Linear system ID utility functions. More...

#include <frc/system/plant/LinearSystemId.h>

Public Types
template<typename Distance >
using	Velocity_t = units::unit_t< units::compound_unit< Distance, units::inverse< units::seconds > > >

template<typename Distance >
using	Acceleration_t = units::unit_t< units::compound_unit< units::compound_unit< Distance, units::inverse< units::seconds > >, units::inverse< units::seconds > > >

Static Public Member Functions
static LinearSystem< 2, 1, 1 >	ElevatorSystem (DCMotor motor, units::kilogram_t mass, units::meter_t radius, double gearing)
	Create a state-space model of the elevator system. More...

static LinearSystem< 2, 1, 1 >	SingleJointedArmSystem (DCMotor motor, units::kilogram_square_meter_t J, double gearing)
	Create a state-space model of a single-jointed arm system.The states of the system are [angle, angular velocity], inputs are [voltage], and outputs are [angle]. More...

template<typename Distance > requires std::same_as<units::meter, Distance> \|\| std::same_as<units::radian, Distance>
static LinearSystem< 1, 1, 1 >	IdentifyVelocitySystem (decltype(1_V/Velocity_t< Distance >(1)) kV, decltype(1_V/Acceleration_t< Distance >(1)) kA)
	Create a state-space model for a 1 DOF velocity system from its kV (volts/(unit/sec)) and kA (volts/(unit/sec²)). More...

template<typename Distance > requires std::same_as<units::meter, Distance> \|\| std::same_as<units::radian, Distance>
static LinearSystem< 2, 1, 1 >	IdentifyPositionSystem (decltype(1_V/Velocity_t< Distance >(1)) kV, decltype(1_V/Acceleration_t< Distance >(1)) kA)
	Create a state-space model for a 1 DOF position system from its kV (volts/(unit/sec)) and kA (volts/(unit/sec²)). More...

static LinearSystem< 2, 2, 2 >	IdentifyDrivetrainSystem (decltype(1_V/1_mps) kVLinear, decltype(1_V/1_mps_sq) kALinear, decltype(1_V/1_mps) kVAngular, decltype(1_V/1_mps_sq) kAAngular)
	Identify a differential drive drivetrain given the drivetrain's kV and kA in both linear {(volts/(meter/sec), (volts/(meter/sec²))} and angular {(volts/(radian/sec), (volts/(radian/sec²))} cases. More...

static LinearSystem< 2, 2, 2 >	IdentifyDrivetrainSystem (decltype(1_V/1_mps) kVLinear, decltype(1_V/1_mps_sq) kALinear, decltype(1_V/1_rad_per_s) kVAngular, decltype(1_V/1_rad_per_s_sq) kAAngular, units::meter_t trackwidth)
	Identify a differential drive drivetrain given the drivetrain's kV and kA in both linear {(volts/(meter/sec)), (volts/(meter/sec²))} and angular {(volts/(radian/sec)), (volts/(radian/sec²))} cases. More...

static LinearSystem< 1, 1, 1 >	FlywheelSystem (DCMotor motor, units::kilogram_square_meter_t J, double gearing)
	Create a state-space model of a flywheel system, the states of the system are [angular velocity], inputs are [voltage], and outputs are [angular velocity]. More...

static LinearSystem< 2, 1, 2 >	DCMotorSystem (DCMotor motor, units::kilogram_square_meter_t J, double gearing)
	Create a state-space model of a DC motor system. More...

template<typename Distance > requires std::same_as<units::meter, Distance> \|\| std::same_as<units::radian, Distance>
static LinearSystem< 2, 1, 2 >	DCMotorSystem (decltype(1_V/Velocity_t< Distance >(1)) kV, decltype(1_V/Acceleration_t< Distance >(1)) kA)
	Create a state-space model of a DC motor system from its kV (volts/(unit/sec)) and kA (volts/(unit/sec²)). More...

static LinearSystem< 2, 2, 2 >	DrivetrainVelocitySystem (const DCMotor &motor, units::kilogram_t mass, units::meter_t r, units::meter_t rb, units::kilogram_square_meter_t J, double gearing)
	Create a state-space model of differential drive drivetrain. More...

Detailed Description

Linear system ID utility functions.

Member Typedef Documentation

◆ Acceleration_t

template<typename Distance >

using frc::LinearSystemId::Acceleration_t = units::unit_t<units::compound_unit< units::compound_unit<Distance, units::inverse<units::seconds> >, units::inverse<units::seconds> >>

◆ Velocity_t

template<typename Distance >

using frc::LinearSystemId::Velocity_t = units::unit_t< units::compound_unit<Distance, units::inverse<units::seconds> >>

Member Function Documentation

◆ DCMotorSystem() [1/2]

static LinearSystem< 2, 1, 2 > frc::LinearSystemId::DCMotorSystem	(	DCMotor	motor,
		units::kilogram_square_meter_t	J,
		double	gearing
	)

static

Create a state-space model of a DC motor system.

