, using 3D only as a medium for localizing this semantic information with respect to the end-effector. We show that when trained end-to-end with several SOTA multi-task IL algorithms, Adapt3R maintains these algorithms' multi-task learning capacity while enabling zero-shot transfer to novel embodiments and camera poses. Furthermore, we provide a detailed suite of ablation and sensitivity experiments to elucidate the design space for point cloud observation encoders.