[OpenArm Troubleshooting] Gravity Compensation Feels Wrong After Tool Change (Intermediate)
OpenArm gravity compensation issues after tool change: payload/CoM validation, hold-drift checks, and go-no-go criteria before production.
A very common OpenArm problem shows up right after a new gripper, tool plate, or end-effector accessory is installed. The arm may hold position poorly, sag in one region, or feel unusually heavy in teleop even though the controller stack did not otherwise change.
How are you diagnosing OpenArm gravity compensation that feels wrong after a tool change?
Please share how you separate payload-model mistakes from friction, balance, or controller issues, and what validation steps tell you the new tool is modeled well enough before normal operation resumes.
If you reply, include one exact symptom after the tool swap and one exact payload or compensation check that exposed the root cause.
Intermediate context: After a gripper swap the arm slowly sank about 6 mm over 10 seconds near horizontal pose, even with no command input. It felt like bad gains at first, but the pattern was pose-dependent and repeatable.
Intermediate context: The useful check was measuring tool mass and center offset with a hanging scale and 100 mm balance fixture. Real CoM was 18 mm forward of the model, which explained the gravity bias error.
Intermediate context: Once payload and CoM were updated, we revalidated with static hold current and slow teleop arcs across the workspace. We only released after hold error stayed under 0.4 mm in five representative poses.
Intermediate context follow-up: Follow-up question: what are your current go/no-go limits for static hold drift (mm) and hold current after payload model updates?