Exemplo n.º 1
0
class Winch:
    def __init__(self, talon_id):
        self.talon = TalonSRX(talon_id)
        self.talon.configSelectedFeedbackSensor(
            TalonSRX.FeedbackDevice.QuadEncoder, 0, 0)
        self.talon.setQuadraturePosition(0, 0)
        self.talon.setInverted(True)

    def forward(self):
        self.talon.set(TalonSRX.ControlMode.PercentOutput, 0.75)

    def reverse(self):
        self.talon.set(TalonSRX.ControlMode.PercentOutput, -0.75)

    def stop(self):
        self.talon.set(TalonSRX.ControlMode.PercentOutput, 0)

    def update_smart_dashboard(self):
        wpilib.SmartDashboard.putNumber(
            "Winch Position", self.talon.getSelectedSensorPosition(0))

        wpilib.SmartDashboard.putNumber("Winch Quad Position",
                                        self.talon.getQuadraturePosition())
Exemplo n.º 2
0
    def setup_talons(self,
                     master: TalonSRX,
                     slave: TalonSRX,
                     invert=False,
                     pidIdx=0,
                     timeoutMs=0,
                     brake=True):
        slave.follow(master)
        master.configSelectedFeedbackSensor(
            FeedbackDevice.CTRE_MagEncoder_Relative, pidIdx, timeoutMs)

        master.enableVoltageCompensation(True)
        master.configOpenLoopRamp(1 / 3, timeoutMs)
        master.configContinuousCurrentLimit(50, timeoutMs)
        master.configPeakCurrentLimit(80, timeoutMs)
        master.configPeakCurrentDuration(500, timeoutMs)

        neut_mode = TalonSRX.NeutralMode.Brake if brake else TalonSRX.NeutralMode.Coast
        master.setNeutralMode(neut_mode)
        slave.setNeutralMode(neut_mode)

        master.setSensorPhase(False)
        master.setInverted(invert)
        slave.setInverted(invert)
Exemplo n.º 3
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class Claw:
    """
    Implements a finite-state automaton for manipulating the claw.

    Parameters:
        talon_id: the ID number of the talon on the claw.
        contact_sensor_channel: the channel that the contact sensor is
            connected to.
    """
    claw_movement_time = 0.5  #: time to allow for the claw to open, in seconds
    claw_adjust_time = 0.25

    def __init__(self, talon_id, follower_id):
        """
        Create a new instance of the claw subsystem.

        This function constructs and configures the CANTalon instance and the
        touch sensor. It also sets the state machine to the neutral starting
        state.
        """
        self.talon = TalonSRX(talon_id)
        self.follower = TalonSRX(follower_id)
        self.follower.set(
            TalonSRX.ControlMode.Follower,
            talon_id
        )
        self.talon.setInverted(True)
        self.follower.setInverted(False)

        # Forward limit switch = claw opening limit switch
        # self.talon.configForwardLimitSwitchSource(
        #     TalonSRX.LimitSwitchSource.FeedbackConnector,
        #     TalonSRX.LimitSwitchNormal.NormallyOpen,
        #     0
        # )

        self.state = 'neutral'

        self.closeAdjustTimer = wpilib.Timer()
        self.movementTimer = wpilib.Timer()

    def set_power(self, power):
        self.state = 'manual_ctrl'
        self.talon.set(TalonSRX.ControlMode.PercentOutput, power)

    def close(self):
        """
        Close the claw.

        This function does a quick check to make sure it is a valid state
        change before actually changing the state to "closing".
        For example you cannot set the state to "closing" if the claw is
        already gripping the cube.
        """
        if self.state != 'closed' and self.state != 'closing':
            self.state = 'closing'
            self.movementTimer.reset()
            self.movementTimer.start()

    def open(self):
        """
        Open the claw.

