#include <spline.hpp>

Classes
struct	ConstrainedState
	An intermediate value used in the parameterization step. More...

struct	GeneratedPoint
	The output of the initial, "naive" generation step. More...

struct	GeneratedVector
	An intermediate value used in the "naive" generation step. More...

Public Member Functions
	SplineGenerator (Constraints iconstraints, std::shared_ptr< PhysicalModel > imodel=std::make_shared< PassthroughModel >(), double idt=0.1)
	Generates curves that match the given motion constraints.

std::vector< ProfilePoint >	generate (std::vector< Pose > iwaypoints, bool fast=false)
	Creates a motion profiled path between the given waypoints.

std::vector< ProfilePoint >	generate (std::initializer_list< Pose > iwaypoints, bool fast=false)

std::vector< ProfilePoint >	generate (std::vector< ControlVector > iwaypoints)
	Creates a motion profiled path between the given waypoints.

std::vector< ProfilePoint >	generate (std::initializer_list< ControlVector > iwaypoints)

std::vector< GeneratedVector >	gen_single_raw_path (ControlVector start, ControlVector end, int duration, double start_vel, double end_vel)

std::vector< GeneratedPoint >	gradient_descent (ControlVector &start, ControlVector &end, bool fast)
	Runs a Gradient Descent algorithm to minimize the linear acceleration, linear jerk, and curvature for the generated path.

template<class Iter >
std::vector< ProfilePoint >	_generate (Iter start, Iter end, bool fast)
	The actual function called by the "generate" functions.

std::vector< GeneratedPoint >	gen_raw_path (ControlVector &start, ControlVector &end, bool fast)
	Performs the "naive" generation step.

std::vector< ProfilePoint >	parameterize (const ControlVector start, const ControlVector end, const std::vector< GeneratedPoint > &raw_path, const double preferred_start_vel, const double preferred_end_vel, const double start_time)
	Imposes a linear motion profile on the raw path.

std::vector< ProfilePoint >	integrate_constrained_states (std::vector< ConstrainedState > constrainedStates)
	Finds the new timestamps for each point along the curve based on the motion profile.

ProfilePoint	get_point_at_time (const ControlVector start, const ControlVector end, std::vector< ProfilePoint > points, double t)
	Finds the ProfilePoint on the profiled curve for the given timestamp.

ProfilePoint	lerp_point (QuinticPolynomial x_qp, QuinticPolynomial y_qp, ProfilePoint start, ProfilePoint end, double i)
	Linearly interpolates between points along the profiled curve.

QuinticPolynomial	get_x_spline (const ControlVector start, const ControlVector end, const double duration)
	Returns the spline curve for the given control vectors and path duration.

QuinticPolynomial	get_y_spline (const ControlVector start, const ControlVector end, const double duration)

void	enforce_accel_lims (ConstrainedState *state)
	Applies the general constraints and model constraints to the given state.

void	forward_pass (ConstrainedState predecessor, ConstrainedState successor)
	Imposes the motion profile constraints on a segment of the path from the perspective of iterating forwards through the path.

void	backward_pass (ConstrainedState predecessor, ConstrainedState successor)
	Imposes the motion profile constraints on a segment of the path from the perspective of iterating backwards through the path.

double	vf (double vi, double a, double ds)
	Calculates the final velocity for a path segment.

double	ai (double vf, double vi, double s)
	Calculates the initial acceleration needed to match the segments' velocities.

Public Attributes
const double	K_DEFAULT_VEL = 1.0
	This is factor is used to create a "dummy velocity" in the initial path generation step one or both of the preferred start or end velocities is zero.

Static Public Attributes
static constexpr double	K_EPSILON = 1e-5
	Values that are closer to each other than this value are considered equal.

Protected Attributes
Constraints	constraints
	The maximum allowable values for the robot's motion.

std::shared_ptr< PhysicalModel >	model
	Defines the physical structure of the robot and translates the linear kinematics to wheel velocities.

double	dt
	The time difference between each value in the generated path.

const int	T_MIN = 2
	The minimum and maximum durations for a path to take.

const int	T_MAX = 15

const int	MAX_GRAD_DESCENT_ITERATIONS = 10

Detailed Description

Definition at line 22 of file spline.hpp.

