OpenArm Tactile Sensor Integration

[Dozgulbas]

Integrate Sensible Tactile sensor with OpenArm

• Develop an interface for the sensors to enable data collection in sync with the robot. Done in AD-SDL/sensible_finger (tracked in AD-SDL/sensible_finger#2), with the LeRobot side merged in OpenArm on lerobot v0.6.1, plus optional tactile finger recording lerobot#2. See the comment below.
• Replace the gripper fingers with new 3D-printed fingers to accommodate the sensors
• Figure out the sensor wiring routing through the robot body to the control PC

08/21: Data collection interface is developed. Physical hardware integration is next

[Dozgulbas]

The first item is done. The sensor driver lives in its own repository, AD-SDL/sensible_finger, and the LeRobot integration is merged into our fork in AD-SDL/lerobot#2.

Data collection is synchronised through the OpenArm follower itself rather than through a separate logger. Tactile is an optional part of the OpenArm follower config, so a robot without sensors installs nothing extra and records exactly what it recorded before. When it is enabled, each finger's readings are written into the same LeRobot dataset frames as the joint states and camera feeds, at the same 30 Hz control rate, so tactile and proprioception share one timestamp instead of needing to be aligned afterwards.

observation.state is left unchanged, which means datasets recorded with and without sensors stay trainable together and tactile can be ablated on or off from the same recordings.

Verified on the bench with both fingers connected. The two channels respond independently, worst case cross talk is 1.5 percent of the pressed finger's signal, and every frame reports valid with no drops. Each frame's tactile reading is at most 17 ms old inside the 33 ms control window, and that age is recorded per frame in a status column, so any drift or stall is visible in the data rather than showing up as plausible looking values.

08/21: Remaining work on this repository is the two hardware items above