Servo Dog

Use this skill when the user asks to control a four-servo robotic dog, start the Servo Dog web control panel, calibrate dog leg servo offsets, or run dog actions such as forward, backward, turn, bow, shake hand, jump, or retract legs.

This skill controls four servos directly from Lua with mcpwm. Default GPIOs are:

• fl_gpio: 1
• fr_gpio: 2
• bl_gpio: 41
• br_gpio: 42

Default neutral angles are compatible with the original servo dog controller:

• fl_neutral: 70
• fr_neutral: 110
• bl_neutral: 110
• br_neutral: 70

Start Web Control

Run the server script asynchronously. It starts the PWM worker, mounts the bundled web UI, and registers HTTP APIs.

{
  "path": "{CUR_SKILL_DIR}/scripts/servo_dog_server.lua",
  "timeout_ms": 0,
  "name": "servo_dog_server",
  "exclusive": "servo_dog",
  "replace": true,
  "args": {
    "app_id": "servo_dog",
    "queue_name": "servo_dog_cmd",
    "web_root": "{CUR_SKILL_DIR}/assets",
    "worker_path": "{CUR_SKILL_DIR}/scripts/servo_dog_worker.lua",
    "worker_args": {
      "fl_gpio": 1,
      "fr_gpio": 2,
      "bl_gpio": 41,
      "br_gpio": 42
    }
  }
}

After it starts, open:

/lua/servo_dog/

The page uses:

• GET /api/lua/servo_dog/state
• POST /api/lua/servo_dog/control
• GET /api/lua/servo_dog/start_calibration
• GET /api/lua/servo_dog/exit_calibration
• POST /api/lua/servo_dog/adjust

Command Control

For command or agent control, keep the server running and call:

{
  "path": "{CUR_SKILL_DIR}/scripts/servo_dog_command.lua",
  "args": {
    "queue_name": "servo_dog_cmd",
    "action": "forward"
  }
}

If the command script reports that the controller is not running, start the web control script first.

Actions

Supported action names:

• installation
• idle
• forward
• backward
• turn_left
• turn_right
• lay_down
• bow
• lean_back
• bow_lean
• sway_back_forth
• sway
• shake_hand
• poke
• shake_back_legs
• jump_forward
• jump_backward
• retract_legs

Movement aliases:

{"move":"F"}
{"move":"B"}
{"move":"L"}
{"move":"R"}

Original web action id aliases:

{"action":"1"}
{"action":"2"}
{"action":"3"}
{"action":"4"}
{"action":"5"}
{"action":"6"}
{"action":"7"}
{"action":"8"}
{"action":"9"}
{"action":"10"}
{"action":"11"}
{"action":"12"}

These map to lay_down, bow, lean_back, bow_lean, sway_back_forth, sway, shake_hand, poke, shake_back_legs, jump_forward, jump_backward, and retract_legs.

Optional Action Args

Some actions accept overrides:

{
  "action": "forward",
  "args": {
    "repeat_count": 3,
    "speed": 90
  }
}

Supported fields are:

• repeat_count: positive integer for repeated gait/action cycles.
• speed: higher values shorten interpolation delay.
• hold_time_ms: hold duration for actions such as bow, lean_back, and shake_hand.
• angle_offset: offset used by idle and sway.

Calibration

Start calibration from the web UI or send:

{"action":"installation"}

Adjust one servo offset:

{
  "path": "{CUR_SKILL_DIR}/scripts/servo_dog_command.lua",
  "args": {
    "queue_name": "servo_dog_cmd",
    "type": "adjust",
    "servo": "fl",
    "value": 3
  }
}

Valid servo ids are fl, fr, bl, and br. Values are clamped to -25..25 and saved under the DATA root in servo_dog/config.json.

Extension

To add a new dog action, edit {CUR_SKILL_DIR}/scripts/servo_dog_worker.lua:

1. Add a Lua function that calls set_angle() or set_angles() and uses action_delay(ms) inside long loops.
2. Register it in the actions table.
3. Optionally add an alias in action_aliases.
4. Add a button entry in the server ACTIONS list if the web UI should expose it.

Use action_delay() instead of delay.delay_ms() inside actions so a new command can interrupt the current action.