{ "title": "RAVEN II Force Actuation Evidence: 6 Motor-Cable Units, 3 Axis MAEs, 0 Released Dataset Files", "rciNumber": "RCI 029", "version": "0.1.0", "schemaVersion": 1, "released": "2026-08-10", "canonical": "https://robotcomponentindex.com/research/raven-ii-force-actuation-evidence-audit/", "scope": "Public-evidence and reproducibility audit of arXiv:2608.06488 v1, a RAVEN II force-actuation system built from six parallel motor-cable units. RCI checked the official arXiv record, hashed and visually reviewed the complete three-page PDF, inspected all ten files in the official TeX source bundle, and separated author-reported architecture and axis-wise errors from independently reproducible evidence. RCI did not build the apparatus, run the controller, receive the recorded dataset or recompute the reported force errors.", "source": { "title": "A Disturbance in the Force: Force Actuation on the RAVEN II Surgical Robot with Parallel Motor-Cable Units", "authors": [ "Haonan Peng", "Dun-Tin Chiang", "Jordan Hendricks", "Andrew Lewis", "Jared Shing", "Haokun Feng", "Yun-Hsuan Su", "Blake Hannaford" ], "affiliations": [ "University of Washington", "Mount Holyoke College" ], "arxivId": "2608.06488", "version": "v1", "submitted": "2026-08-06", "abstractUrl": "https://arxiv.org/abs/2608.06488", "pdfUrl": "https://arxiv.org/pdf/2608.06488", "sourceBundleUrl": "https://arxiv.org/src/2608.06488", "licenseName": "arXiv non-exclusive distribution license 1.0", "licenseUrl": "https://arxiv.org/licenses/nonexclusive-distrib/1.0/", "verifiedDate": "2026-08-10" }, "independentAudit": { "method": "RCI resolved the official arXiv v1 record, downloaded the PDF and TeX source bundle, recorded file sizes and SHA-256 hashes, extracted text, rendered and visually inspected all three PDF pages, enumerated all ten source-bundle files, and audited whether the disclosed hardware, controller, measurement method, result definition and reproduction files were sufficient to independently recompute the reported errors. RCI did not redistribute source figures or files and did not perform a physical or software reproduction.", "pdfPageCount": 3, "pdfPagesVisuallyChecked": [ 1, 2, 3 ], "pdfBytes": 2151930, "pdfSha256": "f6e546bcea4b5f8676ce158432064c051f167ccc9ce081764e98b852cf14775f", "sourceBundleBytes": 2300418, "sourceBundleSha256": "a4b4ebfa51a46afc5d8fcc7bf70fb7e4c4a6d1acc1e9a04238c0278f2bddcb6a", "sourceBundleFileCount": 10, "sourceBundleFigureFileCount": 5, "sourceBundleDatasetFileCount": 0, "sourceBundleCodeFileCount": 0, "sourceBundleCadFileCount": 0, "sourceBundleBomFileCount": 0, "publicRawTraceFileCount": 0, "authorReportedAxisMaeCount": 3, "axisMaeRecomputedByRci": false, "independentReplicationCount": 0, "physicalTestPerformedByRci": false, "sourceFiguresRedistributedByRci": false }, "observations": [ { "id": "RCI029-O01", "field": "motor_cable_unit_count", "value": "6", "unit": "units", "sourceLocation": "Abstract; System; Figure 1 caption", "evidenceRole": "author-reported system architecture", "rciBoundary": "Unit count was read from the paper; RCI did not inspect or count the physical apparatus." }, { "id": "RCI029-O02", "field": "unit_composition", "value": "DC motor; cable reel; load cell; fixing frame", "unit": null, "sourceLocation": "Hardware subsection", "evidenceRole": "author-reported system architecture", "rciBoundary": "The text gives functional part classes, not exact purchasable models or a complete BOM." }, { "id": "RCI029-O03", "field": "force_application_path", "value": "Six controlled-tension cables connect to the RAVEN II end-effector", "unit": null, "sourceLocation": "Abstract; System", "evidenceRole": "author-reported operating description", "rciBoundary": "No independently checked force envelope, collision envelope or cable-elasticity model is public." }, { "id": "RCI029-O04", "field": "software_framework", "value": "ROS; described as compatible with the RAVEN II software controller", "unit": null, "sourceLocation": "Control Software subsection", "evidenceRole": "author-reported implementation", "rciBoundary": "ROS distribution, package versions, repository, commit and launch configuration are not