fix(api): add a buffer to tip action home moves to make sure the limi…

…t switch is triggered (#12743)
Opentrons · May 22, 2023 · 8e800ef · 8e800ef
1 parent acbf638
commit 8e800ef
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Showing 3 changed files with 11 additions and 2 deletions.
diff --git a/api/src/opentrons/hardware_control/instruments/ot3/pipette_handler.py b/api/src/opentrons/hardware_control/instruments/ot3/pipette_handler.py
@@ -79,6 +79,9 @@ class TipMotorPickUpTipSpec:
     pick_up_distance: float
     speed: float
     currents: Dict[OT3Axis, float]
+    # FIXME we should throw this in a config
+    # file of some sort
+    home_buffer: float = 0
 
 
 @dataclass(frozen=True)
@@ -100,6 +103,9 @@ class DropTipMove:
     home_after_safety_margin: float = 0
     home_axes: Sequence[OT3Axis] = tuple()
     is_ht_tip_action: bool = False
+    # FIXME we should throw this in a config
+    # file of some sort
+    home_buffer: float = 0
 
 
 @dataclass(frozen=True)
@@ -691,6 +697,7 @@ def build_presses() -> Iterator[Tuple[float, float]]:
                         pick_up_distance=instrument.pick_up_configurations.distance,
                         speed=instrument.pick_up_configurations.speed,
                         currents={OT3Axis.Q: instrument.pick_up_configurations.current},
+                        home_buffer=10,
                     ),
                 ),
                 add_tip_to_instr,
@@ -769,6 +776,7 @@ def build() -> List[DropTipMove]:
                     home_after_safety_margin=abs(bottom_pos - droptip_pos),
                     home_axes=home_axes,
                     is_ht_tip_action=is_ht_pipette,
+                    home_buffer=10 if is_ht_pipette else 0,
                 ),
                 DropTipMove(  # always finish drop-tip at a known safe plunger position
                     target_position=bottom_pos, current=plunger_currents, speed=None

diff --git a/api/src/opentrons/hardware_control/ot3api.py b/api/src/opentrons/hardware_control/ot3api.py
@@ -1619,7 +1619,7 @@ async def _motor_pick_up_tip(
             # back clamps off the adapter posts
             await self._backend.tip_action(
                 [OT3Axis.of_main_tool_actuator(mount)],
-                pipette_spec.pick_up_distance,
+                pipette_spec.pick_up_distance + pipette_spec.home_buffer,
                 pipette_spec.speed,
                 "home",
             )
@@ -1703,7 +1703,7 @@ async def drop_tip(
                 )
                 await self._backend.tip_action(
                     [OT3Axis.of_main_tool_actuator(mount)],
-                    move.target_position,
+                    move.target_position + move.home_buffer,
                     move.speed,
                     "home",
                 )

diff --git a/api/tests/opentrons/hardware_control/test_pipette_handler.py b/api/tests/opentrons/hardware_control/test_pipette_handler.py
@@ -89,6 +89,7 @@ def test_plan_check_pick_up_tip_with_presses_argument(
                 pick_up_distance=0,
                 speed=10,
                 currents={OT3Axis.Q: 1},
+                home_buffer=10,
             ),
         ),
         (None, 3, 8, None),