Arms: rename GripDirection→GripperDirection (string literal); rotate convention so 0°=+X#1034
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…convention so 0°=+X `GripDirection` was an enum with `FRONT=0°, RIGHT=90°, BACK=180°, LEFT=270°`, which baked the deck-frame "front" axis into the value 0. That entangled the math (CCW yaw about +Z) with a deck convention, and made the type clunky for JSON/serialization. Two changes: 1. Cross-backend convention is now: `direction` (and `CartesianPose.rotation.z`) is the world yaw of the front finger in degrees, CCW about +Z, with **0°=+X**. Cardinal mapping rotates 90°: `right=0°, back=90°, left=180°, front=270°`. 2. `GripDirection` enum → `GripperDirection = Literal["front","back","left","right"]`. `GripOrientation` → `GripperOrientation = Union[GripperDirection, float]`. Resolver in `OrientableArm` validates the string and looks up the new mapping. Backend updates: - iSWAP (`_direction_degrees_to_grip_direction`): firmware grip_direction stays 1..4 in physical-axis order (firmware contract is unchanged); the user-degrees → firmware-code mapping rotates by one step. `iSWAPBackend.rotate` now takes a `GripperDirection` string and string-compares. - Grip-width axis selection in `OrientableArm._resource_width_for_direction` flips: `direction%180==0` is now along +X (right/left), so jaws grip in Y. - Legacy `_LEGACY_TO_NEW_GRIP` becomes a static enum→string dict (no more `_NewGripDirection[d.name]` enum bridging). Tests updated to feed the new degree values; physical poses preserved (e.g. "front" pickup that used to be `direction=0` is now `direction=270`, still producing firmware `gr=1`). All arm/iSWAP/legacy LH tests pass; the 13 unrelated pre-existing xarm6/scila failures on v1b1 are untouched. architecture.md and the user guide spell out the convention with a table. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
… import isn't unused ruff F401 caught the unused `GripperDirection` import in orientable_arm.py. Annotate the dict as Dict[GripperDirection, float] — this also documents the keys, which the lookup at L33 relies on being one of the four literals. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
GripDirectionenum →GripperDirection = Literal[\"front\",\"back\",\"left\",\"right\"](andGripOrientation→GripperOrientation). String-literal type plays nicely with JSON, kwargs, and IDE autocomplete; enum was overkill.direction=0°is+X(CCW about +Z, right-hand rule), instead of-Y. New cardinal mapping:right=0°, back=90°, left=180°, front=270°._direction_degrees_to_grip_directionmapping rotates one step (firmware contract unchanged),iSWAPBackend.rotate(grip_direction=…)now takes a string. Tests updated to feed the new degree values; physical poses unchanged (e.g. "front" pickup that used to bedirection=0is nowdirection=270, still emitting firmwaregr=1).OrientableArm._resource_width_for_directionflips:direction%180==0is now along ±X (right/left), so jaws grip in Y._LEGACY_TO_NEW_GRIPbecomes a static enum→string dict.architecture.mdand the user guide spell out the convention with a table.This PR is the v1 half of the work. KX2 FK/IK in
kx2-backendwill need the same yaw rotation as a follow-up after this lands and merges in.Test plan
pytest pylabrobot/capabilities/arms/ pylabrobot/arms/ pylabrobot/hamilton/ pylabrobot/legacy/liquid_handling/— 582 passed, 0 regressionspytest pylabrobot/— 1699 passed; the 13 unrelated xarm6 / scila failures pre-exist onv1b1and are unaffectedgr=1..4so this should be safe, but worth a sanity move)🤖 Generated with Claude Code