ElevatorFeedforward

class wpimath.ElevatorFeedforward(s: wpimath.units.volts, g: wpimath.units.volts, v: wpimath.units.volt_seconds_per_meter, a: wpimath.units.volt_seconds_squared_per_meter = 0.0, dt: wpimath.units.seconds = 0.02)

Bases: pybind11_object

A helper class that computes feedforward outputs for a simple elevator (modeled as a motor acting against the force of gravity).

Creates a new ElevatorFeedforward with the specified gains.

Parameters:

  • s – The static gain, in volts.

  • g – The gravity gain, in volts.

  • v – The velocity gain, in volt seconds per distance.

  • a – The acceleration gain, in volt seconds² per distance.

  • dt – The period in seconds. @throws IllegalArgumentException for kv < zero. @throws IllegalArgumentException for ka < zero. @throws IllegalArgumentException for period ≤ zero.

WPIStruct = <capsule object "WPyStruct">
calculate(*args, **kwargs)

Overloaded function.

  1. calculate(self: wpimath._wpimath.ElevatorFeedforward, current_velocity: wpimath.units.meters_per_second) -> wpimath.units.volts

Calculates the feedforward from the gains and setpoint assuming discrete control. Use this method when the setpoint does not change.

Parameters:

current_velocity – The velocity setpoint.

Returns:

The computed feedforward, in volts.

  1. calculate(self: wpimath._wpimath.ElevatorFeedforward, current_velocity: wpimath.units.meters_per_second, next_velocity: wpimath.units.meters_per_second) -> wpimath.units.volts

Calculates the feedforward from the gains and setpoints assuming discrete control.

Note this method is inaccurate when the velocity crosses 0.

Parameters:

  • current_velocity – The current velocity setpoint.

  • next_velocity – The next velocity setpoint.

Returns:

The computed feedforward, in volts.

get_ka() → wpimath.units.volt_seconds_squared_per_meter

Returns the acceleration gain.

Returns:

The acceleration gain.

get_kg() → wpimath.units.volts

Returns the gravity gain.

Returns:

The gravity gain.

get_ks() → wpimath.units.volts

Returns the static gain.

Returns:

The static gain.

get_kv() → wpimath.units.volt_seconds_per_meter

Returns the velocity gain.

Returns:

The velocity gain.

max_achievable_acceleration(max_voltage: wpimath.units.volts, velocity: wpimath.units.meters_per_second) → wpimath.units.meters_per_second_squared

Calculates the maximum achievable acceleration given a maximum voltage supply and a velocity. Useful for ensuring that velocity and acceleration constraints for a trapezoidal profile are simultaneously achievable - enter the velocity constraint, and this will give you a simultaneously-achievable acceleration constraint.

Parameters:

  • max_voltage – The maximum voltage that can be supplied to the elevator.

  • velocity – The velocity of the elevator.

Returns:

The maximum possible acceleration at the given velocity.

max_achievable_velocity(max_voltage: wpimath.units.volts, acceleration: wpimath.units.meters_per_second_squared) → wpimath.units.meters_per_second

Calculates the maximum achievable velocity given a maximum voltage supply and an acceleration. Useful for ensuring that velocity and acceleration constraints for a trapezoidal profile are simultaneously achievable - enter the acceleration constraint, and this will give you a simultaneously-achievable velocity constraint.

Parameters:

  • max_voltage – The maximum voltage that can be supplied to the elevator.

  • acceleration – The acceleration of the elevator.

Returns:

The maximum possible velocity at the given acceleration.

min_achievable_acceleration(max_voltage: wpimath.units.volts, velocity: wpimath.units.meters_per_second) → wpimath.units.meters_per_second_squared

Calculates the minimum achievable acceleration given a maximum voltage supply and a velocity. Useful for ensuring that velocity and acceleration constraints for a trapezoidal profile are simultaneously achievable - enter the velocity constraint, and this will give you a simultaneously-achievable acceleration constraint.

Parameters:

  • max_voltage – The maximum voltage that can be supplied to the elevator.

  • velocity – The velocity of the elevator.

Returns:

The minimum possible acceleration at the given velocity.

min_achievable_velocity(max_voltage: wpimath.units.volts, acceleration: wpimath.units.meters_per_second_squared) → wpimath.units.meters_per_second

Calculates the minimum achievable velocity given a maximum voltage supply and an acceleration. Useful for ensuring that velocity and acceleration constraints for a trapezoidal profile are simultaneously achievable - enter the acceleration constraint, and this will give you a simultaneously-achievable velocity constraint.

Parameters:

  • max_voltage – The maximum voltage that can be supplied to the elevator.

  • acceleration – The acceleration of the elevator.

Returns:

The minimum possible velocity at the given acceleration.

set_ka(a: wpimath.units.volt_seconds_squared_per_meter) → None

Sets the acceleration gain.

Parameters:

a – The acceleration gain.

set_kg(g: wpimath.units.volts) → None

Sets the gravity gain.

Parameters:

g – The gravity gain.

set_ks(s: wpimath.units.volts) → None

Sets the static gain.

Parameters:

s – The static gain.

set_kv(v: wpimath.units.volt_seconds_per_meter) → None

Sets the velocity gain.

Parameters:

v – The velocity gain.