        The idea of checking the state change is similar to that of the close()
        function, but it also resets the opening start time.
        """
        if self.state != 'neutral' and self.state != 'opening':
            self.state = 'opening'
            self.movementTimer.reset()
            self.movementTimer.start()

    def toggle(self):
        """
        Toggle the claw state.
        If the claw is closed, open it, and if the claw is opened, close it.
        """
        if self.state == 'closed' or self.state == 'closing':
            self.open()
        elif self.state == 'neutral' or self.state == 'opening':
            self.close()

    def update(self):
        """
        The update function is called periodically and progresses the state
        machine.
        """

        # if the state is manual control, stop update immediately and return.
        if self.state == 'manual_ctrl':
            self.movementTimer.reset()
            self.movementTimer.stop()
            return

        # if the state is neutral, clear the start time and set the talon speed
        # to 0%
        elif self.state == 'neutral':
            self.movementTimer.reset()
            self.movementTimer.stop()
            self.talon.set(TalonSRX.ControlMode.PercentVbus, 0)

        # if the state is "closing", set the talon speed to -100%, and if the
        # touch sensor is depressed, transition to the "closed" state.
        elif self.state == 'closing':
            self.talon.set(TalonSRX.ControlMode.PercentVbus, -1.0)
            # fwdLim, revLim = self.talon.getLimitSwitchState()
            #
            # if revLim:  # contact sensor pressed?
            #     self.state = 'closed'
            #     self.closeAdjustTimer.reset()
            #     self.closeAdjustTimer.start()
            if self.movementTimer.get() > self.claw_movement_time:
                self.state = 'closed'
                self.closeAdjustTimer.reset()
                self.closeAdjustTimer.start()

        # if the state is "closed", use less power to the motors--
        # Maintain grip, but don't squeeze too hard
        elif self.state == 'closed':
            if self.closeAdjustTimer.get() > self.claw_adjust_time:
                self.talon.set(TalonSRX.ControlMode.PercentVbus, -0.5)
            else:
                self.talon.set(TalonSRX.ControlMode.PercentVbus, 0)

        # if the state is "opening", save the current time if the start time
        # is currently empty and set the motor speed to +100%.
        # Run until reaching claw_movement_time, then transition to
        # the "neutral" state.
        elif self.state == 'opening':
            self.talon.set(TalonSRX.ControlMode.PercentVbus, 1.0)
            if self.movementTimer.get() > self.claw_movement_time:
                self.state = 'neutral'
Exemplo n.º 4
0
class SwerveModule(object):
    def __init__(self, name, steer_id, drive_id):
        """
        Performs calculations and bookkeeping for a single swerve module.

        Args:
            name (str): A NetworkTables-friendly name for this swerve
                module. Used for saving and loading configuration data.
            steer_id (number): The CAN ID for the Talon SRX controlling this
                module's steering.
            drive_id (number): The CAN ID for the Talon SRX controlling this
                module's driving.

        Attributes:
            steer_talon (:class:`ctre.cantalon.CANTalon`): The Talon SRX used
                to actuate this module's steering.
            drive_talon (:class:`ctre.cantalon.CANTalon`): The Talon SRX used
                to actuate this module's drive.
            steer_target (number): The current target steering position for
                this module, in radians.
            steer_offset (number): The swerve module's steering zero position.
                This value can be determined by manually steering a swerve
                module so that it faces forwards relative to the chassis, and
                by taking the raw encoder position value (ADC reading); this
                value is the steer offset.
            drive_reversed (boolean): Whether or not the drive motor's output
                is currently reversed.
        """
        self.steer_talon = TalonSRX(steer_id)
        self.drive_talon = TalonSRX(drive_id)

        # Configure steering motors to use abs. encoders
        # and closed-loop control
        self.steer_talon.selectProfileSlot(0, 0)
        self.steer_talon.configSelectedFeedbackSensor(FeedbackDevice.Analog, 0,
                                                      0)  # noqa: E501
        self.steer_talon.configAllowableClosedloopError(
            0, math.ceil(_acceptable_steer_err), 0)

        self.drive_talon.configSelectedFeedbackSensor(
            FeedbackDevice.QuadEncoder, 0, 0)  # noqa: E501
        self.drive_talon.setQuadraturePosition(0, 0)
        self.drive_talon.configAllowableClosedloopError(
            0, math.ceil(_acceptable_drive_err), 0)

        self.name = name
        self.steer_target = 0
        self.steer_target_native = 0
        self.drive_temp_flipped = False
        self.max_speed = 470  # ticks / 100ms
        self.max_observed_speed = 0
        self.raw_drive_speeds = []
        self.raw_target = 0

        self.load_config_values()

    def load_config_values(self):
        """
        Load saved configuration values for this module via WPILib's
        Preferences interface.