disclosed." }, { "id": "RCI029-O05", "field": "tension_optimizer", "value": "SLSQP", "unit": null, "sourceLocation": "Control Software subsection", "evidenceRole": "author-reported implementation", "rciBoundary": "Objective, constraints, tolerances, initialization, solve rate and failure handling are not published." }, { "id": "RCI029-O06", "field": "feedback_levels", "value": "2", "unit": "levels", "sourceLocation": "Control Software subsection", "evidenceRole": "author-reported control architecture", "rciBoundary": "The paper describes force-command and cable-tension feedback but does not publish gains, loop rates or stability results." }, { "id": "RCI029-O07", "field": "minimum_cable_tension", "value": "Maintained continuously", "unit": null, "sourceLocation": "Control Software subsection", "evidenceRole": "author-reported control constraint", "rciBoundary": "No numeric minimum tension or selection rule is given." }, { "id": "RCI029-O08", "field": "load_cell_driver_measurement_rate", "value": "320", "unit": "Hz", "sourceLocation": "Associated Electronics subsection; Figure 3 caption", "evidenceRole": "author-reported electronics rate", "rciBoundary": "The paper does not establish whether 320 Hz is a per-channel output rate, bus transaction rate, timestamp cadence or closed-loop bandwidth." }, { "id": "RCI029-O09", "field": "current_motor_control_path", "value": "Right arm of RAVEN II with modified control software", "unit": null, "sourceLocation": "Associated Electronics subsection", "evidenceRole": "author-reported implementation", "rciBoundary": "Independent motor drivers and microcontrollers are described as future work, not as the tested configuration." }, { "id": "RCI029-O10", "field": "motor_unit_localization", "value": "MicroScribe MX measurements mapped to the robot frame with the Kabsch algorithm", "unit": null, "sourceLocation": "Localization of Motor Units subsection", "evidenceRole": "author-reported calibration workflow", "rciBoundary": "Point count, residuals, repeatability, coordinate uncertainty and calibration files are not published." }, { "id": "RCI029-O11", "field": "recorded_dataset_description", "value": "Robot trajectories with position and external force, intended for future neural-network training", "unit": null, "sourceLocation": "Preliminary Results", "evidenceRole": "author-reported dataset existence", "rciBoundary": "The dataset is described but no public download, manifest, schema, sample count or license is linked." }, { "id": "RCI029-O12", "field": "x_axis_mean_absolute_error", "value": "0.80", "unit": "N", "sourceLocation": "Preliminary Results", "evidenceRole": "author-reported result", "rciBoundary": "Axis-wise MAE only; raw samples, force range, trial count and computation procedure are not public, and RCI did not recompute it." }, { "id": "RCI029-O13", "field": "y_axis_mean_absolute_error", "value": "0.79", "unit": "N", "sourceLocation": "Preliminary Results", "evidenceRole": "author-reported result", "rciBoundary": "Axis-wise MAE only; it is not evidence that every Y-axis sample error was below 1 N." }, { "id": "RCI029-O14", "field": "z_axis_mean_absolute_error", "value": "0.44", "unit": "N", "sourceLocation": "Preliminary Results", "evidenceRole": "author-reported result", "rciBoundary": "Axis-wise MAE only; it is not a three-dimensional vector-error metric or uncertainty statement." }, { "id": "RCI029-O15", "field": "trajectory_figure_scaling", "value": "Position and force normalized by their ranges for visualization", "unit": null, "sourceLocation": "Figure 5 caption", "evidenceRole": "author-reported presentation condition", "rciBoundary": "The normalized plot cannot recover the underlying force range or raw time series." } ], "figureVisibleElectronics": [ { "label": "LTC4311", "sourceLocation": "Figure 3", "evidenceRole": "author-figure label", "rciBoundary": "A visible label, not a complete schematic, ordering code or independently inspected assembly." }, { "label": "NAU7802 Breakout", "sourceLocation": "Figure 3", "evidenceRole": "author-figure label", "rciBoundary": "Board vendor, revision, configuration and load-cell interface calibration are not disclosed." }, { "label": "Arduino