Centralize DifferentialDrive hardware defaults

Move platform-specific wheel defaults into DifferentialDrive, fixes blockly implementation.

defaults.py no longer imports sys.implementation or branches for NanoXRP; it always uses get_default_differential_drive(). DifferentialDrive.__init__ now accepts 0.0 sentinel values for wheel_diam and wheel_track and sets the real defaults (NanoXRP vs other) by inspecting implementation._machine. This removes duplicated platform logic from defaults.py and centralizes hardware-dependent defaults in the drive class.

Author: SaintSampo

XRPLib/defaults.py

@@ -10,7 +10,6 @@
 from .webserver import Webserver
 from .buzzer import Buzzer
 from machine import Pin
-from sys import implementation
 
 """
 A simple file that constructs all of the default objects for the XRP robot
@@ -24,12 +23,7 @@
     motor_four = EncodedMotor.get_default_encoded_motor(index=4)
 
 imu = IMU.get_default_imu()
-
-if "NanoXRP" in implementation._machine:
-    drivetrain = DifferentialDrive(left_motor, right_motor, imu, wheel_diam=3.46, wheel_track=7.8)
-else:
-    drivetrain = DifferentialDrive.get_default_differential_drive()
-
+drivetrain = DifferentialDrive.get_default_differential_drive()
 rangefinder = Rangefinder.get_default_rangefinder()
 reflectance = Reflectance.get_default_reflectance()
 servo_one = Servo.get_default_servo(index=1)

XRPLib/differential_drive.py

@@ -27,7 +27,7 @@ def get_default_differential_drive(cls):
 
         return cls._DEFAULT_DIFFERENTIAL_DRIVE_INSTANCE
 
-    def __init__(self, left_motor: EncodedMotor, right_motor: EncodedMotor, imu: IMU = None, wheel_diam:float = 6.0, wheel_track:float = 15.5):
+    def __init__(self, left_motor: EncodedMotor, right_motor: EncodedMotor, imu: IMU = None, wheel_diam:float = 0.0, wheel_track:float = 0.0):
         """
         A Differential Drive class designed for the XRP two-wheeled drive robot.
 
@@ -48,8 +48,18 @@ def __init__(self, left_motor: EncodedMotor, right_motor: EncodedMotor, imu: IMU
         self.imu = imu
 
         self.brake_at_zero_power = False
-        self.wheel_diam = wheel_diam
-        self.track_width = wheel_track
+
+        if (wheel_diam == 0.0):
+            if "NanoXRP" in implementation._machine:
+                self.wheel_diam = 3.46
+            else:
+                self.wheel_diam = 6.0
+
+        if (wheel_track == 0.0):
+            if "NanoXRP" in implementation._machine:
+                self.wheel_track = 7.8
+            else:
+                self.wheel_track = 15.5
 
         self.heading_pid = None
         self.current_heading = None