        The key names are derived from the name passed to the
        constructor.
        """
        self.steer_talon.selectProfileSlot(0, 0)

        preferences = wpilib.Preferences.getInstance()

        self.max_speed = preferences.getFloat(self.name + '-Max Wheel Speed',
                                              370)

        self.drive_talon.setSensorPhase(
            preferences.getBoolean(
                self.name + '-Sensor Reverse',
                swerve_defaults[self.name]['Sensor Reverse']))

        self.steer_talon.setSensorPhase(
            preferences.getBoolean(
                self.name + '-Steer Sensor Reverse',
                swerve_defaults[self.name]['Steer Sensor Reverse']))

        self.steer_offset = preferences.getFloat(
            self.name + '-offset', swerve_defaults[self.name]['Offset'])

        self.steer_min = 0
        self.steer_max = 1024
        self.steer_range = 1024

        self.drive_reversed = preferences.getBoolean(
            self.name + '-reversed', swerve_defaults[self.name]['Reversed'])

        self.steer_reversed = preferences.getBoolean(
            self.name + '-steer-reversed',
            swerve_defaults[self.name]['Steer Reversed'])

        self.steer_talon.setInverted(self.steer_reversed)

    def save_config_values(self):
        """
        Save configuration values for this module via WPILib's
        Preferences interface.
        """
        preferences = wpilib.Preferences.getInstance()

        preferences.putFloat(self.name + '-offset', self.steer_offset)
        preferences.putBoolean(self.name + '-reversed', self.drive_reversed)

        if _apply_range_hack:
            preferences.putFloat(self.name + '-min', self.steer_min)
            preferences.putFloat(self.name + '-max', self.steer_max)

    def get_steer_angle(self):
        """
        Get the current angular position of the swerve module in
        radians.
        """
        native_units = self.steer_talon.getSelectedSensorPosition()
        native_units -= self.steer_offset

        # Position in rotations
        rotation_pos = native_units / self.steer_range

        return rotation_pos * 2 * math.pi

    def set_steer_angle(self, angle_radians):
        """
        Steer the swerve module to the given angle in radians.
        `angle_radians` should be within :math:`[-2\\pi, 2\\pi]`.
        This method attempts to find the shortest path to the given
        steering angle; thus, it may in actuality servo to the
        position opposite the passed angle and reverse the drive
        direction.
        Args:
            angle_radians (number): The angle to steer towards in radians,
                where 0 points in the chassis forward direction.
        """
        n_rotations = math.trunc(
            (self.steer_talon.getSelectedSensorPosition(0) - self.steer_offset)
            / self.steer_range)

        current_angle = self.steer_talon.getSelectedSensorPosition(0)
        current_angle -= self.steer_offset
        current_angle *= (math.pi / 512)

        adjusted_target = angle_radians + (n_rotations * 2 * math.pi)

        possible_angles = [
            adjusted_target + math.pi,
            adjusted_target - math.pi,
            adjusted_target + (2 * math.pi),
            adjusted_target - (2 * math.pi),
        ]

        # Shortest-path servoing
        should_reverse_drive = False
        shortest_tgt = adjusted_target
        for i, target in enumerate(possible_angles):
            if abs(target - current_angle) < abs(shortest_tgt - current_angle):
                shortest_tgt = target
                if i == 0 or i == 1:
                    should_reverse_drive = True
                else:
                    should_reverse_drive = False
        self.steer_target = shortest_tgt

        self.steer_talon.configSelectedFeedbackSensor(FeedbackDevice.Analog, 0,
                                                      0)

        # Compute and send actual target to motor controller
        native_units = (self.steer_target * 512 / math.pi) + self.steer_offset
        self.raw_target = native_units
        self.steer_talon.set(ControlMode.Position, native_units)

        self.drive_temp_flipped = should_reverse_drive

    def set_drive_speed(self, speed, direct=False):
        """
        Drive the swerve module wheels at a given percentage of
        maximum power or speed.

