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Physical AI & Robotics
Robot training data, teleoperation and egocentric collection, dataset formats, simulation, and policy training for machines that act in the world.
All posts · 20
PHYSICAL AI & ROBOTICS01
UMI Gripper Data Collection vs Teleoperation: What to Buy111 demos an hour vs 35 with SpaceMouse teleop, but the zero-robot result that matched teleop came from a 3 mm rig. What to check before you buy UMI data.
PHYSICAL AI & ROBOTICS02
LeRobot v3 to v2.1: Converting for Isaac-GR00T and openpiLeRobot 0.6.1 has no v3.0 to v2.1 converter. NVIDIA's convert_v3_to_v2.py does the job, and 5 behaviours in its source decide whether your data survives.
PHYSICAL AI & ROBOTICS03
Real Time Chunking in LeRobot: RTC vs Async InferenceLeRobot v0.6.1's async policy server never gives RTC its delay or previous chunk. Pick rtc or async by GPU location, then tune RTC from worst-case latency.
PHYSICAL AI & ROBOTICS04
LeRobot n_action_steps vs chunk_size: How Many to ExecuteSmolVLA's own ablation falls from 82.8% to 51.8% on LIBERO when it plays all 50 predicted actions. What n_action_steps and chunk_size do in LeRobot.
PHYSICAL AI & ROBOTICS05
Which Robot Policy Checkpoint to Deploy After TrainingSelecting on validation loss cost 57.0 to 100.0 percent of the best checkpoint's success rate across eight measured cells. What to rank on instead.
PHYSICAL AI & ROBOTICS06
Running LeRobot Offline: Which Commands Call Hugging FaceLeRobot v0.6.1 records with push_to_hub=True and uploads from a finally block. Three of five rollout strategies upload even with that flag off.
PHYSICAL AI & ROBOTICS07
Sim to Real Gap: Why a Robot Policy Fails on HardwareA zero delay, infinite bandwidth actuator is what you simulate by default, and it was measured at 3.55 Nm of torque error. Four causes, four measurements.
PHYSICAL AI & ROBOTICS08
LeRobot v2.0 to v3.0 Dataset Conversion Takes Two ReleasesA v2.0 LeRobot corpus needs two releases to reach v3.0: 0.3.3 for the first rung, 0.6.1 for the second. The first rung cannot run offline as shipped.
PHYSICAL AI & ROBOTICS09
LeRobot Dataset Merge: What Breaks and How to CheckThe documented merge command raises before it opens a file, and a merged q01/q99 has never been a real quantile at any LeRobot version. Check yours in one pass.