{
  "generator": "twm.force_recovery.export_force_columns",
  "stiffness_n_per_mm": 2.0,
  "penetration": "penetration_mm = force_normal_n / stiffness_n_per_mm  (ASSUMED stiffness)",
  "press_direction": "R(q_row) @ gel_axis_in_rigid from calibration/*/T_gel_to_rigid_<side>.json",
  "no_contact_rule": "force == 0 -> penetration 0 and target_pose is a copy of sensor_<side>_pose",
  "duplicate_rows": "tactile_<side>_is_new == False rows reuse the previous estimate (forward fill, asserted exact)",
  "source_release": "/media/yxma/Disk1/twm/release/motherboard/meta/2026-05-10/episode_004.parquet",
  "force_calibration": [
    "react_calib (calibration-free recon + gain field + clip correction)"
  ],
  "supersedes": "Exports before 2026-08-07 used a calibration that applied pixel-unit weights to mm-unit features (end-to-end rho 0.143, peak force 18.3 N). Those newton values are void; these come from react_calib (held-out rho 0.739, MAE 1.23 N, split by press position).",
  "task": "motherboard",
  "date": "2026-05-10",
  "episode": "episode_004",
  "rows": 2406,
  "sides": [
    {
      "side": "left",
      "rows": 2406,
      "npz": "/media/yxma/Disk1/twm/force_recovery/motherboard/2026-05-10/episode_004_left.npz",
      "force_calibration": "react_calib (calibration-free recon + gain field + clip correction)",
      "pipeline_version": 5,
      "n_contact_rows": 1403,
      "no_contact_frac": 0.4168744804655029,
      "is_new_frac": 0.286783042394015,
      "duplicate_rows_forward_filled": 1716,
      "force_p50_n": 1.1662499904632568,
      "force_p95_n": 4.3677778244018555,
      "force_max_n": 7.869999885559082,
      "force_p50_contact_n": 2.636666774749756,
      "penetration_p50_mm": 0.5831249952316284,
      "penetration_p95_mm": 2.1838889122009277,
      "penetration_max_mm": 3.934999942779541,
      "gel_max_depth_p95_mm": 0.5770630240440369,
      "gel_max_depth_max_mm": 1.2534384727478027,
      "identity_max_abs_dev": 0.0,
      "direction": {
        "usable": true,
        "v_dot_n_rise_mm": -1.2867537413876176,
        "v_dot_n_fall_mm": -0.6577187948106586,
        "corr_dforce_vdotn": -0.027609117419923508,
        "n_rise": 377,
        "n_fall": 412
      }
    },
    {
      "side": "right",
      "rows": 2406,
      "npz": "/media/yxma/Disk1/twm/force_recovery/motherboard/2026-05-10/episode_004_right.npz",
      "force_calibration": "react_calib (calibration-free recon + gain field + clip correction)",
      "pipeline_version": 5,
      "n_contact_rows": 2403,
      "no_contact_frac": 0.0012468827930174342,
      "is_new_frac": 0.2876142975893599,
      "duplicate_rows_forward_filled": 1714,
      "force_p50_n": 1.1662499904632568,
      "force_p95_n": 4.285294055938721,
      "force_max_n": 5.439090728759766,
      "force_p50_contact_n": 1.1662499904632568,
      "penetration_p50_mm": 0.5831249952316284,
      "penetration_p95_mm": 2.1426470279693604,
      "penetration_max_mm": 2.719545364379883,
      "gel_max_depth_p95_mm": 1.0642808079719543,
      "gel_max_depth_max_mm": 1.8097175359725952,
      "identity_max_abs_dev": 0.0,
      "direction": {
        "usable": true,
        "v_dot_n_rise_mm": 1.7850098795861638,
        "v_dot_n_fall_mm": -1.7479678463779726,
        "corr_dforce_vdotn": 0.09774470163324255,
        "n_rise": 389,
        "n_fall": 421
      }
    }
  ],
  "columns": [
    "force_left_normal_n",
    "force_left_penetration_mm",
    "force_left_target_pose",
    "force_right_normal_n",
    "force_right_penetration_mm",
    "force_right_target_pose"
  ]
}