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

#include <frc/controller/ElevatorFeedforward.h>

Public Types
using	Distance = units::meters

using	Velocity = units::compound_unit< Distance, units::inverse< units::seconds > >

using	Acceleration = units::compound_unit< Velocity, units::inverse< units::seconds > >

using	kv_unit = units::compound_unit< units::volts, units::inverse< Velocity > >

using	ka_unit = units::compound_unit< units::volts, units::inverse< Acceleration > >

Public Member Functions
constexpr	ElevatorFeedforward (units::volt_t kS, units::volt_t kG, units::unit_t< kv_unit > kV, units::unit_t< ka_unit > kA=units::unit_t< ka_unit >(0))
	Creates a new ElevatorFeedforward with the specified gains. More...

constexpr units::volt_t	Calculate (units::unit_t< Velocity > velocity, units::unit_t< Acceleration > acceleration=units::unit_t< Acceleration >(0))
	Calculates the feedforward from the gains and setpoints. More...

units::volt_t	Calculate (units::unit_t< Velocity > currentVelocity, units::unit_t< Velocity > nextVelocity, units::second_t dt) const
	Calculates the feedforward from the gains and setpoints. More...

constexpr units::unit_t< Velocity >	MaxAchievableVelocity (units::volt_t maxVoltage, units::unit_t< Acceleration > acceleration)
	Calculates the maximum achievable velocity given a maximum voltage supply and an acceleration. More...

constexpr units::unit_t< Velocity >	MinAchievableVelocity (units::volt_t maxVoltage, units::unit_t< Acceleration > acceleration)
	Calculates the minimum achievable velocity given a maximum voltage supply and an acceleration. More...

constexpr units::unit_t< Acceleration >	MaxAchievableAcceleration (units::volt_t maxVoltage, units::unit_t< Velocity > velocity)
	Calculates the maximum achievable acceleration given a maximum voltage supply and a velocity. More...

constexpr units::unit_t< Acceleration >	MinAchievableAcceleration (units::volt_t maxVoltage, units::unit_t< Velocity > velocity)
	Calculates the minimum achievable acceleration given a maximum voltage supply and a velocity. More...

Public Attributes
const units::volt_t	kS
	The static gain. More...

const units::volt_t	kG
	The gravity gain. More...

const units::unit_t< kv_unit >	kV
	The velocity gain. More...

const units::unit_t< ka_unit >	kA
	The acceleration gain. More...

Detailed Description

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

Member Typedef Documentation

◆ Acceleration

using frc::ElevatorFeedforward::Acceleration = units::compound_unit<Velocity, units::inverse<units::seconds> >

◆ Distance

using frc::ElevatorFeedforward::Distance = units::meters

◆ ka_unit

using frc::ElevatorFeedforward::ka_unit = units::compound_unit<units::volts, units::inverse<Acceleration> >

◆ kv_unit

using frc::ElevatorFeedforward::kv_unit = units::compound_unit<units::volts, units::inverse<Velocity> >

◆ Velocity

using frc::ElevatorFeedforward::Velocity = units::compound_unit<Distance, units::inverse<units::seconds> >

Constructor & Destructor Documentation

◆ ElevatorFeedforward()

constexpr frc::ElevatorFeedforward::ElevatorFeedforward	(	units::volt_t	kS,
		units::volt_t	kG,
		units::unit_t< kv_unit >	kV,
		units::unit_t< ka_unit >	kA = `units::unit_t<ka_unit>(0)`
	)

inlineconstexpr

Creates a new ElevatorFeedforward with the specified gains.

Parameters

kS	The static gain, in volts.
kG	The gravity gain, in volts.
kV	The velocity gain, in volt seconds per distance.
kA	The acceleration gain, in volt seconds² per distance.

Member Function Documentation

◆ Calculate() [1/2]

units::volt_t frc::ElevatorFeedforward::Calculate	(	units::unit_t< Velocity >	currentVelocity,
		units::unit_t< Velocity >	nextVelocity,
		units::second_t	dt
	)		const

inline

Calculates the feedforward from the gains and setpoints.

Parameters

currentVelocity	The current velocity setpoint, in distance per second.
nextVelocity	The next velocity setpoint, in distance per second.
dt	Time between velocity setpoints in seconds.

Returns: The computed feedforward, in volts.

◆ Calculate() [2/2]

constexpr units::volt_t frc::ElevatorFeedforward::Calculate	(	units::unit_t< Velocity >	velocity,
		units::unit_t< Acceleration >	acceleration = `units::unit_t<Acceleration>(0)`
	)

inlineconstexpr

Calculates the feedforward from the gains and setpoints.

Parameters

velocity	The velocity setpoint, in distance per second.
acceleration	The acceleration setpoint, in distance per second².

Returns: The computed feedforward, in volts.

◆ MaxAchievableAcceleration()

constexpr units::unit_t< Acceleration > frc::ElevatorFeedforward::MaxAchievableAcceleration	(	units::volt_t	maxVoltage,
		units::unit_t< Velocity >	velocity
	)

inlineconstexpr

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

maxVoltage	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.

◆ MaxAchievableVelocity()

constexpr units::unit_t< Velocity > frc::ElevatorFeedforward::MaxAchievableVelocity	(	units::volt_t	maxVoltage,
		units::unit_t< Acceleration >	acceleration
	)

inlineconstexpr

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

maxVoltage	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.

◆ MinAchievableAcceleration()

constexpr units::unit_t< Acceleration > frc::ElevatorFeedforward::MinAchievableAcceleration	(	units::volt_t	maxVoltage,
		units::unit_t< Velocity >	velocity
	)

inlineconstexpr

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

maxVoltage	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.

◆ MinAchievableVelocity()

constexpr units::unit_t< Velocity > frc::ElevatorFeedforward::MinAchievableVelocity	(	units::volt_t	maxVoltage,
		units::unit_t< Acceleration >	acceleration
	)

inlineconstexpr

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

maxVoltage	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.

Member Data Documentation

◆ kA

const units::unit_t<ka_unit> frc::ElevatorFeedforward::kA

The acceleration gain.

◆ kG

const units::volt_t frc::ElevatorFeedforward::kG

The gravity gain.

◆ kS

const units::volt_t frc::ElevatorFeedforward::kS

The static gain.

◆ kV

const units::unit_t<kv_unit> frc::ElevatorFeedforward::kV

The velocity gain.

The documentation for this class was generated from the following file:

frc/controller/ElevatorFeedforward.h

Public Types

Public Member Functions

Public Attributes

Detailed Description

Member Typedef Documentation

◆ Acceleration

◆ Distance

◆ ka_unit

◆ kv_unit

◆ Velocity

Constructor & Destructor Documentation

◆ ElevatorFeedforward()

Member Function Documentation

◆ Calculate() [1/2]

◆ Calculate() [2/2]

◆ MaxAchievableAcceleration()

◆ MaxAchievableVelocity()

◆ MinAchievableAcceleration()

◆ MinAchievableVelocity()

Member Data Documentation

◆ kA

◆ kG

◆ kS

◆ kV