Description

Interface base class for scalar->quaternion functions of the type:

q= f(s)

where q is a unit quaternion (i.e. a rotation in 3D) and s is a scalar (ex. time) Classes inherited from ChFunctionRotation are often used to set time-dependent rotation, for example to set the imposed alignment of a rigid body in space. Inherited classes must override at least the Get_q() method, in order to represent more complex functions.

#include <ChFunctionRotation.h>

Inheritance diagram for chrono::ChFunctionRotation:

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Public Member Functions
	ChFunctionRotation (const ChFunctionRotation &other)

virtual ChFunctionRotation *	Clone () const =0
	"Virtual" copy constructor.

virtual ChQuaternion	Get_q (double s) const =0
	Return the rotation as a quaternion, function of s, as q=f(s).

virtual ChVector	Get_w_loc (double s) const
	Return the derivative of the rotation function, at s, expressed as angular velocity w in local frame. More...

virtual ChVector	Get_a_loc (double s) const
	Return the derivative of the rotation function, at s, expressed as angular acceleration in local frame. More...

virtual void	Estimate_s_domain (double &smin, double &smax) const
	Return an estimate of the domain of the function argument. More...

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

virtual void	ArchiveOUT (ChArchiveOut &marchive)
	Method to allow serialization of transient data to archives.

virtual void	ArchiveIN (ChArchiveIn &marchive)
	Method to allow de-serialization of transient data from archives.

Member Function Documentation

◆ Estimate_s_domain()

virtual void chrono::ChFunctionRotation::Estimate_s_domain	(	double &	smin,
		double &	smax
	)		const

inlinevirtual

Return an estimate of the domain of the function argument.

(ex. can be used for automatic zooming in a GUI, or for computing the bounding box)

◆ Get_a_loc()

ChVector chrono::ChFunctionRotation::Get_a_loc ( double s ) const

virtual

Return the derivative of the rotation function, at s, expressed as angular acceleration in local frame.

Note that inherited classes may also avoid overriding this method, because this base method already provide a general-purpose numerical differentiation to get angular acceleration only from the Get_q() function. (however, if the analytical derivative is known, it may be better to implement a custom method).

Reimplemented in chrono::ChFunctionRotation_setpoint, and chrono::ChFunctionRotation_axis.

◆ Get_w_loc()

ChVector chrono::ChFunctionRotation::Get_w_loc ( double s ) const

virtual

Return the derivative of the rotation function, at s, expressed as angular velocity w in local frame.

Note that inherited classes may also avoid overriding this method, because this base method already provide a general-purpose numerical differentiation to get w only from the Get_p() function. (however, if the analytical derivative is known, it may better to implement a custom method).