class Encoder(Sensor):
"""
Sensor wrapper for a quadrature encoder.
Has double attributes distance, rate (distance/second);
boolean attributes stopped and direction.
"""
distance = rate = 0
stopped = direction = True
def __init__(self, channel_a, channel_b, pulse_dist=1.0,
reverse=False, modnum=1, cpr=128,
enctype=CounterBase.EncodingType.k4X):
"""
Initializes the encoder with two channels,
distance per pulse (usu. feet, default 1), no reversing,
on module number 1, 128 CPR, and with 4x counting.
"""
super().__init__()
self.e = WEncoder(channel_a, channel_b, reverse, enctype)
self.cpr = cpr
self.e.setDistancePerPulse(pulse_dist)
def poll(self):
self.distance = self.e.getDistance()
self.rate = self.e.getRate()
self.stopped = self.e.getStopped()
self.direction = self.e.getDirection()
class Robot(TimedRobot):
def robotInit(self):
# Right Motors
self.RightMotor1 = WPI_TalonFX(1)
self.RightMotor2 = WPI_TalonFX(2)
self.RightMotor3 = WPI_TalonFX(3)
self.rightDriveMotors = SpeedControllerGroup(self.RightMotor1,
self.RightMotor2,
self.RightMotor3)
# Left Motors
self.LeftMotor1 = WPI_TalonFX(4)
self.LeftMotor2 = WPI_TalonFX(5)
self.LeftMotor3 = WPI_TalonFX(6)
self.leftDriveMotors = SpeedControllerGroup(self.LeftMotor1,
self.LeftMotor2,
self.LeftMotor3)
self.drive = DifferentialDrive(self.leftDriveMotors,
self.rightDriveMotors)
self.testEncoder = Encoder(1, 2, 3)
self.dashboard = NetworkTables.getTable("SmartDashboard")
def disabledInit(self):
pass
def autonomousInit(self):
pass
def teleopInit(self):
pass
def testInit(self):
pass
def robotPeriodic(self):
self.dashboard.putNumber("Encoder", self.testEncoder.getRate())
def disabledPeriodic(self):
pass
def autonomousPeriodic(self):
self.drive.arcadeDrive(.5, 0)
def teleopPeriodic(self):
pass
def testPeriodic(self):
pass
class Drivetrain(SubsystemBase):
def __init__(self):
super().__init__()
# Create the motor controllers and their respective speed controllers.
self.leftMotors = SpeedControllerGroup(
PWMSparkMax(constants.kLeftMotor1Port),
PWMSparkMax(constants.kLeftMotor2Port),
)
self.rightMotors = SpeedControllerGroup(
PWMSparkMax(constants.kRightMotor1Port),
PWMSparkMax(constants.kRightMotor2Port),
)
# Create the differential drivetrain object, allowing for easy motor control.
self.drive = DifferentialDrive(self.leftMotors, self.rightMotors)
# Create the encoder objects.
self.leftEncoder = Encoder(
constants.kLeftEncoderPorts[0],
constants.kLeftEncoderPorts[1],
constants.kLeftEncoderReversed,
)
self.rightEncoder = Encoder(
constants.kRightEncoderPorts[0],
constants.kRightEncoderPorts[1],
constants.kRightEncoderReversed,
)
# Configure the encoder so it knows how many encoder units are in one rotation.
self.leftEncoder.setDistancePerPulse(
constants.kEncoderDistancePerPulse)
self.rightEncoder.setDistancePerPulse(
constants.kEncoderDistancePerPulse)
# Create the gyro, a sensor which can indicate the heading of the robot relative
# to a customizable position.
self.gyro = ADXRS450_Gyro()
# Create the an object for our odometry, which will utilize sensor data to
# keep a record of our position on the field.
self.odometry = DifferentialDriveOdometry(self.gyro.getRotation2d())
# Reset the encoders upon the initilization of the robot.
self.resetEncoders()
def periodic(self):
"""
Called periodically when it can be called. Updates the robot's
odometry with sensor data.
"""
self.odometry.update(
self.gyro.getRotation2d(),
self.leftEncoder.getDistance(),
self.rightEncoder.getDistance(),
)
def getPose(self):
"""Returns the current position of the robot using it's odometry."""
return self.odometry.getPose()
def getWheelSpeeds(self):
"""Return an object which represents the wheel speeds of our drivetrain."""
speeds = DifferentialDriveWheelSpeeds(self.leftEncoder.getRate(),
self.rightEncoder.getRate())
return speeds
def resetOdometry(self, pose):
""" Resets the robot's odometry to a given position."""
self.resetEncoders()
self.odometry.resetPosition(pose, self.gyro.getRotation2d())
def arcadeDrive(self, fwd, rot):
"""Drive the robot with standard arcade controls."""
self.drive.arcadeDrive(fwd, rot)
def tankDriveVolts(self, leftVolts, rightVolts):
"""Control the robot's drivetrain with voltage inputs for each side."""
# Set the voltage of the left side.
self.leftMotors.setVoltage(leftVolts)
# Set the voltage of the right side. It's
# inverted with a negative sign because it's motors need to spin in the negative direction
# to move forward.
self.rightMotors.setVoltage(-rightVolts)
# Resets the timer for this motor's MotorSafety
self.drive.feed()
def resetEncoders(self):
"""Resets the encoders of the drivetrain."""
self.leftEncoder.reset()
self.rightEncoder.reset()
def getAverageEncoderDistance(self):
"""
Take the sum of each encoder's traversed distance and divide it by two,
since we have two encoder values, to find the average value of the two.
"""
return (self.leftEncoder.getDistance() +
self.rightEncoder.getDistance()) / 2
def getLeftEncoder(self):
"""Returns the left encoder object."""
return self.leftEncoder
def getRightEncoder(self):
"""Returns the right encoder object."""
return self.rightEncoder
def setMaxOutput(self, maxOutput):
"""Set the max percent output of the drivetrain, allowing for slower control."""
self.drive.setMaxOutput(maxOutput)
def zeroHeading(self):
"""Zeroes the gyro's heading."""
self.gyro.reset()
def getHeading(self):
"""Return the current heading of the robot."""
return self.gyro.getRotation2d().getDegrees()
def getTurnRate(self):
"""Returns the turning rate of the robot using the gyro."""
# The minus sign negates the value.
return -self.gyro.getRate()