The states of the system are [angular position, angular velocity], inputs are [voltage], and outputs are [angular position, angular velocity].

Parameters

motor	The motor (or gearbox) attached to the system.
J	the moment of inertia J of the DC motor.
gearing	Gear ratio from motor to output.

Exceptions

std::domain_error if J <= 0 or gearing <= 0.

See also: https://github.com/wpilibsuite/sysid

◆ DCMotorSystem() [2/2]

template<typename Distance >
requires std::same_as<units::meter, Distance> || std::same_as<units::radian, Distance>

static LinearSystem< 2, 1, 2 > frc::LinearSystemId::DCMotorSystem	(	decltype(1_V/Velocity_t< Distance >(1))	kV,
		decltype(1_V/Acceleration_t< Distance >(1))	kA
	)

inlinestatic

Create a state-space model of a DC motor system from its kV (volts/(unit/sec)) and kA (volts/(unit/sec²)).

These constants can be found using SysId. the states of the system are [position, velocity], inputs are [voltage], and outputs are [position].

You MUST use an SI unit (i.e. meters or radians) for the Distance template argument. You may still use non-SI units (such as feet or inches) for the actual method arguments; they will automatically be converted to SI internally.

The parameters provided by the user are from this feedforward model:

u = K_v v + K_a a

Parameters

kV	The velocity gain, in volts/(unit/sec).
kA	The acceleration gain, in volts/(unit/sec²).

Exceptions

std::domain_error if kV < 0 or kA <= 0.

◆ DrivetrainVelocitySystem()

static LinearSystem< 2, 2, 2 > frc::LinearSystemId::DrivetrainVelocitySystem	(	const DCMotor &	motor,
		units::kilogram_t	mass,
		units::meter_t	r,
		units::meter_t	rb,
		units::kilogram_square_meter_t	J,
		double	gearing
	)

static

Create a state-space model of differential drive drivetrain.

In this model, the states are [left velocity, right velocity], the inputs are [left voltage, right voltage], and the outputs are [left velocity, right velocity]

Parameters

motor	The motor (or gearbox) driving the drivetrain.
mass	The mass of the robot in kilograms.
r	The radius of the wheels in meters.
rb	The radius of the base (half of the track width), in meters.
J	The moment of inertia of the robot.
gearing	Gear ratio from motor to wheel.

Exceptions

std::domain_error if mass <= 0, r <= 0, rb <= 0, J <= 0, or gearing <= 0.

◆ ElevatorSystem()

static LinearSystem< 2, 1, 1 > frc::LinearSystemId::ElevatorSystem	(	DCMotor	motor,
		units::kilogram_t	mass,
		units::meter_t	radius,
		double	gearing
	)

static

Create a state-space model of the elevator system.

The states of the system are [position, velocity], inputs are [voltage], and outputs are [position].

Parameters

motor	The motor (or gearbox) attached to the carriage.
mass	The mass of the elevator carriage, in kilograms.
radius	The radius of the elevator's driving drum, in meters.
gearing	Gear ratio from motor to carriage.

Exceptions

std::domain_error if mass <= 0, radius <= 0, or gearing <= 0.

◆ FlywheelSystem()

static LinearSystem< 1, 1, 1 > frc::LinearSystemId::FlywheelSystem	(	DCMotor	motor,
		units::kilogram_square_meter_t	J,
		double	gearing
	)

static

Create a state-space model of a flywheel system, the states of the system are [angular velocity], inputs are [voltage], and outputs are [angular velocity].

Parameters

motor	The motor (or gearbox) attached to the flywheel.
J	The moment of inertia J of the flywheel.
gearing	Gear ratio from motor to flywheel.

Exceptions

std::domain_error if J <= 0 or gearing <= 0.

◆ IdentifyDrivetrainSystem() [1/2]

static LinearSystem< 2, 2, 2 > frc::LinearSystemId::IdentifyDrivetrainSystem	(	decltype(1_V/1_mps)	kVLinear,
		decltype(1_V/1_mps_sq)	kALinear,
		decltype(1_V/1_mps)	kVAngular,
		decltype(1_V/1_mps_sq)	kAAngular
	)

static

Identify a differential drive drivetrain given the drivetrain's kV and kA in both linear {(volts/(meter/sec), (volts/(meter/sec²))} and angular {(volts/(radian/sec), (volts/(radian/sec²))} cases.

These constants can be found using SysId.

States: [[left velocity], [right velocity]]
Inputs: [[left voltage], [right voltage]]
Outputs: [[left velocity], [right velocity]]

Parameters

kVLinear	The linear velocity gain in volts per (meters per second).
kALinear	The linear acceleration gain in volts per (meters per second squared).
kVAngular	The angular velocity gain in volts per (meters per second).
kAAngular	The angular acceleration gain in volts per (meters per second squared).

Exceptions

domain_error if kVLinear <= 0, kALinear <= 0, kVAngular <= 0, or kAAngular <= 0.

