TrapezoidProfileRadians

class wpimath.TrapezoidProfileRadians(constraints: wpimath._wpimath.TrapezoidProfileRadians.Constraints)

Bases: pybind11_object

A trapezoid-shaped velocity profile.

While this class can be used for a profiled movement from start to finish, the intended usage is to filter a reference’s dynamics based on trapezoidal velocity constraints. To compute the reference obeying this constraint, do the following.

Initialization:

constraints = TrapezoidProfile.Constraints(kMaxV, kMaxA)
previous_profiled_reference = initial_reference

Run on update:

profile = TrapezoidProfile(constraints, unprofiled_reference, previous_profiled_reference)
previous_profiled_reference = profile.calculate(time_since_previous_update)

where unprofiled_reference is free to change between calls. Note that when the unprofiled reference is within the constraints, calculate() returns the unprofiled reference unchanged.

Otherwise, a timer can be started to provide monotonic values for calculate() and to determine when the profile has completed via is_finished().

Constructs a TrapezoidProfile.

Parameters:

constraints – The constraints on the profile, like maximum velocity.

class Constraints(max_velocity: wpimath.units.radians_per_second = 0, max_acceleration: wpimath.units.radians_per_second_squared = 0)

Bases: pybind11_object

Profile constraints.

Constructs constraints for a Trapezoid Profile.

Parameters:

  • max_velocity – Maximum velocity, must be non-negative.

  • max_acceleration – Maximum acceleration, must be non-negative.

class State(position: wpimath.units.radians = 0, velocity: wpimath.units.radians_per_second = 0)

Bases: pybind11_object

Profile state.

calculate(t: wpimath.units.seconds, current: wpimath._wpimath.TrapezoidProfileRadians.State, goal: wpimath._wpimath.TrapezoidProfileRadians.State) → wpimath._wpimath.TrapezoidProfileRadians.State

Calculates the position and velocity for the profile at a time t where the current state is at time t = 0.

Parameters:

  • t – How long to advance from the current state toward the desired state.

  • current – The current state.

  • goal – The desired state when the profile is complete.

Returns:

The position and velocity of the profile at time t.

duration() → wpimath.units.seconds

Returns the duration of the profile.

Returns:

The duration of the profile, or zero if no goal was set.

is_finished(t: wpimath.units.seconds) → bool

Returns true if the profile has reached the goal.

The profile has reached the goal if the time since the profile started has exceeded the profile’s total time.

Parameters:

t – The time since the beginning of the profile.

Returns:

True if the profile has reached the goal.

time_left_until(target: wpimath.units.radians) → wpimath.units.seconds

Returns the time left until a target distance in the profile is reached.

Parameters:

target – The target distance.

Returns:

The time left until a target distance in the profile is reached, or zero if no goal was set.