A PID based attitude control system. More...

#include <fsw_attitude_control.h>

Inheritance diagram for fsw_attitude_control:

Public Member Functions
	fsw_attitude_control (const char *mod_name)

void	initialize_data ()
	Create data and request the FSW_ATTITUDE_CONTROL_TRIGGER. More...

void	initialize_data_requests ()

void	handle_event (int code)

int	valid_quaternion (ml_matrix q)
	Checks the validity of a quaternion. More...

int	valid_vector (ml_matrix u)
	Checks the validity of a unit vector. More...

ml_matrix	make_unit_vector (ml_matrix u)
	Make a unit vector. More...

int	get_index (int id, ml_matrix index_list)
	Get the index for the SPICE id. More...

Protected Attributes
Inputs

CD_REQUEST_REF	od_state_ref
	State estimate od_state. More...

CD_REQUEST_REF	inertia_ref
	The spacecraft inertia matrix. More...

CD_REQUEST_REF	quaternion_ref
	The estimated quaternion. More...

CD_REQUEST_REF	omega_ref
	The estimated body rate. More...

CD_REQUEST_REF	ephem_planet_position_ref
	Planet position. More...

CD_REQUEST_REF	ephem_planet_index_ref
	Planet index. More...

CD_REQUEST_REF	ephem_planet_rotation_matrix_ref
	Planet rotation matrix. More...

CD_REQUEST_REF	ephem_planet_radius_ref
	Planet radius. More...

CD_REQUEST_REF	ephem_sun_vector_ref
	Sun vector. More...

Outputs
CD_CREATE_REF	acs_error_ref
	ACS error code (int) More...

CD_CREATE_REF	acs_attitude_error_ref
	Attitude error (3x1) More...

CD_CREATE_REF	acs_torque_demand_ref
	The torque demand for all attitude control (3x1) More...

CD_CREATE_REF	acs_target_quaternion_ref
	Desired quaternion (4x1) More...

ACS Parameters and Commands

CD_CREATE_REF	acs_q_eci_to_body_command_ref

CD_CREATE_REF	acs_omega_command_ref
	Commanded angular rate for rate control (3x1) More...

CD_CREATE_REF	acs_axis_rate_command_ref
	Commanded axis rate. More...

CD_CREATE_REF	acs_eci_align_axis_command_ref
	The eci axis to be aligned (3x1) More...

CD_CREATE_REF	acs_body_align_axis_command_ref
	The body axis to be aligned (3x1) More...

CD_CREATE_REF	acs_rotate_axis_command_ref
	The axis to be rotated about (3x1) More...

CD_CREATE_REF	acs_rotate_angle_command_ref
	The angle to be rotated (double) More...

CD_CREATE_REF	acs_control_mode_command_ref
	Select the control mode (int) More...

CD_CREATE_REF	acs_solar_system_target_command_ref
	Solar system target. Format: integer SPICE ID. More...

CD_CREATE_REF	acs_attitude_gain_a_command_ref
	The ACS control algorithm state space gain a matrix. More...

CD_CREATE_REF	acs_attitude_gain_b_command_ref
	The ACS control algorithm state space gain b matrix. More...

CD_CREATE_REF	acs_attitude_gain_c_command_ref
	The ACS control algorithm state space gain c matrix. More...

CD_CREATE_REF	acs_attitude_gain_d_command_ref
	The ACS control algorithm state space gain d matrix. More...

CD_CREATE_REF	acs_planet_target_command_ref
	Planet target. More...

CD_CREATE_REF	acs_body_rate_gain_command_ref
	The scalar body rate gain (double) More...

CD_CREATE_REF	acs_q_nadir_offset_command_ref
	Nadir offset (4x1) More...

CD_CREATE_REF	acs_control_period_command_ref
	ACS control period (double) More...

CD_CREATE_REF	acs_maximum_delta_angle_command_ref
	Desired maximum delta angle (double) More...

Detailed Description

A PID based attitude control system.

The attitude control system takes inputs from attitude estimation and uses it to control pointing. The control system can control body rates, rotate about a specified axis, align a body axis with an inertial axis, track an attitude quaternion, align a body axis with a planet fixed target or do the last while rotating about that planet aligned axis.

You can compute the gain matrices using

[a,b,c,d] = PIDMIMO( 1, zeta, omega, tau_integral, omega_rolloff, t_samp, 'z' )

from the Spacecraft Control Toolbox (in MATLAB). omega_rolloff is a first order rate filter break frequency. 'z' implies that the controller equations are x[k+1] = a*x[k] + b*u[k]

The output is the torque demand. This is processed by the propulsion module.