Mega", "sourceLocation": "Figure 3", "evidenceRole": "author-figure label", "rciBoundary": "Exact board revision, firmware and timing implementation are not disclosed." }, { "label": "I2C Mux", "sourceLocation": "Figure 3", "evidenceRole": "author-figure label", "rciBoundary": "Exact multiplexer model and bus topology are not specified in text." }, { "label": "RJ45 / SSTP cabling", "sourceLocation": "Figure 3", "evidenceRole": "author-figure label", "rciBoundary": "The label does not define electrical pinout, cable length, shielding termination or data integrity." } ], "disclosureAudit": [ { "id": "RCI029-D01", "field": "system_architecture", "status": "disclosed", "publicEvidence": "Six motor-cable units, end-effector cable path and two feedback levels are described.", "reproductionImpact": "Supports a functional block diagram, not a build-ready implementation." }, { "id": "RCI029-D02", "field": "exact_dc_motor_model_and_specs", "status": "not-disclosed", "publicEvidence": "The text says DC motor only.", "reproductionImpact": "Torque, speed, inertia, electrical limits and procurement identity cannot be reproduced." }, { "id": "RCI029-D03", "field": "exact_load_cell_model_range_accuracy", "status": "not-disclosed", "publicEvidence": "Load cells are described functionally; no exact model, range or accuracy is stated.", "reproductionImpact": "Cable-tension resolution, saturation and uncertainty cannot be reconstructed." }, { "id": "RCI029-D04", "field": "cable_reel_mechanical_definition", "status": "not-disclosed", "publicEvidence": "No cable material, diameter, length, stiffness, reel radius, bearing or frame drawing is published.", "reproductionImpact": "Elasticity, torque-to-tension mapping and force envelope remain unknown." }, { "id": "RCI029-D05", "field": "electronics_identity", "status": "partial-figure-labels", "publicEvidence": "Figure 3 visibly labels LTC4311, NAU7802 Breakout, Arduino Mega, I2C Mux and RJ45/SSTP cabling.", "reproductionImpact": "Useful lead-level identity, but not a schematic, complete BOM, ordering-code list or configuration record." }, { "id": "RCI029-D06", "field": "software_and_firmware_release", "status": "not-disclosed", "publicEvidence": "ROS and modified RAVEN II software are named; no repository, commit, ROS distribution, package lock or firmware image is linked.", "reproductionImpact": "The controller cannot be rebuilt or version-matched." }, { "id": "RCI029-D07", "field": "slsqp_definition_and_rate", "status": "partial", "publicEvidence": "SLSQP is named, but objective, constraints, tolerances, initialization and solve rate are absent.", "reproductionImpact": "Cable-tension allocation and real-time behavior cannot be reproduced." }, { "id": "RCI029-D08", "field": "measurement_rate_semantics", "status": "partial", "publicEvidence": "Load-cell drivers are said to provide measurements at 320 Hz.", "reproductionImpact": "Per-channel rate, bus rate, timestamp cadence and closed-loop bandwidth remain distinct unresolved quantities." }, { "id": "RCI029-D09", "field": "synchronization_latency_filtering", "status": "not-disclosed", "publicEvidence": "No timestamp source, synchronization error, end-to-end latency, digital filtering or channel-skew result is given.", "reproductionImpact": "The force-error time alignment cannot be independently checked." }, { "id": "RCI029-D10", "field": "load_cell_and_force_calibration", "status": "not-disclosed", "publicEvidence": "No calibration procedure, coefficients, reference instrument or residuals are published.", "reproductionImpact": "Traceability and measurement uncertainty remain unknown." }, { "id": "RCI029-D11", "field": "actual_applied_force_reference", "status": "not-disclosed", "publicEvidence": "The paper reports desired versus actual applied force but does not fully define how actual Cartesian force is constructed or independently referenced.", "reproductionImpact": "The ground-truth quantity behind the MAE cannot be independently reconstructed." }, { "id": "RCI029-D12", "field": "force_range_and_trajectory_protocol", "status": "not-disclosed", "publicEvidence": "The figure is normalized; numeric force range, trajectory coordinates, speed, trial