feat(api): decrease plunger acceleration and add drop tip speed to co…

…nfig (#2904)

- decrease plunger acceleration to reduce strain on internal seal
- add drop tip speed to pipette configs and respect it during drop tip

api/src/opentrons/config/pipette_config.py

@@ -26,6 +26,7 @@
         'model_offset',
         'plunger_current',
         'drop_tip_current',
+        'drop_tip_speed',
         'min_volume',
         'max_volume',
         'ul_per_mm',
@@ -99,6 +100,7 @@ def load(pipette_model: str) -> pipette_config:
         model_offset=cfg.get('modelOffset'),
         plunger_current=cfg.get('plungerCurrent'),
         drop_tip_current=cfg.get('dropTipCurrent'),
+        drop_tip_speed=cfg.get('dropTipSpeed'),
         min_volume=cfg.get('minVolume'),
         max_volume=cfg.get('maxVolume'),
         ul_per_mm=cfg.get('ulPerMm'),

api/src/opentrons/config/robot_configs.py

@@ -94,7 +94,22 @@
     [0.00, 0.00, 1.00,  0.00],
     [0.00, 0.00, 0.00,  1.00]]
 
-DEFAULT_ACCELERATION = 'M204 S10000 X3000 Y2000 Z1500 A1500 B2000 C2000'
+X_ACCELERATION = 3000
+Y_ACCELERATION = 2000
+Z_ACCELERATION = 1500
+A_ACCELERATION = 1500
+B_ACCELERATION = 200
+C_ACCELERATION = 200
+
+DEFAULT_ACCELERATION = {
+    'X': X_ACCELERATION,
+    'Y': Y_ACCELERATION,
+    'Z': Z_ACCELERATION,
+    'A': A_ACCELERATION,
+    'B': B_ACCELERATION,
+    'C': C_ACCELERATION
+}
+
 DEFAULT_STEPS_PER_MM = 'M92 X80.00 Y80.00 Z400 A400 B768 C768'
 # This probe height is ~73 from deck to the top surface of the switch body
 # per CAD; 74.3mm is the nominal for engagement from the switch drawing.

api/src/opentrons/drivers/smoothie_drivers/driver_3_0.py

@@ -86,7 +86,8 @@
           'SET_MAX_SPEED': 'M203.1',
           'SET_CURRENT': 'M907',
           'DISENGAGE_MOTOR': 'M18',
-          'HOMING_STATUS': 'G28.6'}
+          'HOMING_STATUS': 'G28.6',
+          'ACCELERATION': 'M204 S10000'}
 
 # Number of digits after the decimal point for coordinates being sent
 # to Smoothie
@@ -301,6 +302,9 @@ def __init__(self, config):
         self._combined_speed = float(DEFAULT_AXES_SPEED)
         self._saved_axes_speed = float(self._combined_speed)
 
+        self._acceleration = config.acceleration.copy()
+        self._saved_acceleration = config.acceleration.copy()
+
         # position after homing
         self._homed_position = HOMED_POSITION.copy()
         self.homed_flags = {}
@@ -599,6 +603,30 @@ def push_axis_max_speed(self):
     def pop_axis_max_speed(self):
         self.set_axis_max_speed(self._saved_max_speed_settings)
 
+    def set_acceleration(self, settings):
+        '''
+        Sets the acceleration (mm/sec^2) that a given axis will move
+
+        settings
+            Dict with axes as valies (e.g.: 'X', 'Y', 'Z', 'A', 'B', or 'C')
+            and floating point number for mm-per-second-squared (mm/sec^2)
+        '''
+        self._acceleration.update(settings)
+        values = ['{}{}'.format(axis.upper(), value)
+                  for axis, value in sorted(settings.items())]
+        command = '{} {}'.format(
+            GCODES['ACCELERATION'],
+            ' '.join(values)
+        )
+        log.debug("set_acceleration: {}".format(command))
+        self._send_command(command)
+
+    def push_acceleration(self):
+        self._saved_acceleration = self._acceleration.copy()
+
+    def pop_acceleration(self):
+        self.set_acceleration(self._saved_acceleration)
+
     def set_active_current(self, settings):
         '''
         Sets the amperage of each motor for when it is activated by driver.
@@ -956,13 +984,13 @@ def _setup(self):
             # use gpio to reset into a known state
             self._smoothie_reset()
         self._reset_from_error()
-        self._send_command(self._config.acceleration)
         self._send_command(self._config.steps_per_mm)
         self._send_command(GCODES['ABSOLUTE_COORDS'])
         self._save_current(self.current, axes_active=False)
         self.update_position(default=self.homed_position)
         self.pop_axis_max_speed()
         self.pop_speed()
+        self.pop_acceleration()
 
     def _read_from_pipette(self, gcode, mount) -> Optional[str]:
         '''

api/src/opentrons/hardware_control/__init__.py

@@ -938,7 +938,8 @@ async def drop_tip(self, mount, home_after=True):
         await self._move_plunger(mount, bottom)
         self._backend.set_active_current(plunger_ax,
                                          instr.config.drop_tip_current)
-        await self._move_plunger(mount, droptip)
+        await self._move_plunger(
+            mount, droptip, speed=instr.config.drop_tip_speed)
         await self._shake_off_tips(mount)
         instr.set_current_volume(0)
         instr.remove_tip()

