gravity-comp

Holds both arms in gravity-compensation mode so you can move them by hand. Each free arm joint is sent set_impedance with kp=0, kd=KD, and a feedforward torque equal to the URDF-modelled gravity. Joints not in the free set are held rigidly at their current position with their configured ArmConfig kp/kd (still gravity-compensated). The grippers are softly held at their current positions. This command is configured via draccus — see Command configuration.

Flag	Description
`--left_channel <ch\|null>` / `--right_channel <ch\|null>`	CAN channel per arm; `null` disables that arm.
`--free_joints [J1,J2,...]`	List of joints to gravity-compensate (e.g. `[WRIST_3]` or `[SHOULDER_1,ELBOW]`). Other arm joints are held in place. Default `null` = all 7 joints free.
`--kd FLOAT`	Velocity damping coefficient on free joints (Nm·s/rad). Higher = less floppy. Default 0.25
`--rate_hz FLOAT`	Control loop rate in Hz (default: 250)
`--telemetry_hz FLOAT`	Joint telemetry poll rate in Hz (default: 500)
`--log_level {DEBUG,INFO,WARNING,ERROR}`	Default: `INFO`
`--config_path PATH`	Load a whole-config JSON/YAML file; CLI overrides layer on top.

axol gravity-comp                                 # all 7 joints free, both arms
axol gravity-comp --right_channel null            # left arm only, all joints free
axol gravity-comp --kd 1.0                        # heavier damping
axol gravity-comp --free_joints [WRIST_3]         # only WRIST_3 free; everything else held rigid
axol gravity-comp --right_channel null --free_joints [SHOULDER_1,WRIST_3]   # one-arm, two-joint isolation

Use --free_joints to test gravity comp on a single joint at a time: only the named joints float freely, while the rest of the arm holds its pose so you can isolate the effect.

If the arm sags or pushes back, tune the per-joint mass and com fields on AxolConfig (each JointConfig carries the inertial of the URDF body it drives) — see Gravity compensation.

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