Replaces the command/status JSON pair with dora's own service pattern:
one request, one response, correlated by the request_id dora puts in the
message metadata. Motions take a wait flag, and their lifecycle is
published as the arm's state on motion_state rather than as a per-goal
stream — the arm is one resource, so a new motion preempts the one in
play and a state describes that exactly.
motion_state is keyed by request_id and publishes accepted before the
control thread reaches the motion. Both exist to close one race: a caller
polling a bare moving/idle flag right after its request would read "not
moving" and conclude the motion had already finished.
Three threads, because the SDK blocks. The control thread carries out one
job at a time and may block; the reporter thread only ever reads the
report cache, so telemetry keeps flowing through a ten-second move; the
stopper thread exists because a stop fits nowhere else — it must not
queue behind the motion it aborts, and emergency_stop re-commands the
controller for up to three seconds, which is far too long to stop routing
a dataflow.
The event loop never calls anything that can block, get_state included:
that one is allowed there only because it reads the cache. The node is
built before the arm threads start, so INIT_MODE cannot move a robot
before the process has joined the dataflow, and a restart leaves the arm
where it is rather than driving it home unasked. Shutdown halts the arm
first — a motion lives in the controller, and dropping the connection
does not abort it.
Apply Z-axis tool offset when publishing tcp_pose so the output
reflects the actual tool tip. Adds TOOL_TYPE (none/vacuum/gripper)
and TOOL_OFFSET_MM env vars with standard Lite6 accessory presets.
Bump version to 0.1.2.
Migrates the ulite6 Python dora node from dora_littlehand into a
self-contained repository following the dora-zed structure. Adds
command lifecycle state ("started"/"done"/"failed") and type
("command"/"error") to the status output so coordinator nodes can
reliably sequence robot actions without polling.
cristhian
cristhian aguilera