eulerRotation

Executive Summary

This module guidance modules creates constant Euler angle rate rotations about a primary axis to create dynamic reference frames.

Message Connection Descriptions

The following table lists all the module input and output messages. The module msg connection is set by the user from python. The msg type contains a link to the message structure definition, while the description provides information on what this message is used for.

Module I/O Messages

Msg Variable Name	Msg Type	Description
attRefOutMsg	AttRefMsgPayload	name of the output message containing the Reference
attRefInMsg	AttRefMsgPayload	name of the guidance reference input message
desiredAttInMsg	AttStateMsgPayload	(optional) name of the incoming message containing the desired Euler angle set

User Guide

The initial orientation of the dynamic reference frame is set through the module variable angleSet. This is a 3-2-1 Euler angle sequence.

To set the desired constant 3-2-1 Euler angel rates, set the module variable angleRates.

Class EulerRotation

class EulerRotation : public SysModel

Top level structure for the sub-module routines.

Public Functions

void reset(uint64_t callTime) override

This resets the module to original states.

Parameters:

callTime – The clock time at which the function was called (nanoseconds)

Returns:

void

void updateState(uint64_t callTime) override

This method takes the input attitude reference frame, and and superimposes the dynamic euler angle scanning motion on top of this.

Parameters:

callTime – The clock time at which the function was called (nanoseconds)

Returns:

void

void checkRasterCommands()

This function checks if there is a new commanded raster maneuver message available.

Parameters:

this – The configuration data associated with the mrpRotation module

Returns:

void

void computeTimeStep(uint64_t callTime)

This function computes control update time.

Parameters:

callTime – The clock time at which the function was called (nanoseconds)

Returns:

void

void computeEulerRotationReference(double sigma_R0N[3], double omega_R0N_N[3], double domega_R0N_N[3], AttRefMsgPayload *attRefOut)

This function computes the reference (Euler angle attitude set, angular velocity and angular acceleration) associated with a rotation defined in terms of an initial euler angle set and a constant euler angle rate.

Parameters:

• this – The configuration data associated with the mrpRotation module

• sigma_R0N – The input reference attitude using MRPs

• omega_R0N_N – The input reference frame angular rate vector

• domega_R0N_N – The input reference frame angular acceleration vector

• attRefOut – The output message copy

Returns:

void

Public Members

double angleSet[3]

[-] current euler angle 321 set R/R0 with respect to the input reference

double angleRates[3]

[rad/s] euler angle 321 rates

double cmdSet[3]

[] msg commanded initial Euler angle 321 set with respect to input reference

double cmdRates[3]

[rad/s] msg commanded constant 321 Euler angle rates

double priorCmdSet[3]

[] prior commanded 321 Euler angle set

double priorCmdRates[3]

[rad/s] prior commanded 321 Euler angle rates

uint64_t priorTime

[ns] last time the guidance module is called

double dt

[s] integration time-step

Message<AttRefMsgPayload> attRefOutMsg

The name of the output message containing the Reference.

ReadFunctor<AttRefMsgPayload> attRefInMsg

The name of the guidance reference input message.

ReadFunctor<AttStateMsgPayload> desiredAttInMsg

The name of the incoming message containing the desired EA set.

BSKLogger bskLogger = {}

BSK Logging.