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9bd9656871
I left "free speed" alone since that's the technical term for it. In general, velocity is a vector quantity, and speed is a magnitude (i.e., a strictly positive value). This PR also replaces the speed verbiage in MotorController with duty cycle. Fixes #8423.
112 lines
4.1 KiB
Python
112 lines
4.1 KiB
Python
#
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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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import wpimath.units
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import swervemodule
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from exampleglobalmeasurementsensor import ExampleGlobalMeasurementSensor
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class Drivetrain:
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"""Represents a swerve drive style drivetrain."""
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kMaxVelocity = 3.0 # 3 meters per second
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kMaxAngularVelocity = math.pi # 1/2 rotation per second
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def __init__(self) -> None:
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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.frontLeft = swervemodule.SwerveModule(1, 2, 0, 1, 2, 3)
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self.frontRight = swervemodule.SwerveModule(3, 4, 4, 5, 6, 7)
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self.backLeft = swervemodule.SwerveModule(5, 6, 8, 9, 10, 11)
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self.backRight = swervemodule.SwerveModule(7, 8, 12, 13, 14, 15)
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self.imu = wpilib.OnboardIMU(wpilib.OnboardIMU.MountOrientation.kFlat)
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self.kinematics = wpimath.SwerveDrive4Kinematics(
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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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# Here we use SwerveDrivePoseEstimator so that we can fuse odometry readings. The numbers
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# used below are robot specific, and should be tuned.
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self.poseEstimator = wpimath.SwerveDrive4PoseEstimator(
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self.kinematics,
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self.imu.getRotation2d(),
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(
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self.frontLeft.getPosition(),
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self.frontRight.getPosition(),
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self.backLeft.getPosition(),
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self.backRight.getPosition(),
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),
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wpimath.Pose2d(),
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(0.05, 0.05, wpimath.units.degreesToRadians(5)),
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(0.5, 0.5, wpimath.units.degreesToRadians(30)),
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)
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self.imu.resetYaw()
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def drive(
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self,
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xVelocity: float,
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yVelocity: float,
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rot: float,
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fieldRelative: bool,
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period: float,
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) -> None:
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"""Method to drive the robot using joystick info.
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:param xVelocity: Velocity of the robot in the x direction (forward).
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:param yVelocity: Velocity of the robot in the y direction (sideways).
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:param rot: Angular rate of the robot.
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:param fieldRelative: Whether the provided x and y velocities are relative to the field.
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"""
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chassisVelocities = wpimath.ChassisVelocities(xVelocity, yVelocity, rot)
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if fieldRelative:
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chassisVelocities = chassisVelocities.toRobotRelative(
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self.poseEstimator.getEstimatedPosition().rotation()
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)
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chassisVelocities = chassisVelocities.discretize(period)
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states = self.kinematics.toSwerveModuleStates(chassisVelocities)
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wpimath.SwerveDrive4Kinematics.desaturateWheelVelocities(states, self.kMaxVelocity)
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self.frontLeft.setDesiredState(states[0])
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self.frontRight.setDesiredState(states[1])
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self.backLeft.setDesiredState(states[2])
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self.backRight.setDesiredState(states[3])
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def updateOdometry(self) -> None:
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"""Updates the field relative position of the robot."""
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self.poseEstimator.update(
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self.imu.getRotation2d(),
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(
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self.frontLeft.getPosition(),
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self.frontRight.getPosition(),
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self.backLeft.getPosition(),
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self.backRight.getPosition(),
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),
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)
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# Also apply vision measurements. We use 0.3 seconds in the past as an example -- on
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# a real robot, this must be calculated based either on latency or timestamps.
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self.poseEstimator.addVisionMeasurement(
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ExampleGlobalMeasurementSensor.getEstimatedGlobalPose(
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self.poseEstimator.getEstimatedPosition()
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),
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wpilib.Timer.getTimestamp() - 0.3,
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)
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