Observations and Actions
This policy is an ACT model trained for SC connector insertion using 3 RGB cameras and a compact robot/task state.
Observation
At each control step, the model receives:
1. Multi-view RGB images
observation.images.left_camera
observation.images.center_camera
observation.images.right_camera
Each image has shape:
These views provide visual information about:
- the cable and plug
- the task board and target port
- the robot end-effector relative to the insertion target
2. Low-dimensional state
observation.state has 16 dimensions:
tcp_pose.position.x
tcp_pose.position.y
tcp_pose.position.z
tcp_pose.orientation.x
tcp_pose.orientation.y
tcp_pose.orientation.z
tcp_pose.orientation.w
task.target_valid
task.cable_type_id
task.plug_type_id
task.port_type_id
task.target_module_id
task.target_port_id
task.target_module_index
task.target_port_index
task.time_limit
This state provides:
- the current tool-center-point pose
- numeric task conditioning describing what to insert and where
Action
The model predicts an action vector of 6 dimensions:
delta.position.x
delta.position.y
delta.position.z
delta.rotation.rx
delta.rotation.ry
delta.rotation.rz
Action semantics
This is a delta pose policy, not an absolute pose policy.
delta.position.* are Cartesian translation increments
delta.rotation.* is a rotation-vector increment
At inference time, the predicted action is applied relative to the previous commanded pose (or current pose on the first step) to produce the next Cartesian target.
In other words, the model learns to output a correction:
- “move a bit in this direction”
- “rotate a bit like this”
instead of directly predicting a final absolute pose.
Why delta actions?
Delta actions are often better suited for fine manipulation and insertion tasks because they:
- encourage closed-loop corrective behavior
- are less sensitive to absolute-frame errors
- are easier to use as incremental servoing commands
This is especially useful for connector insertion, where small visual errors should produce small corrective motions rather than large jumps to an absolute pose.
Model Card for act
Action Chunking with Transformers (ACT) is an imitation-learning method that predicts short action chunks instead of single steps. It learns from teleoperated data and often achieves high success rates.
This policy has been trained and pushed to the Hub using
LeRobot.
See the full documentation at
LeRobot Docs.
How to Get Started with the Model
For a complete walkthrough, see the
training guide.
Below is the short version on how to train and run inference/eval:
Train from scratch
1lerobot-train \
2 --dataset.repo_id=${HF_USER}/<dataset> \
3 --policy.type=act \
4 --output_dir=outputs/train/<desired_policy_repo_id> \
5 --job_name=lerobot_training \
6 --policy.device=cuda \
7 --policy.repo_id=${HF_USER}/<desired_policy_repo_id>
8 --wandb.enable=true
Writes checkpoints to outputs/train/<desired_policy_repo_id>/checkpoints/.
Evaluate the policy/run inference
1lerobot-record \
2 --robot.type=so100_follower \
3 --dataset.repo_id=<hf_user>/eval_<dataset> \
4 --policy.path=<hf_user>/<desired_policy_repo_id> \
5 --episodes=10
Prefix the dataset repo with eval_ and supply --policy.path pointing to a local or hub checkpoint.
Model Details