You must also input the vehicle inertia matrix. It may be necessary to update the torque matrix and inertia matrix as fuel is consumed or when mass properties change.

The following are the pointing modes:

off: Turn off the attitude control system.
quaternion_tracking: Track a desire quaternion.
rate_tracking: Control rates.
axis_align: Align a vector in the body along an ECI vector.
single_axis_rotate: Rotate about a body axis
solar_system_body_align: Align a vector in the body with a planet or moon.
solar_system_body_align_and_rotate: Align a vector in the body with a planet or moon and rotate about that vector.
axis_align_and_rotate: Align a vector in the body along an ECI vector and rotate about that vector.
sun_tracking: Align a vector in the body with the sun.
nadir_tracking: Align a vector in the body with nadir

Member Function Documentation

◆ get_index()

int fsw_attitude_control::get_index	(	int	id,
		ml_matrix	index_list
	)

Get the index for the SPICE id.

◆ initialize_data()

void fsw_attitude_control::initialize_data ( )

◆ make_unit_vector()

ml_matrix fsw_attitude_control::make_unit_vector ( ml_matrix u )

Make a unit vector.

◆ valid_quaternion()

int fsw_attitude_control::valid_quaternion ( ml_matrix q )

Checks the validity of a quaternion.

◆ valid_vector()

int fsw_attitude_control::valid_vector ( ml_matrix u )

Checks the validity of a unit vector.

Member Data Documentation

◆ acs_attitude_error_ref

CD_CREATE_REF fsw_attitude_control::acs_attitude_error_ref

protected

Attitude error (3x1)

Referenced by initialize_data().

◆ acs_error_ref

CD_CREATE_REF fsw_attitude_control::acs_error_ref

protected

ACS error code (int)

0 = no error
1 = no such mode
2 = axis align error
3 = single axis rotate error
4 = solar system align error

Referenced by initialize_data().

◆ acs_target_quaternion_ref

CD_CREATE_REF fsw_attitude_control::acs_target_quaternion_ref

protected

Desired quaternion (4x1)

Referenced by initialize_data().

◆ acs_torque_demand_ref

CD_CREATE_REF fsw_attitude_control::acs_torque_demand_ref

protected

The torque demand for all attitude control (3x1)

Referenced by initialize_data().

◆ ephem_planet_index_ref

CD_REQUEST_REF fsw_attitude_control::ephem_planet_index_ref

protected

Planet index.

◆ ephem_planet_position_ref

CD_REQUEST_REF fsw_attitude_control::ephem_planet_position_ref

protected

Planet position.

◆ ephem_planet_radius_ref

CD_REQUEST_REF fsw_attitude_control::ephem_planet_radius_ref

protected

Planet radius.

◆ ephem_planet_rotation_matrix_ref

CD_REQUEST_REF fsw_attitude_control::ephem_planet_rotation_matrix_ref

protected

Planet rotation matrix.

◆ ephem_sun_vector_ref

CD_REQUEST_REF fsw_attitude_control::ephem_sun_vector_ref

protected

Sun vector.

◆ inertia_ref

CD_REQUEST_REF fsw_attitude_control::inertia_ref

protected

The spacecraft inertia matrix.

◆ od_state_ref

CD_REQUEST_REF fsw_attitude_control::od_state_ref

protected

State estimate od_state.

◆ omega_ref

CD_REQUEST_REF fsw_attitude_control::omega_ref

protected

The estimated body rate.

◆ quaternion_ref

CD_REQUEST_REF fsw_attitude_control::quaternion_ref

protected

The estimated quaternion.

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

fsw_attitude_control.h
fsw_attitude_control.cc

Public Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

◆ get_index()

◆ initialize_data()

◆ make_unit_vector()

◆ valid_quaternion()

◆ valid_vector()

Member Data Documentation

◆ acs_attitude_error_ref

◆ acs_error_ref

◆ acs_target_quaternion_ref

◆ acs_torque_demand_ref

◆ ephem_planet_index_ref

◆ ephem_planet_position_ref

◆ ephem_planet_radius_ref

◆ ephem_planet_rotation_matrix_ref

◆ ephem_sun_vector_ref

◆ inertia_ref

◆ od_state_ref

◆ omega_ref

◆ quaternion_ref