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Ramsetecommand implemented with Overtake and Beartype #42

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2 changes: 2 additions & 0 deletions commands2/__init__.py
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@
from .printcommand import PrintCommand
from .proxycommand import ProxyCommand
from .proxyschedulecommand import ProxyScheduleCommand
from .ramsetecommand import RamseteCommand
from .repeatcommand import RepeatCommand
from .runcommand import RunCommand
from .schedulecommand import ScheduleCommand
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"PrintCommand",
"ProxyCommand",
"ProxyScheduleCommand",
"RamseteCommand",
"RepeatCommand",
"RunCommand",
"ScheduleCommand",
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228 changes: 228 additions & 0 deletions commands2/ramsetecommand.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,228 @@
# Copyright (c) FIRST and other WPILib contributors.
# Open Source Software; you can modify and/or share it under the terms of
# the WPILib BSD license file in the root directory of this project.
from __future__ import annotations

from typing import Callable, Union, Optional, Tuple, overload
from overtake import overtake
from wpimath.controller import (
PIDController,
RamseteController,
SimpleMotorFeedforwardMeters,
)
from wpimath.geometry import Pose2d
from wpimath.kinematics import (
ChassisSpeeds,
DifferentialDriveKinematics,
DifferentialDriveWheelSpeeds,
)
from wpimath.trajectory import Trajectory
from wpimath import units as units
from wpiutil import SendableBuilder
from wpilib import Timer


from .command import Command
from .subsystem import Subsystem


class RamseteCommand(Command):
"""
A command that uses a RAMSETE controller (RamseteController) to follow a trajectory
(Trajectory) with a differential drive.

The command handles trajectory-following, PID calculations, and feedforwards internally. This
is intended to be a more-or-less "complete solution" that can be used by teams without a great
deal of controls expertise.

Advanced teams seeking more flexibility (for example, those who wish to use the onboard PID
functionality of a "smart" motor controller) may use the secondary constructor that omits the PID
and feedforward functionality, returning only the raw wheel speeds from the RAMSETE controller.
"""

@overload
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def __init__(
self,
trajectory: Trajectory,
pose: Callable[[], Pose2d],
controller: RamseteController,
kinematics: DifferentialDriveKinematics,
requirements: Tuple[Subsystem],
output: Callable[[float, float], None],
):
"""Constructs a new RamseteCommand that, when executed, will follow the provided trajectory. PID
control and feedforward are handled internally, and outputs are scaled -12 to 12 representing
units of volts.

Note: The controller will *not* set the outputVolts to zero upon completion of the path -
this is left to the user, since it is not appropriate for paths with nonstationary endstates.

:param trajectory: The trajectory to follow.
:param pose: A function that supplies the robot pose - use one of the odometry classes to
provide this.
:param controller: The RAMSETE controller used to follow the trajectory.
:param kinematics: The kinematics for the robot drivetrain.
:param requirements: The subsystems to require.
:param output A function that consumes the computed left and right outputs in `units.meters_per_second`
"""
super().__init__()

self._timer = Timer()
self.trajectory = trajectory
self.pose = pose
self.follower = controller
self.kinematics = kinematics
self.output = output
self.usePID = False
# All the parameter checks pass, inform scheduler. Type ignoring is set explictitly for the linter because this
# implementation declares the tuple explicitly, whereas the general implementations use the unpack operator (*)
# to pass the requirements to the scheduler.
self.addRequirements(requirements) # type: ignore

@overload
def __init__(
self,
trajectory: Trajectory,
pose: Callable[[], Pose2d],
controller: RamseteController,
kinematics: DifferentialDriveKinematics,
requirements: Tuple[Subsystem],
output: Callable[[float, float], None],
feedforward: SimpleMotorFeedforwardMeters,
leftController: PIDController,
rightController: PIDController,
wheelSpeeds: Callable[[], DifferentialDriveWheelSpeeds],
):
"""Constructs a new RamseteCommand that, when executed, will follow the provided trajectory. PID
control and feedforward are handled internally, and outputs are scaled -12 to 12 representing
units of volts.

Note: The controller will *not* set the outputVolts to zero upon completion of the path -
this is left to the user, since it is not appropriate for paths with nonstationary endstates.

