The teacher model starts from the Cosmos-H-Surgical-Simulator Open-H checkpoint, uses a unified 44-dimensional action representation, and is fine-tuned on the JHU dVRK tabletop hybrid dataset, which includes successful demonstrations as well as failure and out-of-distribution scenarios (e.g., dropped needle, missed throw, knot tying failure). Training gradually increases the time horizon from 12 frames to 72 frames.
The student model first learns the teacher's precomputed denoising trajectories through causal warmup, then employs self-forcing distillation: the student uses its own generated context for rollout, and the teacher model provides distribution-matching supervision, thereby reducing error accumulation during deployment. The student model supports few-step diffusion, requiring only 2 denoising steps per latent frame.