Description

B-Spline motion function.

#include <ChFunctionBSpline.h>

Inheritance diagram for chrono::ChFunctionBSpline:

Collaboration diagram for chrono::ChFunctionBSpline:

Public Member Functions
	ChFunctionBSpline (int p, const ChVectorDynamic<> &cpoints, ChVectorDynamic<> *knots=0)
	Generic univariate B-Spline of order p, approximating given control points. More...

	ChFunctionBSpline (int p, const ChVectorDynamic<> &x_interp, const ChVectorDynamic<> &y_dN_interp, const ChVectorDynamic< int > &der_order, ChVectorDynamic<> *knots=0)
	Univariate B-Spline of order p, exactly interpolating given waypoints and derivatives: internally solve linear problem A * b = c to find proper constrained control points (eg. More...

	ChFunctionBSpline (const ChFunctionBSpline &other)

virtual ChFunctionBSpline *	Clone () const override
	"Virtual" copy constructor (covariant return type).

virtual void	Setup (int p, ChVectorDynamic<> cpoints, ChVectorDynamic<> *knots)
	Setup internal data of B-Spline.

virtual Type	GetType () const override
	Get type of ChFunction.

int	GetOrder () const
	Get B-Spline order.

ChVectorDynamic	GetControlPoints () const
	Get B-Spline control points.

ChVectorDynamic	GetControlPointsAbscissae () const
	Get B-Spline averaged control points abscissae (Greville abscissae) as in [De Boor, chapt. More...

ChVectorDynamic	GetKnots () const
	Get B-Spline knots.

std::shared_ptr< ChBasisToolsBSpline >	GetBasisTool ()
	Get B-Spline internal tool to evaluate basis functions.

virtual double	GetVal (double x) const override
	B-Spline: y(x) = = SUM_i Ni,p(x) b_i.

virtual double	GetDer (double x) const override
	B-Spline 1st derivative: y(x)' = = SUM_i Ni,p(x)' b_i.

virtual double	GetDer2 (double x) const override
	B-Spline 2nd derivative: y(x)'' = = SUM_i Ni,p(x)'' b_i.

virtual double	GetDer3 (double x) const override
	B-Spline 3rd derivative: y(x)''' = = SUM_i Ni,p(x)''' b_i.

virtual void	ApplyInterpolationConstraints (int p, const ChVectorDynamic<> &x_interp, const ChVectorDynamic<> &y_dN_interp, const ChVectorDynamic< int > der_order, ChVectorDynamic<> *knots=0)
	Recompute B-Spline control points to exactly interpolate given waypoints and derivatives (eg. More...

virtual void	ArchiveOut (ChArchiveOut &archive_out) override
	Method to allow serialization of transient data to archives.

virtual void	ArchiveIn (ChArchiveIn &archive_in) override
	Method to allow de-serialization of transient data from archives.

Public Member Functions inherited from chrono::ChFunction
	ChFunction (const ChFunction &other)

virtual double	GetDerN (double x, int der_order) const
	Return the Nth derivative of the function (up to 3rd derivative). More...

virtual double	GetWeight (double x) const
	Return the weight of the function (useful for applications where you need to mix different weighted ChFunctions)

virtual void	Update (double x)
	Update could be implemented by children classes, ex. to launch callbacks.

virtual double	GetMax (double xmin, double xmax, double sampling_step, int der_order) const
	Estimate the maximum of the function (or its der_order derivative) in the range [xmin, xmax], using sampling method.

virtual double	GetMin (double xmin, double xmax, double sampling_step, int der_order) const
	Estimate the minimum of the function (or its der_order derivative) in the range [xmin, xmax], using sampling method.

virtual double	GetMean (double xmin, double xmax, double sampling_step, int der_order) const
	Estimate the mean of the function (or its der_order derivative) in the range [xmin, xmax], using sampling method.

virtual double	GetSquaredMean (double xmin, double xmax, double sampling_step, int der_order) const
	Estimate the squared mean of the function (or its der_order derivative) in the range [xmin, xmax], using sampling method.

virtual double	GetIntegral (double xmin, double xmax, double sampling_step, int der_order) const
	Estimate the integral of the function (or its der_order derivative) over the range [xmin, xmax], using sampling method.