api/src/opentrons/legacy_api/api.py

@@ -249,6 +249,7 @@ def _create_pipette_from_config(
             max_volume=config.max_volume,
             plunger_current=config.plunger_current,
             drop_tip_current=config.drop_tip_current,
+            drop_tip_speed=config.drop_tip_speed,
             plunger_positions=config.plunger_positions.copy(),
             ul_per_mm=config.ul_per_mm,
             pick_up_current=config.pick_up_current,

api/src/opentrons/legacy_api/instruments/pipette.py

@@ -24,6 +24,7 @@
 }
 
 DROP_TIP_RELEASE_DISTANCE = 20
+DEFAULT_DROP_TIP_SPEED = 5
 
 DEFAULT_ASPIRATE_SPEED = 5
 DEFAULT_DISPENSE_SPEED = 10
@@ -122,6 +123,7 @@ def __init__(
             dispense_flow_rate=None,
             plunger_current=0.5,
             drop_tip_current=0.5,
+            drop_tip_speed=DEFAULT_DROP_TIP_SPEED,
             plunger_positions=PLUNGER_POSITIONS,
             pick_up_current=DEFAULT_PLUNGE_CURRENT,
             pick_up_distance=DEFAULT_TIP_PRESS_MM,
@@ -197,13 +199,12 @@ def __init__(
         self._pick_up_distance = pick_up_distance
         self._pick_up_current = pick_up_current
 
-        # TODO (andy) these values maybe should persist between sessions,
-        # by saving within `robot_config`
         self._plunger_current = plunger_current
         self._drop_tip_current = drop_tip_current
 
         self.speeds = {}
         self.set_speed(aspirate=aspirate_speed, dispense=dispense_speed)
+        self._drop_tip_speed = drop_tip_speed
 
         self.set_flow_rate(
             aspirate=aspirate_flow_rate, dispense=dispense_flow_rate)
@@ -1046,10 +1047,13 @@ def _drop_tip(location, instrument=self):
                 x=pos_bottom
             )
             self.instrument_actuator.set_active_current(self._drop_tip_current)
+            self.instrument_actuator.push_speed()
+            self.instrument_actuator.set_speed(self._drop_tip_speed)
             self.robot.poses = self.instrument_actuator.move(
                 self.robot.poses,
                 x=pos_drop_tip
             )
+            self.instrument_actuator.pop_speed()
             self._shake_off_tips(location)
             if home_after:
                 self._home_after_drop_tip()

api/src/opentrons/legacy_api/robot/mover.py

@@ -99,6 +99,18 @@ def push_active_current(self):
     def pop_active_current(self):
         self._driver.pop_active_current()
 
+    def set_acceleration(self, acceleration):
+        self._driver.set_acceleration({
+                axis.upper(): acceleration
+                for axis in self._axis_mapping.values()
+            })
+
+    def push_acceleration(self):
+        self._driver.push_acceleration()
+
+    def pop_acceleration(self):
+        self._driver.pop_acceleration()
+
     def probe(self, pose_tree, axis, movement):
         assert axis in self._axis_mapping, "mapping is not set for " + axis
 

api/tests/opentrons/drivers/test_driver.py

@@ -313,6 +313,45 @@ def _parse_position_response(arg):
     fuzzy_assert(result=command_log, expected=expected)
 
 
+def test_set_acceleration(smoothie, monkeypatch):
+    from opentrons.drivers import serial_communication
+    from opentrons.drivers.smoothie_drivers import driver_3_0
+    command_log = []
+    smoothie._setup()
+    smoothie.home()
+    smoothie.simulating = False
+
+    def write_with_log(command, ack, connection, timeout):
+        command_log.append(command.strip())
+        return driver_3_0.SMOOTHIE_ACK
+
+    def _parse_position_response(arg):
+        return smoothie.position
+
+    monkeypatch.setattr(serial_communication, 'write_and_return',
+                        write_with_log)
+    monkeypatch.setattr(
+        driver_3_0, '_parse_position_response', _parse_position_response)
+
+    smoothie.set_acceleration(
+        {'X': 1, 'Y': 2, 'Z': 3, 'A': 4, 'B': 5, 'C': 6})
+    smoothie.push_acceleration()
+    smoothie.pop_acceleration()
+    smoothie.set_acceleration(
+        {'X': 10, 'Y': 20, 'Z': 30, 'A': 40, 'B': 50, 'C': 60})
+    smoothie.pop_acceleration()
+
+    expected = [
+        ['M204 S10000 A4 B5 C6 X1 Y2 Z3 M400'],
+        ['M204 S10000 A4 B5 C6 X1 Y2 Z3 M400'],
+        ['M204 S10000 A40 B50 C60 X10 Y20 Z30 M400'],
+        ['M204 S10000 A4 B5 C6 X1 Y2 Z3 M400']
+    ]
+    # from pprint import pprint
+    # pprint(command_log)
+    fuzzy_assert(result=command_log, expected=expected)
+
+
 def test_active_dwelling_current_push_pop(smoothie):
     assert smoothie._active_current_settings != \
         smoothie._dwelling_current_settings