frc::ExponentialProfile< Distance, Input > Class Template Reference

A Exponential-shaped velocity profile. More...

#include <frc/trajectory/ExponentialProfile.h>

Classes
class	Constraints
	Profile constraints. More...
class	ProfileTiming
	Profile timing. More...
class	State
	Profile state. More...

Public Types
using	Distance_t = units::unit_t< Distance >
using	Velocity = units::compound_unit< Distance, units::inverse< units::seconds > >
using	Velocity_t = units::unit_t< Velocity >
using	Acceleration = units::compound_unit< Velocity, units::inverse< units::seconds > >
using	Input_t = units::unit_t< Input >
using	A_t = units::unit_t< units::inverse< units::seconds > >
using	B_t = units::unit_t< units::compound_unit< Acceleration, units::inverse< Input > > >
using	KV = units::compound_unit< Input, units::inverse< Velocity > >
using	kV_t = units::unit_t< KV >
using	KA = units::compound_unit< Input, units::inverse< Acceleration > >
using	kA_t = units::unit_t< KA >

Public Member Functions
	ExponentialProfile (Constraints constraints)
	Constructs a ExponentialProfile. More...
	ExponentialProfile (const ExponentialProfile &)=default
ExponentialProfile &	operator= (const ExponentialProfile &)=default
	ExponentialProfile (ExponentialProfile &&)=default
ExponentialProfile &	operator= (ExponentialProfile &&)=default
State	Calculate (const units::second_t &t, const State &current, const State &goal) const
	Calculates the position and velocity for the profile at a time t where the current state is at time t = 0. More...
State	CalculateInflectionPoint (const State &current, const State &goal) const
	Calculates the point after which the fastest way to reach the goal state is to apply input in the opposite direction. More...
units::second_t	TimeLeftUntil (const State &current, const State &goal) const
	Calculates the time it will take for this profile to reach the goal state. More...
ProfileTiming	CalculateProfileTiming (const State &current, const State &goal) const
	Calculates the time it will take for this profile to reach the inflection point, and the time it will take for this profile to reach the goal state. More...

Detailed Description

template<class Distance, class Input>
class frc::ExponentialProfile< Distance, Input >

A Exponential-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 ExponentialProfile velocity constraints. To compute the reference obeying this constraint, do the following.

Initialization:

ExponentialProfile::Constraints constraints{kMaxV, kV, kA};
State previousProfiledReference = {initialReference, 0_mps};

Run on update:

previousProfiledReference = profile.Calculate(timeSincePreviousUpdate,
previousProfiledReference, unprofiledReference);

where unprofiledReference 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 IsFinished().

Member Typedef Documentation

A_t

template<class Distance , class Input >

using frc::ExponentialProfile< Distance, Input >::A_t = units::unit_t<units::inverse<units::seconds> >

Acceleration

template<class Distance , class Input >

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

B_t

template<class Distance , class Input >

using frc::ExponentialProfile< Distance, Input >::B_t = units::unit_t<units::compound_unit<Acceleration, units::inverse<Input> >>

Distance_t

template<class Distance , class Input >

using frc::ExponentialProfile< Distance, Input >::Distance_t = units::unit_t<Distance>

Input_t

template<class Distance , class Input >

using frc::ExponentialProfile< Distance, Input >::Input_t = units::unit_t<Input>

KA

template<class Distance , class Input >

using frc::ExponentialProfile< Distance, Input >::KA = units::compound_unit<Input, units::inverse<Acceleration> >

kA_t

template<class Distance , class Input >

using frc::ExponentialProfile< Distance, Input >::kA_t = units::unit_t<KA>

KV

template<class Distance , class Input >

using frc::ExponentialProfile< Distance, Input >::KV = units::compound_unit<Input, units::inverse<Velocity> >

kV_t

template<class Distance , class Input >

using frc::ExponentialProfile< Distance, Input >::kV_t = units::unit_t<KV>

Velocity

template<class Distance , class Input >

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

Velocity_t

template<class Distance , class Input >

using frc::ExponentialProfile< Distance, Input >::Velocity_t = units::unit_t<Velocity>

Constructor & Destructor Documentation

ExponentialProfile() [1/3]

template<class Distance , class Input >

frc::ExponentialProfile< Distance, Input >::ExponentialProfile ( Constraints  constraints )

explicit

Constructs a ExponentialProfile.

Parameters

constraints

The constraints on the profile, like maximum input.

ExponentialProfile() [2/3]

template<class Distance , class Input >

frc::ExponentialProfile< Distance, Input >::ExponentialProfile ( const ExponentialProfile< Distance, Input > &  )

default

ExponentialProfile() [3/3]

template<class Distance , class Input >

frc::ExponentialProfile< Distance, Input >::ExponentialProfile ( ExponentialProfile< Distance, Input > &&  )

default

Member Function Documentation

Calculate()

template<class Distance , class Input >

ExponentialProfile< Distance, Input >::State frc::ExponentialProfile< Distance, Input >::Calculate	(	const units::second_t &	t,
		const State &	current,
		const State &	goal
	)		const

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.

CalculateInflectionPoint()

template<class Distance , class Input >

ExponentialProfile< Distance, Input >::State frc::ExponentialProfile< Distance, Input >::CalculateInflectionPoint	(	const State &	current,
		const State &	goal
	)		const

Calculates the point after which the fastest way to reach the goal state is to apply input in the opposite direction.

Parameters

current	The current state.
goal	The desired state when the profile is complete.

Returns

The position and velocity of the profile at the inflection point.

CalculateProfileTiming()

template<class Distance , class Input >

ExponentialProfile< Distance, Input >::ProfileTiming frc::ExponentialProfile< Distance, Input >::CalculateProfileTiming	(	const State &	current,
		const State &	goal
	)		const

Calculates the time it will take for this profile to reach the inflection point, and the time it will take for this profile to reach the goal state.

Parameters

current	The current state.
goal	The desired state when the profile is complete.

Returns

The timing information for this profile.

operator=() [1/2]

template<class Distance , class Input >

ExponentialProfile & frc::ExponentialProfile< Distance, Input >::operator= ( const ExponentialProfile< Distance, Input > &  )

default

operator=() [2/2]

template<class Distance , class Input >

ExponentialProfile & frc::ExponentialProfile< Distance, Input >::operator= ( ExponentialProfile< Distance, Input > &&  )

default

TimeLeftUntil()

template<class Distance , class Input >

units::second_t frc::ExponentialProfile< Distance, Input >::TimeLeftUntil	(	const State &	current,
		const State &	goal
	)		const

Calculates the time it will take for this profile to reach the goal state.

Parameters

current	The current state.
goal	The desired state when the profile is complete.

Returns

The total duration of this profile.

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

• frc/trajectory/ExponentialProfile.h
• frc/trajectory/ExponentialProfile.inc