virtual double	GetPositiveAccelerationCoeff () const
	Computes the positive acceleration coefficient (inherited classes should override this).

virtual double	GetNegativeAccelerationCoeff () const
	Compute the negative acceleration coefficient (inherited classes should override this).

virtual double	GetVelocityCoefficient () const
	Compute the velocity coefficient (inherited classes must override this).

virtual void	OutputToASCIIFile (std::ostream &file, double xmin, double xmax, int samples, char delimiter)
	Store X-Y pairs to an ASCII File. More...

virtual ChMatrixDynamic	SampleUpToDerN (double xmin, double xmax, double step, int derN=0)
	Sample function on given interval [xmin, xmax], up to derN derivative (0 being the function ouput itself). More...

double	operator() (double arg) const
	Alias operator of the GetVal function.

Additional Inherited Members
Public Types inherited from chrono::ChFunction
enum	Type { BSPLINE, CONSTANT, CONSTACC, CONSTJERK, CUSTOM, CYCLOIDAL, DERIVATIVE, FILLET3, INTEGRAL, INTERP, LAMBDA, MIRROR, OPERATOR, POLY, POLY23, POLY345, RAMP, REPEAT, SEQUENCE, SINE, SINE_STEP }
	Enumeration of function types.

Constructor & Destructor Documentation

◆ ChFunctionBSpline() [1/2]

chrono::ChFunctionBSpline::ChFunctionBSpline	(	int	p,
		const ChVectorDynamic<> &	cpoints,
		ChVectorDynamic<> *	knots = `0`
	)

Generic univariate B-Spline of order p, approximating given control points.

If knot vector is not provided, initialize it as equally spaced and clamped at both ends.

Parameters

p	order
cpoints	control points
knots	knot vector

◆ ChFunctionBSpline() [2/2]

chrono::ChFunctionBSpline::ChFunctionBSpline	(	int	p,
		const ChVectorDynamic<> &	x_interp,
		const ChVectorDynamic<> &	y_dN_interp,
		const ChVectorDynamic< int > &	der_order,
		ChVectorDynamic<> *	knots = `0`
	)

Univariate B-Spline of order p, exactly interpolating given waypoints and derivatives: internally solve linear problem A * b = c to find proper constrained control points (eg.

useful to pass through given points with assigned velocities, at specific times). If knot vector is not provided, initialize it as equally spaced and clamped at both ends.

Parameters

p	order
x_interp	parameters (eg. times) at which to perform interpolation
y_dN_interp	output value to interpolate, Nth derivative: y(x)^(Nth)
der_order	derivative order of given interpolation output (0: pos, 1: vel, 2: acc, ...)
knots	knot vector

Member Function Documentation

◆ ApplyInterpolationConstraints()

void chrono::ChFunctionBSpline::ApplyInterpolationConstraints	(	int	p,
		const ChVectorDynamic<> &	x_interp,
		const ChVectorDynamic<> &	y_dN_interp,
		const ChVectorDynamic< int >	der_order,
		ChVectorDynamic<> *	knots = `0`
	)

virtual

Recompute B-Spline control points to exactly interpolate given waypoints and derivatives (eg.

satisfy position, velocity, acceleration constraints).

Parameters

p	order
x_interp	parameters (eg. times) at which perform interpolation
y_dN_interp	output value to interpolate, Nth derivative: y(x)^(Nth)
der_order	derivative order of given interpolation output (0: pos, 1: vel, 2: acc, ...)
knots	knot vector

◆ GetControlPointsAbscissae()

ChVectorDynamic chrono::ChFunctionBSpline::GetControlPointsAbscissae ( ) const

Get B-Spline averaged control points abscissae (Greville abscissae) as in [De Boor, chapt.

XI] averaging formula. Useful, in univariate B-Spline functions, to get csi(x) abscissae associated to control points y(x), ie. b_i = [cpointx_i, cpointy_i] = [csi(x)_i, y(x)_i]

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

/builds/uwsbel/chrono/src/chrono/functions/ChFunctionBSpline.h
/builds/uwsbel/chrono/src/chrono/functions/ChFunctionBSpline.cpp

Description

Public Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ ChFunctionBSpline() [1/2]

◆ ChFunctionBSpline() [2/2]

Member Function Documentation

◆ ApplyInterpolationConstraints()

◆ GetControlPointsAbscissae()