frc::TrapezoidProfile< Distance > Class Template Reference

A trapezoid-shaped velocity profile. More...

#include <frc/trajectory/TrapezoidProfile.h>

Classes
class	Constraints
class	State

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	Acceleration_t = units::unit_t< Acceleration >

Public Member Functions
	TrapezoidProfile (Constraints constraints, State goal, State initial=State{Distance_t{0}, Velocity_t{0}})
	Construct a TrapezoidProfile. More...
	TrapezoidProfile (const TrapezoidProfile &)=default
TrapezoidProfile &	operator= (const TrapezoidProfile &)=default
	TrapezoidProfile (TrapezoidProfile &&)=default
TrapezoidProfile &	operator= (TrapezoidProfile &&)=default
State	Calculate (units::second_t t) const
	Calculate the correct position and velocity for the profile at a time t where the beginning of the profile was at time t = 0. More...
units::second_t	TimeLeftUntil (Distance_t target) const
	Returns the time left until a target distance in the profile is reached. More...
units::second_t	TotalTime () const
	Returns the total time the profile takes to reach the goal. More...
bool	IsFinished (units::second_t t) const
	Returns true if the profile has reached the goal. More...

Detailed Description

template<class Distance>
class frc::TrapezoidProfile< Distance >

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:

TrapezoidProfile::Constraints constraints{kMaxV, kMaxA};
double previousProfiledReference = initialReference;

Run on update:

TrapezoidProfile profile{constraints, unprofiledReference,
                         previousProfiledReference};
previousProfiledReference = profile.Calculate(timeSincePreviousUpdate);

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

Acceleration

template<class Distance >

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

Acceleration_t

template<class Distance >

using frc::TrapezoidProfile< Distance >::Acceleration_t = units::unit_t<Acceleration>

Distance_t

template<class Distance >

using frc::TrapezoidProfile< Distance >::Distance_t = units::unit_t<Distance>

Velocity

template<class Distance >

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

Velocity_t

template<class Distance >

using frc::TrapezoidProfile< Distance >::Velocity_t = units::unit_t<Velocity>

Constructor & Destructor Documentation

TrapezoidProfile() [1/3]

template<class Distance >

frc::TrapezoidProfile< Distance >::TrapezoidProfile	(	Constraints	constraints,
		State	goal,
		State	initial = State{Distance_t{0}, Velocity_t{0}}
	)

Construct a TrapezoidProfile.

Parameters

constraints	The constraints on the profile, like maximum velocity.
goal	The desired state when the profile is complete.
initial	The initial state (usually the current state).

TrapezoidProfile() [2/3]

template<class Distance >

frc::TrapezoidProfile< Distance >::TrapezoidProfile ( const TrapezoidProfile< Distance > &  )

default

TrapezoidProfile() [3/3]

template<class Distance >

frc::TrapezoidProfile< Distance >::TrapezoidProfile ( TrapezoidProfile< Distance > &&  )

default

Member Function Documentation

Calculate()

template<class Distance >

TrapezoidProfile< Distance >::State frc::TrapezoidProfile< Distance >::Calculate

(

units::second_t

t

)

const

Calculate the correct position and velocity for the profile at a time t where the beginning of the profile was at time t = 0.

Parameters

t	The time since the beginning of the profile.

IsFinished()

template<class Distance >

bool frc::TrapezoidProfile< Distance >::IsFinished ( units::second_t  t ) const

inline

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.

operator=() [1/2]

template<class Distance >

TrapezoidProfile & frc::TrapezoidProfile< Distance >::operator= ( const TrapezoidProfile< Distance > &  )

default

operator=() [2/2]

template<class Distance >

TrapezoidProfile & frc::TrapezoidProfile< Distance >::operator= ( TrapezoidProfile< Distance > &&  )

default

TimeLeftUntil()

template<class Distance >

units::second_t frc::TrapezoidProfile< Distance >::TimeLeftUntil

(

Distance_t

target

)

const

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

Parameters

target

The target distance.

TotalTime()

template<class Distance >

units::second_t frc::TrapezoidProfile< Distance >::TotalTime ( ) const

inline

Returns the total time the profile takes to reach the goal.

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

• frc/trajectory/TrapezoidProfile.h
• frc/trajectory/TrapezoidProfile.inc