phoenix6.swerve.utility.wheel_force_calculator

Module Contents

class phoenix6.swerve.utility.wheel_force_calculator.WheelForceCalculator(module_locations: list[phoenix6.swerve.utility.geometry.Translation2d], mass_kg: float, moi_kg_m_sq: float)

Calculates wheel force feedforwards for a SwerveDrivetrain. Wheel force feedforwards can be used to improve accuracy of path following in regions of acceleration.

Many path planning libraries (such as PathPlanner and Choreo) already provide per-module force feedforwards, which should be preferred over this class.

Constructs a new wheel force feedforward calculator for the given drivetrain characteristics.

Parameters:

  • module_locations (list[Translation2d]) – The drivetrain swerve module locations

  • mass_kg (float) – The mass of the robot in kg

  • moi_kg_m_sq (float) – The moment of inertia of the robot in kg m^2

class Feedforwards(num_modules: int)

Wheel force feedforwards to apply to a swerve drivetrain.

Constructs a new set of wheel force feedforwards.

Parameters:

num_modules (int) – The number of swerve modules

x_newtons

The X component of the forces in Newtons.

y_newtons

The Y component of the forces in Newtons.

calculate(ax: float, ay: float, alpha: float, center_of_rotation: phoenix6.swerve.utility.geometry.Translation2d = Translation2d()) → Feedforwards

Calculates wheel force feedforwards for the desired robot acceleration. This can be used with either robot-centric or field-centric accelerations; the returned force feedforwards will match in being robot-/field-centric.

Parameters:

  • ax (float) – Acceleration in the X direction (forward) in m/s^2

  • ay (float) – Acceleration in the Y direction (left) in m/s^2

  • alpha (float) – Angular acceleration in rad/s^2

  • center_of_rotation (Translation2d) – Center of rotation

Returns:

Wheel force feedforwards to apply

Return type:

Feedforwards

calculate_from_speeds(dt: float, prev: phoenix6.swerve.utility.kinematics.ChassisSpeeds, current: phoenix6.swerve.utility.kinematics.ChassisSpeeds, center_of_rotation: phoenix6.swerve.utility.geometry.Translation2d = Translation2d()) → Feedforwards

Calculates wheel force feedforwards for the desired change in speeds. This can be used with either robot-centric or field-centric speeds; the returned force feedforwards will match in being robot-/field-centric.

Parameters:

  • dt (float) – The change in time between the path setpoints

  • prev (ChassisSpeeds) – The previous ChassisSpeeds setpoint of the path

  • current (ChassisSpeeds) – The new ChassisSpeeds setpoint of the path

  • center_of_rotation (Translation2d) – Center of rotation

Returns:

Wheel force feedforwards to apply

Return type:

Feedforwards