        Args:
            percent_speed (number): The speed to drive the module at, expressed
                as a percentage of maximum speed. Negative values drive in
                reverse.
        """
        if self.drive_reversed:
            speed *= -1

        if self.drive_temp_flipped:
            speed *= -1

        self.drive_talon.selectProfileSlot(1, 0)
        self.drive_talon.config_kF(0, 1023 / self.max_speed, 0)

        if direct:
            self.drive_talon.set(ControlMode.Velocity, speed)
        else:
            self.drive_talon.set(ControlMode.Velocity, speed * self.max_speed)

    def set_drive_percent_out(self, pct_out):
        if self.drive_reversed:
            pct_out *= -1

        if self.drive_temp_flipped:
            pct_out *= -1

        self.drive_talon.set(ControlMode.PercentOutput, pct_out)

    def set_drive_distance(self, ticks):
        if self.drive_reversed:
            ticks *= -1

        if self.drive_temp_flipped:
            ticks *= -1

        self.drive_talon.selectProfileSlot(0, 0)
        self.drive_talon.set(ControlMode.Position, ticks)

    def reset_drive_position(self):
        self.drive_talon.setQuadraturePosition(0, 0)

    def apply_control_values(self, angle_radians, speed, direct=False):
        """
        Set a steering angle and a drive speed simultaneously.

        Args:
            angle_radians (number): The desired angle to steer towards.
            percent_speed (number): The desired percentage speed to drive at.

        See Also:
            :func:`~set_drive_speed` and :func:`~set_steer_angle`
        """
        self.set_steer_angle(angle_radians)
        self.set_drive_speed(speed, direct)

    def update_smart_dashboard(self):
        """
        Push various pieces of info to the Smart Dashboard.

        This method calls to NetworkTables (eventually), thus it may
        be _slow_.

        As of right now, this displays the current raw absolute encoder reading
        from the steer Talon, and the current target steer position.
        """
        self.raw_drive_speeds.append(self.drive_talon.getQuadratureVelocity())
        if len(self.raw_drive_speeds) > 50:
            self.raw_drive_speeds = self.raw_drive_speeds[-50:]

        self.cur_drive_spd = np.mean(self.raw_drive_speeds)

        if abs(self.cur_drive_spd) > abs(self.max_observed_speed):
            self.max_observed_speed = self.cur_drive_spd

        wpilib.SmartDashboard.putNumber(
            self.name + ' CL Position',
            self.steer_talon.getSelectedSensorPosition(0))

        wpilib.SmartDashboard.putNumber(self.name + ' ADC',
                                        self.steer_talon.getAnalogInRaw())

        wpilib.SmartDashboard.putNumber(
            self.name + ' Drive Ticks',
            self.drive_talon.getQuadraturePosition())

        wpilib.SmartDashboard.putNumber(self.name + ' Drive Velocity',
                                        self.cur_drive_spd)

        wpilib.SmartDashboard.putNumber(self.name + ' Steer Error',
                                        self.steer_talon.getClosedLoopError(0))

        wpilib.SmartDashboard.putNumber(self.name + ' Drive Error',
                                        self.drive_talon.getClosedLoopError(0))

        if _enable_debug_dashboard_values:
            wpilib.SmartDashboard.putNumber(
                self.name + ' Position',
                (self.steer_talon.getAnalogIn() - self.steer_offset) *
                (180 / 512))

            wpilib.SmartDashboard.putNumber(self.name + ' Raw Position',
                                            self.steer_talon.getAnalogIn())

            wpilib.SmartDashboard.putNumber(self.name + ' Target',
                                            self.raw_target)

            wpilib.SmartDashboard.putNumber(
                self.name + ' Drive Velocity (Max)', self.max_observed_speed)

        if wpilib.RobotBase.isReal():
            if _enable_debug_dashboard_values:
                wpilib.SmartDashboard.putNumber(
                    self.name + ' Drive Percent Output',
                    self.drive_talon.getMotorOutputPercent())

            wpilib.SmartDashboard.putNumber(
                self.name + ' Drive Current',
                self.drive_talon.getOutputCurrent())

            wpilib.SmartDashboard.putNumber(
                self.name + ' Steer Current',
                self.steer_talon.getOutputCurrent())
Exemplo n.º 5
0
class Elevator(FaultableSystem):
    def __init__(self, mock=False):
        super().__init__("Elevator")

        self.talon_master = TalonSRX(4)
        self.talon_slave = TalonSRX(5)

        self._state = ElevatorState.HOLDING

        self.nlogger = Logger("elevator")
        self.nlogger.add("Time", robot_time.delta_time)
        self.nlogger.add("Position", self.get_elevator_position)
        self.nlogger.add("Voltage", self.talon_master.getMotorOutputVoltage)
        self.nlogger.add("Current", self.talon_master.getOutputCurrent)
        # self.nlogger.start()