See also: https://github.com/wpilibsuite/sysid

◆ IdentifyDrivetrainSystem() [2/2]

static LinearSystem< 2, 2, 2 > frc::LinearSystemId::IdentifyDrivetrainSystem	(	decltype(1_V/1_mps)	kVLinear,
		decltype(1_V/1_mps_sq)	kALinear,
		decltype(1_V/1_rad_per_s)	kVAngular,
		decltype(1_V/1_rad_per_s_sq)	kAAngular,
		units::meter_t	trackwidth
	)

static

Identify a differential drive drivetrain given the drivetrain's kV and kA in both linear {(volts/(meter/sec)), (volts/(meter/sec²))} and angular {(volts/(radian/sec)), (volts/(radian/sec²))} cases.

This can be found using SysId.

States: [[left velocity], [right velocity]]
Inputs: [[left voltage], [right voltage]]
Outputs: [[left velocity], [right velocity]]

Parameters

kVLinear	The linear velocity gain in volts per (meters per second).
kALinear	The linear acceleration gain in volts per (meters per second squared).
kVAngular	The angular velocity gain in volts per (radians per second).
kAAngular	The angular acceleration gain in volts per (radians per second squared).
trackwidth	The distance between the differential drive's left and right wheels, in meters.

Exceptions

domain_error if kVLinear <= 0, kALinear <= 0, kVAngular <= 0, kAAngular <= 0, or trackwidth <= 0.

See also: https://github.com/wpilibsuite/sysid

◆ IdentifyPositionSystem()

template<typename Distance >
requires std::same_as<units::meter, Distance> || std::same_as<units::radian, Distance>

static LinearSystem< 2, 1, 1 > frc::LinearSystemId::IdentifyPositionSystem	(	decltype(1_V/Velocity_t< Distance >(1))	kV,
		decltype(1_V/Acceleration_t< Distance >(1))	kA
	)

inlinestatic

Create a state-space model for a 1 DOF position system from its kV (volts/(unit/sec)) and kA (volts/(unit/sec²)).

These constants can be found using SysId. the states of the system are [position, velocity], inputs are [voltage], and outputs are [position].

You MUST use an SI unit (i.e. meters or radians) for the Distance template argument. You may still use non-SI units (such as feet or inches) for the actual method arguments; they will automatically be converted to SI internally.

The parameters provided by the user are from this feedforward model:

u = K_v v + K_a a

Parameters

kV	The velocity gain, in volts/(unit/sec).
kA	The acceleration gain, in volts/(unit/sec²).

Exceptions

std::domain_error if kV < 0 or kA <= 0.

See also: https://github.com/wpilibsuite/sysid

◆ IdentifyVelocitySystem()

template<typename Distance >
requires std::same_as<units::meter, Distance> || std::same_as<units::radian, Distance>

static LinearSystem< 1, 1, 1 > frc::LinearSystemId::IdentifyVelocitySystem	(	decltype(1_V/Velocity_t< Distance >(1))	kV,
		decltype(1_V/Acceleration_t< Distance >(1))	kA
	)

inlinestatic

Create a state-space model for a 1 DOF velocity system from its kV (volts/(unit/sec)) and kA (volts/(unit/sec²)).

These constants can be found using SysId. The states of the system are [velocity], inputs are [voltage], and outputs are [velocity].

You MUST use an SI unit (i.e. meters or radians) for the Distance template argument. You may still use non-SI units (such as feet or inches) for the actual method arguments; they will automatically be converted to SI internally.

The parameters provided by the user are from this feedforward model:

u = K_v v + K_a a

Parameters

kV	The velocity gain, in volts/(unit/sec).
kA	The acceleration gain, in volts/(unit/sec²).

Exceptions

std::domain_error if kV < 0 or kA <= 0.

See also: https://github.com/wpilibsuite/sysid

◆ SingleJointedArmSystem()

static LinearSystem< 2, 1, 1 > frc::LinearSystemId::SingleJointedArmSystem	(	DCMotor	motor,
		units::kilogram_square_meter_t	J,
		double	gearing
	)

static

Create a state-space model of a single-jointed arm system.The states of the system are [angle, angular velocity], inputs are [voltage], and outputs are [angle].

Parameters

motor	The motor (or gearbox) attached to the arm.
J	The moment of inertia J of the arm.
gearing	Gear ratio from motor to arm.

Exceptions

std::domain_error if J <= 0 or gearing <= 0.

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

frc/system/plant/LinearSystemId.h

Public Types

Static Public Member Functions

Detailed Description

Member Typedef Documentation

◆ Acceleration_t

◆ Velocity_t

Member Function Documentation

◆ DCMotorSystem() [1/2]

◆ DCMotorSystem() [2/2]

◆ DrivetrainVelocitySystem()

◆ ElevatorSystem()

◆ FlywheelSystem()

◆ IdentifyDrivetrainSystem() [1/2]

◆ IdentifyDrivetrainSystem() [2/2]

◆ IdentifyPositionSystem()

◆ IdentifyVelocitySystem()

◆ SingleJointedArmSystem()