Constructor & Destructor Documentation

◆ SplineGenerator()

squiggles::SplineGenerator::SplineGenerator	(	Constraints	iconstraints,
		std::shared_ptr< PhysicalModel >	imodel = `std::make_shared< PassthroughModel >()`,
		double	idt = `0.1`
	)

Generates curves that match the given motion constraints.

Parameters

iconstraints	The maximum allowable values for the robot's motion.
imodel	The robot's physical characteristics and constraints
idt	The difference in time in seconds between each state for the generated paths.

Member Function Documentation

◆ _generate()

template<class Iter >

std::vector< ProfilePoint > squiggles::SplineGenerator::_generate	(	Iter	start,
		Iter	end,
		bool	fast
	)

The actual function called by the "generate" functions.

Parameters

start	An iterator pointing to the first ControlVector in the path
end	An iterator pointting to the last ControlVector in the path

Returns: The points from each path concatenated together

◆ ai()

double squiggles::SplineGenerator::ai	(	double	vf,
		double	vi,
		double	s
	)

Calculates the initial acceleration needed to match the segments' velocities.

◆ backward_pass()

void squiggles::SplineGenerator::backward_pass	(	ConstrainedState *	predecessor,
		ConstrainedState *	successor
	)

Imposes the motion profile constraints on a segment of the path from the perspective of iterating backwards through the path.

◆ enforce_accel_lims()

void squiggles::SplineGenerator::enforce_accel_lims ( ConstrainedState * state )

Applies the general constraints and model constraints to the given state.

◆ forward_pass()

void squiggles::SplineGenerator::forward_pass	(	ConstrainedState *	predecessor,
		ConstrainedState *	successor
	)

Imposes the motion profile constraints on a segment of the path from the perspective of iterating forwards through the path.

◆ gen_raw_path()

std::vector< GeneratedPoint > squiggles::SplineGenerator::gen_raw_path	(	ControlVector &	start,
		ControlVector &	end,
		bool	fast
	)

Performs the "naive" generation step.

This step calculates the spline polynomials that fit within the SplineGenerator's acceleration and jerk constraints and returns the points that form the curve.

◆ gen_single_raw_path()

std::vector< GeneratedVector > squiggles::SplineGenerator::gen_single_raw_path	(	ControlVector	start,
		ControlVector	end,
		int	duration,
		double	start_vel,
		double	end_vel
	)

◆ generate() [1/4]

std::vector< ProfilePoint > squiggles::SplineGenerator::generate ( std::initializer_list< ControlVector > iwaypoints )

◆ generate() [2/4]

std::vector< ProfilePoint > squiggles::SplineGenerator::generate	(	std::initializer_list< Pose >	iwaypoints,
		bool	fast = `false`
	)

◆ generate() [3/4]

std::vector< ProfilePoint > squiggles::SplineGenerator::generate ( std::vector< ControlVector > iwaypoints )

Creates a motion profiled path between the given waypoints.

Parameters

iwaypoints The list of vectors that the robot should reach along the path.

Returns: A series of robot states defining a path between the vectors.

◆ generate() [4/4]

std::vector< ProfilePoint > squiggles::SplineGenerator::generate	(	std::vector< Pose >	iwaypoints,
		bool	fast = `false`
	)

Creates a motion profiled path between the given waypoints.

Parameters

iwaypoints	The list of poses that the robot should reach along the path.
fast	If true, the path optimization process will stop as soon as the constraints are met. If false, the optimizer will find the smoothest possible path between the points.

Returns: A series of robot states defining a path between the poses.

◆ get_point_at_time()

ProfilePoint squiggles::SplineGenerator::get_point_at_time	(	const ControlVector	start,
		const ControlVector	end,
		std::vector< ProfilePoint >	points,
		double	t
	)

Finds the ProfilePoint on the profiled curve for the given timestamp.

This with interpolate between points on the curve if a point with an exact matching timestamp is not found.

◆ get_x_spline()

QuinticPolynomial squiggles::SplineGenerator::get_x_spline	(	const ControlVector	start,
		const ControlVector	end,
		const double	duration
	)

Returns the spline curve for the given control vectors and path duration.