        dashboard2.add_graph("Elevator Position", self.get_elevator_position)
        dashboard2.add_graph("Elevator Voltage", self.talon_master.getMotorOutputVoltage)
        dashboard2.add_graph("Elevator Current", self.talon_master.getOutputCurrent)
        dashboard2.add_graph("Elevator Current2", self.talon_slave.getOutputCurrent)
        dashboard2.add_graph("Elevator State", lambda: self._state)

        if not mock:
            self.mp_manager = SRXMotionProfileManager(self.talon_master, 1000 // FREQUENCY)

            self.talon_master.setQuadraturePosition(0, 0)

            self.talon_slave.follow(self.talon_master)
            # 1023 units per 12V
            # This lets us pass in feedforward as voltage
            self.talon_master.config_kF(MAIN_IDX, 1023/12, 0)
            self.talon_master.config_kF(EXTENT_IDX, 1023/12, 0)

            kP = 0.05 * 1023 / 4096
            # self.talon_master.config_kP(MAIN_IDX, kP, 0)
            # self.talon_master.config_kP(EXTENT_IDX, kP, 0)

            self.talon_master.config_kP(HOLD_MAIN_IDX, .1 * 1023 / 4096, 0)
            self.talon_master.config_kP(HOLD_EXTENT_IDX, .3 * 1023 / 4096, 0)

            self.talon_master.configSelectedFeedbackSensor(FeedbackDevice.CTRE_MagEncoder_Relative, 0, 0)
            self.talon_master.setSensorPhase(True)
            invert = False
            self.talon_master.setInverted(invert)
            self.talon_slave.setInverted(invert)

    def init_profile(self, new_pos):
        if self._state != ElevatorState.HOLDING:
            return False
        profile, _ = self.gen_profile(self.get_elevator_position(), new_pos)
        self.mp_manager.init_profile(profile)
        self.talon_master.configSelectedFeedbackSensor(FeedbackDevice.CTRE_MagEncoder_Relative, 0, 0)
        return True

    def start_profile(self):
        self._state = ElevatorState.MOVING
        return self.mp_manager.start_profile()

    def has_finished_profile(self):
        return self.mp_manager.is_done()

    def finish_profile(self):
        self._state = ElevatorState.HOLDING
        self.hold()

    def set_power(self, power):
        self._state = ElevatorState.MANUAL
        self.talon_master.set(ControlMode.PercentOutput, power)

    def get_mass(self, pos):
        """
        Mass in lbm
        :param pos:
        :return:
        """
        if pos <= CARRIAGE_TRAVEL:
            return CARRIAGE_WEIGHT

        return CARRIAGE_WEIGHT + EXTENT_WEIGHT

    def get_hold_torque(self, pos):
        """
        Torque in lb-in
        :param pos:
        :return:
        """
        return self.get_mass(pos) * SPOOL_RADIUS

    def get_pid_index(self, pos):
        if pos <= CARRIAGE_TRAVEL:
            return MAIN_IDX
        return EXTENT_IDX

    def calc_ff(self, pos, vel, acc):
        """
        Returns feedforward in volts
        :param pos: Position of the elevator, in inches
        :param vel: Desired velocity, in in/s
        :param acc: Desired acceleration, in in/s^2
        :return: Feedforward voltage
        """
        hold_voltage = 12 * self.get_hold_torque(pos) / self.get_stall_torque()
        vel_maxv = 12 - hold_voltage
        vel_voltage = vel_maxv * vel / (self.get_max_speed() * (vel_maxv / 12))
        acc_maxv = 12 - hold_voltage - vel_voltage
        acc_voltage = 0

        return hold_voltage + vel_voltage + acc_voltage

    def gen_profile(self, start, end) -> Tuple[List[TalonPoint], int]:
        # if not 0 <= end <= TOP_EXTENT:
        #     raise ValueError(f"End must be within 0 and {TOP_EXTENT}")
        talon_points = []
        rawmp = MotionProfile(start=start, end=end, cruise_speed=CRUISE_SPEED, acc=ACC, frequency=FREQUENCY)
        for point in rawmp:
            last = point == rawmp[-1]
            talonpt = TalonPoint(position=-self.in_to_native_units(point.position),
                                 velocity=self.calc_ff(point.position, point.velocity, point.acc),
                                 headingDeg=0,
                                 profileSlotSelect0=self.get_pid_index(point.position),
                                 profileSlotSelect1=0,
                                 isLastPoint=last,
                                 zeroPos=False,
                                 timeDur=0)
            talon_points.append(talonpt)

        return talon_points, FREQUENCY

    def get_elevator_position(self):
        """

