Stiffness (Kp) sets how strongly a joint corrects position error. Increasing it can reduce drift, but can also cause vibration. Damping (Kd) resists motion and helps settle oscillation; too much can make movement sluggish.

Gravity scale adjusts the modeled weight support: 1× uses the model as calculated. Gravity limit caps only that support in Nm. Increasing the cap helps only when gravity compensation is reaching it; it does not raise the total motor torque limit.

Gripper hold ceiling caps motor holding torque after contact. It is not jaw force. The temperature-adjusted readings show the lower ceiling currently applied as the motor warms.

Motor specifications are output-shaft references, not tuning targets. Rated torque and short-term peak torque are different limits.

Reference: OpenArm 2.0 Damiao motor specifications. Rated torque is a specification reference; available continuous torque depends on operating conditions.

Upper bound: not yet established. We have not measured how far these settings can be raised under the intended loads. The current save limits are commissioning limits, not measured maximum capability.

Increases are finite. Higher stiffness or damping can demand more motor torque. Available torque, heat, mechanical loads and oscillation constrain usable gains. The limit changes with joint, payload, pose and movement.

Establishing a usable ceiling: test one joint and parameter at a time across intended loads and poses, recording torque/current, temperature and tracking stability. Set an operating limit with margin below the first constraint. Gravity compensation should match the load.

Evidence so far: a 60-second unloaded wrist hold. A loaded upper bound has not been validated.