count and duration are not reported.", "reproductionImpact": "Operating-envelope coverage and result comparability are unknown." }, { "id": "RCI029-D13", "field": "mae_computation_and_aggregation", "status": "partial", "publicEvidence": "Three axis MAEs are printed, but sample selection, weighting, alignment, filtering and aggregation are not defined.", "reproductionImpact": "The three numbers cannot be recomputed from public evidence." }, { "id": "RCI029-D14", "field": "uncertainty_dispersion_and_worst_case", "status": "not-disclosed", "publicEvidence": "No standard deviation, confidence interval, percentile, maximum error or uncertainty budget is reported.", "reproductionImpact": "Axis MAE does not establish worst-case or metrological accuracy." }, { "id": "RCI029-D15", "field": "raw_dataset_release", "status": "not-released", "publicEvidence": "The paper says a dataset was recorded; the arXiv page and ten-file source bundle contain no dataset file or dataset link.", "reproductionImpact": "The trajectory, force range, timestamps and errors cannot be independently inspected." }, { "id": "RCI029-D16", "field": "analysis_and_controller_code_release", "status": "not-released", "publicEvidence": "The arXiv record and source bundle contain no analysis or controller code link or file.", "reproductionImpact": "Neither the controller nor the MAE analysis can be rerun." }, { "id": "RCI029-D17", "field": "cad_bom_and_schematic_release", "status": "not-released", "publicEvidence": "No CAD, BOM or schematic file is present in the ten-file source bundle.", "reproductionImpact": "The apparatus is not build-ready from the public package." }, { "id": "RCI029-D18", "field": "independent_replication", "status": "not-found", "publicEvidence": "No independent reproduction is linked from the arXiv record or paper.", "reproductionImpact": "The reported system behavior remains author evidence only." } ], "resultBoundary": { "abstractWording": "The abstract describes preliminary force-actuation errors below 1 N.", "reportedAxisMaeN": { "x": 0.8, "y": 0.79, "z": 0.44 }, "assessment": "three-axis-wise-mae-values-only", "conclusion": "The public evidence supports that the authors reported three per-axis mean absolute errors below 1 N. It does not show that every sample error was below 1 N, does not publish a three-dimensional vector MAE or RMSE, and does not provide the data required for RCI to recompute any error metric. The three axis MAEs must not be combined as though they were one measured vector statistic." }, "rightsBoundary": { "sourceLicense": "The arXiv record uses the arXiv non-exclusive distribution license 1.0 rather than a Creative Commons reuse license.", "rciTreatment": "RCI links the official abstract, PDF and source-bundle routes but does not mirror the paper, TeX bundle or five source figures. This release contains minimal facts, file hashes, disclosure counts and original analysis.", "figureTreatment": "Figure-visible electronics labels are recorded as labels only; source figures are not reproduced." }, "limitations": [ "RCI audited public files and disclosures only; it did not inspect the apparatus, run the controller or perform a force test.", "The three axis MAEs are author-reported preliminary results and were not independently recomputed.", "The absence of a public dataset, code or build package is bounded to arXiv v1, its ten-file source bundle and linked surfaces checked on 2026-08-10; private or later artifacts may exist.", "Figure-visible electronics labels do not establish exact ordering codes, revisions, firmware, calibration or a complete BOM.", "The 320 Hz statement is a reported load-cell-driver measurement rate, not a demonstrated six-channel closed-loop bandwidth or end-to-end latency.", "No claim is made about clinical safety, surgical effectiveness, sterilization, regulatory status or suitability for use on patients." ], "suggestedCitation": "Robot Component Index. “RAVEN II Force Actuation Evidence: 6 Motor-Cable Units, 3 Axis MAEs, 0 Released Dataset Files.” RCI 029, research dataset version 0.1.0, 2026-08-10. https://robotcomponentindex.com/research/raven-ii-force-actuation-evidence-audit/" }