        :return: The elevator's position as measured by the encoder, in inches. 0 is bottom, 70 is top
        """
        return -self.native_to_inches(self.talon_master.getQuadraturePosition())

    def get_stall_torque(self):
        """
        Motor stall torque (N-m) * # of motors * gear ratio * 8.851 lb-in/N-m
        :return: 12V stall torque in lb-in
        """
        return 0.71 * 2 * GEAR_RATIO * 8.851

    def get_max_speed(self):
        """
        Motor free speed (rpm) * (1/60) seconds/minute / gear ratio
        2*pi*r * RPS = IPS
        :return: 12V speed of the elevator in in/s
        """
        return 2*math.pi*SPOOL_RADIUS*(18730 * (1/60) / GEAR_RATIO)

    def in_to_native_units(self, inches):
        return (inches / (2*math.pi*SPOOL_RADIUS)) * 4096 / TRAVEL_RATIO

    def native_to_inches(self, native_distance):
        return (native_distance / 4096) * (2*math.pi*SPOOL_RADIUS) * TRAVEL_RATIO

    def start_zero_position(self):
        self.talon_master.selectProfileSlot(MAIN_IDX, 0)
        self.talon_master.configSelectedFeedbackSensor(FeedbackDevice.CTRE_MagEncoder_Absolute, 0, 0)
        self.talon_master.set(ControlMode.Position, ZERO_POS)
        self._state = ElevatorState.ZEROING

    def is_done_zeroing(self):
        return self._state == ElevatorState.ZEROING and self.talon_master.getClosedLoopError(0) < ZERO_MAX_ERR

    def finish_zero_position(self):
        self._state = ElevatorState.HOLDING
        self.talon_master.setQuadraturePosition(0, 0)

    def hold(self):
        pos = self.get_elevator_position()
        target = self.in_to_native_units(pos)
        pid = self.get_pid_index(pos) + 2
        self.talon_master.selectProfileSlot(pid, 0)
        ff = (1023/12) * self.calc_ff(pos, 0, 0)
        if target == 0:
            ff = 0
        else:
            ff /= target
        self.talon_master.config_kF(pid, ff, 0)
        self.talon_master.set(ControlMode.Position, target)
        self._state = ElevatorState.HOLDING

    def move_to(self, target):
        pos = self.get_elevator_position()
        target_n = self.in_to_native_units(target)
        pid = self.get_pid_index(pos) + 2
        self.talon_master.selectProfileSlot(pid, 0)
        ff = (1023/12) * self.calc_ff(pos, 0, 0)
        if target_n == 0:
            ff = 0
        else:
            ff /= target_n
        self.talon_master.config_kF(pid, ff, 0)
        self.talon_master.set(ControlMode.Position, target_n)
        self._state = ElevatorState.HOLDING

    def is_at_top(self):
        return self.talon_master.isFwdLimitSwitchClosed()

    def is_at_bottom(self):
        return self.talon_master.isRevLimitSwitchClosed()

    def check_continuous_faults(self):
        """
        Check if the system is faulted.

        For the elevator, we are interested in whether the versa dual-input has failed.
        :return:
        """
        master_current = self.talon_master.getOutputCurrent()
        slave_current = self.talon_slave.getOutputCurrent()
        ref = master_current
        if ref == 0:
            ref = slave_current
        if ref == 0:
            ref = 1
        eps = 1e-1
        return (master_current > eps or slave_current > eps) and abs(master_current - slave_current) / ref < 1
Exemplo n.º 6
0
class ManualControlLift:
    def __init__(
        self,
        main_lift_id, follower_id,
        bottom_limit_channel, start_lim_channel
    ):
        self.main_lift_id = main_lift_id
        self.follower_id = follower_id

        self.lift_main = TalonSRX(main_lift_id)
        self.lift_follower = TalonSRX(follower_id)

