Manipulation

Description

Reports one MoveIt MoveGroup goal's lifecycle: a manipulation_start Record when the goal is accepted, a manipulation_end Record when it reaches a terminal state. This is a manipulation goal — it moves a robot arm for one planning group. MoveIt has its own outcome vocabulary here: one flat signed MoveItErrorCodes space, distinct from nav2's succeeded/failed/cancelled/aborted split used by the Mission Measurements.

The Measurement is a passive observer: it never sends the goal itself. It reads the action's status topic (<action_name>/_action/status, published for every goal the server knows about, regardless of which client sent it) to see a goal appear and reach a terminal state, then calls the action's get_result service -- a plain service any client may call given the goal's UUID, not only the one that sent it -- to read MoveGroup::Result's error_code and planning_time. group_name is this instance's own configuration rather than something read off the goal: MoveGroup's Goal (the only place a group name appears) is sent privately to the action server and never broadcast, so a passive observer structurally cannot see it. Run one Manipulation Measurement instance per planning group your robot moves.

outcome on the end Record is derived from error_code, not from the action's own terminal status: SUCCESS maps to succeeded, PREEMPTED maps to cancelled (the closest thing MoveIt has), and every other -- necessarily negative -- MoveItErrorCodes value maps to failed. sequence is a monotonically increasing counter across every Record this instance emits, so a dropped Record shows up as a gap rather than silently corrupting a downstream count.

A goal still executing when collection stops simply never gets a matching manipulation_end Record: nothing downstream can average an interval that was never closed as a zero, because there is no end Record to average.

Parameters

Schema

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Manipulation",
  "description": "One MoveIt MoveGroup goal's lifecycle: a Record when it is accepted, one when it reaches a terminal state",
  "properties": {
    "event": {
      "description": "Whether this Record is the start or the end of one manipulation goal",
      "type": "string",
      "enum": ["manipulation_start", "manipulation_end"]
    },
    "goal_id": {
      "description": "The MoveGroup goal's own UUID, as a canonical hex string, correlating a start Record with its end",
      "type": "string"
    },
    "group_name": {
      "description": "The planning group this Measurement instance watches, as configured -- not read off the goal, which is never broadcast",
      "type": "string"
    },
    "sequence": {
      "description": "Monotonically increasing across every Record from this Measurement instance, so a dropped Record shows up as a gap",
      "type": "integer",
      "minimum": 1
    },
    "outcome": {
      "description": "Derived from MoveIt's own error_code: SUCCESS succeeds, PREEMPTED is the closest thing MoveIt has to cancelled, everything else fails",
      "type": "string",
      "enum": ["succeeded", "cancelled", "failed"]
    },
    "error_code": {
      "description": "MoveIt's own numeric MoveItErrorCodes, carried through verbatim",
      "type": "integer"
    },
    "planning_time": {
      "description": "Seconds MoveGroup spent planning, from MoveGroup::Result",
      "type": "number",
      "minimum": 0
    },
    "duration_sec": {
      "description": "How long the goal took from accepted to terminal",
      "type": "number",
      "minimum": 0
    }
  },
  "required": ["event", "goal_id", "group_name", "sequence"],
  "type": "object"
}

The full file (plugins/measurements/json/manipulation.json) also requires outcome, error_code, planning_time and duration_sec on a manipulation_end Record.

Configuration

...
manipulation:
  plugin: "dc_measurements/Manipulation"
  topic_output: "/dc/measurement/manipulation"
  group_key: "manipulation"
  action_name: "move_action"
  group_name: "arm"

Example output

Start:

{
  "event": "manipulation_start",
  "goal_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "group_name": "arm",
  "sequence": 5
}

and end:

{
  "event": "manipulation_end",
  "goal_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "group_name": "arm",
  "sequence": 6,
  "outcome": "succeeded",
  "error_code": 1,
  "planning_time": 0.842,
  "duration_sec": 3.15
}