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128 lines
5.2 KiB
Python
Executable File
128 lines
5.2 KiB
Python
Executable File
#
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# Copyright (c) FIRST and other WPILib contributors.
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# Open Source Software; you can modify and/or share it under the terms of
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# the WPILib BSD license file in the root directory of this project.
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#
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import math
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import wpilib
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import wpimath
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class Drivetrain:
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"""Represents a mecanum drive style drivetrain."""
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kMaxSpeed = 3.0 # 3 meters per second
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kMaxAngularSpeed = math.pi # 1/2 rotation per second
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def __init__(self) -> None:
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self.frontLeftMotor = wpilib.PWMSparkMax(1)
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self.frontRightMotor = wpilib.PWMSparkMax(2)
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self.backLeftMotor = wpilib.PWMSparkMax(3)
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self.backRightMotor = wpilib.PWMSparkMax(4)
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self.frontLeftEncoder = wpilib.Encoder(0, 1)
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self.frontRightEncoder = wpilib.Encoder(2, 3)
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self.backLeftEncoder = wpilib.Encoder(4, 5)
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self.backRightEncoder = wpilib.Encoder(6, 7)
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self.frontLeftLocation = wpimath.Translation2d(0.381, 0.381)
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self.frontRightLocation = wpimath.Translation2d(0.381, -0.381)
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self.backLeftLocation = wpimath.Translation2d(-0.381, 0.381)
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self.backRightLocation = wpimath.Translation2d(-0.381, -0.381)
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self.frontLeftPIDController = wpimath.PIDController(1, 0, 0)
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self.frontRightPIDController = wpimath.PIDController(1, 0, 0)
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self.backLeftPIDController = wpimath.PIDController(1, 0, 0)
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self.backRightPIDController = wpimath.PIDController(1, 0, 0)
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self.imu = wpilib.OnboardIMU(wpilib.OnboardIMU.MountOrientation.kFlat)
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self.kinematics = wpimath.MecanumDriveKinematics(
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self.frontLeftLocation,
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self.frontRightLocation,
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self.backLeftLocation,
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self.backRightLocation,
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)
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self.odometry = wpimath.MecanumDriveOdometry(
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self.kinematics, self.imu.getRotation2d(), self.getCurrentDistances()
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)
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# Gains are for example purposes only - must be determined for your own robot!
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self.feedforward = wpimath.SimpleMotorFeedforwardMeters(1, 3)
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self.imu.resetYaw()
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# We need to invert one side of the drivetrain so that positive voltages
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# result in both sides moving forward. Depending on how your robot's
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# gearbox is constructed, you might have to invert the left side instead.
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self.frontRightMotor.setInverted(True)
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self.backRightMotor.setInverted(True)
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def getCurrentState(self) -> wpimath.MecanumDriveWheelSpeeds:
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"""Returns the current state of the drivetrain."""
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return wpimath.MecanumDriveWheelSpeeds(
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self.frontLeftEncoder.getRate(),
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self.frontRightEncoder.getRate(),
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self.backLeftEncoder.getRate(),
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self.backRightEncoder.getRate(),
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)
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def getCurrentDistances(self) -> wpimath.MecanumDriveWheelPositions:
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"""Returns the current distances measured by the drivetrain."""
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positions = wpimath.MecanumDriveWheelPositions()
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positions.frontLeft = self.frontLeftEncoder.getDistance()
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positions.frontRight = self.frontRightEncoder.getDistance()
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positions.rearLeft = self.backLeftEncoder.getDistance()
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positions.rearRight = self.backRightEncoder.getDistance()
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return positions
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def setSpeeds(self, speeds: wpimath.MecanumDriveWheelSpeeds) -> None:
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"""Sets the desired speeds for each wheel."""
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frontLeftFeedforward = self.feedforward.calculate(speeds.frontLeft)
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frontRightFeedforward = self.feedforward.calculate(speeds.frontRight)
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backLeftFeedforward = self.feedforward.calculate(speeds.rearLeft)
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backRightFeedforward = self.feedforward.calculate(speeds.rearRight)
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frontLeftOutput = self.frontLeftPIDController.calculate(
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self.frontLeftEncoder.getRate(), speeds.frontLeft
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)
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frontRightOutput = self.frontRightPIDController.calculate(
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self.frontRightEncoder.getRate(), speeds.frontRight
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)
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backLeftOutput = self.frontLeftPIDController.calculate(
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self.backLeftEncoder.getRate(), speeds.rearLeft
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)
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backRightOutput = self.frontRightPIDController.calculate(
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self.backRightEncoder.getRate(), speeds.rearRight
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)
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self.frontLeftMotor.setVoltage(frontLeftOutput + frontLeftFeedforward)
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self.frontRightMotor.setVoltage(frontRightOutput + frontRightFeedforward)
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self.backLeftMotor.setVoltage(backLeftOutput + backLeftFeedforward)
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self.backRightMotor.setVoltage(backRightOutput + backRightFeedforward)
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def drive(
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self,
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xSpeed: float,
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ySpeed: float,
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rot: float,
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fieldRelative: bool,
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periodSeconds: float,
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) -> None:
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"""Method to drive the robot using joystick info."""
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chassisSpeeds = wpimath.ChassisSpeeds(xSpeed, ySpeed, rot)
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if fieldRelative:
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chassisSpeeds = chassisSpeeds.toRobotRelative(self.imu.getRotation2d())
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self.setSpeeds(
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self.kinematics.toWheelSpeeds(
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chassisSpeeds.discretize(periodSeconds)
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).desaturate(self.kMaxSpeed)
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)
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def updateOdometry(self) -> None:
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"""Updates the field-relative position."""
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self.odometry.update(self.imu.getRotation2d(), self.getCurrentDistances())
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