rigid_body_staging Class Reference

Rigid body dynamical model applying both force and torque to the spacecraft. More...

#include <rigid_body_staging.h>

Inherits dsim_model.

Public Member Functions
void	initialize_data ()
	Initialize outlets and output variables.
void	initialization_complete ()
	Finish initialization.
void	initialize_timestep ()
	Computation done prior to numerical integration.
void	complete_timestep ()
	Computation done after numerical integration.
void	rhs (double t, double jd)
	Computation done during numerical integration. More...
dsim_value	handle_message (const std::string &sender_path, const std::string &message_name, const dsim_value &argument)
	Handle force and torque messages. More...

Protected Member Functions
double	get_adj_mass ()
	Check for changed mass of children and recompute new adjusted mass. More...
ml_matrix	get_adj_center_of_mass ()
	Check for changed mass of children and recompute new adjusted center of mass.
ml_matrix	get_adj_inertia ()
	Check for changed mass of children and recompute new adjusted inertia. More...
double	get_adj_mass_derivative ()
	Check for changed mass of children and recompute new adjusted mass derivative. More...
ml_matrix	get_adj_center_of_mass_derivative ()
	Check for changed mass of children and recompute new adjusted center of mass derivative. More...
ml_matrix	get_adj_inertia_derivative ()
	Check for changed mass of children and recompute new adjusted inertia derivative. More...

Protected Attributes
dsim_variable	spacecraft_name_dsim
	Spacecraft name.
dsim_variable	spacecraft_type_dsim
	Spacecraft type.
dsim_variable	position_dsim
	object position
dsim_variable	velocity_dsim
	object velocity
dsim_variable	quaternion_dsim
	attitude quaternion ([scalar;x;y;z])
dsim_variable	bodyRate_dsim
	body rotational rates (rad/s)
dsim_variable	mass_base
	dry mass (kg)
dsim_variable	totalMass_dsim
	total mass, including mass of children
dsim_variable	totalInertia_dsim
	total inertia, including children
dsim_variable	centerOfMass_dsim
	object center of mass, including children
dsim_variable	centerOfMass_base
	object center of mass
dsim_variable	inertia_base
	rigid body inertia
dsim_variable	totalMassDerivative_dsim
	mass derivative
dsim_variable	totalCenterOfMassDerivative_dsim
	center of mass derivative
dsim_variable	totalInertiaDerivative_dsim
	inertia derivative
dsim_variable	frame_dsim
	frame for initial conditions
dsim_variable	stagingCommand_dsim
	Staging command for rigid_body_staging_assembly.
dsim_variable	ang_momentum_dsim
	Angular momentum.
dsim_variable	acceleration_dsim
	object linear acceleration in body frame
dsim_variable	angular_acceleration_dsim
	Angular acceleration.
dsim_variable	parent_com
	Center of mass of parent.
dsim_variable	parent_q_eci_to_body
	Quaternion of the parent.
dsim_variable	parent_position
	Position of the parent.
std::string	parent_path
	Path of the parent.
dsim_variable	quaternionCommand_dsim
	Commanded quaternion.
ml_matrix	inertia
	Stored inertia for computational efficiency.
ml_matrix	invInertia
	Stored inverse inertia for computational efficiency.
ml_matrix	force
	The external force on the spacecraft.
ml_matrix	torque
	The external torque on the spacecraft.
double	m_to_km
	Convert meters to kilometers.
double	baseMass
	Base mass to be added to children.
bool	child_obj
	Flag if child.

Detailed Description

Rigid body dynamical model applying both force and torque to the spacecraft.

Integrates the position, velocity, quaternion, and body rates. Allows the mass of the spacecraft to change. Children can use the apply_torque, apply_force, or mass_changed messages. Ignores any effect of or changes in center of mass. Does not add up or compute changes in inertia. Assumes all torques are about the center of mass.

Member Function Documentation

rhs()

void rigid_body_staging::rhs	(	double	t,
		double	jd
	)

Computation done during numerical integration.

Quaternion kinematics and orbit derivative.

Uses qi_to_b_dot from the SCControl framework.

handle_message()

dsim_value rigid_body_staging::handle_message	(	const std::string &	sender_path,
		const std::string &	message_name,
		const dsim_value &	argument
	)

Handle force and torque messages.

Handle the apply_force and apply_torque messages.

The units should be N and Nm. Force should be in the ECI frame and torque should be in the body frame.

get_adj_mass()

double rigid_body_staging::get_adj_mass ( )

protected

Check for changed mass of children and recompute new adjusted mass.

Add up the mass of any children that have a mass variable.

Store the new mass and reset the changed mass flag.

get_adj_inertia()

ml_matrix rigid_body_staging::get_adj_inertia ( )

protected

Check for changed mass of children and recompute new adjusted inertia.

If the child has an inertia matrix, rotate and translate and add to parent inertia If the child has a mass value, but not inertia, treat as a point mass and add to parent inertia if a center_mass value is available.

get_adj_mass_derivative()

double rigid_body_staging::get_adj_mass_derivative ( )

protected

Check for changed mass of children and recompute new adjusted mass derivative.

Add up the mass of this object and any children that have a mass variable.

get_adj_center_of_mass_derivative()

ml_matrix rigid_body_staging::get_adj_center_of_mass_derivative ( )

protected

Check for changed mass of children and recompute new adjusted center of mass derivative.

Determine the center of mass derivaitve of this object and any children that have a mass variable.

get_adj_inertia_derivative()

ml_matrix rigid_body_staging::get_adj_inertia_derivative ( )

protected

Check for changed mass of children and recompute new adjusted inertia derivative.

Determine the time derivative of the inertia matrix.

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

• rigid_body_staging.h
• rigid_body_staging.cc