:param trajectory: The trajectory to follow.
:param pose: A function that supplies the robot pose - use one of the odometry classes to
provide this.
:param controller: The RAMSETE controller used to follow the trajectory.
:param kinematics: The kinematics for the robot drivetrain.
:param requirements: The subsystems to require.
:param output A function that consumes the computed left and right outputs in `units.volts`
:param feedforward The feedforward to use for the drive
:param leftController: The PIDController for the left side of the robot drive.
:param rightController: The PIDController for the right side of the robot drive.
:param wheelSpeeds: A function that supplies the speeds of the left and right sides of the robot
drive.
"""
super().__init__()

self._timer = Timer()

# Store all the requirements that are required
self.trajectory = trajectory
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self.pose = pose
self.follower = controller
self.kinematics = kinematics
self.output = output
self.leftController = leftController
self.rightController = rightController
self.wheelspeeds = wheelSpeeds
self.feedforward = feedforward
self._prevSpeeds = DifferentialDriveWheelSpeeds()
self._prevTime = -1.0
self.usePID = True
# All the parameter checks pass, inform scheduler. Type ignoring is set explictitly for the linter because this
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... I don't understand this comment? Shouldn't you unpack here?

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When I keep things as they are with other commands, the '*' throws off the dispatch to the point where incorrect constructors get called, as well as mypy coming up with type errors. Basically, for me to get it to work, I had to declare the requirements explicitly as a Tuple, without unpacking since that's what addRequirements wants. Mypy was not happy with this solution, so I just type:ignore.

There is possibly a way to get it to work, but I couldn't figure it out.

# implementation declares the tuple explicitly, whereas the general implementations use the unpack operator (*)
# to pass the requirements to the scheduler.
self.addRequirements(requirements) # type: ignore

@overtake(runtime_type_checker="beartype")
def __init__(
self,
*,
trajectory: Trajectory,
pose: Callable[[], Pose2d],
controller: RamseteController,
kinematics: DifferentialDriveKinematics,
requirements: Tuple[Subsystem],
output: Callable[[float, float], None],
feedforward: Optional[SimpleMotorFeedforwardMeters] = None,
leftController: Optional[PIDController] = None,
rightController: Optional[PIDController] = None,
wheelSpeeds: Optional[Callable[[], DifferentialDriveWheelSpeeds]] = None,
):
...

def initialize(self):
self._prevTime = -1
initial_state = self.trajectory.sample(0)
self._prevSpeeds = self.kinematics.toWheelSpeeds(
ChassisSpeeds(
initial_state.velocity,
0,
initial_state.curvature * initial_state.velocity,
)
)
self._timer.restart()
if self.usePID:
self.leftController.reset()
self.rightController.reset()

def execute(self):
curTime = self._timer.get()
dt = curTime - self._prevTime

if self._prevTime < 0:
self.output(0.0, 0.0)
self._prevTime = curTime
return

targetWheelSpeeds = self.kinematics.toWheelSpeeds(
self.follower.calculate(self.pose(), self.trajectory.sample(curTime))
)

leftSpeedSetpoint = targetWheelSpeeds.left
rightSpeedSetpoint = targetWheelSpeeds.right

if self.usePID:
leftFeedforward = self.feedforward.calculate(
leftSpeedSetpoint, (leftSpeedSetpoint - self._prevSpeeds.left) / dt
)

rightFeedforward = self.feedforward.calculate(
rightSpeedSetpoint,
(rightSpeedSetpoint - self._prevSpeeds.right) / dt,
)

leftOutput = leftFeedforward + self.leftController.calculate(
self.wheelspeeds().left, leftSpeedSetpoint
)

rightOutput = rightFeedforward + self.rightController.calculate(
self.wheelspeeds().right, rightSpeedSetpoint
)
self.output(leftOutput, rightOutput)
else:
leftOutput = leftSpeedSetpoint
rightOutput = rightSpeedSetpoint
self.output(leftOutput, rightOutput)

self._prevSpeeds = targetWheelSpeeds
self._prevTime = curTime

def end(self, interrupted: bool):
self._timer.stop()

if interrupted:
self.output(0.0, 0.0)

def isFinished(self):
return self._timer.hasElapsed(self.trajectory.totalTime())

def initSendable(self, builder: SendableBuilder):
super().initSendable(builder)
builder.addDoubleProperty(
"leftVelocity", lambda: self._prevSpeeds.left, lambda *float: None
)
builder.addDoubleProperty(
"rightVelocity", lambda: self._prevSpeeds.right, lambda *float: None
)
7 changes: 6 additions & 1 deletion setup.py
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,12 @@
description="WPILib command framework v2",
url="https://github.com/robotpy/robotpy-commands-v2",
packages=["commands2"],
install_requires=["wpilib<2025,>=2024.0.0b2", "typing_extensions>=4.1.0,<5"],
install_requires=[
"wpilib<2025,>=2024.0.0b2",
"typing_extensions>=4.1.0,<5",
"overtake>=0.4.0",
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"beartype>=0.16.4",
],
license="BSD-3-Clause",
python_requires=">=3.8",
include_package_data=True,
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