A helper class that computes feedforward voltages for a simple permanent-magnet DC motor. More...

#include <frc/controller/SimpleMotorFeedforward.h>

Public Types
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	SimpleMotorFeedforward (units::volt_t kS, units::unit_t< kv_unit > kV, units::unit_t< ka_unit > kA=units::unit_t< ka_unit >(0))
	Creates a new SimpleMotorFeedforward 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)) const
	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) const
	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) const
	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) const
	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) const
	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::unit_t< kv_unit >	kV
	The velocity gain. More...

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

Detailed Description

template<class Distance>
class frc::SimpleMotorFeedforward< Distance >

A helper class that computes feedforward voltages for a simple permanent-magnet DC motor.

Member Typedef Documentation

◆ Acceleration

template<class Distance >

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

◆ ka_unit

template<class Distance >

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

◆ kv_unit

template<class Distance >

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

◆ Velocity

template<class Distance >

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

Constructor & Destructor Documentation

◆ SimpleMotorFeedforward()

template<class Distance >

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

inlineconstexpr

Creates a new SimpleMotorFeedforward with the specified gains.

Parameters

kS	The static 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]

template<class Distance >

units::volt_t frc::SimpleMotorFeedforward< Distance >::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]

template<class Distance >

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

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()

template<class Distance >

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

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 motor.
velocity	The velocity of the motor.

Returns: The maximum possible acceleration at the given velocity.

◆ MaxAchievableVelocity()

template<class Distance >

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

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 motor.
acceleration	The acceleration of the motor.

Returns: The maximum possible velocity at the given acceleration.

◆ MinAchievableAcceleration()

template<class Distance >

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

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 motor.
velocity	The velocity of the motor.

Returns: The minimum possible acceleration at the given velocity.

◆ MinAchievableVelocity()

template<class Distance >

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

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