◆ get_y_spline()

QuinticPolynomial squiggles::SplineGenerator::get_y_spline	(	const ControlVector	start,
		const ControlVector	end,
		const double	duration
	)

◆ gradient_descent()

std::vector< GeneratedPoint > squiggles::SplineGenerator::gradient_descent	(	ControlVector &	start,
		ControlVector &	end,
		bool	fast
	)

Runs a Gradient Descent algorithm to minimize the linear acceleration, linear jerk, and curvature for the generated path.

This is used when there is not a start/end velocity specified for a given path.

◆ integrate_constrained_states()

std::vector< ProfilePoint > squiggles::SplineGenerator::integrate_constrained_states ( std::vector< ConstrainedState > constrainedStates )

Finds the new timestamps for each point along the curve based on the motion profile.

◆ lerp_point()

ProfilePoint squiggles::SplineGenerator::lerp_point	(	QuinticPolynomial	x_qp,
		QuinticPolynomial	y_qp,
		ProfilePoint	start,
		ProfilePoint	end,
		double	i
	)

Linearly interpolates between points along the profiled curve.

◆ parameterize()

std::vector< ProfilePoint > squiggles::SplineGenerator::parameterize	(	const ControlVector	start,
		const ControlVector	end,
		const std::vector< GeneratedPoint > &	raw_path,
		const double	preferred_start_vel,
		const double	preferred_end_vel,
		const double	start_time
	)

Imposes a linear motion profile on the raw path.

This step creates the velocity and acceleration values to command the robot at each point along the curve.

◆ vf()

double squiggles::SplineGenerator::vf	(	double	vi,
		double	a,
		double	ds
	)

Calculates the final velocity for a path segment.

Member Data Documentation

◆ constraints

Constraints squiggles::SplineGenerator::constraints

protected

The maximum allowable values for the robot's motion.

Definition at line 69 of file spline.hpp.

◆ dt

double squiggles::SplineGenerator::dt

protected

The time difference between each value in the generated path.

Definition at line 80 of file spline.hpp.

◆ K_DEFAULT_VEL

const double squiggles::SplineGenerator::K_DEFAULT_VEL = 1.0

This is factor is used to create a "dummy velocity" in the initial path generation step one or both of the preferred start or end velocities is zero.

The velocity will be replaced with the preferred start/end velocity in parameterization but a nonzero velocity is needed for the spline calculation.

This was 1.2 in the WPILib example but that large of a value seems to create wild paths, 0.12 worked better in testing with VEX-sized paths.

Definition at line 101 of file spline.hpp.

◆ K_EPSILON

constexpr double squiggles::SplineGenerator::K_EPSILON = 1e-5

staticconstexpr

Values that are closer to each other than this value are considered equal.

Definition at line 306 of file spline.hpp.

◆ MAX_GRAD_DESCENT_ITERATIONS

const int squiggles::SplineGenerator::MAX_GRAD_DESCENT_ITERATIONS = 10

protected

Definition at line 88 of file spline.hpp.

◆ model

std::shared_ptr<PhysicalModel> squiggles::SplineGenerator::model

protected

Defines the physical structure of the robot and translates the linear kinematics to wheel velocities.

Definition at line 75 of file spline.hpp.

◆ T_MAX

const int squiggles::SplineGenerator::T_MAX = 15

protected

Definition at line 87 of file spline.hpp.

◆ T_MIN

const int squiggles::SplineGenerator::T_MIN = 2

protected

The minimum and maximum durations for a path to take.

A larger range allows for longer possible paths at the expense of a longer path generation time.

Definition at line 86 of file spline.hpp.

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

include/okapi/squiggles/spline.hpp

Classes

Public Member Functions

Public Attributes

Static Public Attributes

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ SplineGenerator()

Member Function Documentation

◆ _generate()

◆ ai()

◆ backward_pass()

◆ enforce_accel_lims()

◆ forward_pass()

◆ gen_raw_path()

◆ gen_single_raw_path()

◆ generate() [1/4]

◆ generate() [2/4]

◆ generate() [3/4]

◆ generate() [4/4]

◆ get_point_at_time()

◆ get_x_spline()

◆ get_y_spline()

◆ gradient_descent()

◆ integrate_constrained_states()

◆ lerp_point()

◆ parameterize()

◆ vf()

Member Data Documentation

◆ constraints

◆ dt

◆ K_DEFAULT_VEL

◆ K_EPSILON

◆ MAX_GRAD_DESCENT_ITERATIONS

◆ model

◆ T_MAX

◆ T_MIN