        self.lift_main.configSelectedFeedbackSensor(
            TalonSRX.FeedbackDevice.PulseWidthEncodedPosition,
            0, 0
        )
        # self.lift_main.setPulseWidthPosition(0, 0)

        self.lift_follower.configSelectedFeedbackSensor(
            TalonSRX.FeedbackDevice.PulseWidthEncodedPosition,
            0, 0
        )
        # self.lift_follower.setPulseWidthPosition(0, 0)

        self.lift_follower.set(
            TalonSRX.ControlMode.Follower,
            main_lift_id
        )
        self.lift_follower.setInverted(True)

        self.lift_timer = wpilib.Timer()
        self.timer_started = False

        self.lift_stop_timer = wpilib.Timer()
        self.lift_stop_timer_started = False

        self.lift_zero_found = False
        self.bottom_limit_switch = wpilib.DigitalInput(bottom_limit_channel)
        self.start_limit_switch = wpilib.DigitalInput(start_lim_channel)

        self.sustain =  -0.08

    def load_config_values(self):
        prefs = wpilib.Preferences.getInstance()

        phase = prefs.getBoolean("Lift: Invert Sensor Phase", True)

        self.sustain = prefs.getFloat("Lift: Idle Sustain", -0.08)

        self.upper_limit = prefs.getInt("Lift: Upper Limit", None)
        self.limits_enabled = prefs.getBoolean("Lift: Limits Enabled", False)

        if self.limits_enabled:
            # Note: positive / forward power to the motors = lift moves down
            # negative / reverse power to the motors = lift moves up
            if self.upper_limit is not None:
                self.lift_main.configReverseSoftLimitThreshold(
                    int(self.upper_limit), 0
                )
                self.lift_main.configReverseSoftLimitEnable(True, 0)
            else:
                self.lift_main.configReverseSoftLimitEnable(False, 0)

        self.lift_main.setSensorPhase(phase)
        self.lift_follower.setSensorPhase(phase)

    def set_soft_limit_status(self, status):
        if self.upper_limit is not None:
            self.lift_main.configReverseSoftLimitEnable(status, 0)
        else:
            self.lift_main.configReverseSoftLimitEnable(False, 0)

    def update_smart_dashboard(self):
        wpilib.SmartDashboard.putNumber(
            "Lift Main Position",
            self.lift_main.getSelectedSensorPosition(0)
        )

        wpilib.SmartDashboard.putNumber(
            "Lift Follower Position",
            self.lift_follower.getSelectedSensorPosition(0)
        )

        wpilib.SmartDashboard.putBoolean(
            "Lift Bottom Limit Switch",
            not self.bottom_limit_switch.get()
        )

        wpilib.SmartDashboard.putBoolean(
            "Lift Found Zero",
            self.lift_zero_found
        )

        wpilib.SmartDashboard.putBoolean(
            "Lift Start Position Switch",
            not self.start_limit_switch.get()
        )

    def moveTimed(self, time, power):
        if not self.timer_started:
            self.timer_started = True
            self.lift_timer.reset()
            self.lift_timer.start()
        elif self.lift_timer.get() < time:
            self.lift_main.set(TalonSRX.ControlMode.PercentOutput, power)
        else:
            self.lift_main.set(TalonSRX.ControlMode.PercentOutput, 0)

    def setLiftPower(self, power):
        if power > 0 and not self.bottom_limit_switch.get():
            self.lift_main.set(TalonSRX.ControlMode.PercentOutput, 0)
        else:
            self.lift_main.set(TalonSRX.ControlMode.PercentOutput, power)

    def checkLimitSwitch(self):
        self.set_soft_limit_status(self.lift_zero_found)

        if not self.bottom_limit_switch.get():
            self.lift_zero_found = True

            self.lift_main.setPulseWidthPosition(0, 0)
            self.lift_follower.setPulseWidthPosition(0, 0)

            self.lift_main.setQuadraturePosition(0, 0)
            self.lift_follower.setQuadraturePosition(0, 0)

    def driveToStartingPosition(self):
        if self.start_limit_switch.get():
            self.lift_main.set(TalonSRX.ControlMode.PercentOutput, -0.25)
        else:
            self.lift_main.set(TalonSRX.ControlMode.PercentOutput, 0)