The 2F sidecar Web UI, should be designed as a non-invasive visualization adapter, requiring no changes to the upper-level tactile publisher or lower-level control logic.

Design intent:
- Transform ROS tactile payloads into browser-ready states with low integration costs.
- Provide runtime mode switching as a stable ROS service contract.
- Support both global and namespace-based TF delivery models via launch remapping.

This ensures that the web visualization remains evolving independently of the control stack release cycle.

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xela_taxel_sidecar_2f¶

1. Overview and design objective¶

The 2F sidecar is designed as a non-invasive visualization adapter: it does not alter upstream tactile publishers or downstream control logic.

Design intent:

• transform ROS tactile payloads into browser-consumable state with low integration cost
• expose runtime mode switching as a stable ROS service contract
• support both global and namespaced TF transport models through launch remapping

This keeps web visualization evolvable independently of control-stack release cycles.

2. Node architecture¶

2.1 Bridge node (xela_taxel_web_bridge_node)¶

• subscribes tactile array topic
• optionally subscribes grasp telemetry/event topics and embeds recent JSON metadata
• normalizes/maps values
• publishes compact JSON payload
• optional TF lookups for URDF points

2.2 Mode manager (xela_viz_mode_manager_node)¶

• service facade: /xela_viz_mode_manager/set_mode
• writes bridge params: viz_mode, emit_urdf_points, freeze_urdf_positions
• forwards request to viz node service
• startup sync retry timer

2.3 Web transport¶

• static HTTP server for web/taxel_sidecar
• optional dedicated rosbridge instance
• browser websocket fallback order: :9090, :3201, /ros

2.4 Web UI runtime¶

• browser-side display modes are GridMode, XelaModel, and RobotModel
• GridMode/XelaModel/RobotModel are distinct from ROS-side grid/urdf
• RobotModel includes optional FollowCam logic and telemetry analysis rendering
• FollowCam / Analysis toolbar exposure can be toggled independently from the underlying code paths

2.5 Runtime wiring diagram¶

Generated PNG: docs/runtime_wiring_diagram.png

Browser (index.html + rosbridge_client.js)
  |-- HTTP GET / ----------------------------> sidecar_http_server.py (:8765)
  |
  |-- WebSocket ws://<host>:9090 -----------> rosbridge_websocket_sidecar
  |                                            (rosbridge_server/rosbridge_websocket)
  |                                              |
  |                                              |-- subscribe / publish --> /x_taxel_2f/web_state
  |                                              |-- service call ---------> /xela_viz_mode_manager/set_mode
  |                                              |-- optional access ------> /tf, /tf_static, /robot_description
  |                                                                      or namespaced std-viz equivalents
  |
  `-- sidecar UI renders GridMode / XelaModel / RobotModel

/x_taxel_2f ----------------------------------> xela_taxel_web_bridge_cpp
/x_telemetry_2f/grasp_telemetry --------------> xela_taxel_web_bridge_cpp
/x_telemetry_2f/grasp_event ------------------> xela_taxel_web_bridge_cpp
/tf, /tf_static (or namespaced TF) -----------> xela_taxel_web_bridge_cpp
xela_taxel_web_bridge_cpp --------------------> /x_taxel_2f/web_state

/xela_viz_mode_manager/set_mode --------------> xela_viz_mode_manager_cpp
xela_viz_mode_manager_cpp -- set_parameters --> xela_taxel_web_bridge_cpp
xela_viz_mode_manager_cpp -- SetBool -------> /xela_taxel_viz_2f/set_mode
                                           or /xviz2f/std_xela_taxel_viz_2f/set_mode

Notes:

• The browser uses two separate paths: HTTP for static assets and WebSocket for ROS traffic.
• rosbridge_client.js tries :9090 first; :3201 and /ros are fallbacks.
• xela_viz_mode_manager_cpp is the ROS-facing mode-switch facade.

3. Launch architecture¶

• primary: xela_taxel_sidecar_cpp.launch.py
• compatibility: xela_taxel_sidecar.launch.py
• primary launch exposes bind hosts for the static web server and sidecar rosbridge (default 0.0.0.0)

4. Integration strategy¶

• default target: viz_node_name=/xela_taxel_viz_2f
• std-viz namespaced target via overrides:
  • viz_node_name:=/xviz2f/std_xela_taxel_viz_2f
  • bridge_tf_topic:=/xviz2f/tf
  • bridge_tf_static_topic:=/xviz2f/tf_static

5. Design risks¶

• target viz service unavailable
• TF remap mismatch in URDF mode
• duplicate transport nodes from multiple launch variants

6. Validation¶

• launch smoke test
• topic publish-rate observation
• service toggle test
• web render check on sidecar URL
• browser websocket fallback check (9090 -> 3201 -> /ros)
• verify URL query defaults are used when no follow_cam_* overrides are present

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